Ordinance No. 23-09 CITY OF TIGARD,OREGON
TIGARD CITY COUNCIL
ORDINANCE NO. 23-09
AN ORDINANCE AMENDING TIGARD COMMUNITY DEVELOPMENT CODE CHAPTERS 18.30
(DEFINITIONS) AND 18.510 (SENSITIVE LANDS) AND ADOPTING A NEW TITLE 9 OF THE
TIGARD MUNICIPAL CODE (AREAS OF SPECIAL FLOOD HAZARD) TO ADOPT UPDATED
FLOODPLAIN REGULATIONS IN ORDER TO MAINTAIN PARTICIPATION IN THE NATIONAL
FLOOD INSURANCE PROGRAM.
WHEREAS, the State of Oregon has, in ORS 197.175, delegated the responsibility to local governmental
units to adopt floodplain management regulations designed to promote the public health, safety, and general
welfare of its citizenry;and
WHEREAS, the flood hazard areas of the City of Tigard are subject to periodic inundation which may
result in loss of life and property,health and safety hazards, disruption of commerce and governmental
services, extraordinary public expenditures for flood protection and relief,and impairment of the tax base,
all of which adversely affect the public health, safety,and general welfare;and
WHEREAS, these flood losses may be caused by the cumulative effect of obstructions in areas of special
flood hazard which increase flood heights and velocities,and when inadequately anchored, cause damage in
other areas. Uses that are inadequately floodproofed, elevated, or otherwise protected from flood damage
also contribute to flood loss;and
WHEREAS,it is the purpose of this ordinance to promote public health, safety, and general welfare,and to
minimize public and private losses due to flooding in flood hazard areas by provisions designed to:
A. Protect human life and health;
B. Minimize expenditure of public money for costly flood control projects;
C. Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at
the expense of the general public;
D. Minimize prolonged business interruptions;
E. Minimize damage to public facilities and utilities such as water and gas mains;electric,telephone and
sewer lines;and streets and bridges located in areas of special flood hazard;
F. Help maintain a stable tax base by providing for the sound use and development of flood hazard
areas so as to minimize blight areas caused by flooding;
G. Notify potential buyers that the property is in an area of special flood hazard;
H. Notify those who occupy areas of special flood hazard that they assume responsibility for their
actions;and
I. Participate in and maintain eligibility for flood insurance and disaster relief;and
WHEREAS,in order to accomplish its purposes, this ordinance includes methods and provisions for:
A. Restricting or prohibiting development which is dangerous to health, safety, and property due to
water or erosion hazards, or which result in damaging increases in erosion or in flood heights or
velocities;
B. Requiring that development vulnerable to floods,including facilities which serve such uses,be
protected against flood damage at the time of initial construction;
ORDINANCE No.23-09
Page 1
C. Controlling the alteration of natural floodplains, stream channels, and natural protective barriers,
which help accommodate or channel flood waters;
D. Controlling filling,grading, dredging, and other development which may increase flood damage; and
E. Preventing or regulating the construction of flood barriers which will unnaturally divert flood waters
or may increase flood hazards in other areas;and
WHEREAS,in the interpretation and application of this ordinance, all provisions will be:
A. Considered as minimum requirements;
B. liberally construed in favor of the governing body;and
C. Deemed neither to limit nor repeal any other powers granted under state statutes;and
WHEREAS, this ordinance will not create liability on the part of the City of Tigard,any officer or employee
thereof, or the Federal Insurance Administrator for any flood damages that result from reliance on this
ordinance or any administrative decision lawfully made hereunder;and
WHEREAS, the Assistant Community Development Director, serving as the City's Floodplain
Administrator, or their designee is hereby appointed to administer,implement,and enforce this ordinance
by granting or denying development permits in accordance with its provisions.The Floodplain
Administrator may delegate authority to implement these provisions;and
WHEREAS, the duties of the Floodplain Administrator, or their designee,include, but are not limited to
review all development permits to determine that:
A. The permit requirements of this ordinance have been satisfied;
B. 'All other required local, state, and federal permits have been obtained and approved;
C. Review all development permits to determine if the proposed development is located in a floodway.
If located in the floodway assure that the floodway provisions are met;
D. Review all development permits to determine if the proposed development is located in an area
where Base Flood Elevation (BFE) data is available either through the Flood Insurance Study (FIS)
or from another authoritative source. If BFE data is not available then ensure compliance with the
provisions of Code of Federal Regulations (CFR) 60.3(a)(3);60.3(b)(4); 60.3(b)(3); and Technical
Bulletin 10-01;
E. Provide to building officials the Base Flood Elevation (BFE) applicable to any building requiring a
development permit;
F. Review all development permit applications to determine if the proposed development qualifies as a
substantial improvement as defined by CFR 59.1;
G. Review all development permits to determine if the proposed development activity is a watercourse
alteration. If a watercourse alteration is proposed, ensure compliance with the provisions in CFR
60.3(b)(6) and (7);and
H. Review all development permits to determine if the proposed development activity includes the
placement of fill or excavation;and
WHEREAS, the Floodplain Administrator will notify the Federal Insurance Administrator in writing
whenever the boundaries of the community have been modified by annexation or the community has
otherwise assumed authority or no longer has authority to adopt and enforce floodplain management
regulations for a particular area,to ensure that all Flood Hazard Boundary Maps (FHBM) and Flood
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Insurance Rate Maps (FIRM) accurately represent the community's boundaries. Include within such
notification a copy of a map of the community, suitable for reproduction, clearly delineating the new
corporate limits or new area for which the community has assumed or relinquished floodplain management
regulatory authority;and
WHEREAS, amendments to the Tigard Community Development Code Chapter 18.30, Chapter 18.510, and
amendments to the Tigard Municipal Code to create a new Title 9, Areas of Special Flood Hazard, would
ensure the City's participation in the National Flood Insurance Program;and
WHEREAS,FEMA reviewed the amendments and approved the changes as being compliant with the National
Flood Insurance Program requirements;and
WHEREAS, notice was provided to the Department of Land Conservation and Development at least 35 days
prior to the first evidentiary public hearing;and
WHEREAS, notice of the public hearing was given in conformance with Community Development Code
Section 18.710.120;and
WHEREAS, the Tigard Planning Commission held a duly noticed public hearing on November 13, 2023 and
recommended with a unanimous vote that Council approve the proposed code amendment,as amended;and
WHEREAS, the Tigard City Council held a public hearing on December 12, 2023 to consider the proposed
amendments;and
WHEREAS, the Tigard City Council has considered the Planning Commission recommendation;and
WHEREAS, the Tigard City Council has considered the applicable Statewide Planning Goals and Guidelines
adopted under Oregon Revised Statutes Chapter 197; applicable federal and state statutes and regulations;
applicable Metro regulations; applicable Comprehensive Plan Policies; and applicable provisions of the City's
implementing ordinances;and
WHEREAS, the Tigard City Council has determined that the proposed development code amendments are
consistent with the applicable review criteria and approves amendments to the Tigard Community
Development Code as being in the best interest of the City of Tigard.
NOW,THEREFORE,THE CITY OF TIGARD ORDAINS AS FOLLOWS:
SECTION 1: Council adopts the findings recommended by the Planning Commission as contained in the
November 20, 2023 Staff Report to the City Council, included as "Exhibit A" to this
Ordinance,as the basis in support of the corresponding code amendments.
SECTION 2: Tigard Municipal Code Tide 9 is a new tide for Areas of Special Flood Hazard as shown in
"Exhibit B" to this Ordinance.
SECTION 3: Tigard Community Development Code Chapter 18.30 Definitions is amended as shown in
"Exhibit C" and Chapter 18.510 Sensitive Lands is amended as shown in "Exhibit D" to
this Ordinance.
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SECTION 4: If any provision of this ordinance or the application thereof to any person or circumstance
is held invalid, such invalidity does not affect the other provisions or applications of the
ordinance which can be given effect without the invalid provision or application,and to this
end the provisions of this ordinance are severable. This City Council hereby declares that it
would have adopted this ordinance irrespective of the invalidity of any particular portion
thereof and intends that the invalid portions should be severed and the balance of the
ordinance be enforced.
SECTION 5: This ordinance shall be effective 30 days after its passage by the council, signature by the
mayor,and posting by the city recorder.
PASSED: By A V1 114111-.f vote of all Council members present after being read by
number and title only,this l o qday of De(e h?b y ,2023.
Jesse B. Raymundo,Deputy City Recorder
APPROVED: By Tigard City Council this la day of Inc(,2 ryl be i- ,2023.
Ap roved as to form: Yi-Ka g Hu, Cocil President
City Attorney
I I 9.0'a-fS
Date
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Page 4
EXHIBIT A
Agenda Item: #1
Hearing Date: December 12,2023 Time: 6:30 PM
PLANNING COMMISSION
RECOMMENDATION TO THE
CITY COUNCIL
FOR THE CITY OF TIGARD, OREGON TIGARD
SECTION I. APPLICATION SUMMARY
CASE NAME: REQUIRED FEMA NFIP REGULATORY UPDATES
CASE NO.: Development Code Amendment (DCA) DCA2023-00002
PROPOSAL: The City is proposing development code and municipal code amendments to
the Area of Special Flood Hazard regulations. These amendments are
necessary to incorporate regulatory changes required by the Federal
Emergency Management Agency (FEMA). These regulatory changes are
required in order for the City of Tigard to continue participation in the
National Flood Insurance Program (NFIP). The proposed amendments
include:
- A new Municipal Code Title 9 that contains definitions, applicability,
general provisions,NFIP standards, and violation procedures;
- Updates to Tigard Community Development Code (TCDC) Chapter
18.30, Definitions; and
- Updates to TCDC Chapter 18.510, Sensitive Lands,that move
procedural requirements and general standards to the new Title 9.
The proposed text amendments for the City Council's review are included in
Attachment 1, and summarized below in this report.
APPLICANT: City of Tigard
13125 SW Hall Blvd.
Tigard,OR 97223
ZONES: Citywide
LOCATION: Citywide
APPLICABLE
REVIEW
CRITERIA: Statewide Planning Goals 1 (Citizen Involvement), 2 (Land Use Planning), 7
(Areas subject to Natural Hazards); METRO's Urban Growth Management
Functional Plan Titles 3, and 8; Comprehensive Plan Goals 1.1.2, 2.1.1, 2.1.2,
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EXHIBIT A
2.1.3, 2.1.11, 2.1.20, 7.1.4, 7.1.5, 7.1.7, 7.1.8, 7.1.9, 7.1.11, 7.1.14, and 11.1.1;
and TCDC Chapters 18.790.
SECTION II. PLANNING COMMISSION RECOMMENDATION
Planning Commission recommends approval by ordinance of the proposed development code and
municipal code text amendments (Attachment 1)
SECTION III. BACKGROUND INFORMATION AND PROJECT SUMMARY
Required FEMA NFIP Regulatory Update
The purpose of the proposed amendments is to incorporate regulatory changes required by the
Federal Emergency Management Agency (FEMA). These regulatory changes are required in order
for the City of Tigard to continue participation in the National Flood Insurance Program (NFIP). A
brief summary of the National Flood Insurance Program and the proposed changes is provided
below.
The NFIP is a federal program that was established in 1968 through the passage of the National
Flood Insurance Act and administered by FEMA. The program allows owners of properties within
the Area of Special Flood Hazard to obtain federally-backed insurance for their properties in
jurisdictions that have adopted land use regulations for development in the floodplain.
The Area of Special Flood Hazard is a term that has evolved over the years and, to avoid confusion,
needs some explanation. In the past, this area was often referred to, erroneously, as the "100-year
floodplain." Technically, it is an area near water bodies that has a statistical one percent chance of
flooding in any given year. The term 100-year floodplain is misleading because it gives the
impression that the area will only flood once every 100 years. In reality that level of flooding or
higher could occur in consecutive years as the one percent chance is estimated based on only
decades of data. Additionally, urban development can increase flooding levels over time. The term
"Special Flood Hazard Area" was used for a time by FEMA but they have now changed that term
again to "Area of Special Flood Hazard" (ASFH),which is the term used throughout this report and
the proposed new regulations.
In addition to providing insurance, the NFIP provides maps the Nation's floodplains, known as
Flood Insurance Rate Maps (FIRM) which results from a Flood Insurance Study. The FIRM is an
official map on which FEMA has delineated both the ASFH and other flood zones within a
community. The FIRM is used in determining which properties are subject to a jurisdiction's
floodplain regulations and whether a property owner is required to obtain flood insurance as well as
providing information on the insurance rate.
Floodplain boundaries do not stay constant but rather undergo change over time due to the effects
of erosion, development impacts, vegetation removal, and other factors. To account for floodplain
boundary changes, FEMA periodically adjusts the ASFH maps used by local jurisdictions. The City
of Tigard does not conduct floodplain inventories and relies on FEMA for the determination of the
ASFH boundary. Prior to amending the FIRM and/or developing new or revised floodplain
requirements as part of the NFIP updates, FEMA coordinates with local jurisdictions to determine
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EXHIBIT A
changes in local flood conditions. Updates to the local FIRM and a corresponding Flood Insurance
Study (FIS) Report for all of Washington County were most recently completed by FEMA in 2017.
Additionally, FEMA periodically amends the regulatory requirements of the NFIP.
In 2018, the City adopted a new FIRM. At that time the City was notified that with the adoption of
the new FIRM, FEMA Region 10 was requiring jurisdictions to review their current floodplain
regulations to ensure they continue to meet the requirements for participation in the NFIP. Also in
2018, the City adopted new development code amendments (DCA2018-00002) in accordance with
FEMA's review.
In 2021, the City was notified by the Oregon Department of Land Conservation and Development
(DLCD) through FEMA's Community Assistance Contact (CAC) process that Tigard was due for a
FEMA audit. Periodic FEMA audits are conducted by DLCD staff on behalf of FEMA. The FEMA
Community Assistance Program helps states proactively identify, prevent, and resolve floodplain
management issues in participating communities before a flood event occurs. As part of the audit
DLCD staff notified Tigard that further amendments to the ASFH regulations would be required to
meet the minimum standards for participation in the NFIP. Tigard was informed by FEMA that
adoption of their model ordinance would be required in order for the City of Tigard to remain a
participant in NFIP.
Tigard was given no choice in the matter and the proposed amendments reflect the exact language
in FEMA's model ordinance. However, Tigard was allowed some flexibility in where to place the
model ordinance language within our municipal and development codes. Given the complexity and
breadth of the model ordinance language, staff is proposing a new Municipal Code Title—Title 9
Areas of Special Flood Hazard—for exclusive placement of the ASFH regulations.
The new title will contain definitions, applicability,general provisions,NFIP standards, and violation
procedures. The creation of the new Title 9 also necessitates changes to the development code to
reflect the transfer of some of the regulations and to add cross references. Most of the standards
and language contained in TCDC Chapter 18.510 is out of compliance with the model
ordinance language, as described below. Finally, having the regulations in a new Title 9 will
allow for easier future changes to the regulations in compliance with FEMA direction.
Proposed Amendments
Amend the Tigard Community Development Code Definitions (TCDC 18.30) and Sensitive Lands
Chapter (TDC 18.510) as proposed:
o Text Amendments to Chapter 18.30 (Definitions) to establish a new definition for"Area
of Special Flood Hazard" and move definitions for"Critical Facilities" to new Title 9;
o Text Amendments to Chapter 18.510 (Sensitive Lands) to add references to standards in
the new Title 9;
o Text Amendments to Chapter 18.510 (Sensitive Lands) to move the administrative
provisions to new Title 9 (Areas of Special Flood Hazard) under General Provisions;
o Text Amendments to Chapter 18.510 (Sensitive Lands) to move development standards
to new Title 9 (Areas of Special Flood Hazard) under NFIP Standards;
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EXHIBIT A
o Text Amendments to Chapter 18.510 (Sensitive Lands) to move definitions to new Title
9 (Areas of Special Flood Hazard) under Definitions; and
o Text Amendments to Chapter 18.510 (Sensitive Lands) to move violation language to
new Title 9 (Areas of Special Flood Hazard) under Violations.
SECTION V. SUMMARY OF APPLICABLE REVIEW CRITERIA
This section contains all of the applicable city, state, and Metro policies, provisions, and criteria that
apply to the proposed amendments.
City of Tigard Community Development Code:
Chapter 18.790: Text and Map Amendments
City of Tigard Comprehensive Plan:
Chapter 1: Citizen Involvement
Chapter 2: Land Use Planning
Chapter 7: Hazards
Chapter 11: Public Facilities
Metro Functional Plan:
Title 3: Water Quality and Flood Management
Title 8: Compliance Procedures
Statewide Planning Goals:
Goal 1: Citizen Involvement
Goal 2: Land Use Planning
Goal 7: Areas subject to Natural Hazards
Goal 11: Public Facilities and Services
SECTION IV. APPLICABLE CRITERIA AND FINDINGS
18.790.020 Legislative Amendments
A. Legislative amendments shall be processed through a Legislative procedure, as provided
in Section 18.710.120.
FINDING: The proposed amendments are legislative in nature. Therefore, the amendments will be
reviewed under the Legislative procedure. This procedure requires public hearings by both the
Planning Commission and City Council. Public hearings are scheduled for November 13, 2023 and
December 12, 2023. This standard is satisfied.
B. Approval considerations.A recommendation or a decision for a legislative amendment
application may be based on consideration of the applicable legal requirements. They
may, but do not necessarily include: Oregon Revised Statutes, Oregon Administrative
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EXHIBIT A
Rules, one or more Statewide Planning Goals, Metro's Urban Growth Management
Functional Plan and any other regional plans.
FINDING: Findings and conclusions are provided in this staff report for the applicable legal
requirements on which the recommendation by the Commission and the decision by the Council
must be based. This standard is satisfied.
CONCLUSION: Based on the findings above, staff concludes that the proposed code text
amendments are consistent with the requirements for legislative
amendments.
TIGARD COMPREHENSIVE PLAN
State planning regulations require cities to adopt and amend Comprehensive Plans and land use
regulations in compliance with the state land use goals and consistent with State Goals and Policies.
Because the development code amendments have a limited scope and the text amendments address
only some of the topics in the Tigard Comprehensive Plan, only applicable comprehensive plan
goals and associated policies are addressed below.
Comprehensive Plan Goal 1: Citizen Involvement
Policy 1.1.2: The City shall define and publicize an appropriate role for citizens in each
phase of the land use planning process.
FINDING: This policy has been met by complying with the Tigard Community Development Code
notice requirements set forth in Section 18.710.120. Planning Commission public hearing notices
were sent by US Postal Service on October 16, 2023 to affected government agencies and the latest
version of the City's interested parties list. A notice was published in the Tigard Times newspaper
October 19, 2023. City Council public hearing notices were sent by US Postal Service on November
20, 2023 to affected government agencies and the latest version of the City's interested parties list. A
notice was published in the Tigard Times newspaper November 23, 2023. Project information and
documents were published to the City website prior to the public hearing. A minimum of two
public hearings will be held where an opportunity for public input is provided. The Planning
Commission hearing was held on November 13, 2023 and a City Council hearing is scheduled for
December 12, 2023. This policy is met.
Comprehensive Plan Goal 2: Land Use Planning
Policy 2.1.1: The City's land use program shall establish clear policy direction, comply with
state and regional requirements, and serve its citizens' own interests.
FINDING: As demonstrated in this staff report, the proposed amendments to the Tigard
Community Development Code continue to establish clear policy direction, comply with state and
regional requirements, serve the City's citizens' own interests, and are consistent with the Tigard
Comprehensive Plan. This policy is satisfied.
Policy 2.1.2: The City's land use regulations, related plans, and implementing actions shall
be consistent with and implement its Comprehensive Plan.
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FINDING: As demonstrated in this staff report, the proposed land use regulations (amendments to
the Tigard Community Development Code), related plans, and implementing actions continue to be
consistent with and implement the Tigard Comprehensive Plan. This policy is satisfied.
Policy 2.1.3: The City shall coordinate the adoption, amendment, and implementation of its
land use program with other potentially affected jurisdictions and agencies.
FINDING: Copies of the proposed text amendments were sent to other affected jurisdictions and
agencies, who were invited to comment on the proposal. Responses are discussed in Section V of
this report. Comments submitted by affected agencies have been incorporated into this report and
the proposed amendments. This policy is satisfied.
Policy 2.1.11: The City shall adopt regulations and standards to protect public safety and
welfare from hazardous conditions related to land use activities.
FINDING: The proposed amendments include the adoption of regulatory changes required by
FEMA, which will maintain the City's participation in the National Flood Insurance Program and
protect public safety and welfare for properties located within the ASFH. This policy is satisfied.
Policy 2.1.20: The City shall periodically review and,if necessary, update its Comprehensive
Plan and regulatory maps and implementing measures to ensure they are current and
responsive to community needs,provide reliable information, and conform to applicable
state law, administrative rules, and regional requirements.
FINDING: In 2021, the City was notified by DLCD through FEMA's Community Assistance
Contact process that amendments to the special flood hazard area regulations are required to meet
the minimum standards for participation in the NFIP. FEMA's Community Assistance Program
helps states proactively identify,prevent, and resolve floodplain management issues in participating
communities before a flood event occurs. The proposed amendments include the adoption of
regulatory changes required by FEMA,which will maintain the City's participation in the National
Flood Insurance Program and protect the public welfare for properties located within the ASFH.
The proposed amendments ensure that the City's implementing measures are current and responsive
to community needs,provide reliable information, and conform to applicable state law,
administrative rules, and regional requirements.This policy is satisfied.
Comprehensive Plan Goal 7: Hazards
Policy 7.1.4: The City shall design and construct public facilities to withstand hazardous
events with a priority on hazard protection of public services and facilities that are needed to
provide emergency response services.
FINDING: The proposed amendments include the adoption of updated regulations for the design
and construction of public facilities to withstand hazardous events—with specific regulations that
prioritize hazard protection of public services and facilities that are needed to provide emergency
response services. These amendments include a new Tide 9 that provides standards for various
development activities including the design and construction of critical public facilities. Additionally,
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adoption of these amendments will ensure the City's continued participation in the NFIP. This
policy is satisfied.
Policy 7.1.5: The City shall apply and enforce the most current building code standards to
protect the built environment from natural disasters and other hazards.
FINDING: The City of Tigard administers and enforces the State of Oregon Specialty Codes,which
contain certain provisions that apply to the design and construction of buildings and structures
located in ASFH.The proposed amendments will to be administered and enforced in conjunction
with the Oregon Specialty Codes. The proposed amendments include the adoption of updated
regulations for development within the ASFH. These amendments, together with the Oregon
Specialty Codes,will ensure that the City will apply and enforce the most current building code
standards to protect the built environment from natural disasters and flood hazards. This policy is
satisfied.
Policy 7.1.7: The City shall comply with the Federal Emergency Management Agency
(FEMA) flood regulations, which include standards for base flood levels, flood proofing,
and minimum finished floor elevations.
FINDING: The proposed amendments implement the latest FEMA required regulatory updates
including standards for base flood level, flood proofing, and minimum finished floor elevations.
This policy is satisfied.
Policy 7.1.8: The City shall prohibit any land form alterations or developments in the 100-
year floodplain which would result in any rise in elevation of the 100-year floodplain.
FINDING: The City's current development code prohibits landform alterations or developments in
the 100-year floodplain that would result in any rise in elevation of the 100-year floodplain. Changes
to this requirement are not proposed. Under the proposed amendments all new development will
continue to meet this requirement. This policy is satisfied.
Policy 7.1.9: The City shall not allow land form alterations of development within the 100-
year floodplain outside the zero-foot rise floodway unless:
A. The streamflow capacity of the zero-foot rise and floodway is maintained; and
B. Engineered drawings and/or documentation shows there will be no detrimental
upstream or downstream effects in the floodplain area.
FINDING: The City's current development code prohibits landform alterations or developments in
the 100-year floodplain that would result in any rise in elevation of the 100-year floodplain. Changes
to this requirement are not proposed Under the proposed amendments all new development will
continue to meet this requirement and will need to provide the required documentation and
engineered drawings. This policy is satisfied.
Policy 7.1.11: The City shall comply with Metro Title 3 Functional Plan requirements for
balanced fill and removal in the floodplain.
FINDING: The proposed amendments will ensure that the City's regulations will continue to
comply with Metro Title 3 Functional Plan requirements for balanced fill and removal in the
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floodplain. This is a basic requirement of the FEMA regulations, which is also a component of
Metro Title 3 regulations.This policy is satisfied.
Policy 7.1.14: The City shall work to reduce the risk of loss of life and damage to property
from severe weather events.
FINDING: The proposed amendments included in the new Title 9 reduce the risk of loss of life
and damage to property from severe weather events, particularly flooding events. These standards
are applied in conjunction with the state building code to reduce the risk of damage to property.
This policy is satisfied.
Comprehensive Plan Goal 11: Public Facilities and Services
Policy 11.1.1: The City shall require that all new development:
C. Meet or exceed regional, state, and federal standards for water quality and flood
protection.
FINDING: The proposed amendments adopt the FEMA required regulatory updates for
development within the ASFH—meeting federal standards for flood protection. The purpose of
the proposed amendments is to incorporate regulatory changes required by the Federal Emergency
Management Agency (FEMA) to comply with the latest standards and continue participation in the
NFIP. This policy is satisfied.
CONCLUSION: Based on the findings above, staff concludes that the proposed code text
amendments are consistent with applicable provisions of the Tigard
Comprehensive Plan.
METRO Urban Growth Management Functional Plan
State planning regulations require cities to adopt and amend Comprehensive Plans and land use
regulations in compliance with the state land use goals. Within the Portland metropolitan region,
METRO also has responsibility for administering state planning regulations. This is accomplished
through METRO's adopted Urban Growth Management Functional Plan (UGMFP). Because the
proposed Code Amendments have a limited scope and the text amendments address only some of
the topics in the UGMFP, only applicable UGMFP Titles are addressed below.
Title 3: Water Quality and Flood Management:
The intent of this goal is to protect the beneficial water uses and functions and values of
resources within the Water Quality and Flood Management Areas by limiting or mitigating
the impact on these areas from development activities and protecting life and property from
dangers associated with flooding.
FINDING: The proposed amendments will ensure that the City's regulations will continue to
comply with Metro Title 3 UGMFP requirements for limiting or mitigating the impact from
development activities on Metro's designated Water Quality and Flood Management Areas as well as
protecting life and property from the dangers associated with flooding. This is a basic requirement
of the FEMA regulations, which is also a component of Metro Title 3 regulations. This policy is
satisfied.
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Title 8: Compliance Procedures
The purposes of this chapter are to establish a process for ensuring city or county
compliance with requirements of the Urban Growth Management Functional Plan and for
evaluating and informing the region about the effectiveness of those requirements.
FINDING: This title has been met by complying with the Tigard Community Development Code
notice requirements set forth in Section 18.710.120. Planning Commission public hearing notices
were sent by US Postal Service on October 16, 2023 to affected government agencies and the latest
version of the City's interested parties list. A notice was published in the Tigard Times newspaper
October 19, 2023. City Council public hearing notices were sent by US Postal Service on November
20, 2023 to affected government agencies and the latest version of the City's interested parties list. A
notice was published in the Tigard Times newspaper November 23, 2023. Project information and
documents were published to the City website prior to the public hearing. A minimum of two
public hearings will be held where an opportunity for public input is provided. The Planning
Commission hearing was held on November 13, 2023 and a City Council hearing is scheduled for
December 12, 2023. These actions meet or exceed the specific requirements contained in Metro
Title 8. This title is satisfied.
CONCLUSION: Based on the findings above, staff finds that the proposed code amendments
are consistent with Metro's Urban Growth Management Functional Plan.
Statewide Planning Goals
Goal 1—Citizen Involvement:
This goal outlines the citizen involvement requirement for the land use planning process,
including the adoption of Comprehensive Plans and changes to the Comprehensive Plan
and implementing documents.
Goal 2—Land Use Planning:
This goal outlines the land use planning process and policy framework.
Goal 7—Areas Subject to Natural Hazards:
This goal requires that local comprehensive plans to address Oregon's natural hazards.
Protecting people and property from natural hazards requires knowledge, planning,
coordination, and education.
Goal 11—Public Facilities and Services:
This goal requires that local comprehensive plans to address Oregon's natural hazards.
Protecting people and
The proposed amendments comply with Statewide Planning Goals 1, 2, 7, and 11 through the
implementation of the City of Tigard Comprehensive Plan, which was most recently acknowledged
by the State on June 23. 2022. The applicable City Comprehensive Plan goals and polices have been
addressed previously in this report. These goals and policies are satisfied.
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EXHIBIT A
CONCLUSION: Based on the findings above, staff finds the proposed code amendments are
consistent with applicable Statewide Planning Goals.
SUMMARY
CONCLUSION: As shown in the findings provided in this report, staff concludes that the
proposed amendments are consistent with the applicable Statewide Planning
Goals; METRO's UGMFP; applicable Comprehensive Plan goals and
policies, and the applicable provisions of the City's implementing ordinances.
SECTION V. AGENCY COMMENTS
Washington County, Metro, ODOT, DLCD, DEQ, ODFW, OR Dept. of Geo. & Mineral
Ind., Beaverton School District, CWS, Comcast, Lumen, NW Natural, PGE, Portland &
Western Railroad, TTSD, Tri-Met, TVWD, TVF&R, Pride Disposal, Union Pacific
Railroad, Waste Management, Ziply Fiber were notified of the proposed code text amendments
but provided no comment.
SECTION VI. PUBLIC COMMENTS
The City had not received any public comments at the time this report was written.
ATTACHMENTS:
Attachments:
1. Text Amendments
// November 20, 2023
PREPA 'CY: Agnes Lindor DATE
Senior Planner
November 20, 2023
APPROVED BY: Tom McGuire DATE
Assistant Community Development Director
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EXHIBIT A Attachment 1
Chapter 9.10
AREAS OF SPECIAL FLOOD HAZARD
Sections:
9.10.010 Purpose
9.10.020 Definitions
9.10.030 Applicability
9.10.040 General Provisions
9.10.050 National Flood Insurance Program Standards
9.10.060 Violations
9.10.010 Purpose
The purpose of this chapter is to promote public health, safety, and general welfare, and to
minimize public and private losses due to flooding in flood hazard areas by provisions designed
to:
A. Protect human life and health;
B. Minimize expenditure of public money for costly flood control projects;
C. Minimize the need for rescue and relief efforts associated with flooding and generally
undertaken at the expense of the general public;
D. Minimize prolonged business interruptions;
E. Minimize damage to public facilities and utilities such as water and gas mains; electric,
telephone and sewer lines; and streets and bridges located in areas of special flood hazard;
F. Help maintain a stable tax base by providing for the sound use and development of flood
hazard areas so as to minimize blight areas caused by flooding;
G. Notify potential buyers that the property is in an area of special flood hazard;
H. Notify those who occupy areas of special flood hazard that they assume responsibility for
their actions; and
I. Participate in and maintain eligibility for flood insurance and disaster relief.
9.10.020 Definitions
Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as
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to give them the meaning they have in common usage. These definitions are only applicable to
this chapter and Tigard Community Development Code (TCDC) Chapter 18.510, Sensitive
Lands.
A. Appeal: A request for a review of the interpretation of any provision of this chapter or a
request for a variance.
B. Area of shallow flooding: A designated Zone AO, AH, AR/AO or AR/AH (or VO) on the
city's Flood Insurance Rate Map (FIRM) with a one percent or greater annual chance of
flooding to an average depth of one to three feet where a clearly defined channel does not
exist, where the path of flooding is unpredictable, and where velocity flow may be evident.
Such flooding is characterized by ponding or sheet flow.
C. Area of Special Flood Hazard: The land in the floodplain within the city subject to a 1
percent or greater chance of flooding in any given year. It is shown on the Flood Insurance
Rate Map (FIRM) as Zone A, AO, AH, A1-30, AE, A99, AR. "Special flood hazard area" is
synonymous in meaning and definition with the phrase "area of special flood hazard".
D. Base flood: A flood having a one percent chance of being equaled or exceeded in any given
year.
E. Base flood elevation (BFE): The elevation to which floodwater is anticipated to rise during
the base flood.
F. Basement: Any area of the building having its floor subgrade (below ground level) on all
sides.
G. Critical facility: A facility for which even a slight chance of flooding might be too great.
Critical facilities include, but are not limited to, schools; nursing homes; new and
replacement bridges; hospitals; police, fire, and emergency response installations; and
installations that produce, use, or store hazardous materials or hazardous waste.
H. Development: Any man-made change to improved or unimproved real estate, including but
not limited to buildings or other structures, mining, dredging, filling, grading, paving,
excavation or drilling operations or storage of equipment or materials.
I. Flood or Flooding:
1. A general and temporary condition of partial or complete inundation of normally dry land
areas from:
a. The overflow of inland or tidal waters.
b. The unusual and rapid accumulation or runoff of surface waters from any source.
c. Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in
Tigard Municipal Code (TMC) 9.10.020.I.1.b of this definition and are akin to a river
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of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is
carried by a current of water and deposited along the path of the current.
2. The collapse or subsidence of land along the shore of a lake or other body of water as a
result of erosion or undermining caused by waves or currents of water exceeding
anticipated cyclical levels or suddenly caused by an unusually high water level in a
natural body of water, accompanied by a severe storm, or by an unanticipated force of
nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and
unforeseeable event which results in flooding as defined in TMC 9.10.020.I.1.a of this
definition.
J. Flood elevation study: See "Flood Insurance Study."
K. Flood Insurance Rate Map (FIRM): The official map of the city, on which the Federal
Insurance Administrator has delineated both the special hazard areas and the risk premium
zones applicable to the city. A FIRM that has been made available digitally is called a Digital
Flood Insurance Rate Map (DFIRM).
L. Flood Insurance Study (FIS): An examination, evaluation and determination of flood
hazards and, if appropriate, corresponding water surface elevations, or an examination,
evaluation and determination of mudslide (i.e., mudflow) or flood-related erosion hazards.
M. Flood proofing: Any combination of structural and nonstructural additions, changes, or
adjustments to structures which reduce or eliminate risk of flood damage to real estate or
improved real property, water and sanitary facilities, structures, and their contents.
N. Floodway: The channel of a river or other watercourse and the adjacent land areas that must
be reserved in order to discharge the base flood without cumulatively increasing the water
surface elevation more than one foot. Also referred to as "Regulatory Floodway."
0. Functionally dependent use: A use which cannot perform its intended purpose unless it is
located or carried out in close proximity to water. The term includes only docking facilities,
port facilities that are necessary for the loading and unloading of cargo or passengers, and
ship building and ship repair facilities, and does not include long term storage or related
manufacturing facilities.
P. Highest adjacent grade: The highest natural elevation of the ground surface prior to
construction next to the proposed walls of a structure.
Q. Historic structure: Any structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the
Department of the Interior) or preliminarily determined by the Secretary of the Interior as
meeting the requirements for individual listing on the National Register;
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2. Certified or preliminarily determined by the Secretary of the Interior as contributing to
the historical significance of a registered historic district or a district preliminarily
determined by the Secretary to qualify as a registered historic district;
3. Individually listed on a state inventory of historic places in states with historic
preservation programs which have been approved by the Secretary of the Interior; or
4. Individually listed on a City of Tigard Historic Resources list acknowledged by the
Secretary of the Interior.
R. Lowest floor: The lowest floor of the lowest enclosed area (including basement). An
unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access
or storage in an area other than a basement area is not considered a building's lowest floor,
provided that such enclosure is not built so as to render the structure in violation of the
applicable non-elevation design requirements of this chapter.
S. Manufactured dwelling: A structure, transportable in one or more sections, which is built on
a permanent chassis and is designed for use with or without a permanent foundation when
attached to the required utilities. The term "manufactured dwelling" does not include a
"recreational vehicle" and is synonymous with"manufactured home."
T. Manufactured dwelling park or subdivision: A parcel (or contiguous parcels) of land divided
into two or more manufactured dwelling lots for rent or sale.
U. Mean sea level: For purposes of the National Flood Insurance Program, the National
Geodetic Vertical Datum (NGVD) of 1929 or other datum, to which Base Flood Elevations
shown on the city's Flood Insurance Rate Map are referenced.
V. New construction: For floodplain management purposes, "new construction" means
structures for which the "start of construction" commenced on or after the effective date of a
floodplain management regulation adopted by City of Tigard and includes any subsequent
improvements to such structures.
W. Recreational vehicle: A vehicle which is:
1. Built on a single chassis;
2. 400 square feet or less when measured at the largest horizontal projection;
3. Designed to be self-propelled or permanently towable by a light duty truck; and
4. Designed primarily not for use as a permanent dwelling but as temporary living quarters
for recreational, camping, travel, or seasonal use.
X. Special flood hazard area: See "Area of special flood hazard" for this definition.
Y. Start of construction: Includes substantial improvement and means the date the building
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permit was issued, provided the actual start of construction, repair, reconstruction,
rehabilitation, addition, placement, or other improvement was within 180 days from the date
of the permit. The actual start means either the first placement of permanent construction of
a structure on a site, such as the pouring of slab or footings, the installation of piles, the
construction of columns, or any work beyond the stage of excavation; or the placement of a
manufactured dwelling on a foundation. Permanent construction does not include land
preparation, such as clearing, grading, and filling; nor does it include the installation of
streets and/or walkways; nor does it include excavation for a basement, footings, piers, or
foundations or the erection of temporary forms; nor does it include the installation on the
property of accessory buildings, such as garages or sheds not occupied as dwelling units or
not part of the main structure. For a substantial improvement, the actual start of construction
means the first alteration of any wall, ceiling, floor, or other structural part of a building,
whether or not that alteration affects the external dimensions of the building.
Z. Structure: For floodplain management purposes, a walled and roofed building, including a
gas or liquid storage tank, that is principally above ground, as well as a manufactured
dwelling.
AA. Substantial damage: Damage of any origin sustained by a structure whereby the cost of
restoring the structure to its before damaged condition would equal or exceed 50 percent of
the market value of the structure before the damage occurred.
BB. Substantial improvement: Any reconstruction, rehabilitation, addition, or other
improvement of a structure, the cost of which equals or exceeds 50 percent of the market
value of the structure before the "start of construction" of the improvement. This term
includes structures which have incurred "substantial damage," regardless of the actual repair
work performed. The term does not, however, include either:
1. Any project for improvement of a structure to correct existing violations of state or local
health, sanitary, or safety code specifications which have been identified by the local
code enforcement official and which are the minimum necessary to assure safe living
conditions; or
2. Any alteration of a "historic structure," provided that the alteration will not preclude the
structure's continued designation as a "historic structure."
CC. Violation: The failure of a structure or other development to be fully compliant with the
city's floodplain management regulations. A structure or other development without the
elevation certificate, other certifications, or other evidence of compliance required in this
chapter is presumed to be in violation until such time as that documentation is provided.
9.10.030 Applicability
A. All development within areas of special flood hazard is subject to the terms of this chapter
and is required to comply with its provisions and all other applicable regulations including
but not limited to TCDC Chapter 18.510, Sensitive Lands.
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B. The areas of special flood hazard identified by FEMA in a scientific and engineering report
entitled"The Flood Insurance Study for Washington County, Oregon and Incorporated Areas
effective October 19, 2018"with accompanying Flood Insurance Map (FIRM
Panels:41067C0529F, 41067C0533E, 41067C0534E, 41067C0541E through 41067C0544E,
and 41067C0563E) is hereby adopted by reference and declared to be a part of this
ordinance.
9.10.040 General Provisions
A. Coordination with State of Oregon Specialty Codes. Pursuant to the requirement established
in ORS 455 that the City of Tigard administers and enforces the State of Oregon Specialty
Codes, the City of Tigard does hereby acknowledge that the Oregon Specialty Codes contain
certain provisions that apply to the design and construction of buildings and structures
located in areas of special flood hazard. Therefore, this chapter is intended to be administered
and enforced in conjunction with the Oregon Specialty Codes.
B. Warning. The degree of flood protection required by this chapter is considered reasonable
for regulatory purposes and is based on scientific and engineering considerations. Larger
floods can and will occur on rare occasions. Flood heights may be increased by man-made or
natural causes. This chapter does not imply that land outside the areas of special flood
hazards or uses permitted within such areas will be free from flooding or flood damages.
C. Permit Review. The duties of the Floodplain Administrator, or their designee, shall include,
but not be limited to review all development permits to determine that:
1. The permit requirements of this ordinance have been satisfied;
2. All other required local, state, and federal permits have been obtained and approved;
3. Review all development permits to determine if the proposed development is located in a
floodway. If located in the floodway assure that the floodway provisions are met;
4. Review all development permits to determine if the proposed development is located in
an area where Base Flood Elevation data is available either through the Flood Insurance
Study or from another authoritative source. If Base Flood Elevation data is not available
then ensure compliance with the provisions of TMC 9.10.050.J;
5. Provide to building officials the Base Flood Elevation applicable to any building
requiring a development permit;
6. Review all development permit applications to determine if the proposed development
qualifies as a substantial improvement as defined by TMC 9.10.020;
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7. Review all development permits to determine if the proposed development activity is a
watercourse alteration. If a watercourse alteration is proposed, ensure compliance with
the provisions in TMC 9.10.050.C; and
8. Review all development permits to determine if the proposed development activity
includes the placement of fill or excavation.
D. Information to be Obtained and Maintained. The following information shall be obtained and
maintained and shall be made available for public inspection as needed:
1. Obtain, record, and maintain the actual elevation (in relation to mean sea level) of the
lowest floor (including basements) and all attendant utilities of all new or substantially
improved structures where Base Flood Elevation data is provided through the Flood
Insurance Study, Flood Insurance Rate Map, or obtained in accordance with TMC
9.10.050.J.
2. Obtain and record the elevation (in relation to mean sea level) of the natural grade of the
building site for a structure prior to the start of construction and the placement of any fill
and ensure that the requirements of TMC 9.10.050.N are adhered to and all other required
local, state, and federal permits have been obtained and approved.
3. Upon placement of the lowest floor of a structure (including basement) but prior to
further vertical construction, obtain documentation, prepared and sealed by a professional
licensed surveyor or engineer, certifying the elevation (in relation to mean sea level) of
the lowest floor(including basement).
4. Where base flood elevation data are utilized, obtain record drawing certification of the
elevation(in relation to mean sea level) of the lowest floor(including basement) prepared
and sealed by a professional licensed surveyor or engineer, prior to the final inspection.
5. Maintain all Elevation Certificates submitted to the City of Tigard.
6. Obtain, record, and maintain the elevation (in relation to mean sea level) to which the
structure and all attendant utilities were floodproofed for all new or substantially
improved floodproofed structures where allowed under this chapter and where Base
Flood Elevation data is provided through the FIS, FIRM, or obtained in accordance with
TMC 9.10.050.J.
7. Maintain all floodproofing certificates required under this chapter.
8. Record and maintain all variance actions, including justification for their issuance.
9. Obtain and maintain all hydrologic and hydraulic analyses performed as required under
TMC 9.10.050.N.
10. Record and maintain all Substantial Improvement and Substantial Damage calculations
and determinations as required under TMC 9.10.040.H.
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11. Maintain for public inspection all records pertaining to the provisions of this chapter.
E. City Boundary Alterations. The Floodplain Administrator shall notify the Federal Insurance
Administrator in writing whenever the boundaries of the city have been modified by
annexation or the city has otherwise assumed authority or no longer has authority to adopt
and enforce floodplain management regulations for a particular area, to ensure that all Flood
Hazard Boundary Maps and Flood Insurance Rate Maps accurately represent the city's
boundaries. The notification will include a copy of a map of the city suitable for
reproduction, clearly delineating the new corporate limits or new area for which the city has
assumed or relinquished floodplain management regulatory authority.
F. Watercourse Alterations. The Floodplain Administrator shall notify adjacent communities,
the Department of Land Conservation and Development, and other appropriate state and
federal agencies, prior to any alteration or relocation of a watercourse, and submit evidence
of such notification to the Federal Insurance Administration. This notification shall be
provided by the applicant to the Federal Insurance Administration as a Letter of Map
Revision along with either a proposed maintenance plan to assure the flood carrying capacity
within the altered or relocated portion of the watercourse is maintained; or Certification by a
registered professional engineer that the project has been designed to retain its flood carrying
capacity without periodic maintenance. The applicant shall be required to submit a
Conditional Letter of Map Revision when required under TMC 9.10.040.G to ensure
compliance with all applicable requirements in TMC 9.10.040.G and 9.10.050.C.
G. Requirement to Submit New Technical Data. The city's base flood elevations may increase
or decrease resulting from physical changes affecting flooding conditions. As soon as
practicable, but not later than six months after the date such information becomes available,
the city must notify the Federal Insurance Administrator of the changes by submitting
technical or scientific data in accordance with Title 44 of the Code of Federal Regulations
(CFR), Section 65.3. The city may require the applicant to submit such data and review fees
required for compliance with this section through the applicable FEMA Letter of Map
Change process. The Floodplain Administrator shall require a Conditional Letter of Map
Revision prior to the issuance of a floodplain development permit for proposed floodway
encroachments that increase the base flood elevation and proposed development which
increases the base flood elevation by more than one foot in areas where FEMA has provided
base flood elevations but no floodway. An applicant shall notify FEMA within six months of
project completion when an applicant has obtained a Conditional Letter of Map Revision
from FEMA. This notification to FEMA shall be provided as a Letter of Map Revision.
H. Substantial Improvement and Substantial Damage Assessments and Determinations. The
Floodplain Administrator shall:
1. Conduct Substantial Improvement(as defined in TMC 9.10.020)reviews for all structural
development proposal applications and maintain a record of Substantial Improvement
calculations within permit files in accordance with TMC 9.10.040.D.
2. Conduct Substantial Damage assessments when structures are damaged due to a natural
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hazard event or other causes.
3. Make Substantial Damage determinations whenever structures within the area of special
flood hazard (as established in TMC 9.10.030.B) are damaged to the extent that the cost
of restoring the structure to its before damaged condition would equal or exceed 50
percent of the market value of the structure before the damage occurred.
I. Floodplain Development Permit Required. A development permit shall be obtained before
construction or development begins within any area horizontally within the area of special
flood hazard established in TMC 9.10.030.B. The development permit shall be required for
all structures, including manufactured dwellings, and for all other development, as defined in
TMC 9.10.020, including fill and other development activities.
J. Application for Development Permit. Application for a development permit may be made on
forms furnished by the Floodplain Administrator and may include, but not be limited to,
plans in duplicate drawn to scale showing the nature, location, dimensions, and elevations of
the area in question; existing or proposed structures, fill, storage of materials, drainage
facilities; and the location of the foregoing. Specifically, the following information is
required:
1. In riverine flood zones, the proposed elevation(in relation to mean sea level), of the
lowest floor(including basement) and all attendant utilities of all new and substantially
improved structures; in accordance with the requirements of TMC 9.10.040.D;
2. Proposed elevation in relation to mean sea level to which any non-residential structure
will be floodproofed;
3. Certification by a registered professional engineer or architect licensed in the State of
Oregon that the floodproofing methods proposed for any non-residential structure meet
the floodproofing criteria for non-residential structures in TMC 9.10.050.M.3;
4. Description of the extent to which any watercourse will be altered or relocated;
5. Base Flood Elevation data for subdivision proposals or other development when required
by this chapter;
6. Substantial improvement calculation for any improvement, addition, reconstruction,
renovation, or rehabilitation of an existing structure; and
7. The amount and location of any fill or excavation activities proposed.
K. Severability. This chapter and the various parts thereof are hereby declared to be severable. If
any section clause, sentence, or phrase of this chapter is held to be invalid or unconstitutional
by any court of competent jurisdiction, then said holding shall in no way effect the validity of
the remaining portions of this chapter.
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L. Abrogation. This ordinance is not intended to repeal, abrogate, or impair any existing
easements, covenants, or deed restrictions. However, where this ordinance and another
ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the
more stringent restrictions shall prevail.
9.10.050 National Flood Insurance Program General Standards
In all areas of special flood hazard, the following standards shall be adhered to:
A. All new construction and substantial improvements shall be constructed with materials and
utility equipment resistant to flood damage.
B. All new construction and substantial improvements shall be constructed using methods and
practices that minimize flood damage.
C. Alteration of watercourses. The Floodplain Administrator shall require that the flood
carrying capacity within the altered or relocated portion of said watercourse is maintained
and that maintenance is provided within the altered or relocated portion of said watercourse
to ensure that the flood carrying capacity is not diminished. Compliance with TMC
9.10.040.F and 9.10.040.G.
D. Anchoring. All new construction and substantial improvements shall be anchored to prevent
flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and
hydrostatic loads, including the effects of buoyancy. All manufactured dwellings shall be
anchored in accordance with TMC 9.10.050.M.4.
E. Water Supply, Sanitary Sewer, and On-Site Waste Disposal Systems.
1. All new and replacement water supply systems shall be designed to minimize or
eliminate infiltration of flood waters into the system.
2. New and replacement sanitary sewage systems shall be designed to minimize or eliminate
infiltration of flood waters into the systems and discharge from the systems into flood
waters.
3. On-site waste disposal systems shall be located to avoid impairment to them or
contamination from them during flooding consistent with Oregon Department of
Environmental Quality regulations.
F. Electrical, Mechanical, Plumbing, and Other Equipment. Electrical, heating, ventilating, air-
conditioning, plumbing, duct systems, and other equipment and service facilities shall be
elevated at or above the base flood level or shall be designed and installed to prevent water
from entering or accumulating within the components and to resist hydrostatic and
hydrodynamic loads and stresses, including the effects of buoyancy, during conditions of
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flooding. In addition, electrical, heating, ventilating, air-conditioning, plumbing, duct
systems, and other equipment and service facilities shall, if replaced as part of a substantial
improvement, meet all the requirements of this section.
G. Tanks. Underground tanks shall be anchored to prevent flotation, collapse and lateral
movement under conditions of the base flood. Above-ground tanks shall be installed at or
above the base flood level or shall be anchored to prevent flotation, collapse, and lateral
movement under conditions of the base flood.
H. Critical facilities. Construction of new critical facilities must be, to the extent practicable,
located outside areas of special flood hazard.
1. Construction of new critical facilities, other than critical bridges, are allowed within areas
of special flood hazard if no feasible alternative site is available and the following
applicable criteria are met:
a. Critical facilities constructed within areas of special flood hazard must have the
lowest floor elevated 3 feet above base flood elevation or to the height of the 500-
year flood, whichever is higher.
b. To the extent practicable, access to and from the critical facility should also be
protected to 3 feet above base flood elevation or to the height of the 500-year flood,
whichever is higher.
c. Floodproofing and sealing measures must be taken to ensure that toxic substances
will not be displaced by or released into floodwaters.
2. All new and replacement critical bridges must have the lowest extension of the bridge
superstructure elevated 3 feet above base flood elevation or to the height of the 500-year
flood, whichever is higher.
3. Where standard TMC 9.10.050.H.2 cannot be met, an analysis of alternative bridge
designs is required by a registered professional civil engineer. The proposed
encroachment will result in the least impact to base flood levels in the area of special
flood hazard of the practicable alternative bridge designs—as demonstrated through
hydrologic and hydraulic analyses performed in accordance with standard engineering
practice.
I. Subdivision Proposals.
1. All new subdivision proposals and other proposed new developments (including
proposals for manufactured dwelling parks and subdivisions) greater than 50 lots or 5
acres, whichever is the lesser, shall include within such proposals, Base Flood Elevation
data.
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2. All new subdivision proposals and other proposed new developments (including
proposals for manufactured dwelling parks and subdivisions) shall:
a. Be consistent with the need to minimize flood damage;
b. Have public utilities and facilities such as sewer, gas, electrical, and water systems
located and constructed to minimize or eliminate flood damage; and
c. Have adequate drainage provided to reduce exposure to flood hazards.
J. Use of Other Base Flood Data. When Base Flood Elevation data has not been provided in
accordance with TCDC 9.10.030.B the local floodplain administrator shall obtain, review,
and reasonably utilize any Base Flood Elevation data available from a federal, state, or other
source, in order to administer TMC 9.10.050. All new subdivision proposals and other
proposed new developments (including proposals for manufactured dwelling parks and
subdivisions) must meet the requirements of TMC 9.10.050.I. Base Flood Elevations shall be
determined for development proposals that are 5 acres or more in size or are 50 lots or more,
whichever is lesser in any A zone that does not have an established base flood elevation.
Development proposals located within a riverine unnumbered A Zone shall be reasonably
safe from flooding; the test of reasonableness includes use of historical data, high water
marks, FEMA provided Base Level Engineering data, and photographs of past flooding, etc.
When no base flood elevation data is available, the elevation requirement for development
proposals within a riverine unnumbered A Zone is a minimum of two (2) feet above the
highest adjacent grade, to be reasonably safe from flooding. Failure to elevate at least two
feet above grade in these zones may result in higher insurance rates.
K. Structures Located in Multiple or Partial Flood Zones. In coordination with the State of
Oregon Specialty Codes:
1. When a structure is located in multiple flood zones on the city's pertinent Flood
Insurance Rate Maps (FIRM)the provisions for the more restrictive flood zone shall
apply.
2. When a structure is partially located in an area of special flood hazard, the entire structure
shall meet the requirements for new construction and substantial improvements.
L. Specific Standards for Riverine (including all non-coastal) flood zones. These specific
standards shall apply to all new construction and substantial improvements in addition to the
general standards contained in TMC 9.10.050.A through K.
1. Flood Openings. All new construction and substantial improvements with fully enclosed
areas below the lowest floor (excluding basements) are subject to the following
requirements. Enclosed areas below the Base Flood Elevation, including crawl spaces
shall:
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a. Be designed to automatically equalize hydrostatic flood forces on walls by allowing
for the entry and exist of floodwaters;
b. Be used solely for parking, storage, or building access; and
c. Be certified by a registered professional engineer or architect or meet or exceed all of
the following minimum criteria:
i. A minimum of two openings;
ii. The total net area of non-engineered openings shall be not less than one (1) square
inch for each square foot of enclosed area, where the enclosed area is measured
on the exterior of the enclosure walls;
iii. The bottom of all openings shall be no higher than one (1) foot above grade;
iv. Openings may be equipped with screens, louvers, valves, or other coverings or
devices provided that they shall allow the automatic flow of floodwater into and
out of the enclosed areas and shall be accounted for in the determination of the net
open area; and
v. All additional higher standards for flood openings in the State of Oregon
Residential Specialty Codes Section R322.2.2 shall be complied with when
applicable.
2. Garages. Attached garages may be constructed with the garage floor slab below the Base
Flood Elevation in riverine flood zones, if the following requirements are met:
a. If located within a floodway the proposed garage must comply with the requirements
of TMC 9.10.050.N;
b. The floors are at or above grade on at least than one side;
c. The garage is used solely for parking,building access, and/or storage;
d. The garage is constructed with flood openings in compliance with TMC 9.10.050.L.1
to equalize hydrostatic flood forces on exterior walls by allowing for the automatic
entry and exit of floodwater;
e. The portions of the garage constructed below the Base Flood Elevation are
constructed with materials resistant to flood damage;
f. The garage is constructed in compliance with the general standards TMC 9.10.050.A
through K; and
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g. The garage is constructed with electrical, and other service facilities located and
installed so as to prevent water from entering or accumulating within the components
during conditions of the base flood.
3. Detached Garages. Detached garages must be constructed in compliance with the
standards for appurtenant structures in TMC 9.10.050.M.6 or non-residential structures in
TMC 9.10.050.M.3 depending on the square footage of the garage.
M. For Riverine (non-coastal) Areas of Special Flood Hazard with Base Flood Elevations. In
addition to the general standards in TMC 9.10.050.A through K, the following specific
standards shall apply in riverine (non-coastal) areas of special flood hazard with Base Flood
Elevations: Zones Al-A30, AH, and AE.
1. Before Regulatory Floodway. In areas where a regulatory floodway has not been
designated, no new construction, substantial improvement, or other development
(including fill) shall be permitted within Zones Al-30 and AE on the city's Flood
Insurance Rate Map (FIRM), unless it is demonstrated that the cumulative effect of the
proposed development, when combined with all other existing and anticipated
development, will not increase the water surface elevation of the base flood at any point
within the city.
2. Residential Construction.
a. New construction, conversion to, and substantial improvement of any residential
structure shall have the lowest floor, including basement, elevated at one (1) foot
above the Base Flood Elevation.
b. Enclosed areas below the lowest floor shall comply with the flood opening
requirements in TMC 9.10.050.L.1.
3. Non-Residential Construction.
a. New construction, conversion to, and substantial improvement of any commercial,
industrial, or other non-residential structure shall have the lowest floor, including
basement elevated at one (1) foot above the Base Flood Elevation. Or, together with
attendant utility and sanitary facilities:
i. Be floodproofed so that below the base flood level the structure is watertight with
walls substantially impermeable to the passage of water;
ii. Have structural components capable of resisting hydrostatic and hydrodynamic
loads and effects of buoyancy; and
iii. Be certified by a registered professional engineer or architect that the design and
methods of construction are in accordance with accepted standards of practice for
meeting provisions of this section based on their development or review of the
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EXHIBIT A Attachment 1
structural design, specifications and plans. Such certifications shall be provided to
the Floodplain Administrator as set forth TMC 9.10.040.D.
b. Non-residential structures that are elevated, not floodproofed, shall comply with the
standards for enclosed areas below the lowest floor in TMC 9.10.050.L.1.
c. Applicants floodproofing non-residential buildings shall be notified that flood
insurance premiums will be based on rates that are one (1) foot below the
floodproofed level (e.g. a building floodproofed to the base flood level will be rated
as one (1) foot below.
4. Manufactured Dwellings.
a. Manufactured dwellings to be placed(new or replacement) or substantially improved
that are supported on solid foundation walls shall be constructed with flood openings
that comply with TMC 9.10.050.L.1;
b. The bottom of the longitudinal chassis frame beam shall be at or above Base Flood
Elevation;
c. Manufactured dwellings to be placed(new or replacement) or substantially improved
shall be anchored to prevent flotation, collapse, and lateral movement during the base
flood. Anchoring methods may include, but are not limited to, use of over-the-top or
frame ties to ground anchors (Reference FEMA's "Manufactured Home Installation
in Flood Hazard Areas" guidebook for additional techniques); and
d. Electrical crossover connections shall be a minimum of twelve (12) inches above
Base Flood Elevation (BFE).
5. Recreational Vehicles. Recreational vehicles placed on sites are required to:
a. Be on the site for fewer than 180 consecutive days; and
b. Be fully licensed and ready for highway use, on its wheels or jacking system, is
attached to the site only by quick disconnect type utilities and security devices, and
has no permanently attached additions; or
c. Meet the requirements of TMC 9.10.050.M.4, including the anchoring and elevation
requirements for manufactured dwellings.
6. Appurtenant(Accessory) Structures. Relief from elevation or floodproofing
requirements for residential and non-residential structures in Riverine (non-coastal) flood
zones may be granted for appurtenant structures that meet the following requirements:
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EXHIBIT A Attachment 1
a. Appurtenant structures located partially or entirely within the floodway must comply
with requirements for development within a floodway found in TMC 9.10.050.N;
b. Appurtenant structures must only be used for parking, access, or storage and shall not
be used for human habitation;
c. Appurtenant structures on properties are limited to one-story structures less than 600
square feet in A zones and must meet applicable setbacks from property lines;
d. The portions of the appurtenant structure located below the Base Flood Elevation
must be built using flood resistant materials;
e. The appurtenant structure must be adequately anchored to prevent flotation, collapse,
and lateral movement of the structure resulting from hydrodynamic and hydrostatic
loads, including the effects of buoyancy, during conditions of the base flood;
f. The appurtenant structure must be designed and constructed to equalize hydrostatic
flood forces on exterior walls and comply with the requirements for flood openings in
TMC 9.10.050.L.1;
g. Appurtenant structures shall be located and constructed to have low damage potential;
h. Appurtenant structures shall not be used to store toxic material, oil, or gasoline, or
any priority persistent pollutant identified by the Oregon Department of
Environmental Quality unless confined in a tank installed incompliance with TMC
9.10.050.G; and
i. Appurtenant structures shall be constructed with electrical, mechanical, and other
service facilities located and installed so as to prevent water from entering or
accumulating within the components during conditions of the base flood.
N. Floodways. Located within the areas of special flood hazard established in TMC 9.10.030.B
are areas designated as floodways. Because the floodway is an extremely hazardous area due
to the velocity of the floodwaters which carry debris, potential projectiles, and erosion
potential, the following provisions apply:
1. Prohibit encroachments, including fill, new construction, substantial improvements, and
other development within the adopted regulatory floodway unless:
a. Certification by a registered professional civil engineer is provided demonstrating
through hydrologic and hydraulic analyses performed in accordance with standard
engineering practice that the proposed encroachment shall not result in any increase
in flood levels within the city during the occurrence of the base flood discharge; or,
b. A city may permit encroachments within the adopted regulatory floodway that would
result in an increase in base flood elevations,provided that a Conditional Letter of
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EXHIBIT A Attachment 1
Map Revision is applied for and approved by the Federal Insurance Administrator,
and the requirements for such revision as established under Volume 44 of the Code of
Federal Regulations, Section 65.12 are fulfilled.
2. If the requirements of TMC 9.10.050.N.1 are satisfied, all new construction, substantial
improvements, and other development shall comply with all other applicable flood
hazard reduction provisions of TMC 9.10.050.
0. Standards for Shallow Flooding Areas. Shallow flooding areas appear on FIRMs as AO
zones with depth designations or as AH zones with Base Flood Elevations. For AO zones the
base flood depths range from one to three feet above ground where a clearly defined channel
does not exist, or where the path of flooding is unpredictable and where velocity flow may be
evident. Such flooding is usually characterized as sheet flow. For both AO and AH zones,
adequate drainage paths are required around structures on slopes to guide floodwaters around
and away from proposed structures.
1. Standards for AH Zones. Development within AH Zones must comply with the
standards in TMC 9.10.050.A through 0.
2. Standards for AO Zones. In AO zones, the following provisions apply in addition to the
requirements in TMC 9.10.050.A through K and TMC 9.10.050.0.
a. New construction, conversion to, and substantial improvement of residential
structures and manufactured dwellings within AO zones shall have the lowest floor,
including basement, elevated above the highest grade adjacent to the building, at
minimum to or above the depth number specified on the Flood Insurance Rate Maps
or at least two (2) feet if no depth number is specified. For manufactured dwellings
the lowest floor is considered to be the bottom of the longitudinal chassis frame
beam.
b. New construction, conversion to, and substantial improvements of non-residential
structures within AO zones shall either:
i. Have the lowest floor(including basement) elevated above the highest adjacent
grade of the building site, at minimum to or above the depth number specified on
the Flood Insurance Rate Maps or at least two (2) feet if no depth number is
specified; or
ii. Together with attendant utility and sanitary facilities, be completely floodproofed
to or above the depth number specified on the Flood Insurance Rate Map or a
minimum of two (2) feet above the highest adjacent grade if no depth number is
specified, so that any space below that level is watertight with walls substantially
impermeable to the passage of water and with structural components having the
capability of resisting hydrostatic and hydrodynamic loads and the effects of
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buoyancy. If this method is used, compliance shall be certified by a registered
professional engineer or architect as stated in TMC 9.10.050.M.3.a.iii.
c. Recreational vehicles placed on sites within AO Zones on the city's Flood Insurance
Rate Maps shall either:
i. Be on the site for fewer than 180 consecutive days, and
ii. Be fully licensed and ready for highway use, on its wheels or jacking system, is
attached to the site only by quick disconnect type utilities and security devices,
and has no permanently attached additions; or
iii. Meet the elevation requirements of TMC 9.10.050.O.2.a, and the anchoring and
other requirements for manufactured dwellings of TMC 9.10.050.M.4.
d. In AO zones, new and substantially improved appurtenant structures must comply
with the standards in TMC 9.10.050.M.6.
e. In AO zones, enclosed areas beneath elevated structures shall comply with the
requirements in TMC 9.10.050.L.1.
9.10.060 Violations
No structure or land shall hereafter be constructed, located, extended, converted, or altered
without full compliance with the terms of this chapter and other applicable regulations including
but not limited to TCDC Chapter 18.510, Sensitive Lands. Violations of the provisions of this
chapter by failure to comply with any of its requirements (including violations of conditions and
safeguards established in connection with conditions) shall constitute a Class 1 civil infraction,
processed according to the procedures in the civil infractions ordinance, set out in TMC Chapter
1.16. Each violation of a separate provision of this chapter shall constitute a separate infraction,
and each day that a violation of this chapter is committed or permitted to continue shall
constitute a separate infraction. A finding of a violation of this chapter shall not relieve the
responsible party of the duty to abate the violation. The penalties imposed by this section are in
addition and not in lieu of any remedies available to the city. If a provision of this chapter is
violated by a firm or corporation, the officer or officers, or person or persons responsible for the
violation shall be subject to the penalties imposed by this chapter. Nothing contained herein
shall prevent the City of Tigard from taking such other lawful action as is necessary to prevent or
remedy any violation.
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EXHIBIT A Attachment 1
Chapter 18.30
DEFINITIONS
Sections:
18.30.010 List of Terms
18.30.020 Definitions
18.30.010 List of Terms
-A-
Area of Special Flood Hazard -See Flood-Related Definitions
-C-
Critical Facility See Flood Related Definitions
-F-
Flood-Related Definitions:
• Area of Special Flood Hazard
• Base Flood
• Critical Facility
• Flood or Flooding
• Floodway
• Floodway Fringe
• Special Flood Hazard Area
Flood or Flooding- See Flood-Related Definitions
18.30.020 Definitions
As used in this title and corresponding administrative rules, terms, and phrases are defined as
provided in this section. For additional definitions, see Chapter 18.60, Use Categories; Chapter
18.435, Signs; and Chapter 18.510, Sensitive Lands.
F. "F" definitions.
7. Flood-related definitions:
a. Area of Special Flood Hazard: The land in the floodplain within a community
subject to a one percent or greater chance of flooding in any given year.It is shown
on the Flood Insurance Rate Map (FIRM) as Zone A, AO, AH, A1-30, AE, A99,
or AR. "Special flood hazard area"is synonymous in meaning and definition with
the phrase "area of special flood hazard".
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b. "Base flood" - A flood having a one percent chance of being equaled or exceeded
in any given year. Also referred to as the "100 year flood."
b. "Critical facility" A facility for which even a slight chance of flooding might be too
great. Critical facilities include, but are not limited to, schools; nursing homes;
hospitals; police, fire, and emergency response installations; and installations that
produce, use, or store hazardous materials or hazardous waste.
c. "Flood or Flooding" - A general and temporary condition of partial or complete
inundation of normally dry land areas from: the overflow of inland or tidal waters or
the unusual and rapid accumulation of runoff of surface waters from any source.
i. The overflow of inland or tidal waters.
ii. The unusual and rapid accumulation or runoff of surface waters from any
source.
iii. Mudslides (i.e., mudflows) which are proximately caused by flooding as
defined in TMC 18.30.020.F.7.c.ii of this definition and are akin to a river of
liquid and flowing mud on the surfaces of normally dry land areas, as when
earth is carried by a current of water and deposited along the path of the
current.
d. "Floodway" - The channel of a river or other watercourse and the adjacent land areas
that must be reserved in order to discharge the base flood without cumulatively
increasing the water surface elevation more than one foot.
e. "Floodway fringe" - The area of the special flood hazard area lying outside of the
floodway.
f. "Special Flood Hazard Area"-See"Area of special flood hazard"for this definition.
The land area covered by the floodwaters of the base flood is the Special Flood Hazard
Area(SFHA)on NFIP maps. The SFHA is the arca where the National Flood Insurance
Program's (NFIP's) floodplain management regulations must be enforced and the area
where the mandatory purchase of flood insurance applies. The SFHA includes Zones
A, AO, AH, Al 30, AE, A99, AR, AR/AI 30, AR/AE, AR/AO, AR/AH, AR/A, VO,
V1 30, VE, and V. Also referred to as the "100 year floodplain."
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EXHIBIT A Attachment 1
Chapter 18.510
SENSITIVE LANDS
Sections:
18.510.010 Purpose
18.510.020 Applicability
18.510.030 Administrative Provisions
18.510.040 . • • • . ' . . . . . . . - . . . • . Reserved
18.510.050 General Provisions for Wetlands
18.510.060 Approval Period and Extensions
18.510.070 Sensitive Lands Applications
18.510.080 Development within Locally Significant Wetlands and Along the Tualatin
River, Fanno Creek, Ball Creek, and the South Fork of Ash Creek
18.510.090 Density Transfer and Reductions
18.510.100 Plan Amendment Option
18.510.110 Significant Habitat Areas Map Verification Procedures
18.510.010 Purpose
A. Maintain integrity of rivers, streams, and creeks. Sensitive land regulations in this chapter are
intended to maintain the integrity of the rivers, streams, and creeks in Tigard by minimizing
erosion, promoting bank stability, maintaining and enhancing water quality and fish and
wildlife habitats, and preserving scenic quality and recreation potential.
B. Implement comprehensive plan and floodplain management program. The regulations of this
chapter apply to all areas of special flood hazard within the City of Tigard. These
regulations are intended to implement the comprehensive plan and the city's floodplain
management program as required by the Federal Emergency Management Agency (FEMA)
through the National Flood Insurance Program, to help to preserve sensitive land areas from
encroaching use, and to maintain the October 19, 2018, zero-foot rise floodway elevation. All
development within the areas of special flood hazard are subject to the terms of this
ordinance and required to comply with its provisions and all other applicable
regulations including Tigard Municipal (TMC) Chapter 9.10.
C. Implement Clean Water Service (CWS) design and construction standards. The regulations
of this chapter are intended to protect the beneficial uses of water within the Tualatin River
Basin in compliance with the CWS "Design and Construction Standards."
D. Implement the Metro Urban Growth Management Functional Plan. The regulations of this
chapter are intended to protect the beneficial water uses and functions and values of
resources within water quality and flood management areas and to implement the
performance standards of the Metro Urban Growth Management Functional Plan.
E. Implement Statewide Planning Goal 5 (Natural Resources). The regulations in this chapter
are intended to address the requirements of Statewide Planning Goal 5 (Natural Resources)
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EXHIBIT A Attachment 1
and the safe harbor provisions of the Goal 5 administrative rule pertaining to wetland and
riparian corridors.
F. Protect public health, safety, and welfare. Sensitive land areas are designated as such to
protect the public health, safety, and welfare of the community through the regulation of
these sensitive land areas.
G. Location. Sensitive lands are lands potentially unsuitable for development because of their
location within:
1. The special flood hazard areaareas of special flood hazard or 1996 flood inundation
line, whichever is greater;
2. Natural drainageways;
3. Wetland areas that are regulated by the other agencies including the U.S. Army Corps of
Engineers and the Division of State Lands, or are designated as significant wetland on the
City of Tigard"Wetland and Stream Corridors Map";
4. Steep slopes of 25 percent or greater and unstable ground;
5. Significant fish and wildlife habitat areas designated on the City of Tigard "Significant
Habitat Areas Map"; and
6. Significant tree groves as shown on the "City of Tigard Significant Tree Grove Map."
(Ord. 20-01 §1; Ord. 18-21 §2; Ord. 17-22 §2)
18.510.020 Applicability
A. CWS stormwater connection permit. All proposed development must obtain a stormwater
connection permit from CWS in compliance with its design and construction standards.
B. Allowed uses with no approval required. Except as provided below and by Subsections
18.510.020.D, F, and G of this section, the following uses are allowed uses within
drainageways, slopes that are 25 percent or greater, and unstable ground when the use does
not involve paving. For the purposes of this chapter, the word "structure" excludes:
children's play equipment, picnic tables, sand boxes, grills, basketball hoops, and similar
recreational equipment.
1. Accessory uses such as lawns, gardens, or play areas; except in a water quality sensitive
area or vegetated corridor, as defined in the CWS "Design and Construction Standards"
or the Statewide Goal 5 vegetated corridor established for the Tualatin River, as defined
in Section 18.510.080.
2. Farm uses conducted without locating a structure within the sensitive land area; except in
a water quality sensitive area or vegetative corridor, as defined in CWS "Design and
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EXHIBIT A Attachment 1
Construction Standards" or the Statewide Goal 5 vegetated corridor established for the
Tualatin River, as defined in Section 18.510.080.
3. Community recreation uses, excluding structures; except in a water quality sensitive area
or vegetated corridor, as defined in the CWS "Design and Construction Standards" or the
Statewide Goal 5 vegetated corridor established for the Tualatin River, as defined in
Section 18.510.080.
4. Public and private conservation areas for water, soil, open space, forest, and wildlife
resources.
5. Removal of poison oak, tansy ragwort, blackberry, English ivy, or other noxious
vegetation.
6. Maintenance of floodway excluding re-channeling; except in a water quality sensitive
area or vegetated corridor, as defined in the CWS "Design and Construction Standards"
or the Statewide Goal 5 vegetated corridor established for the Tualatin River, as defined
in Section 18.510.080.
7. Fences; except in a water quality sensitive area or vegetated corridor, as defined in the
CSW "Design and Construction Standards"; or the Statewide Goal 5 vegetated corridor
established for the Tualatin River, as defined in Section 18.510.080.
8. Accessory structures that are less than 120 square feet in size; except in a water quality
sensitive area or vegetated corridor, as defined in the CSW "Design and Construction
Standards"; or the Statewide Goal 5 vegetated corridor established for the Tualatin River,
as defined in Section 18.510.080.
9. Land form alterations involving up to 10 cubic yards of material; except in a water
quality sensitive area or vegetated corridor, as defined in the CSW "Design and
Construction Standards"; or the Statewide Goal 5 vegetated corridor established for the
Tualatin River, as defined in Section 18.510.080.
C. Exemptions. When performed under the direction of the city, the following are exempt from
the provisions of this section:
1. Responses to public emergencies, including emergency repairs to public facilities;
2. Stream and wetlands restoration and enhancement programs, except in areas of special
flood hazard areas when meeting the definition of development in Paragraph
18.510.040.R.1 TMC 9.10.020;
3. Non-native vegetation removal;
4. Planting of native plant species; and
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5. Routine maintenance or replacement of existing public facilities projects, except in
special flood hazard areasareas of special flood hazard when meeting the definition of
development in TMC 9.10.020Paragraph 18.510.04 O.R.1.
D. Jurisdictional wetlands. Landform alterations or developments that are only within wetland
areas that meet the jurisdictional requirements and permit criteria of the U.S. Army Corps of
Engineers, Division of State Lands, CWS, or other federal, state, or regional agencies, and
are not designated as significant wetlands on the City of Tigard "Wetland and Streams
Corridors Map," do not require a sensitive lands review. The city will require that all
necessary approvals from other agencies are obtained. All other applicable city requirements
must be met, including sensitive land reviews for areas within the special flood hazard
areaaareas of special flood hazard, slopes of 25 percent or greater or unstable ground,
drainageways, and wetlands that are not under state or federal jurisdiction.
E. Administrative sensitive lands review.
1. Administrative sensitive lands reviews within the special flood hazard arca(excluding the
floodway), drainageways, slopes that are 25 percent or greater, and unstable ground are
processed through a Type I procedure, as provided in Section 18.710.050, for the
following actions:
a. The repair, reconstruction, or improvement of an existing structure or utility, the cost
of which is less than 50 percent of the market value of the structure prior to the
improvement or the damage requiring reconstruction.
b. Minimal ground disturbance or landform alteration involving 10 to 50 cubic
yards of material; and
c. Building permits for accessory structures that are 120 to 528 square feet in size.
2. Administrative sensitive lands reviews within the areas of special flood hazard are
processed through a Type I procedure, as provided in Section 18.710.050, for the
following actions:
a. Within the areas of special flood hazard but outside the floodway (floodway
fringe):
i. The construction of accessory structures up to 528 square feet in size; and
ii. Any landform alteration involving up to 50 cubic yards of material.
b. Stream and wetland restoration and enhancement programs, including work in
the floodway,when performed under the direction of the city.
b. Actions within the special flood hazard area:
iii. The construction of accessory structures up to 528 square feet in size; and
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EXHIBIT A Attachment 1
iv. Any landform alternation involving up to 50 cubic yards of material.
c. Actions within drainageways and slopes that are 25 percent or greater, and unstable
ground:
i. Minimal ground disturbances or landform alterations involving 10 to 50 cubic
ii. Building permits for accessory structures that are 120 to 528 square feet in size.
32. The approval authority will approve, approve with conditions, or deny a sensitive land
review application using the standards and approval criteria Sections 18.510.040,
18.510.050, 18.510.070 and 18.510.080.
F. Sensitive lands approvals issued by the director.
1. Sensitive land reviews within drainageways, slopes that are 25 percent or greater or
unstable ground, and wetland areas that are not regulated by other local, state, or federal
agencies and are designated as significant wetlands on the City of Tigard "Wetland and
Streams Corridors Map" are processed through a Type II procedure, as provided in
Section 18.710.060, for the following actions:
a. Ground disturbance or land form alterations involving more than 50 cubic yards of
material;
b. Repair, reconstruction, or improvement of an existing structure or utility, the cost of
which equals or exceeds 50 percent of the market value of the structure prior to the
improvement or the damage requiring reconstruction;
c. Residential and nonresidential structures intended for human habitation; and
d. Accessory structures that are greater than 528 square feet in size.
2. The approval authority will approve, approve with conditions, or deny a sensitive lands
review application using the approval criteria provided in Section 18.510.070.
G. Sensitive lands approvals issued by the hearings officer.
1. Sensitive land reviews within special flood hazard areasareas of special flood hazard
are processed through a Type III-HO procedure, as provided in Section 18.710.0780, for
the following actions:
a. Ground disturbance or landform alterations in all floodway areas;
b. Ground disturbance or landform alterations in floodway fringe locations involving
more than 50 cubic yards of material;
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EXHIBIT A Attachment 1
c. Repair, reconstruction, or improvement of an existing structure or utility, the cost of
which equals or exceeds 50 percent of the market value of the structure prior to the
improvement or the damage requiring reconstruction provided no development occurs
in the floodway;
d. Structures intended for human habitation; and
e. Accessory structures that are greater than 528 square feet in size, outside of floodway
areas.
2. The approval authority will approve, approve with conditions, or deny a sensitive lands
review application using the approval criteria provided in Section 18.510.070.
H. Other uses. Except as explicitly authorized by other provisions of this chapter, all other uses
are prohibited on sensitive land areas.
I. Nonconforming uses. A use established prior to the effective date of this title, which would
be prohibited by this chapter or that would be subject to the limitations and controls imposed
by this chapter, shall be considered a nonconforming use. Nonconforming uses shall be
subject to the provisions of Chapter 18.50, Nonconforming Circumstances. (Ord. 20-01 §1;
Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-22 §2)
18.510.030 Administrative Provisions
A. Interagency coordination. The approval authority will review all applications for a sensitive
lands review to determine that all necessary approvals be obtained from those federal, state,
or local governmental agencies, from which prior approval is also required.
As provided in CWS "Design and Construction Standards," the necessary permits for all
"development" must comply include a CWS service provider letter, which specifies the
conditions and requirements necessary, if any, for an applicant to comply with CWS water
quality protection standards and for the agency to issue a stormwater connection permit.
B. Alteration or relocation of water course.
1. The director will notify communities adjaccnt to the affected ar a and the State
Department of Land Conservation and Development prior to any alteration or relocation
of a watercourse, and submit evidence of such notification to the Federal Insurance
Administration;
2. The director will require that maintenance is provided within the altered or relocated
portion of a watercourse so that the flood carrying capacity is not diminished.
GB. Applicable standards and criteria. The approval authority will apply the standards and
criteria provided in this chapter when reviewing an application for a sensitive lands review.
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EXHIBIT A Attachment 1
D. Elevation and floodproofing certification. The approval authority will require that the
elevations and floodproofing certification required in Subsection 18.510.030.E be provided
prior to permit issuance and verification upon occupancy and final approval.
E. Maintenance of records.
1. Where base flood elevation data is provided through the flood insurance study, the
of the lowest floor (including basement) of all new or substantially improved structures,
and whether or not the structure contains a basement;
a. Verify and record the actual elevation (in relation to mean sea level); and
b. Maintain the floodproofing certifications required in this chapter.
3. The director will maintain for public inspection all other records pertaining to the
provisions in this chapter. (Ord. 18 23 §2; Ord. 18 21 §2; Ord. 17 22 §2)
18.510.040 . • • • ' . . _ . . - . . . - . Reserved
A. Review. The approval authority will review all applications to determine whether proposed
building sites will minimize the potential for flood damage.
B. Special flood hazard. The areas of special flood hazard identified by FEMA in a scientific
and engineering report entitled "The Flood Insurance Study for Washington County, Oregon
and Incorporated Areas effective October 19, 2018" with accompanying Flood Insurance
Map is hereby adopted by reference and declared to be a part of this ordinance.
C. Base flood elevation data. When base flood elevation data has not been provided in
compliance with Subsection 18.510.040.B, the approval authority will obtain, review and
reasonably utilize any base flood elevation and floodway data available from a federal, state
or other source, in order to administer Subsections 18.510.040.M and N.
D. Test of reasonableness. Where elevation data is not available either through the flood
insurance study or from another authoritative source, applications for building permits will
be reviewed to assure that the potential for flood damage to the proposed construction will be
minimized. The test of reasonableness is a local judgment and includes use of historical data,
high water marks, photographs of past flooding, etc., where available. Failure to elevate at
least 2 feet above grade in these sensitive land areas may result in higher insurance rates.
E. Resistant to flood damage. All new construction and substantial improvements, including
manufactured homes, must be constructed with materials and utility equipment resistant to
flood damage.
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EXHIBIT A Attachment 1
F. Minimize flood damage. All new construction and substantial improvements, including
manufactured homes, must be constructed using methods and practices that minimize flood
damage.
G. Equipment protection. Electrical, heating, ventilation, plumbing, and air conditioning
to prevent water from entering or accumulating within the components during conditions of
flooding.
H. Water supply systems. All new and replacement water supply systems must be designed to
I. Anchorin.. All new construction, all manufactured homes and substantial improvements
must be anchored to prevent flotation, collapse, or lateral movement of the structure.
J. Sanitary sewerage systems. New and replacement sanitary sewerage systems must be
designed to minimize or eliminate infiltration of floodwater into the systems and discharge
from the systems into floodwater.
K. On site waste disposal systems. On site waste disposal systems must be located to avoid
impairment to them or contamination from them during flooding.
L. Residential construction.
1. New construction and substantial improvement of any residential structure, including
manufactured homes, must have the lowest floor, including the basement, elevated at
least 1 foot above base flood elevation;
2. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited or
must be designed to automatically equalize hydrostatic flood forces on exterior walls by
allowing for the entry and exit of floodwater. Designs for meeting this requirement must
either be certified by a registered professional engineer or architect, or must meet or
exceed the following minimum criteria:
a. A minimum of 2 openings having a total net area of not less than 1 square inch for
every square foot of enclosed arca subject to flooding must be provided;
b. The bottom of all openings must be no higher than 1 foot above grade; and
c. Openings may be equipped with screens, louvers, or other coverings or devices,
provided that they permit the automatic entry and exit of flood waters.
foundation system to prevent flotation, collapse, and lateral movement during the base
flood. Anchoring methods may include, but are not limited to, use of over the top or
frame ties to ground anchors. Electrical crossover connections shall be a minimum of 12
inches above BFE.
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EXHIBIT A Attachment 1
M. Nonresidential construction. New construction and substantial improvement of any
commercial, industrial, or other nonresidential structure must either have the lowest floor,
including basement, elevated to the level of the base flood elevation, or together with
substantially impermeable to the passage of water;
2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy;
3. Be certified by a registered professional engineer or architect that the design and methods
of construction are in compliance with accepted standards of practice for meeting
design, specifications and plans. Such certifications must be provided to the building
official as provided in Paragraph_18.510.030.E.2; and
1. Nonresidential structures that are elevated, not floodproofed, must meet the same
standards for space below the lowest floor as described in Paragraph 18.510.040.L.2.
Applicants flood proofing nonresidential buildings must be notified that flood insurance
building constructed to the base flood level will be rated as 1 foot below that level).
N. Subdivisions and partitions in special flood hazard areas. Subdivisions and partitions in the
special flood hazard area must meet the following criteria:
1. The design must minimize the potential for flood damage;
2. Public utilities and facilities such as sewer, gas, electrical, and water systems must be
located and constructed so as to minimize flood damage;
3. Adequate drainage must be provided to reduce exposure to flood damage; and
1. For subdivisions or partitions that contain more than 50 lots or 5 acres and where base
flood elevation data is not available from the Federal Emergency Management Agency
(FEMA) or another authoritative source, the applicant must generate base flood elevation
data to be reviewed as part of the application.
O. Recreational vehicles. Recreational vehicles placed on sites within Zones Al A30, AH, and
AE on the flood insurance rate map either:
1. Are on the site for fewer than 180 consecutive days;
2. Are fully licensed and ready for highway use:
a. Are on wheels or jacking system,
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EXHIBIT A Attachment 1
b. Are attached to the site only by quick disconnect type utilities and security devices,
and have no permanently attached additions, or
c. Meet the requirements of Subsections 18.510.040.E, F, I, and L and the elevation and
anchoring requirements for manufactured homes.
P. Critical facilities. Construction of new critical facilities must be, to the extent possible,
located outside of the limits of the special flood hazard area. Construction of new critical
facilities are allowed within the special flood hazard area if no feasible alternative site is
available. Critical facilities constructed within the special flood hazard area must have the
lowest floor elevated 3 feet above base flood elevation or to the height of the 500 year flood,
whichever is higher. Access to and from the critical facility should also be protected to the
height utilized above. Floodproofing and sealing measures must be taken to ensure that toxic
- • - - A - • - -
above the level of the base flood elevation must be provided to all critical facilities to the
Q. Severability. If any section, clause, sentence, or phrase of the ordinance is held to be invalid
or unconstitutional by any court of competent jurisdiction, then said holding will in no way
affect the validity of the remaining portions of this chapter.
■- - - -
1. Basement Any area of the building having its floor subgrade (below ground level) on all
sides.
2. Development Any man made change to improved or unimproved real estate, including
but not limited to buildings or other structures, mining, dredging, filling, grading, paving,
excavation or drilling operations or storage of equipment or materials.
3. Elevated Building For insurance purposed, a non basement building and that has its
lowest elevated floor raised above ground level by foundation walls, shear walls, posts,
piers, pilings, or columns.
1. Flood Insurance Rate Map (FIRM) The official map of a community, on which the
premium zones applicable to the community. A FIRM that has been made available
digitally is called a Digital Flood Insurance Rate Map (DFIRM).
5. Flood Insurance Study (FIS) The official report provided by the Federal Insurance
Administration that includes flood profiles, the Flood Boundary Floodway Map, and the
water surface elevation of the base flood.
6. Lowest Floor The lowest floor of the lowest enclosed area (including basement). An
unfinished or flood resistant enclosure, usable solely for parking of vehicles, building
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EXHIBIT A Attachment 1
lowest floor; Provided, that such enclosure is not built so as to render the structure in
• • - - -- . -.
7. Manufactured Home A structure, transportable in one or more sections, which is built
on a permanent chassis and is designed for use with or without a permanent foundation
when attached to the required utilities. The term "manufactured" home does not include a
"recreational vehicle."
8. Manufactured Home Park or Subdivision A parcel (or contiguous parcels) of land
divided into two or more manufactured home lots for rent or sale
9. New Construction For the purposes of determining insurance rates, structures for which
the "start of construction" commenced on or after the effective date of an initial FIRM or
after December 31, 1974, whichever is later, and includes any subsequent improvements
to such structures. For floodplain management purposes, new construction means
structures for which the start of construction commenced on or after the effective date of
a floodplain management regulation adopted by a community and includes any
subsequent improvements to such structures.
10. Recreational Vehicle a vehicle which is: (a) Built on a single chassis; (b) 400 square
feet or less when measured at the largest horizontal projection; (c) Designed to be self
propelled or permanently towable by a light duty truck; and (d) Designed primarily not
for use as a permanent dwelling but as temporary living quarters for recreational,
camping, travel, or seasonal use.
11. Start of Construction Includes substantial improvement, and means the date the building
permit was issued, provided the actual start of construction, repair, reconstruction,
means either the first placement of permanent construction of a structure on a site, such
any work beyond the stage of excavation; or the placement of a manufactured home on a
foundation. Permanent construction does not include land preparation, such as clearing,
grading and filling; nor does it include the installation of streets or walkways; nor does it
include excavation for a basement, footings, piers, or foundations or the erection of
temporary forms; nor does it include the installation on the property of accessory
structure. For a substantial improvement, the actual start of construction means the first
that alteration affects the external dimensions of the building.
12. Structure for floodplain management purposes, a walled and roofed building, including
a gas or liquid storage tank, that is principally above ground.
13. Substantial Damage means damage of any origin sustained by a structure whereby the
cost of restoring the structure to its before damaged condition would equal or exceed 50
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EXHIBIT A Attachment 1
11. Substantial Improvement Any reconstruction, rehabilitation, addition, or other
improvement of a structure, the cost of which equals or exceeds 50 percent of the market
a. Before the "start of construction" of the improvement; or
b. If the structure has been damaged and is being restored, before the damage occurred.
c. The term does not, however, include either:
i. Any project for improvement of a structure to correct existing violations of state
or local health, sanitary, or safety code specifications which have been identified
by the local code enforcement official and which are the minimum necessary to
ii. Any alteration of a structure listed on the National Register of Historic Places or a
State Inventory of Historic Places, provided that the alteration will not preclude
the structure's designation as a"historic structure."
15. Violation The failure of a structure or other development to be fully compliant with the
: -A -A . -• .. -
without the elevation certificate, other certifications, or other evidence of compliance
required in Section 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4), or (e)(5) is presumed
to be in violation until such time as that documentation is provided.
S. Disclaimer of liability. This section provides a reasonable degree of flood protection but does
not imply total flood protection.
T. Greater restriction. This section does not in any way impair or remove the necessity of
compliance with any other applicable laws, ordinances, regulations, etc. Where this section
imposes a greater restriction, the provisions of this section govern.
U. New technical data. Notify FEMA within 6 months of project completion when an applicant
has obtained a Conditional Letter of Map Revision (CLOMR) from FEMA, or when
development altered a watercourse, modified floodplain boundaries, or modified Base Flood
Elevations. This notification shall be provided as a Letter of Map Revision (LOMR). (Ord.
20 01 §1; Ord. 18 23 §2; Ord. 18 21 §2; Ord. 17 22 §2)
18.510.050 General Provisions for Wetlands
A. Code compliance requirements. Wetland regulations apply to those areas classified as
significant on the City of Tigard "Wetland and Streams Corridors Map," and to a vegetated
corridor ranging from 25 to 200 feet wide, measured horizontally, from the defined
boundaries of the wetland, as provided in "Table 3.1, Vegetated Corridor Widths," and
"Appendix C, Natural Resource Assessments," of the CWS "Design and Construction
Standards." Wetland locations may include but are not limited to those areas identified as
wetlands in "Wetland Inventory and Assessment for the City of Tigard, Oregon," Fishman
Environmental Services, 1994.
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B. Delineation of wetland boundaries. Precise boundaries may vary from those shown on
wetland maps; specific delineation of wetland boundaries may be necessary. Wetland
delineation will be done by qualified professionals at the applicant's expense. (Ord. 18-21
§2; Ord. 17-22 §2)
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EXHIBIT A Attachment 1
18.510.060 Approval Period and Extensions
Expirations and extensions of approvals are provided in Subsection 18.20.040.G. (Ord. 18-28 §1;
Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-22 §2)
18.510.070 Sensitive Lands Applications
A. Approval required. An applicant, who wishes to develop within a sensitive area, as defined in
this chapter, must obtain approval in certain situations. Depending on the nature and intensity
of the proposed activity within a sensitive area, either a Type II or Type III review is
required, as provided in Subsections 18.510.020.F and G. The approval criteria for different
types of sensitive areas are provided in Subsections 18.510.070.B—E.
B. Within the special flood hazard areasareas of special flood hazard. The approval authority
will approve or approve with conditions an application for sensitive lands review within the
special flood hazard areasareas of special flood hazard when all of the following criteria are
met:
1. Compliance with all of the applicable requirements of this title and TMC Chapter 9.10;
2. Land form alterations must preserve or enhance the special flood hazard areasareas of
special flood hazard storage function and maintenance of the zero-foot rise floodway
must not result in any encroachments, including fill, new construction, substantial
improvements and other development unless certified by a registered professional
engineer that the encroachment will not result in any increase in flood levels during the
base flood discharge;
a. If in the floodway and no-rise requirement is met, the development will comply with
all applicable flood hazard reduction provisions.
3. Land form alterations or developments within the special flood hazard areasareas of
special flood hazard are allowed only in areas designated as commercial=s industrial=
or parks and recreation on the comprehensive plan land use map, except that alterations
or developments associated with community service uses, utilities, or public support
facilities are allowed on residentially zoned properties subject to applicable zoning
standards;
4. Where a land form alteration or development is allowed to occur within the special flood
hazard areasareas of special flood hazard it will not result in any increase in the water
surface elevation of the 100-year flood;
5. The land form alteration or development plan includes a pedestrian or bicycle pathway in
compliance with the adopted Transportation System Plan or Greenways Trail System
Master Plan, unless the construction of said pathway is deemed as untimely;
6. Pedestrian or bicycle pathway projects within the special flood hazard areasareas of
special flood hazard must include a wildlife habitat assessment that shows the proposed
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EXHIBIT A Attachment 1
alignment minimizes impacts to significant wildlife habitat while balancing the
community's recreation and environmental educational goals;
7. The necessary U.S. Army Corps of Engineers and State of Oregon Land Board, Division
of State Lands, and CWS permits and approvals must be obtained; and
8. Where land form alterations or development are allowed within and adjacent to the
special flood hazard areaaareas of special flood hazard, the city will require the
consideration of dedication of sufficient open land area within and adjacent to the special
flood hazard areasareas of special flood hazard in compliance with the comprehensive
plan. This area must include portions of a suitable elevation for the construction of a
pedestrian or bicycle pathway within the special flood hazard areaaareas of special flood
hazard in compliance with the adopted Transportation System Plan or Greenways Trail
System Master Plan.
C. With steep slopes. The approval authority will approve or approve with conditions an
application for a sensitive lands review on slopes of 25 percent or greater or unstable ground
when all of the following criteria are met:
1. Compliance with all of the applicable requirements of this title;
2. The extent and nature of the proposed land form alteration or development will not create
site disturbances to an extent greater than that required for the use;
3. The proposed land form alteration or development will not result in erosion, stream
sedimentation, ground instability, or other adverse on-site and off-site effects or hazards
to life or property;
4. The structures are appropriately sited and designed to ensure structural stability and
proper drainage of foundation and crawl space areas for development with any of the
following soil conditions: wet or high water table; high shrink-swell capability;
compressible or organic; and shallow depth-to-bedrock; and
5. Where natural vegetation has been removed due to land form alteration or development,
the areas not covered by structures or impervious surfaces will be replanted to prevent
erosion in compliance with CWS "Design and Construction Standards".
D. Within drainageways. The approval authority will approve or approve with conditions an
application for a sensitive lands review within drainageways when all of the following
criteria are met:
1. Compliance with all of the applicable requirements of this title;
2. The extent and nature of the proposed land form alteration or development will not create
site disturbances to an extent greater than that required for the use;
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3. The proposed land form alteration or development will not result in erosion, stream
sedimentation, ground instability, or other adverse on-site and off-site effects or hazards
to life or property;
4. The water flow capacity of the drainageway is not decreased;
5. Where natural vegetation has been removed due to land form alteration or development,
the areas not covered by structures or impervious surfaces will be replanted to prevent
erosion in compliance with CWS "Design and Construction Standards";
6. The drainageway will be replaced by a public facility of adequate size to accommodate
maximum flow in compliance with Clean Water Services requirements and the city's
adopted stormwater master plan;
7. The necessary U.S. Army Corps of Engineers and State of Oregon Land Board, Division
of State Lands, and CWS approvals must be obtained;
8. Where land form alterations or development are allowed within and adjacent to the
special flood hazard areasareas of special flood hazard, the city will require the
consideration of dedication of sufficient open land area within and adjacent to the special
flood hazard areasareas of special flood hazard in compliance with the comprehensive
plan. This area will include portions of a suitable elevation for the construction of a
pedestrian or bicycle pathway within the special flood hazard areasareas of special flood
hazard in compliance with the adopted pedestrian bicycle pathway plan.
E. Within wetlands. The approval authority will approve or approve with conditions an
application for a sensitive lands review within wetlands when all of the following criteria are
met:
1. Compliance with all of the applicable requirements of this title;
2. The proposed land form alteration or development is neither on wetland in an area
designated as significant wetland on the comprehensive plan special flood hazard
areasareas of special flood hazard and wetland map nor is within the vegetative corridor
as provided in "Table 3.1 Vegetative Corridor Widths" and "Appendix C: Natural
Resources Assessments" of the CWS "Design and Construction Standards," for such a
wetland;
3. The extent and nature of the proposed land form alteration or development will not create
site disturbances to an extent greater than the minimum required for the use;
4. Any encroachment or change in on-site or off-site drainage that would adversely impact
wetland characteristics have been mitigated;
5. Where natural vegetation has been removed due to land form alteration or development,
erosion control provisions of the Surface Water Management program of Washington
County must be met and areas not covered by structures or impervious surfaces will be
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EXHIBIT A Attachment 1
replanted in like or similar species in compliance with CWS "Design and Construction
Standards";
6. All other sensitive lands requirements of this chapter have been met;
7. The necessary U.S. Army Corps of Engineers and State of Oregon Land Board, Division
of State Lands, and CWS approvals must be obtained;
8. Physical limitations and natural hazards, special flood hazard areaJareas of special flood
hazard and wetlands, natural areas, and parks, recreation and open space policies of the
comprehensive plan have been met. (Ord. 18-28 §1; Ord. 18-23 §2; Ord. 18-21 §2; Ord.
17-22 §2)
18.510.080 Special Provisions within Locally Significant Wetlands and Along the
Tualatin River, Fanno Creek,Ball Creek, and the South Fork of Ash Creek
A. In order to address the requirements of Statewide Planning Goal 5 (Natural Resources) and
the safe harbor provisions of the Goal 5 administrative rule (OAR 666-023-0030) pertaining
to wetlands, all wetlands classified as significant on the City of Tigard "Wetlands and
Streams Corridors Map" are protected. No land form alterations or developments are allowed
within or partially within a significant wetland, except as allowed or approved in compliance
with Section 18.510.100.
B. In order to address the requirements of Statewide Planning Goal 5 (Natural Resources) and
the safe harbor provisions of the Goal 5 administrative rule (OAR 660-023-0030) pertaining
to riparian corridors, a standard setback distance or vegetated corridor area, measured
horizontally from and parallel to the top of the bank, is established for the Tualatin River,
Fanno Creek, Ball Creek, and the South Fork of Ash Creek.
1. The standard width for "good condition" vegetated corridors along the Tualatin River is
75 feet, unless wider in compliance with CWS "Design and Construction Standards," or
modified in compliance with Section 18.510.100. If all or part of a locally significant
wetland (a wetland identified as significant on the City of Tigard "Wetlands and Streams
Corridors Map") is located within the 75-foot setback area, the vegetated corridor is
measured from the upland edge of the associated wetland.
2. The standard width for "good condition" vegetated corridors along Fanno Creek, Ball
Creek, and the South Fork of Ash Creek is 50 feet, unless wider in compliance with CWS
"Design and Construction Standards," or modified in compliance with Section
18.510.100. If all or part of a locally significant wetland (a wetland identified as
significant on the City of Tigard "Wetlands and Streams Corridors Map") is located
within the 50-foot setback area, the vegetated corridor is measured from the upland edge
of the associated wetland.
3. The minimum width for "marginal or degraded condition" vegetated corridors along the
Tualatin River, Fanno Creek, Ball Creek, and the South Fork of Ash Creek is 50 percent
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EXHIBIT A Attachment 1
of the standard width, unless wider in compliance with CWS "Design and Construction
Standards," or modified in compliance with Section 18.510.100.
4. The determination of corridor condition is based on the natural resource assessment
guidelines as provided in the CWS "Design and Construction Standards."
5. The standard setback distance or vegetated corridor area applies to all development
proposed on property located within or partially within the vegetated corridors, except as
allowed below:
a. Roads, pedestrian or bike paths crossing the vegetated corridor from one side to the
other in order to provide access to the sensitive area or across the sensitive area, as
approved by the city in compliance with Section 18.510.070 and by CWS "Design
and Construction Standards";
b. Utility or service provider infrastructure construction (i.e. storm, sanitary sewer,
water,phone, gas, cable, etc.), if approved by the city and CWS;
c. A pedestrian or bike path, not exceeding 10 feet in width and in compliance with the
CWS "Design and Construction Standards";
d. Grading for the purpose of enhancing the vegetated corridor, as approved by the city
and CWS;
e. Measures to remove or abate hazards, nuisances, or fire and life safety violations, as
approved by the regulating jurisdiction;
f. Enhancement of the vegetated corridor for water quality or quantity benefits, fish, or
wildlife habitat, as approved by the city and CWS;
g. Measures to repair, maintain, alter, remove, add to, or replace existing structures,
roadways, driveways, utilities, accessory uses, or other developments provided they
are in compliance with city and CWS regulations, and do not encroach further into
the vegetated corridor or sensitive area than allowed by the CWS "Design and
Construction Standards."
6. Land form alterations or developments located within or partially within the Goal 5
safeharbor setback or vegetated corridor areas established for the Tualatin River, Fanno
Creek, Ball Creek, and the South Fork of Ash Creek that meet the jurisdictional
requirements and permit criteria of the CWS, U.S. Army Corps of Engineers, Department
of State Lands, or other federal, state, or regional agencies, are not subject to this
subsection B, except where the:
a. Land form alterations or developments are located within or partially within a good
condition vegetated corridor, as provided in Paragraphs 18.510.080.B.1 and 2;
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b. Land form alterations or developments are located within or partially within the
minimum width area established for marginal or a degraded condition vegetated
corridor, as provided in Paragraph 18.510.080.B.3.
These exceptions reflect instances of the greater protection of riparian corridors provided
by the safe harbor provisions of the Goal 5 administrative rule. (Ord. 18-23 §2; Ord. 18-
21 §2; Ord. 17-22 §2)
18.510.090 Density Transfer and Reductions
A. Density transfer. Required residential density for apartments, rowhouses, and single detached
houses may be transferred from sensitive lands using the following methods:
1. The units per acre calculated by subtracting land areas listed in Subparagraphs
18.40.020.A.1.a--c from the gross acres may be transferred to the remaining buildable
land areas subject to the following limitations:
a. The number of units that can be transferred is limited to the number of units that
would have been allowed on 25 percent of the unbuildable area if not for these
regulations; and
b. The total number of units per site does not exceed 125 percent of the maximum
number of units per gross acre allowed.
2. Units per acre calculated by subtracting land areas listed in Subparagraph
18.40.020.A.1.d from the gross acres may be transferred to the remaining buildable land
areas on land zoned R-12, R-25, and R-40 subject to the following limitations:
a. The number of units that can be transferred is limited to the number of units that
would have been allowed on the wetland area, if not for these regulations;
b. The total number of units per site does not exceed the maximum number of units per
gross acre allowed.
B. Density reduction. The minimum number of residential units required in a development may
be reduced if necessary to ensure that impacts on habitat areas are minimized. The amount of
reduction in the minimum density is calculated by subtracting the square footage of
inventoried significant habitat that is permanently protected from the total square footage
used to calculate the minimum density requirement. The approval authority may impose any
reasonable condition necessary to mitigate identified impacts resulting from development on
otherwise unbuildable land.
The approval authority will approve, approve with conditions, or deny the density reduction
provided that the proposal will directly result in the protection of significant habitat areas
through placement in a non-buildable tract or protected with a restrictive easement. (Ord. 18-
28 §1; Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-22 §2)
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18.510.100 Plan Amendment Option
A. Comprehensive plan amendment. Any owner of property affected by the Goal 5 safeharbor
(1) protection of significant wetlands or (2) vegetated areas established for the Tualatin
River, Fanno Creek, Ball Creek, and the South Fork of Ash Creek may apply for a
comprehensive plan amendment as provided in Chapter 18.790, Text and Map Amendments.
This amendment must be based on a specific development proposal. The effect of the
amendment would be to remove Goal 5 protection from the property, but not to remove the
requirements related to the CWS Stormwater Connection Permit, which must be addressed
separately through an alternatives analysis, as described in Section 3.02.5 of the CWS
"Design and Construction Standards." The applicant must demonstrate that such an
amendment is justified by either of the following:
B. ESEE analysis. The applicant may prepare an environmental, social, economic and energy
(ESEE) consequences analysis prepared in compliance with OAR 660-23-040.
1. The analysis must consider the ESEE consequences of allowing the proposed conflicting
use, considering both the impacts on the specific resource site and the comparison with
other comparable sites within the Tigard Planning Area;
2. The ESEE analysis must demonstrate to the satisfaction of the city council that the
adverse economic consequences of not allowing the conflicting use are sufficient to
justify the loss, or partial loss, of the resource;
3. In particular, ESEE analysis must demonstrate why the use cannot be located on
buildable land, consistent with the provisions of this chapter, and that there are no other
sites within the Tigard Planning Area that can meet the specific needs of the proposed
use;
4. The ESEE analysis must be prepared by a team consisting of a wildlife biologist or
wetlands ecologist and a land use planner or land use attorney, all of whom are qualified
in their respective fields and experienced in the preparation of Goal 5 ESEE analysis;
5. If the application is approved, then the ESEE analysis must be incorporated by reference
into the Tigard Comprehensive Plan, and the "Tigard Wetland and Stream Corridor Map"
be amended to remove the site from the inventory.
C. Demonstration of change. In this case, the applicant must demonstrate that the sensitive area
site no longer meets the applicable significance threshold defined by the Goal 5
administrative rule, relative to other comparable resources within the Tigard Planning Area.
1. Significance thresholds are described and applied in the addendum to the City of Tigard
Local Wetlands Inventory adopted by reference as part of this chapter.
2. To approve this claim, the city council must find that the decline in identified resource
values did not result from a violation of this title. (Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-
22 §2)
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EXHIBIT A Attachment 1
18.510.110 Significant Habitat Areas Map Verification Procedures
A. Applicants who concur that the significant habitat areas map is accurate must submit the
following information to serve as the basis for verifying the boundaries of inventoried habitat
areas:
1. Submission requirements.
a. A detailed property description;
b. A scale map of the property showing the locations of significant habitat areas, any
existing built area, wetlands or water bodies, Clean Water Services' vegetated
corridor, the special flood hazard areasareas of special flood hazard, the 1996 flood
inundation line, and contour lines (2-foot intervals for slope less than 15 percent and
10-foot intervals for slopes 15 percent or greater); and
c. A current aerial photograph of the property.
2. The approval authority's decision will be based on consideration of submitted
information, site visit information, and other factual information. Should the applicant
disagree with the determination on the location of significant habitat areas on the
property, the precise boundaries must be verified by the applicant in compliance with the
detailed delineation methodology outlined in Subsection 18.510.110.B.
B. Applicants who believe that the map is inaccurate must submit a detailed delineation
conducted by a qualified professional in compliance with the following methodology to
verify the precise boundaries of the inventoried habitat areas by means of a Type II
procedure.
1. Verifying boundaries of inventoried riparian habitat. Locating habitat and determining its
riparian habitat class is a 4-step process:
a. Locate the water feature that is the basis for identifying riparian habitat.
i. Locate the top of bank of all streams, rivers, and open water within 200 feet of the
property.
ii. Locate the special flood hazard areasareas of special flood hazard or 1996 flood
inundation line, whichever is greater,within 100 feet of the property.
iii. Locate all wetlands within 150 feet of the property. Identified wetlands on the
property must be further delineated consistent with methods currently accepted by
the Oregon Division of State Lands and the U.S. Army Corps of Engineers.
b. Identify the vegetative cover status of all areas on the property that are within 200
feet of the top of bank of streams, rivers, and open water, are wetlands or are within
150 feet of wetlands, and are flood areas and within 100 feet of flood areas.
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EXHIBIT A Attachment 1
i. Vegetative cover status must be as identified on the metro vegetative cover map.
ii. The vegetative cover status of a property may be adjusted only if(a) the property
was developed prior to the time the regional program was approved; or (b) an
error was made at the time the vegetative cover status was determined. To assert
the latter type of error, applicants must submit an analysis of the vegetative cover
on their property using summer 2002 aerial photographs and the following
definition of vegetative cover types in Table 18.510.1.
Table 18.510.1
Definitions of Vegetative Cover Types
ype 1 Definition
Low structure vegetation Areas that are part of a contiguous area 1 acre or larger of grass,
or open soils meadow, croplands, or areas of open soils located within 300 feet of a
surface stream (low structure vegetation areas may include areas of
shrub vegetation less than 1 acre in size if they are contiguous with
areas of grass, meadow, croplands, orchards, Christmas tree farms,
holly farms, or areas of open soils located within 300 feet of a surface
stream and together form an area of 1 acre in size or larger).
Woody vegetation Areas that are part of a contiguous area 1 acre or larger of shrub or
open or scattered forest canopy(less than 60 percent crown closure)
located within 300 feet of a surface stream.
Forest canopy Areas that are part of a contiguous grove of trees 1 acre or larger in
area with approximately 60 percent or greater crown closure,
irrespective of whether the entire grove is within 200 feet of the
relevant water feature.
c. Determine whether the degree that the land slope upward from all streams, rivers, and
open water within 200 feet of the property is greater than or less than 25 percent
(using the vegetated corridor measurement methodology as provided in Clean Water
Services Design and Construction Standards; and
d. Identify the riparian habitat classes applicable to all areas on the property using Table
18.510.2 and Table 18.510.3.
Table 18.510.2
Method for Locating Boundaries of Class I and II Riparian Areas
Development/Vegetation Status[1]
Distance in Developed areas Low structure Woody vegetation Forest canopy
feet from (shrub and
not providing vegetation or open (closed to open
water feature vegetative cover soils scattered forest forest canopy)
canopy)
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Surface streams
0-50 Class II Class I Class I Class I
50-100 Class II [2] Class I Class I
100-150 Class II [2] Class II [2] Class II [2]
if slope>25 if slope>25
percent percent
150-200 Class II [2] Class II [2] Class II [2]
if slope>25 if slope>25 if slope>25
percent percent percent
Wetlands (Wetland feature itself is a Class I Riparian Area)
0-100 Class II [2] Class I Class I
100-150 Class II [2]
Flood Areas (Undeveloped portion of flood area is a Class I Riparian Area)
0-100 Class II [2] Class II [2]
[1] The vegetative cover type assigned to any particular area was based on 2 factors: the type of
vegetation observed in aerial photographs and the size of the overall contiguous area of
vegetative cover to which a particular piece of vegetation belonged. As an example of how
the categories were assigned, in order to qualify as a "forest canopy" the forested area had to
be part of a larger patch of forest land at least 1 acre in size.
[2] Areas that have been identified as habitats of concern, as designated on the Metro Habitats of
Concern Map, will be treated as Class I riparian habitat areas in all cases, subject to the
provision of additional information that establishes that they do not meet the criteria used to
identity habitats of concern as described in Metro's Technical Report for Fish and Wildlife.
Examples of habitats of concern include: Oregon white oak woodlands, bottomland
hardwood forests, wetlands, native grasslands, riverine islands or deltas, and important
wildlife migration corridors.
Table 18.510.3
Tualatin Basin "Limit"Decision [1]
Conflicting Use Category
Resource Future Urban
High Intensity Non-Urban
Category Urban Other Urban (2002 and 2004 (outside UGB)
additions)
Class I & II Riparian Moderately Strictly Limit Strictly Limit N/A
inside vegetated corridor Limit
Class I & II Riparian Moderately Moderately Moderately Moderately
outside vegetated corridor Limit Limit Limit Limit
All other Resource Areas Lightly Limit Lightly Limit Lightly Limit Lightly Limit
Inner Impact Area Lightly Limit Lightly Limit Lightly Limit Lightly Limit
Outer Impact Area Lightly Limit Lightly Limit Lightly Limit Lightly Limit
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[1] Vegetated corridor standards are applied consistently throughout the District; in HIU areas
they supersede the "limit" decision.
2. Verifying boundaries of inventoried upland habitat was identified based on the existence
of contiguous patches of forest canopy, with limited canopy openings. The "forest
canopy" designation is made based on analysis of aerial photographs as part of
determining the vegetative cover status of land within the region. Upland habitat is as
identified on the Significant Habitat Areas Map unless corrected as provided in this
subsection.
a. The only allowed corrections to the vegetative cover status of a property area as
follows:
i. To correct errors made when the vegetative status of an area was determined
based on analysis of the aerial photographs used to inventory the habitat. The
perimeter of an area delineated as "forest canopy" on the Metro Vegetative Cover
Map may be adjusted to more precisely indicate the dripline of the trees within the
canopied area provided that no areas providing greater than 60 percent canopy
crown closure are de-classified from the "forest canopy" designation. To assert
such errors, applicants must submit an analysis of the vegetative habitat cover on
their property using the aerial photographs that were used to inventory the habitat
and the definitions of the different vegetative cover types provided in Table
18.510.1; and
ii. To remove tree orchards and Christmas tree farms from inventoried habitat;
provided, however, that Christmas tree farms where the trees were planted prior to
1975 and have not been harvested for sale as Christmas trees may not be removed
from the habitat inventory.
b. If the vegetative cover status of any area identified as upland habitat is corrected in
compliance with Subparagraph 18.510.110.B.2.a to change the status of an area
originally identified as "forest canopy," then such area will not be considered upland
habitat unless it remains part of a forest canopy opening less than 1 acre in area
completely surrounded by an area of contiguous forest canopy. (Ord. 18-23 §2; Ord.
18-21 §2; Ord. 17-22 §2) ■
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Chapter 9.10
AREAS OF SPECIAL FLOOD HAZARD
Sections:
9.10.010 Purpose
9.10.020 Definitions
9.10.030 Applicability
9.10.040 General Provisions
9.10.050 National Flood Insurance Program Standards
9.10.060 Violations
9.10.010 Purpose
The purpose of this chapter is to promote public health, safety, and general welfare, and to
minimize public and private losses due to flooding in flood hazard areas by provisions designed
to:
A. Protect human life and health;
B. Minimize expenditure of public money for costly flood control projects;
C. Minimize the need for rescue and relief efforts associated with flooding and generally
undertaken at the expense of the general public;
D. Minimize prolonged business interruptions;
E. Minimize damage to public facilities and utilities such as water and gas mains; electric,
telephone and sewer lines; and streets and bridges located in areas of special flood hazard;
F. Help maintain a stable tax base by providing for the sound use and development of flood
hazard areas so as to minimize blight areas caused by flooding;
G. Notify potential buyers that the property is in an area of special flood hazard;
H. Notify those who occupy areas of special flood hazard that they assume responsibility for
their actions; and
I. Participate in and maintain eligibility for flood insurance and disaster relief.
9.10.020 Definitions
Unless specifically defined below, words or phrases used in this chapter shall be interpreted so as
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to give them the meaning they have in common usage. These definitions are only applicable to
this chapter and Tigard Community Development Code (TCDC) Chapter 18.510, Sensitive
Lands.
A. Appeal: A request for a review of the interpretation of any provision of this chapter or a
request for a variance.
B. Area of shallow flooding: A designated Zone AO, AH, AR/AO or AR/AH (or VO) on the
city's Flood Insurance Rate Map (FIRM) with a one percent or greater annual chance of
flooding to an average depth of one to three feet where a clearly defined channel does not
exist, where the path of flooding is unpredictable, and where velocity flow may be evident.
Such flooding is characterized by ponding or sheet flow.
C. Area of Special Flood Hazard: The land in the floodplain within the city subject to a 1
percent or greater chance of flooding in any given year. It is shown on the Flood Insurance
Rate Map (FIRM) as Zone A, AO, AH, A1-30, AE, A99, AR. "Special flood hazard area" is
synonymous in meaning and definition with the phrase "area of special flood hazard".
D. Base flood: A flood having a one percent chance of being equaled or exceeded in any given
year.
E. Base flood elevation (BFE): The elevation to which floodwater is anticipated to rise during
the base flood.
F. Basement: Any area of the building having its floor subgrade (below ground level) on all
sides.
G. Critical facility: A facility for which even a slight chance of flooding might be too great.
Critical facilities include, but are not limited to, schools; nursing homes; new and
replacement bridges; hospitals; police, fire, and emergency response installations; and
installations that produce, use, or store hazardous materials or hazardous waste.
H. Development: Any man-made change to improved or unimproved real estate, including but
not limited to buildings or other structures, mining, dredging, filling, grading, paving,
excavation or drilling operations or storage of equipment or materials.
I. Flood or Flooding:
1. A general and temporary condition of partial or complete inundation of normally dry land
areas from:
a. The overflow of inland or tidal waters.
b. The unusual and rapid accumulation or runoff of surface waters from any source.
c. Mudslides (i.e., mudflows) which are proximately caused by flooding as defined in
Tigard Municipal Code (TMC) 9.10.020.I.1.b of this definition and are akin to a river
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of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is
carried by a current of water and deposited along the path of the current.
2. The collapse or subsidence of land along the shore of a lake or other body of water as a
result of erosion or undermining caused by waves or currents of water exceeding
anticipated cyclical levels or suddenly caused by an unusually high water level in a
natural body of water, accompanied by a severe storm, or by an unanticipated force of
nature, such as flash flood or an abnormal tidal surge, or by some similarly unusual and
unforeseeable event which results in flooding as defined in TMC 9.10.020.I.1.a of this
definition.
J. Flood elevation study: See "Flood Insurance Study."
K. Flood Insurance Rate Map (FIRM): The official map of the city, on which the Federal
Insurance Administrator has delineated both the special hazard areas and the risk premium
zones applicable to the city. A FIRM that has been made available digitally is called a Digital
Flood Insurance Rate Map (DFIRM).
L. Flood Insurance Study (FIS): An examination, evaluation and determination of flood
hazards and, if appropriate, corresponding water surface elevations, or an examination,
evaluation and determination of mudslide (i.e., mudflow) or flood-related erosion hazards.
M. Flood proofing: Any combination of structural and nonstructural additions, changes, or
adjustments to structures which reduce or eliminate risk of flood damage to real estate or
improved real property, water and sanitary facilities, structures, and their contents.
N. Floodway: The channel of a river or other watercourse and the adjacent land areas that must
be reserved in order to discharge the base flood without cumulatively increasing the water
surface elevation more than one foot. Also referred to as "Regulatory Floodway."
0. Functionally dependent use: A use which cannot perform its intended purpose unless it is
located or carried out in close proximity to water. The term includes only docking facilities,
port facilities that are necessary for the loading and unloading of cargo or passengers, and
ship building and ship repair facilities, and does not include long term storage or related
manufacturing facilities.
P. Highest adjacent grade: The highest natural elevation of the ground surface prior to
construction next to the proposed walls of a structure.
Q. Historic structure: Any structure that is:
1. Listed individually in the National Register of Historic Places (a listing maintained by the
Department of the Interior) or preliminarily determined by the Secretary of the Interior as
meeting the requirements for individual listing on the National Register;
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2. Certified or preliminarily determined by the Secretary of the Interior as contributing to
the historical significance of a registered historic district or a district preliminarily
determined by the Secretary to qualify as a registered historic district;
3. Individually listed on a state inventory of historic places in states with historic
preservation programs which have been approved by the Secretary of the Interior; or
4. Individually listed on a City of Tigard Historic Resources list acknowledged by the
Secretary of the Interior.
R. Lowest floor: The lowest floor of the lowest enclosed area (including basement). An
unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access
or storage in an area other than a basement area is not considered a building's lowest floor,
provided that such enclosure is not built so as to render the structure in violation of the
applicable non-elevation design requirements of this chapter.
S. Manufactured dwelling: A structure, transportable in one or more sections, which is built on
a permanent chassis and is designed for use with or without a permanent foundation when
attached to the required utilities. The term "manufactured dwelling" does not include a
"recreational vehicle" and is synonymous with"manufactured home."
T. Manufactured dwelling park or subdivision: A parcel (or contiguous parcels) of land divided
into two or more manufactured dwelling lots for rent or sale.
U. Mean sea level: For purposes of the National Flood Insurance Program, the National
Geodetic Vertical Datum (NGVD) of 1929 or other datum, to which Base Flood Elevations
shown on the city's Flood Insurance Rate Map are referenced.
V. New construction: For floodplain management purposes, "new construction" means
structures for which the "start of construction" commenced on or after the effective date of a
floodplain management regulation adopted by City of Tigard and includes any subsequent
improvements to such structures.
W. Recreational vehicle: A vehicle which is:
1. Built on a single chassis;
2. 400 square feet or less when measured at the largest horizontal projection;
3. Designed to be self-propelled or permanently towable by a light duty truck; and
4. Designed primarily not for use as a permanent dwelling but as temporary living quarters
for recreational, camping, travel, or seasonal use.
X. Special flood hazard area: See "Area of special flood hazard" for this definition.
Y. Start of construction: Includes substantial improvement and means the date the building
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permit was issued, provided the actual start of construction, repair, reconstruction,
rehabilitation, addition, placement, or other improvement was within 180 days from the date
of the permit. The actual start means either the first placement of permanent construction of
a structure on a site, such as the pouring of slab or footings, the installation of piles, the
construction of columns, or any work beyond the stage of excavation; or the placement of a
manufactured dwelling on a foundation. Permanent construction does not include land
preparation, such as clearing, grading, and filling; nor does it include the installation of
streets and/or walkways; nor does it include excavation for a basement, footings, piers, or
foundations or the erection of temporary forms; nor does it include the installation on the
property of accessory buildings, such as garages or sheds not occupied as dwelling units or
not part of the main structure. For a substantial improvement, the actual start of construction
means the first alteration of any wall, ceiling, floor, or other structural part of a building,
whether or not that alteration affects the external dimensions of the building.
Z. Structure: For floodplain management purposes, a walled and roofed building, including a
gas or liquid storage tank, that is principally above ground, as well as a manufactured
dwelling.
AA. Substantial damage: Damage of any origin sustained by a structure whereby the cost of
restoring the structure to its before damaged condition would equal or exceed 50 percent of
the market value of the structure before the damage occurred.
BB. Substantial improvement: Any reconstruction, rehabilitation, addition, or other
improvement of a structure, the cost of which equals or exceeds 50 percent of the market
value of the structure before the "start of construction" of the improvement. This term
includes structures which have incurred "substantial damage," regardless of the actual repair
work performed. The term does not, however, include either:
1. Any project for improvement of a structure to correct existing violations of state or local
health, sanitary, or safety code specifications which have been identified by the local
code enforcement official and which are the minimum necessary to assure safe living
conditions; or
2. Any alteration of a "historic structure," provided that the alteration will not preclude the
structure's continued designation as a "historic structure."
CC. Violation: The failure of a structure or other development to be fully compliant with the
city's floodplain management regulations. A structure or other development without the
elevation certificate, other certifications, or other evidence of compliance required in this
chapter is presumed to be in violation until such time as that documentation is provided.
9.10.030 Applicability
A. All development within areas of special flood hazard is subject to the terms of this chapter
and is required to comply with its provisions and all other applicable regulations including
but not limited to TCDC Chapter 18.510, Sensitive Lands.
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B. The areas of special flood hazard identified by FEMA in a scientific and engineering report
entitled"The Flood Insurance Study for Washington County, Oregon and Incorporated Areas
effective October 19, 2018"with accompanying Flood Insurance Map (FIRM
Panels:41067C0529F, 41067C0533E, 41067C0534E, 41067C0541E through 41067C0544E,
and 41067C0563E) is hereby adopted by reference and declared to be a part of this
ordinance.
9.10.040 General Provisions
A. Coordination with State of Oregon Specialty Codes. Pursuant to the requirement established
in ORS 455 that the City of Tigard administers and enforces the State of Oregon Specialty
Codes, the City of Tigard does hereby acknowledge that the Oregon Specialty Codes contain
certain provisions that apply to the design and construction of buildings and structures
located in areas of special flood hazard. Therefore, this chapter is intended to be administered
and enforced in conjunction with the Oregon Specialty Codes.
B. Warning. The degree of flood protection required by this chapter is considered reasonable
for regulatory purposes and is based on scientific and engineering considerations. Larger
floods can and will occur on rare occasions. Flood heights may be increased by man-made or
natural causes. This chapter does not imply that land outside the areas of special flood
hazards or uses permitted within such areas will be free from flooding or flood damages.
C. Permit Review. The duties of the Floodplain Administrator, or their designee, shall include,
but not be limited to review all development permits to determine that:
1. The permit requirements of this ordinance have been satisfied;
2. All other required local, state, and federal permits have been obtained and approved;
3. Review all development permits to determine if the proposed development is located in a
floodway. If located in the floodway assure that the floodway provisions are met;
4. Review all development permits to determine if the proposed development is located in
an area where Base Flood Elevation data is available either through the Flood Insurance
Study or from another authoritative source. If Base Flood Elevation data is not available
then ensure compliance with the provisions of TMC 9.10.050.J;
5. Provide to building officials the Base Flood Elevation applicable to any building
requiring a development permit;
6. Review all development permit applications to determine if the proposed development
qualifies as a substantial improvement as defined by TMC 9.10.020;
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7. Review all development permits to determine if the proposed development activity is a
watercourse alteration. If a watercourse alteration is proposed, ensure compliance with
the provisions in TMC 9.10.050.C; and
8. Review all development permits to determine if the proposed development activity
includes the placement of fill or excavation.
D. Information to be Obtained and Maintained. The following information shall be obtained and
maintained and shall be made available for public inspection as needed:
1. Obtain, record, and maintain the actual elevation (in relation to mean sea level) of the
lowest floor (including basements) and all attendant utilities of all new or substantially
improved structures where Base Flood Elevation data is provided through the Flood
Insurance Study, Flood Insurance Rate Map, or obtained in accordance with TMC
9.10.050.J.
2. Obtain and record the elevation (in relation to mean sea level) of the natural grade of the
building site for a structure prior to the start of construction and the placement of any fill
and ensure that the requirements of TMC 9.10.050.N are adhered to and all other required
local, state, and federal permits have been obtained and approved.
3. Upon placement of the lowest floor of a structure (including basement) but prior to
further vertical construction, obtain documentation, prepared and sealed by a professional
licensed surveyor or engineer, certifying the elevation (in relation to mean sea level) of
the lowest floor(including basement).
4. Where base flood elevation data are utilized, obtain record drawing certification of the
elevation(in relation to mean sea level) of the lowest floor(including basement) prepared
and sealed by a professional licensed surveyor or engineer, prior to the final inspection.
5. Maintain all Elevation Certificates submitted to the City of Tigard.
6. Obtain, record, and maintain the elevation (in relation to mean sea level) to which the
structure and all attendant utilities were floodproofed for all new or substantially
improved floodproofed structures where allowed under this chapter and where Base
Flood Elevation data is provided through the FIS, FIRM, or obtained in accordance with
TMC 9.10.050.J.
7. Maintain all floodproofing certificates required under this chapter.
8. Record and maintain all variance actions, including justification for their issuance.
9. Obtain and maintain all hydrologic and hydraulic analyses performed as required under
TMC 9.10.050.N.
10. Record and maintain all Substantial Improvement and Substantial Damage calculations
and determinations as required under TMC 9.10.040.H.
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11. Maintain for public inspection all records pertaining to the provisions of this chapter.
E. City Boundary Alterations. The Floodplain Administrator shall notify the Federal Insurance
Administrator in writing whenever the boundaries of the city have been modified by
annexation or the city has otherwise assumed authority or no longer has authority to adopt
and enforce floodplain management regulations for a particular area, to ensure that all Flood
Hazard Boundary Maps and Flood Insurance Rate Maps accurately represent the city's
boundaries. The notification will include a copy of a map of the city suitable for
reproduction, clearly delineating the new corporate limits or new area for which the city has
assumed or relinquished floodplain management regulatory authority.
F. Watercourse Alterations. The Floodplain Administrator shall notify adjacent communities,
the Department of Land Conservation and Development, and other appropriate state and
federal agencies, prior to any alteration or relocation of a watercourse, and submit evidence
of such notification to the Federal Insurance Administration. This notification shall be
provided by the applicant to the Federal Insurance Administration as a Letter of Map
Revision along with either a proposed maintenance plan to assure the flood carrying capacity
within the altered or relocated portion of the watercourse is maintained; or Certification by a
registered professional engineer that the project has been designed to retain its flood carrying
capacity without periodic maintenance. The applicant shall be required to submit a
Conditional Letter of Map Revision when required under TMC 9.10.040.G to ensure
compliance with all applicable requirements in TMC 9.10.040.G and 9.10.050.C.
G. Requirement to Submit New Technical Data. The city's base flood elevations may increase
or decrease resulting from physical changes affecting flooding conditions. As soon as
practicable, but not later than six months after the date such information becomes available,
the city must notify the Federal Insurance Administrator of the changes by submitting
technical or scientific data in accordance with Title 44 of the Code of Federal Regulations
(CFR), Section 65.3. The city may require the applicant to submit such data and review fees
required for compliance with this section through the applicable FEMA Letter of Map
Change process. The Floodplain Administrator shall require a Conditional Letter of Map
Revision prior to the issuance of a floodplain development permit for proposed floodway
encroachments that increase the base flood elevation and proposed development which
increases the base flood elevation by more than one foot in areas where FEMA has provided
base flood elevations but no floodway. An applicant shall notify FEMA within six months of
project completion when an applicant has obtained a Conditional Letter of Map Revision
from FEMA. This notification to FEMA shall be provided as a Letter of Map Revision.
H. Substantial Improvement and Substantial Damage Assessments and Determinations. The
Floodplain Administrator shall:
1. Conduct Substantial Improvement(as defined in TMC 9.10.020)reviews for all structural
development proposal applications and maintain a record of Substantial Improvement
calculations within permit files in accordance with TMC 9.10.040.D.
2. Conduct Substantial Damage assessments when structures are damaged due to a natural
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hazard event or other causes.
3. Make Substantial Damage determinations whenever structures within the area of special
flood hazard (as established in TMC 9.10.030.B) are damaged to the extent that the cost
of restoring the structure to its before damaged condition would equal or exceed 50
percent of the market value of the structure before the damage occurred.
I. Floodplain Development Permit Required. A development permit shall be obtained before
construction or development begins within any area horizontally within the area of special
flood hazard established in TMC 9.10.030.B. The development permit shall be required for
all structures, including manufactured dwellings, and for all other development, as defined in
TMC 9.10.020, including fill and other development activities.
J. Application for Development Permit. Application for a development permit may be made on
forms furnished by the Floodplain Administrator and may include, but not be limited to,
plans in duplicate drawn to scale showing the nature, location, dimensions, and elevations of
the area in question; existing or proposed structures, fill, storage of materials, drainage
facilities; and the location of the foregoing. Specifically, the following information is
required:
1. In riverine flood zones, the proposed elevation(in relation to mean sea level), of the
lowest floor(including basement) and all attendant utilities of all new and substantially
improved structures; in accordance with the requirements of TMC 9.10.040.D;
2. Proposed elevation in relation to mean sea level to which any non-residential structure
will be floodproofed;
3. Certification by a registered professional engineer or architect licensed in the State of
Oregon that the floodproofing methods proposed for any non-residential structure meet
the floodproofing criteria for non-residential structures in TMC 9.10.050.M.3;
4. Description of the extent to which any watercourse will be altered or relocated;
5. Base Flood Elevation data for subdivision proposals or other development when required
by this chapter;
6. Substantial improvement calculation for any improvement, addition, reconstruction,
renovation, or rehabilitation of an existing structure; and
7. The amount and location of any fill or excavation activities proposed.
K. Severability. This chapter and the various parts thereof are hereby declared to be severable. If
any section clause, sentence, or phrase of this chapter is held to be invalid or unconstitutional
by any court of competent jurisdiction, then said holding shall in no way effect the validity of
the remaining portions of this chapter.
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L. Abrogation. This ordinance is not intended to repeal, abrogate, or impair any existing
easements, covenants, or deed restrictions. However, where this ordinance and another
ordinance, easement, covenant, or deed restriction conflict or overlap, whichever imposes the
more stringent restrictions shall prevail.
9.10.050 National Flood Insurance Program General Standards
In all areas of special flood hazard, the following standards shall be adhered to:
A. All new construction and substantial improvements shall be constructed with materials and
utility equipment resistant to flood damage.
B. All new construction and substantial improvements shall be constructed using methods and
practices that minimize flood damage.
C. Alteration of watercourses. The Floodplain Administrator shall require that the flood
carrying capacity within the altered or relocated portion of said watercourse is maintained
and that maintenance is provided within the altered or relocated portion of said watercourse
to ensure that the flood carrying capacity is not diminished. Compliance with TMC
9.10.040.F and 9.10.040.G.
D. Anchoring. All new construction and substantial improvements shall be anchored to prevent
flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and
hydrostatic loads, including the effects of buoyancy. All manufactured dwellings shall be
anchored in accordance with TMC 9.10.050.M.4.
E. Water Supply, Sanitary Sewer, and On-Site Waste Disposal Systems.
1. All new and replacement water supply systems shall be designed to minimize or
eliminate infiltration of flood waters into the system.
2. New and replacement sanitary sewage systems shall be designed to minimize or eliminate
infiltration of flood waters into the systems and discharge from the systems into flood
waters.
3. On-site waste disposal systems shall be located to avoid impairment to them or
contamination from them during flooding consistent with Oregon Department of
Environmental Quality regulations.
F. Electrical, Mechanical, Plumbing, and Other Equipment. Electrical, heating, ventilating, air-
conditioning, plumbing, duct systems, and other equipment and service facilities shall be
elevated at or above the base flood level or shall be designed and installed to prevent water
from entering or accumulating within the components and to resist hydrostatic and
hydrodynamic loads and stresses, including the effects of buoyancy, during conditions of
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flooding. In addition, electrical, heating, ventilating, air-conditioning, plumbing, duct
systems, and other equipment and service facilities shall, if replaced as part of a substantial
improvement, meet all the requirements of this section.
G. Tanks. Underground tanks shall be anchored to prevent flotation, collapse and lateral
movement under conditions of the base flood. Above-ground tanks shall be installed at or
above the base flood level or shall be anchored to prevent flotation, collapse, and lateral
movement under conditions of the base flood.
H. Critical facilities. Construction of new critical facilities must be, to the extent practicable,
located outside areas of special flood hazard.
1. Construction of new critical facilities, other than critical bridges, are allowed within areas
of special flood hazard if no feasible alternative site is available and the following
applicable criteria are met:
a. Critical facilities constructed within areas of special flood hazard must have the
lowest floor elevated 3 feet above base flood elevation or to the height of the 500-
year flood, whichever is higher.
b. To the extent practicable, access to and from the critical facility should also be
protected to 3 feet above base flood elevation or to the height of the 500-year flood,
whichever is higher.
c. Floodproofing and sealing measures must be taken to ensure that toxic substances
will not be displaced by or released into floodwaters.
2. All new and replacement critical bridges must have the lowest extension of the bridge
superstructure elevated 3 feet above base flood elevation or to the height of the 500-year
flood, whichever is higher.
3. Where standard TMC 9.10.050.H.2 cannot be met, an analysis of alternative bridge
designs is required by a registered professional civil engineer. The proposed
encroachment will result in the least impact to base flood levels in the area of special
flood hazard of the practicable alternative bridge designs—as demonstrated through
hydrologic and hydraulic analyses performed in accordance with standard engineering
practice.
I. Subdivision Proposals.
1. All new subdivision proposals and other proposed new developments (including
proposals for manufactured dwelling parks and subdivisions) greater than 50 lots or 5
acres, whichever is the lesser, shall include within such proposals, Base Flood Elevation
data.
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2. All new subdivision proposals and other proposed new developments (including
proposals for manufactured dwelling parks and subdivisions) shall:
a. Be consistent with the need to minimize flood damage;
b. Have public utilities and facilities such as sewer, gas, electrical, and water systems
located and constructed to minimize or eliminate flood damage; and
c. Have adequate drainage provided to reduce exposure to flood hazards.
J. Use of Other Base Flood Data. When Base Flood Elevation data has not been provided in
accordance with TCDC 9.10.030.B the local floodplain administrator shall obtain, review,
and reasonably utilize any Base Flood Elevation data available from a federal, state, or other
source, in order to administer TMC 9.10.050. All new subdivision proposals and other
proposed new developments (including proposals for manufactured dwelling parks and
subdivisions) must meet the requirements of TMC 9.10.050.I. Base Flood Elevations shall be
determined for development proposals that are 5 acres or more in size or are 50 lots or more,
whichever is lesser in any A zone that does not have an established base flood elevation.
Development proposals located within a riverine unnumbered A Zone shall be reasonably
safe from flooding; the test of reasonableness includes use of historical data, high water
marks, FEMA provided Base Level Engineering data, and photographs of past flooding, etc.
When no base flood elevation data is available, the elevation requirement for development
proposals within a riverine unnumbered A Zone is a minimum of two (2) feet above the
highest adjacent grade, to be reasonably safe from flooding. Failure to elevate at least two
feet above grade in these zones may result in higher insurance rates.
K. Structures Located in Multiple or Partial Flood Zones. In coordination with the State of
Oregon Specialty Codes:
1. When a structure is located in multiple flood zones on the city's pertinent Flood
Insurance Rate Maps (FIRM)the provisions for the more restrictive flood zone shall
apply.
2. When a structure is partially located in an area of special flood hazard, the entire structure
shall meet the requirements for new construction and substantial improvements.
L. Specific Standards for Riverine (including all non-coastal) flood zones. These specific
standards shall apply to all new construction and substantial improvements in addition to the
general standards contained in TMC 9.10.050.A through K.
1. Flood Openings. All new construction and substantial improvements with fully enclosed
areas below the lowest floor (excluding basements) are subject to the following
requirements. Enclosed areas below the Base Flood Elevation, including crawl spaces
shall:
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a. Be designed to automatically equalize hydrostatic flood forces on walls by allowing
for the entry and exist of floodwaters;
b. Be used solely for parking, storage, or building access; and
c. Be certified by a registered professional engineer or architect or meet or exceed all of
the following minimum criteria:
i. A minimum of two openings;
ii. The total net area of non-engineered openings shall be not less than one (1) square
inch for each square foot of enclosed area, where the enclosed area is measured
on the exterior of the enclosure walls;
iii. The bottom of all openings shall be no higher than one (1) foot above grade;
iv. Openings may be equipped with screens, louvers, valves, or other coverings or
devices provided that they shall allow the automatic flow of floodwater into and
out of the enclosed areas and shall be accounted for in the determination of the net
open area; and
v. All additional higher standards for flood openings in the State of Oregon
Residential Specialty Codes Section R322.2.2 shall be complied with when
applicable.
2. Garages. Attached garages may be constructed with the garage floor slab below the Base
Flood Elevation in riverine flood zones, if the following requirements are met:
a. If located within a floodway the proposed garage must comply with the requirements
of TMC 9.10.050.N;
b. The floors are at or above grade on at least than one side;
c. The garage is used solely for parking,building access, and/or storage;
d. The garage is constructed with flood openings in compliance with TMC 9.10.050.L.1
to equalize hydrostatic flood forces on exterior walls by allowing for the automatic
entry and exit of floodwater;
e. The portions of the garage constructed below the Base Flood Elevation are
constructed with materials resistant to flood damage;
f. The garage is constructed in compliance with the general standards TMC 9.10.050.A
through K; and
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g. The garage is constructed with electrical, and other service facilities located and
installed so as to prevent water from entering or accumulating within the components
during conditions of the base flood.
3. Detached Garages. Detached garages must be constructed in compliance with the
standards for appurtenant structures in TMC 9.10.050.M.6 or non-residential structures in
TMC 9.10.050.M.3 depending on the square footage of the garage.
M. For Riverine (non-coastal) Areas of Special Flood Hazard with Base Flood Elevations. In
addition to the general standards in TMC 9.10.050.A through K, the following specific
standards shall apply in riverine (non-coastal) areas of special flood hazard with Base Flood
Elevations: Zones Al-A30, AH, and AE.
1. Before Regulatory Floodway. In areas where a regulatory floodway has not been
designated, no new construction, substantial improvement, or other development
(including fill) shall be permitted within Zones Al-30 and AE on the city's Flood
Insurance Rate Map (FIRM), unless it is demonstrated that the cumulative effect of the
proposed development, when combined with all other existing and anticipated
development, will not increase the water surface elevation of the base flood at any point
within the city.
2. Residential Construction.
a. New construction, conversion to, and substantial improvement of any residential
structure shall have the lowest floor, including basement, elevated at one (1) foot
above the Base Flood Elevation.
b. Enclosed areas below the lowest floor shall comply with the flood opening
requirements in TMC 9.10.050.L.1.
3. Non-Residential Construction.
a. New construction, conversion to, and substantial improvement of any commercial,
industrial, or other non-residential structure shall have the lowest floor, including
basement elevated at one (1) foot above the Base Flood Elevation. Or, together with
attendant utility and sanitary facilities:
i. Be floodproofed so that below the base flood level the structure is watertight with
walls substantially impermeable to the passage of water;
ii. Have structural components capable of resisting hydrostatic and hydrodynamic
loads and effects of buoyancy; and
iii. Be certified by a registered professional engineer or architect that the design and
methods of construction are in accordance with accepted standards of practice for
meeting provisions of this section based on their development or review of the
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structural design, specifications and plans. Such certifications shall be provided to
the Floodplain Administrator as set forth TMC 9.10.040.D.
b. Non-residential structures that are elevated, not floodproofed, shall comply with the
standards for enclosed areas below the lowest floor in TMC 9.10.050.L.1.
c. Applicants floodproofing non-residential buildings shall be notified that flood
insurance premiums will be based on rates that are one (1) foot below the
floodproofed level (e.g. a building floodproofed to the base flood level will be rated
as one (1) foot below.
4. Manufactured Dwellings.
a. Manufactured dwellings to be placed(new or replacement) or substantially improved
that are supported on solid foundation walls shall be constructed with flood openings
that comply with TMC 9.10.050.L.1;
b. The bottom of the longitudinal chassis frame beam shall be at or above Base Flood
Elevation;
c. Manufactured dwellings to be placed(new or replacement) or substantially improved
shall be anchored to prevent flotation, collapse, and lateral movement during the base
flood. Anchoring methods may include, but are not limited to, use of over-the-top or
frame ties to ground anchors (Reference FEMA's "Manufactured Home Installation
in Flood Hazard Areas" guidebook for additional techniques); and
d. Electrical crossover connections shall be a minimum of twelve (12) inches above
Base Flood Elevation (BFE).
5. Recreational Vehicles. Recreational vehicles placed on sites are required to:
a. Be on the site for fewer than 180 consecutive days; and
b. Be fully licensed and ready for highway use, on its wheels or jacking system, is
attached to the site only by quick disconnect type utilities and security devices, and
has no permanently attached additions; or
c. Meet the requirements of TMC 9.10.050.M.4, including the anchoring and elevation
requirements for manufactured dwellings.
6. Appurtenant(Accessory) Structures. Relief from elevation or floodproofing
requirements for residential and non-residential structures in Riverine (non-coastal) flood
zones may be granted for appurtenant structures that meet the following requirements:
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a. Appurtenant structures located partially or entirely within the floodway must comply
with requirements for development within a floodway found in TMC 9.10.050.N;
b. Appurtenant structures must only be used for parking, access, or storage and shall not
be used for human habitation;
c. Appurtenant structures on properties are limited to one-story structures less than 600
square feet in A zones and must meet applicable setbacks from property lines;
d. The portions of the appurtenant structure located below the Base Flood Elevation
must be built using flood resistant materials;
e. The appurtenant structure must be adequately anchored to prevent flotation, collapse,
and lateral movement of the structure resulting from hydrodynamic and hydrostatic
loads, including the effects of buoyancy, during conditions of the base flood;
f. The appurtenant structure must be designed and constructed to equalize hydrostatic
flood forces on exterior walls and comply with the requirements for flood openings in
TMC 9.10.050.L.1;
g. Appurtenant structures shall be located and constructed to have low damage potential;
h. Appurtenant structures shall not be used to store toxic material, oil, or gasoline, or
any priority persistent pollutant identified by the Oregon Department of
Environmental Quality unless confined in a tank installed incompliance with TMC
9.10.050.G; and
i. Appurtenant structures shall be constructed with electrical, mechanical, and other
service facilities located and installed so as to prevent water from entering or
accumulating within the components during conditions of the base flood.
N. Floodways. Located within the areas of special flood hazard established in TMC 9.10.030.B
are areas designated as floodways. Because the floodway is an extremely hazardous area due
to the velocity of the floodwaters which carry debris, potential projectiles, and erosion
potential, the following provisions apply:
1. Prohibit encroachments, including fill, new construction, substantial improvements, and
other development within the adopted regulatory floodway unless:
a. Certification by a registered professional civil engineer is provided demonstrating
through hydrologic and hydraulic analyses performed in accordance with standard
engineering practice that the proposed encroachment shall not result in any increase
in flood levels within the city during the occurrence of the base flood discharge; or,
b. A city may permit encroachments within the adopted regulatory floodway that would
result in an increase in base flood elevations,provided that a Conditional Letter of
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Map Revision is applied for and approved by the Federal Insurance Administrator,
and the requirements for such revision as established under Volume 44 of the Code of
Federal Regulations, Section 65.12 are fulfilled.
2. If the requirements of TMC 9.10.050.N.1 are satisfied, all new construction, substantial
improvements, and other development shall comply with all other applicable flood
hazard reduction provisions of TMC 9.10.050.
0. Standards for Shallow Flooding Areas. Shallow flooding areas appear on FIRMs as AO
zones with depth designations or as AH zones with Base Flood Elevations. For AO zones the
base flood depths range from one to three feet above ground where a clearly defined channel
does not exist, or where the path of flooding is unpredictable and where velocity flow may be
evident. Such flooding is usually characterized as sheet flow. For both AO and AH zones,
adequate drainage paths are required around structures on slopes to guide floodwaters around
and away from proposed structures.
1. Standards for AH Zones. Development within AH Zones must comply with the
standards in TMC 9.10.050.A through 0.
2. Standards for AO Zones. In AO zones, the following provisions apply in addition to the
requirements in TMC 9.10.050.A through K and TMC 9.10.050.0.
a. New construction, conversion to, and substantial improvement of residential
structures and manufactured dwellings within AO zones shall have the lowest floor,
including basement, elevated above the highest grade adjacent to the building, at
minimum to or above the depth number specified on the Flood Insurance Rate Maps
or at least two (2) feet if no depth number is specified. For manufactured dwellings
the lowest floor is considered to be the bottom of the longitudinal chassis frame
beam.
b. New construction, conversion to, and substantial improvements of non-residential
structures within AO zones shall either:
i. Have the lowest floor(including basement) elevated above the highest adjacent
grade of the building site, at minimum to or above the depth number specified on
the Flood Insurance Rate Maps or at least two (2) feet if no depth number is
specified; or
ii. Together with attendant utility and sanitary facilities, be completely floodproofed
to or above the depth number specified on the Flood Insurance Rate Map or a
minimum of two (2) feet above the highest adjacent grade if no depth number is
specified, so that any space below that level is watertight with walls substantially
impermeable to the passage of water and with structural components having the
capability of resisting hydrostatic and hydrodynamic loads and the effects of
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buoyancy. If this method is used, compliance shall be certified by a registered
professional engineer or architect as stated in TMC 9.10.050.M.3.a.iii.
c. Recreational vehicles placed on sites within AO Zones on the city's Flood Insurance
Rate Maps shall either:
i. Be on the site for fewer than 180 consecutive days, and
ii. Be fully licensed and ready for highway use, on its wheels or jacking system, is
attached to the site only by quick disconnect type utilities and security devices,
and has no permanently attached additions; or
iii. Meet the elevation requirements of TMC 9.10.050.O.2.a, and the anchoring and
other requirements for manufactured dwellings of TMC 9.10.050.M.4.
d. In AO zones, new and substantially improved appurtenant structures must comply
with the standards in TMC 9.10.050.M.6.
e. In AO zones, enclosed areas beneath elevated structures shall comply with the
requirements in TMC 9.10.050.L.1.
9.10.060 Violations
No structure or land shall hereafter be constructed, located, extended, converted, or altered
without full compliance with the terms of this chapter and other applicable regulations including
but not limited to TCDC Chapter 18.510, Sensitive Lands. Violations of the provisions of this
chapter by failure to comply with any of its requirements (including violations of conditions and
safeguards established in connection with conditions) shall constitute a Class 1 civil infraction,
processed according to the procedures in the civil infractions ordinance, set out in TMC Chapter
1.16. Each violation of a separate provision of this chapter shall constitute a separate infraction,
and each day that a violation of this chapter is committed or permitted to continue shall
constitute a separate infraction. A finding of a violation of this chapter shall not relieve the
responsible party of the duty to abate the violation. The penalties imposed by this section are in
addition and not in lieu of any remedies available to the city. If a provision of this chapter is
violated by a firm or corporation, the officer or officers, or person or persons responsible for the
violation shall be subject to the penalties imposed by this chapter. Nothing contained herein
shall prevent the City of Tigard from taking such other lawful action as is necessary to prevent or
remedy any violation.
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Chapter 18.30
DEFINITIONS
Sections:
18.30.010 List of Terms
18.30.020 Definitions
18.30.010 List of Terms
-A-
Area of Special Flood Hazard -See Flood-Related Definitions
-C-
Critical Facility See Flood Related Definitions
-F-
Flood-Related Definitions:
• Area of Special Flood Hazard
• Base Flood
• Critical Facility
• Flood or Flooding
• Floodway
• Floodway Fringe
• Special Flood Hazard Area
Flood or Flooding- See Flood-Related Definitions
18.30.020 Definitions
As used in this title and corresponding administrative rules, terms, and phrases are defined as
provided in this section. For additional definitions, see Chapter 18.60, Use Categories; Chapter
18.435, Signs; and Chapter 18.510, Sensitive Lands.
F. "F" definitions.
7. Flood-related definitions:
a. Area of Special Flood Hazard: The land in the floodplain within a community
subject to a one percent or greater chance of flooding in any given year.It is shown
on the Flood Insurance Rate Map (FIRM) as Zone A, AO, AH, A1-30, AE, A99,
or AR. "Special flood hazard area"is synonymous in meaning and definition with
the phrase "area of special flood hazard".
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b. "Base flood" - A flood having a one percent chance of being equaled or exceeded
in any given year. Also referred to as the "100 year flood."
b. "Critical facility" A facility for which even a slight chance of flooding might be too
great. Critical facilities include, but are not limited to, schools; nursing homes;
hospitals; police, fire, and emergency response installations; and installations that
produce, use, or store hazardous materials or hazardous waste.
c. "Flood or Flooding" - A general and temporary condition of partial or complete
inundation of normally dry land areas from: the overflow of inland or tidal waters or
the unusual and rapid accumulation of runoff of surface waters from any source.
i. The overflow of inland or tidal waters.
ii. The unusual and rapid accumulation or runoff of surface waters from any
source.
iii. Mudslides (i.e., mudflows) which are proximately caused by flooding as
defined in TMC 18.30.020.F.7.c.ii of this definition and are akin to a river of
liquid and flowing mud on the surfaces of normally dry land areas, as when
earth is carried by a current of water and deposited along the path of the
current.
d. "Floodway" - The channel of a river or other watercourse and the adjacent land areas
that must be reserved in order to discharge the base flood without cumulatively
increasing the water surface elevation more than one foot.
e. "Floodway fringe" - The area of the special flood hazard area lying outside of the
floodway.
f. "Special Flood Hazard Area"-See"Area of special flood hazard"for this definition.
The land area covered by the floodwaters of the base flood is the Special Flood Hazard
Area(SFHA)on NFIP maps. The SFHA is the arca where the National Flood Insurance
Program's (NFIP's) floodplain management regulations must be enforced and the area
where the mandatory purchase of flood insurance applies. The SFHA includes Zones
A, AO, AH, Al 30, AE, A99, AR, AR/AI 30, AR/AE, AR/AO, AR/AH, AR/A, VO,
V1 30, VE, and V. Also referred to as the "100 year floodplain."
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Chapter 18.510
SENSITIVE LANDS
Sections:
18.510.010 Purpose
18.510.020 Applicability
18.510.030 Administrative Provisions
18.510.040 . • • • . ' . . . . . . . - . . . • . Reserved
18.510.050 General Provisions for Wetlands
18.510.060 Approval Period and Extensions
18.510.070 Sensitive Lands Applications
18.510.080 Development within Locally Significant Wetlands and Along the Tualatin
River, Fanno Creek, Ball Creek, and the South Fork of Ash Creek
18.510.090 Density Transfer and Reductions
18.510.100 Plan Amendment Option
18.510.110 Significant Habitat Areas Map Verification Procedures
18.510.010 Purpose
A. Maintain integrity of rivers, streams, and creeks. Sensitive land regulations in this chapter are
intended to maintain the integrity of the rivers, streams, and creeks in Tigard by minimizing
erosion, promoting bank stability, maintaining and enhancing water quality and fish and
wildlife habitats, and preserving scenic quality and recreation potential.
B. Implement comprehensive plan and floodplain management program. The regulations of this
chapter apply to all areas of special flood hazard within the City of Tigard. These
regulations are intended to implement the comprehensive plan and the city's floodplain
management program as required by the Federal Emergency Management Agency (FEMA)
through the National Flood Insurance Program, to help to preserve sensitive land areas from
encroaching use, and to maintain the October 19, 2018, zero-foot rise floodway elevation. All
development within the areas of special flood hazard are subject to the terms of this
ordinance and required to comply with its provisions and all other applicable
regulations including Tigard Municipal (TMC) Chapter 9.10.
C. Implement Clean Water Service (CWS) design and construction standards. The regulations
of this chapter are intended to protect the beneficial uses of water within the Tualatin River
Basin in compliance with the CWS "Design and Construction Standards."
D. Implement the Metro Urban Growth Management Functional Plan. The regulations of this
chapter are intended to protect the beneficial water uses and functions and values of
resources within water quality and flood management areas and to implement the
performance standards of the Metro Urban Growth Management Functional Plan.
E. Implement Statewide Planning Goal 5 (Natural Resources). The regulations in this chapter
are intended to address the requirements of Statewide Planning Goal 5 (Natural Resources)
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EXHIBIT D
and the safe harbor provisions of the Goal 5 administrative rule pertaining to wetland and
riparian corridors.
F. Protect public health, safety, and welfare. Sensitive land areas are designated as such to
protect the public health, safety, and welfare of the community through the regulation of
these sensitive land areas.
G. Location. Sensitive lands are lands potentially unsuitable for development because of their
location within:
1. The special flood hazard areaareas of special flood hazard or 1996 flood inundation
line, whichever is greater;
2. Natural drainageways;
3. Wetland areas that are regulated by the other agencies including the U.S. Army Corps of
Engineers and the Division of State Lands, or are designated as significant wetland on the
City of Tigard"Wetland and Stream Corridors Map";
4. Steep slopes of 25 percent or greater and unstable ground;
5. Significant fish and wildlife habitat areas designated on the City of Tigard "Significant
Habitat Areas Map"; and
6. Significant tree groves as shown on the "City of Tigard Significant Tree Grove Map."
(Ord. 20-01 §1; Ord. 18-21 §2; Ord. 17-22 §2)
18.510.020 Applicability
A. CWS stormwater connection permit. All proposed development must obtain a stormwater
connection permit from CWS in compliance with its design and construction standards.
B. Allowed uses with no approval required. Except as provided below and by Subsections
18.510.020.D, F, and G of this section, the following uses are allowed uses within
drainageways, slopes that are 25 percent or greater, and unstable ground when the use does
not involve paving. For the purposes of this chapter, the word "structure" excludes:
children's play equipment, picnic tables, sand boxes, grills, basketball hoops, and similar
recreational equipment.
1. Accessory uses such as lawns, gardens, or play areas; except in a water quality sensitive
area or vegetated corridor, as defined in the CWS "Design and Construction Standards"
or the Statewide Goal 5 vegetated corridor established for the Tualatin River, as defined
in Section 18.510.080.
2. Farm uses conducted without locating a structure within the sensitive land area; except in
a water quality sensitive area or vegetative corridor, as defined in CWS "Design and
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Construction Standards" or the Statewide Goal 5 vegetated corridor established for the
Tualatin River, as defined in Section 18.510.080.
3. Community recreation uses, excluding structures; except in a water quality sensitive area
or vegetated corridor, as defined in the CWS "Design and Construction Standards" or the
Statewide Goal 5 vegetated corridor established for the Tualatin River, as defined in
Section 18.510.080.
4. Public and private conservation areas for water, soil, open space, forest, and wildlife
resources.
5. Removal of poison oak, tansy ragwort, blackberry, English ivy, or other noxious
vegetation.
6. Maintenance of floodway excluding re-channeling; except in a water quality sensitive
area or vegetated corridor, as defined in the CWS "Design and Construction Standards"
or the Statewide Goal 5 vegetated corridor established for the Tualatin River, as defined
in Section 18.510.080.
7. Fences; except in a water quality sensitive area or vegetated corridor, as defined in the
CSW "Design and Construction Standards"; or the Statewide Goal 5 vegetated corridor
established for the Tualatin River, as defined in Section 18.510.080.
8. Accessory structures that are less than 120 square feet in size; except in a water quality
sensitive area or vegetated corridor, as defined in the CSW "Design and Construction
Standards"; or the Statewide Goal 5 vegetated corridor established for the Tualatin River,
as defined in Section 18.510.080.
9. Land form alterations involving up to 10 cubic yards of material; except in a water
quality sensitive area or vegetated corridor, as defined in the CSW "Design and
Construction Standards"; or the Statewide Goal 5 vegetated corridor established for the
Tualatin River, as defined in Section 18.510.080.
C. Exemptions. When performed under the direction of the city, the following are exempt from
the provisions of this section:
1. Responses to public emergencies, including emergency repairs to public facilities;
2. Stream and wetlands restoration and enhancement programs, except in areas of special
flood hazard areas when meeting the definition of development in Paragraph
18.510.040.R.1 TMC 9.10.020;
3. Non-native vegetation removal;
4. Planting of native plant species; and
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5. Routine maintenance or replacement of existing public facilities projects, except in
special flood hazard areasareas of special flood hazard when meeting the definition of
development in TMC 9.10.020Paragraph 18.510.04 O.R.1.
D. Jurisdictional wetlands. Landform alterations or developments that are only within wetland
areas that meet the jurisdictional requirements and permit criteria of the U.S. Army Corps of
Engineers, Division of State Lands, CWS, or other federal, state, or regional agencies, and
are not designated as significant wetlands on the City of Tigard "Wetland and Streams
Corridors Map," do not require a sensitive lands review. The city will require that all
necessary approvals from other agencies are obtained. All other applicable city requirements
must be met, including sensitive land reviews for areas within the special flood hazard
areaaareas of special flood hazard, slopes of 25 percent or greater or unstable ground,
drainageways, and wetlands that are not under state or federal jurisdiction.
E. Administrative sensitive lands review.
1. Administrative sensitive lands reviews within the special flood hazard arca(excluding the
floodway), drainageways, slopes that are 25 percent or greater, and unstable ground are
processed through a Type I procedure, as provided in Section 18.710.050, for the
following actions:
a. The repair, reconstruction, or improvement of an existing structure or utility, the cost
of which is less than 50 percent of the market value of the structure prior to the
improvement or the damage requiring reconstruction.
b. Minimal ground disturbance or landform alteration involving 10 to 50 cubic
yards of material; and
c. Building permits for accessory structures that are 120 to 528 square feet in size.
2. Administrative sensitive lands reviews within the areas of special flood hazard are
processed through a Type I procedure, as provided in Section 18.710.050, for the
following actions:
a. Within the areas of special flood hazard but outside the floodway (floodway
fringe):
i. The construction of accessory structures up to 528 square feet in size; and
ii. Any landform alteration involving up to 50 cubic yards of material.
b. Stream and wetland restoration and enhancement programs, including work in
the floodway,when performed under the direction of the city.
b. Actions within the special flood hazard area:
iii. The construction of accessory structures up to 528 square feet in size; and
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iv. Any landform alternation involving up to 50 cubic yards of material.
c. Actions within drainageways and slopes that are 25 percent or greater, and unstable
ground:
i. Minimal ground disturbances or landform alterations involving 10 to 50 cubic
ii. Building permits for accessory structures that are 120 to 528 square feet in size.
32. The approval authority will approve, approve with conditions, or deny a sensitive land
review application using the standards and approval criteria Sections 18.510.040,
18.510.050, 18.510.070 and 18.510.080.
F. Sensitive lands approvals issued by the director.
1. Sensitive land reviews within drainageways, slopes that are 25 percent or greater or
unstable ground, and wetland areas that are not regulated by other local, state, or federal
agencies and are designated as significant wetlands on the City of Tigard "Wetland and
Streams Corridors Map" are processed through a Type II procedure, as provided in
Section 18.710.060, for the following actions:
a. Ground disturbance or land form alterations involving more than 50 cubic yards of
material;
b. Repair, reconstruction, or improvement of an existing structure or utility, the cost of
which equals or exceeds 50 percent of the market value of the structure prior to the
improvement or the damage requiring reconstruction;
c. Residential and nonresidential structures intended for human habitation; and
d. Accessory structures that are greater than 528 square feet in size.
2. The approval authority will approve, approve with conditions, or deny a sensitive lands
review application using the approval criteria provided in Section 18.510.070.
G. Sensitive lands approvals issued by the hearings officer.
1. Sensitive land reviews within special flood hazard areasareas of special flood hazard
are processed through a Type III-HO procedure, as provided in Section 18.710.0780, for
the following actions:
a. Ground disturbance or landform alterations in all floodway areas;
b. Ground disturbance or landform alterations in floodway fringe locations involving
more than 50 cubic yards of material;
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c. Repair, reconstruction, or improvement of an existing structure or utility, the cost of
which equals or exceeds 50 percent of the market value of the structure prior to the
improvement or the damage requiring reconstruction provided no development occurs
in the floodway;
d. Structures intended for human habitation; and
e. Accessory structures that are greater than 528 square feet in size, outside of floodway
areas.
2. The approval authority will approve, approve with conditions, or deny a sensitive lands
review application using the approval criteria provided in Section 18.510.070.
H. Other uses. Except as explicitly authorized by other provisions of this chapter, all other uses
are prohibited on sensitive land areas.
I. Nonconforming uses. A use established prior to the effective date of this title, which would
be prohibited by this chapter or that would be subject to the limitations and controls imposed
by this chapter, shall be considered a nonconforming use. Nonconforming uses shall be
subject to the provisions of Chapter 18.50, Nonconforming Circumstances. (Ord. 20-01 §1;
Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-22 §2)
18.510.030 Administrative Provisions
A. Interagency coordination. The approval authority will review all applications for a sensitive
lands review to determine that all necessary approvals be obtained from those federal, state,
or local governmental agencies, from which prior approval is also required.
As provided in CWS "Design and Construction Standards," the necessary permits for all
"development" must comply include a CWS service provider letter, which specifies the
conditions and requirements necessary, if any, for an applicant to comply with CWS water
quality protection standards and for the agency to issue a stormwater connection permit.
B. Alteration or relocation of water course.
1. The director will notify communities adjaccnt to the affected ar a and the State
Department of Land Conservation and Development prior to any alteration or relocation
of a watercourse, and submit evidence of such notification to the Federal Insurance
Administration;
2. The director will require that maintenance is provided within the altered or relocated
portion of a watercourse so that the flood carrying capacity is not diminished.
GB. Applicable standards and criteria. The approval authority will apply the standards and
criteria provided in this chapter when reviewing an application for a sensitive lands review.
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D. Elevation and floodproofing certification. The approval authority will require that the
elevations and floodproofing certification required in Subsection 18.510.030.E be provided
prior to permit issuance and verification upon occupancy and final approval.
E. Maintenance of records.
1. Where base flood elevation data is provided through the flood insurance study, the
of the lowest floor (including basement) of all new or substantially improved structures,
and whether or not the structure contains a basement;
a. Verify and record the actual elevation (in relation to mean sea level); and
b. Maintain the floodproofing certifications required in this chapter.
3. The director will maintain for public inspection all other records pertaining to the
provisions in this chapter. (Ord. 18 23 §2; Ord. 18 21 §2; Ord. 17 22 §2)
18.510.040 . • • • ' . . _ . . - . . . - . Reserved
A. Review. The approval authority will review all applications to determine whether proposed
building sites will minimize the potential for flood damage.
B. Special flood hazard. The areas of special flood hazard identified by FEMA in a scientific
and engineering report entitled "The Flood Insurance Study for Washington County, Oregon
and Incorporated Areas effective October 19, 2018" with accompanying Flood Insurance
Map is hereby adopted by reference and declared to be a part of this ordinance.
C. Base flood elevation data. When base flood elevation data has not been provided in
compliance with Subsection 18.510.040.B, the approval authority will obtain, review and
reasonably utilize any base flood elevation and floodway data available from a federal, state
or other source, in order to administer Subsections 18.510.040.M and N.
D. Test of reasonableness. Where elevation data is not available either through the flood
insurance study or from another authoritative source, applications for building permits will
be reviewed to assure that the potential for flood damage to the proposed construction will be
minimized. The test of reasonableness is a local judgment and includes use of historical data,
high water marks, photographs of past flooding, etc., where available. Failure to elevate at
least 2 feet above grade in these sensitive land areas may result in higher insurance rates.
E. Resistant to flood damage. All new construction and substantial improvements, including
manufactured homes, must be constructed with materials and utility equipment resistant to
flood damage.
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F. Minimize flood damage. All new construction and substantial improvements, including
manufactured homes, must be constructed using methods and practices that minimize flood
damage.
G. Equipment protection. Electrical, heating, ventilation, plumbing, and air conditioning
to prevent water from entering or accumulating within the components during conditions of
flooding.
H. Water supply systems. All new and replacement water supply systems must be designed to
I. Anchorin.. All new construction, all manufactured homes and substantial improvements
must be anchored to prevent flotation, collapse, or lateral movement of the structure.
J. Sanitary sewerage systems. New and replacement sanitary sewerage systems must be
designed to minimize or eliminate infiltration of floodwater into the systems and discharge
from the systems into floodwater.
K. On site waste disposal systems. On site waste disposal systems must be located to avoid
impairment to them or contamination from them during flooding.
L. Residential construction.
1. New construction and substantial improvement of any residential structure, including
manufactured homes, must have the lowest floor, including the basement, elevated at
least 1 foot above base flood elevation;
2. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited or
must be designed to automatically equalize hydrostatic flood forces on exterior walls by
allowing for the entry and exit of floodwater. Designs for meeting this requirement must
either be certified by a registered professional engineer or architect, or must meet or
exceed the following minimum criteria:
a. A minimum of 2 openings having a total net area of not less than 1 square inch for
every square foot of enclosed arca subject to flooding must be provided;
b. The bottom of all openings must be no higher than 1 foot above grade; and
c. Openings may be equipped with screens, louvers, or other coverings or devices,
provided that they permit the automatic entry and exit of flood waters.
foundation system to prevent flotation, collapse, and lateral movement during the base
flood. Anchoring methods may include, but are not limited to, use of over the top or
frame ties to ground anchors. Electrical crossover connections shall be a minimum of 12
inches above BFE.
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M. Nonresidential construction. New construction and substantial improvement of any
commercial, industrial, or other nonresidential structure must either have the lowest floor,
including basement, elevated to the level of the base flood elevation, or together with
substantially impermeable to the passage of water;
2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and
effects of buoyancy;
3. Be certified by a registered professional engineer or architect that the design and methods
of construction are in compliance with accepted standards of practice for meeting
design, specifications and plans. Such certifications must be provided to the building
official as provided in Paragraph_18.510.030.E.2; and
/I. Nonresidential structures that are elevated, not floodproofed, must meet the same
standards for space below the lowest floor as described in Paragraph 18.510.040.L.2.
Applicants flood proofing nonresidential buildings must be notified that flood insurance
building constructed to the base flood level will be rated as 1 foot below that level).
N. Subdivisions and partitions in special flood hazard areas. Subdivisions and partitions in the
special flood hazard area must meet the following criteria:
1. The design must minimize the potential for flood damage;
2. Public utilities and facilities such as sewer, gas, electrical, and water systems must be
located and constructed so as to minimize flood damage;
3. Adequate drainage must be provided to reduce exposure to flood damage; and
/I. For subdivisions or partitions that contain more than 50 lots or 5 acres and where base
flood elevation data is not available from the Federal Emergency Management Agency
(FEMA) or another authoritative source, the applicant must generate base flood elevation
data to be reviewed as part of the application.
O. Recreational vehicles. Recreational vehicles placed on sites within Zones Al A30, AH, and
AE on the flood insurance rate map either:
1. Are on the site for fewer than 180 consecutive days;
2. Are fully licensed and ready for highway use:
a. Are on wheels or jacking system,
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b. Are attached to the site only by quick disconnect type utilities and security devices,
and have no permanently attached additions, or
c. Meet the requirements of Subsections 18.510.040.E, F, I, and L and the elevation and
anchoring requirements for manufactured homes.
P. Critical facilities. Construction of new critical facilities must be, to the extent possible,
located outside of the limits of the special flood hazard area. Construction of new critical
facilities are allowed within the special flood hazard area if no feasible alternative site is
available. Critical facilities constructed within the special flood hazard area must have the
lowest floor elevated 3 feet above base flood elevation or to the height of the 500 year flood,
whichever is higher. Access to and from the critical facility should also be protected to the
height utilized above. Floodproofing and sealing measures must be taken to ensure that toxic
- • - - A - • - -
above the level of the base flood elevation must be provided to all critical facilities to the
Q. Severability. If any section, clause, sentence, or phrase of the ordinance is held to be invalid
or unconstitutional by any court of competent jurisdiction, then said holding will in no way
affect the validity of the remaining portions of this chapter.
■- - - -
1. Basement Any area of the building having its floor subgrade (below ground level) on all
sides.
2. Development Any man made change to improved or unimproved real estate, including
but not limited to buildings or other structures, mining, dredging, filling, grading, paving,
excavation or drilling operations or storage of equipment or materials.
3. Elevated Building For insurance purposed, a non basement building and that has its
lowest elevated floor raised above ground level by foundation walls, shear walls, posts,
piers, pilings, or columns.
/I. Flood Insurance Rate Map (FIRM) The official map of a community, on which the
premium zones applicable to the community. A FIRM that has been made available
digitally is called a Digital Flood Insurance Rate Map (DFIRM).
5. Flood Insurance Study (FIS) The official report provided by the Federal Insurance
Administration that includes flood profiles, the Flood Boundary Floodway Map, and the
water surface elevation of the base flood.
6. Lowest Floor The lowest floor of the lowest enclosed area (including basement). An
unfinished or flood resistant enclosure, usable solely for parking of vehicles, building
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lowest floor; Provided, that such enclosure is not built so as to render the structure in
• • - - -- . -.
7. Manufactured Home A structure, transportable in one or more sections, which is built
on a permanent chassis and is designed for use with or without a permanent foundation
when attached to the required utilities. The term "manufactured" home does not include a
"recreational vehicle."
8. Manufactured Home Park or Subdivision A parcel (or contiguous parcels) of land
divided into two or more manufactured home lots for rent or sale
9. New Construction For the purposes of determining insurance rates, structures for which
the "start of construction" commenced on or after the effective date of an initial FIRM or
after December 31, 1974, whichever is later, and includes any subsequent improvements
to such structures. For floodplain management purposes, new construction means
structures for which the start of construction commenced on or after the effective date of
a floodplain management regulation adopted by a community and includes any
subsequent improvements to such structures.
10. Recreational Vehicle a vehicle which is: (a) Built on a single chassis; (b) 400 square
feet or less when measured at the largest horizontal projection; (c) Designed to be self
propelled or permanently towable by a light duty truck; and (d) Designed primarily not
for use as a permanent dwelling but as temporary living quarters for recreational,
camping, travel, or seasonal use.
11. Start of Construction Includes substantial improvement, and means the date the building
permit was issued, provided the actual start of construction, repair, reconstruction,
means either the first placement of permanent construction of a structure on a site, such
any work beyond the stage of excavation; or the placement of a manufactured home on a
foundation. Permanent construction does not include land preparation, such as clearing,
grading and filling; nor does it include the installation of streets or walkways; nor does it
include excavation for a basement, footings, piers, or foundations or the erection of
temporary forms; nor does it include the installation on the property of accessory
structure. For a substantial improvement, the actual start of construction means the first
that alteration affects the external dimensions of the building.
12. Structure for floodplain management purposes, a walled and roofed building, including
a gas or liquid storage tank, that is principally above ground.
13. Substantial Damage means damage of any origin sustained by a structure whereby the
cost of restoring the structure to its before damaged condition would equal or exceed 50
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11. Substantial Improvement Any reconstruction, rehabilitation, addition, or other
improvement of a structure, the cost of which equals or exceeds 50 percent of the market
a. Before the "start of construction" of the improvement; or
b. If the structure has been damaged and is being restored, before the damage occurred.
c. The term does not, however, include either:
i. Any project for improvement of a structure to correct existing violations of state
or local health, sanitary, or safety code specifications which have been identified
by the local code enforcement official and which are the minimum necessary to
ii. Any alteration of a structure listed on the National Register of Historic Places or a
State Inventory of Historic Places, provided that the alteration will not preclude
the structure's designation as a"historic structure."
15. Violation The failure of a structure or other development to be fully compliant with the
: -A -A . -• .. -
without the elevation certificate, other certifications, or other evidence of compliance
required in Section 60.3(b)(5), (c)(4), (c)(10), (d)(3), (e)(2), (e)(4), or (e)(5) is presumed
to be in violation until such time as that documentation is provided.
S. Disclaimer of liability. This section provides a reasonable degree of flood protection but does
not imply total flood protection.
T. Greater restriction. This section does not in any way impair or remove the necessity of
compliance with any other applicable laws, ordinances, regulations, etc. Where this section
imposes a greater restriction, the provisions of this section govern.
U. New technical data. Notify FEMA within 6 months of project completion when an applicant
has obtained a Conditional Letter of Map Revision (CLOMR) from FEMA, or when
development altered a watercourse, modified floodplain boundaries, or modified Base Flood
Elevations. This notification shall be provided as a Letter of Map Revision (LOMR). (Ord.
20 01 §1; Ord. 18 23 §2; Ord. 18 21 §2; Ord. 17 22 §2)
18.510.050 General Provisions for Wetlands
A. Code compliance requirements. Wetland regulations apply to those areas classified as
significant on the City of Tigard "Wetland and Streams Corridors Map," and to a vegetated
corridor ranging from 25 to 200 feet wide, measured horizontally, from the defined
boundaries of the wetland, as provided in "Table 3.1, Vegetated Corridor Widths," and
"Appendix C, Natural Resource Assessments," of the CWS "Design and Construction
Standards." Wetland locations may include but are not limited to those areas identified as
wetlands in "Wetland Inventory and Assessment for the City of Tigard, Oregon," Fishman
Environmental Services, 1994.
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B. Delineation of wetland boundaries. Precise boundaries may vary from those shown on
wetland maps; specific delineation of wetland boundaries may be necessary. Wetland
delineation will be done by qualified professionals at the applicant's expense. (Ord. 18-21
§2; Ord. 17-22 §2)
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18.510.060 Approval Period and Extensions
Expirations and extensions of approvals are provided in Subsection 18.20.040.G. (Ord. 18-28 §1;
Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-22 §2)
18.510.070 Sensitive Lands Applications
A. Approval required. An applicant, who wishes to develop within a sensitive area, as defined in
this chapter, must obtain approval in certain situations. Depending on the nature and intensity
of the proposed activity within a sensitive area, either a Type II or Type III review is
required, as provided in Subsections 18.510.020.F and G. The approval criteria for different
types of sensitive areas are provided in Subsections 18.510.070.B—E.
B. Within the special flood hazard areasareas of special flood hazard. The approval authority
will approve or approve with conditions an application for sensitive lands review within the
special flood hazard areasareas of special flood hazard when all of the following criteria are
met:
1. Compliance with all of the applicable requirements of this title and TMC Chapter 9.10;
2. Land form alterations must preserve or enhance the special flood hazard areasareas of
special flood hazard storage function and maintenance of the zero-foot rise floodway
must not result in any encroachments, including fill, new construction, substantial
improvements and other development unless certified by a registered professional
engineer that the encroachment will not result in any increase in flood levels during the
base flood discharge;
a. If in the floodway and no-rise requirement is met, the development will comply with
all applicable flood hazard reduction provisions.
3. Land form alterations or developments within the special flood hazard areasareas of
special flood hazard are allowed only in areas designated as commercial=s industrial=
or parks and recreation on the comprehensive plan land use map, except that alterations
or developments associated with community service uses, utilities, or public support
facilities are allowed on residentially zoned properties subject to applicable zoning
standards;
4. Where a land form alteration or development is allowed to occur within the special flood
hazard areasareas of special flood hazard it will not result in any increase in the water
surface elevation of the 100-year flood;
5. The land form alteration or development plan includes a pedestrian or bicycle pathway in
compliance with the adopted Transportation System Plan or Greenways Trail System
Master Plan, unless the construction of said pathway is deemed as untimely;
6. Pedestrian or bicycle pathway projects within the special flood hazard areasareas of
special flood hazard must include a wildlife habitat assessment that shows the proposed
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alignment minimizes impacts to significant wildlife habitat while balancing the
community's recreation and environmental educational goals;
7. The necessary U.S. Army Corps of Engineers and State of Oregon Land Board, Division
of State Lands, and CWS permits and approvals must be obtained; and
8. Where land form alterations or development are allowed within and adjacent to the
special flood hazard areaaareas of special flood hazard, the city will require the
consideration of dedication of sufficient open land area within and adjacent to the special
flood hazard areasareas of special flood hazard in compliance with the comprehensive
plan. This area must include portions of a suitable elevation for the construction of a
pedestrian or bicycle pathway within the special flood hazard areaaareas of special flood
hazard in compliance with the adopted Transportation System Plan or Greenways Trail
System Master Plan.
C. With steep slopes. The approval authority will approve or approve with conditions an
application for a sensitive lands review on slopes of 25 percent or greater or unstable ground
when all of the following criteria are met:
1. Compliance with all of the applicable requirements of this title;
2. The extent and nature of the proposed land form alteration or development will not create
site disturbances to an extent greater than that required for the use;
3. The proposed land form alteration or development will not result in erosion, stream
sedimentation, ground instability, or other adverse on-site and off-site effects or hazards
to life or property;
4. The structures are appropriately sited and designed to ensure structural stability and
proper drainage of foundation and crawl space areas for development with any of the
following soil conditions: wet or high water table; high shrink-swell capability;
compressible or organic; and shallow depth-to-bedrock; and
5. Where natural vegetation has been removed due to land form alteration or development,
the areas not covered by structures or impervious surfaces will be replanted to prevent
erosion in compliance with CWS "Design and Construction Standards".
D. Within drainageways. The approval authority will approve or approve with conditions an
application for a sensitive lands review within drainageways when all of the following
criteria are met:
1. Compliance with all of the applicable requirements of this title;
2. The extent and nature of the proposed land form alteration or development will not create
site disturbances to an extent greater than that required for the use;
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3. The proposed land form alteration or development will not result in erosion, stream
sedimentation, ground instability, or other adverse on-site and off-site effects or hazards
to life or property;
4. The water flow capacity of the drainageway is not decreased;
5. Where natural vegetation has been removed due to land form alteration or development,
the areas not covered by structures or impervious surfaces will be replanted to prevent
erosion in compliance with CWS "Design and Construction Standards";
6. The drainageway will be replaced by a public facility of adequate size to accommodate
maximum flow in compliance with Clean Water Services requirements and the city's
adopted stormwater master plan;
7. The necessary U.S. Army Corps of Engineers and State of Oregon Land Board, Division
of State Lands, and CWS approvals must be obtained;
8. Where land form alterations or development are allowed within and adjacent to the
special flood hazard areasareas of special flood hazard, the city will require the
consideration of dedication of sufficient open land area within and adjacent to the special
flood hazard areasareas of special flood hazard in compliance with the comprehensive
plan. This area will include portions of a suitable elevation for the construction of a
pedestrian or bicycle pathway within the special flood hazard areasareas of special flood
hazard in compliance with the adopted pedestrian bicycle pathway plan.
E. Within wetlands. The approval authority will approve or approve with conditions an
application for a sensitive lands review within wetlands when all of the following criteria are
met:
1. Compliance with all of the applicable requirements of this title;
2. The proposed land form alteration or development is neither on wetland in an area
designated as significant wetland on the comprehensive plan special flood hazard
areasareas of special flood hazard and wetland map nor is within the vegetative corridor
as provided in "Table 3.1 Vegetative Corridor Widths" and "Appendix C: Natural
Resources Assessments" of the CWS "Design and Construction Standards," for such a
wetland;
3. The extent and nature of the proposed land form alteration or development will not create
site disturbances to an extent greater than the minimum required for the use;
4. Any encroachment or change in on-site or off-site drainage that would adversely impact
wetland characteristics have been mitigated;
5. Where natural vegetation has been removed due to land form alteration or development,
erosion control provisions of the Surface Water Management program of Washington
County must be met and areas not covered by structures or impervious surfaces will be
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replanted in like or similar species in compliance with CWS "Design and Construction
Standards";
6. All other sensitive lands requirements of this chapter have been met;
7. The necessary U.S. Army Corps of Engineers and State of Oregon Land Board, Division
of State Lands, and CWS approvals must be obtained;
8. Physical limitations and natural hazards, special flood hazard areaJareas of special flood
hazard and wetlands, natural areas, and parks, recreation and open space policies of the
comprehensive plan have been met. (Ord. 18-28 §1; Ord. 18-23 §2; Ord. 18-21 §2; Ord.
17-22 §2)
18.510.080 Special Provisions within Locally Significant Wetlands and Along the
Tualatin River, Fanno Creek,Ball Creek, and the South Fork of Ash Creek
A. In order to address the requirements of Statewide Planning Goal 5 (Natural Resources) and
the safe harbor provisions of the Goal 5 administrative rule (OAR 666-023-0030) pertaining
to wetlands, all wetlands classified as significant on the City of Tigard "Wetlands and
Streams Corridors Map" are protected. No land form alterations or developments are allowed
within or partially within a significant wetland, except as allowed or approved in compliance
with Section 18.510.100.
B. In order to address the requirements of Statewide Planning Goal 5 (Natural Resources) and
the safe harbor provisions of the Goal 5 administrative rule (OAR 660-023-0030) pertaining
to riparian corridors, a standard setback distance or vegetated corridor area, measured
horizontally from and parallel to the top of the bank, is established for the Tualatin River,
Fanno Creek, Ball Creek, and the South Fork of Ash Creek.
1. The standard width for "good condition" vegetated corridors along the Tualatin River is
75 feet, unless wider in compliance with CWS "Design and Construction Standards," or
modified in compliance with Section 18.510.100. If all or part of a locally significant
wetland (a wetland identified as significant on the City of Tigard "Wetlands and Streams
Corridors Map") is located within the 75-foot setback area, the vegetated corridor is
measured from the upland edge of the associated wetland.
2. The standard width for "good condition" vegetated corridors along Fanno Creek, Ball
Creek, and the South Fork of Ash Creek is 50 feet, unless wider in compliance with CWS
"Design and Construction Standards," or modified in compliance with Section
18.510.100. If all or part of a locally significant wetland (a wetland identified as
significant on the City of Tigard "Wetlands and Streams Corridors Map") is located
within the 50-foot setback area, the vegetated corridor is measured from the upland edge
of the associated wetland.
3. The minimum width for "marginal or degraded condition" vegetated corridors along the
Tualatin River, Fanno Creek, Ball Creek, and the South Fork of Ash Creek is 50 percent
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of the standard width, unless wider in compliance with CWS "Design and Construction
Standards," or modified in compliance with Section 18.510.100.
4. The determination of corridor condition is based on the natural resource assessment
guidelines as provided in the CWS "Design and Construction Standards."
5. The standard setback distance or vegetated corridor area applies to all development
proposed on property located within or partially within the vegetated corridors, except as
allowed below:
a. Roads, pedestrian or bike paths crossing the vegetated corridor from one side to the
other in order to provide access to the sensitive area or across the sensitive area, as
approved by the city in compliance with Section 18.510.070 and by CWS "Design
and Construction Standards";
b. Utility or service provider infrastructure construction (i.e. storm, sanitary sewer,
water,phone, gas, cable, etc.), if approved by the city and CWS;
c. A pedestrian or bike path, not exceeding 10 feet in width and in compliance with the
CWS "Design and Construction Standards";
d. Grading for the purpose of enhancing the vegetated corridor, as approved by the city
and CWS;
e. Measures to remove or abate hazards, nuisances, or fire and life safety violations, as
approved by the regulating jurisdiction;
f. Enhancement of the vegetated corridor for water quality or quantity benefits, fish, or
wildlife habitat, as approved by the city and CWS;
g. Measures to repair, maintain, alter, remove, add to, or replace existing structures,
roadways, driveways, utilities, accessory uses, or other developments provided they
are in compliance with city and CWS regulations, and do not encroach further into
the vegetated corridor or sensitive area than allowed by the CWS "Design and
Construction Standards."
6. Land form alterations or developments located within or partially within the Goal 5
safeharbor setback or vegetated corridor areas established for the Tualatin River, Fanno
Creek, Ball Creek, and the South Fork of Ash Creek that meet the jurisdictional
requirements and permit criteria of the CWS, U.S. Army Corps of Engineers, Department
of State Lands, or other federal, state, or regional agencies, are not subject to this
subsection B, except where the:
a. Land form alterations or developments are located within or partially within a good
condition vegetated corridor, as provided in Paragraphs 18.510.080.B.1 and 2;
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b. Land form alterations or developments are located within or partially within the
minimum width area established for marginal or a degraded condition vegetated
corridor, as provided in Paragraph 18.510.080.B.3.
These exceptions reflect instances of the greater protection of riparian corridors provided
by the safe harbor provisions of the Goal 5 administrative rule. (Ord. 18-23 §2; Ord. 18-
21 §2; Ord. 17-22 §2)
18.510.090 Density Transfer and Reductions
A. Density transfer. Required residential density for apartments, rowhouses, and single detached
houses may be transferred from sensitive lands using the following methods:
1. The units per acre calculated by subtracting land areas listed in Subparagraphs
18.40.020.A.1.a--c from the gross acres may be transferred to the remaining buildable
land areas subject to the following limitations:
a. The number of units that can be transferred is limited to the number of units that
would have been allowed on 25 percent of the unbuildable area if not for these
regulations; and
b. The total number of units per site does not exceed 125 percent of the maximum
number of units per gross acre allowed.
2. Units per acre calculated by subtracting land areas listed in Subparagraph
18.40.020.A.1.d from the gross acres may be transferred to the remaining buildable land
areas on land zoned R-12, R-25, and R-40 subject to the following limitations:
a. The number of units that can be transferred is limited to the number of units that
would have been allowed on the wetland area, if not for these regulations;
b. The total number of units per site does not exceed the maximum number of units per
gross acre allowed.
B. Density reduction. The minimum number of residential units required in a development may
be reduced if necessary to ensure that impacts on habitat areas are minimized. The amount of
reduction in the minimum density is calculated by subtracting the square footage of
inventoried significant habitat that is permanently protected from the total square footage
used to calculate the minimum density requirement. The approval authority may impose any
reasonable condition necessary to mitigate identified impacts resulting from development on
otherwise unbuildable land.
The approval authority will approve, approve with conditions, or deny the density reduction
provided that the proposal will directly result in the protection of significant habitat areas
through placement in a non-buildable tract or protected with a restrictive easement. (Ord. 18-
28 §1; Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-22 §2)
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18.510.100 Plan Amendment Option
A. Comprehensive plan amendment. Any owner of property affected by the Goal 5 safeharbor
(1) protection of significant wetlands or (2) vegetated areas established for the Tualatin
River, Fanno Creek, Ball Creek, and the South Fork of Ash Creek may apply for a
comprehensive plan amendment as provided in Chapter 18.790, Text and Map Amendments.
This amendment must be based on a specific development proposal. The effect of the
amendment would be to remove Goal 5 protection from the property, but not to remove the
requirements related to the CWS Stormwater Connection Permit, which must be addressed
separately through an alternatives analysis, as described in Section 3.02.5 of the CWS
"Design and Construction Standards." The applicant must demonstrate that such an
amendment is justified by either of the following:
B. ESEE analysis. The applicant may prepare an environmental, social, economic and energy
(ESEE) consequences analysis prepared in compliance with OAR 660-23-040.
1. The analysis must consider the ESEE consequences of allowing the proposed conflicting
use, considering both the impacts on the specific resource site and the comparison with
other comparable sites within the Tigard Planning Area;
2. The ESEE analysis must demonstrate to the satisfaction of the city council that the
adverse economic consequences of not allowing the conflicting use are sufficient to
justify the loss, or partial loss, of the resource;
3. In particular, ESEE analysis must demonstrate why the use cannot be located on
buildable land, consistent with the provisions of this chapter, and that there are no other
sites within the Tigard Planning Area that can meet the specific needs of the proposed
use;
4. The ESEE analysis must be prepared by a team consisting of a wildlife biologist or
wetlands ecologist and a land use planner or land use attorney, all of whom are qualified
in their respective fields and experienced in the preparation of Goal 5 ESEE analysis;
5. If the application is approved, then the ESEE analysis must be incorporated by reference
into the Tigard Comprehensive Plan, and the "Tigard Wetland and Stream Corridor Map"
be amended to remove the site from the inventory.
C. Demonstration of change. In this case, the applicant must demonstrate that the sensitive area
site no longer meets the applicable significance threshold defined by the Goal 5
administrative rule, relative to other comparable resources within the Tigard Planning Area.
1. Significance thresholds are described and applied in the addendum to the City of Tigard
Local Wetlands Inventory adopted by reference as part of this chapter.
2. To approve this claim, the city council must find that the decline in identified resource
values did not result from a violation of this title. (Ord. 18-23 §2; Ord. 18-21 §2; Ord. 17-
22 §2)
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18.510.110 Significant Habitat Areas Map Verification Procedures
A. Applicants who concur that the significant habitat areas map is accurate must submit the
following information to serve as the basis for verifying the boundaries of inventoried habitat
areas:
1. Submission requirements.
a. A detailed property description;
b. A scale map of the property showing the locations of significant habitat areas, any
existing built area, wetlands or water bodies, Clean Water Services' vegetated
corridor, the special flood hazard areasareas of special flood hazard, the 1996 flood
inundation line, and contour lines (2-foot intervals for slope less than 15 percent and
10-foot intervals for slopes 15 percent or greater); and
c. A current aerial photograph of the property.
2. The approval authority's decision will be based on consideration of submitted
information, site visit information, and other factual information. Should the applicant
disagree with the determination on the location of significant habitat areas on the
property, the precise boundaries must be verified by the applicant in compliance with the
detailed delineation methodology outlined in Subsection 18.510.110.B.
B. Applicants who believe that the map is inaccurate must submit a detailed delineation
conducted by a qualified professional in compliance with the following methodology to
verify the precise boundaries of the inventoried habitat areas by means of a Type II
procedure.
1. Verifying boundaries of inventoried riparian habitat. Locating habitat and determining its
riparian habitat class is a 4-step process:
a. Locate the water feature that is the basis for identifying riparian habitat.
i. Locate the top of bank of all streams, rivers, and open water within 200 feet of the
property.
ii. Locate the special flood hazard areasareas of special flood hazard or 1996 flood
inundation line, whichever is greater,within 100 feet of the property.
iii. Locate all wetlands within 150 feet of the property. Identified wetlands on the
property must be further delineated consistent with methods currently accepted by
the Oregon Division of State Lands and the U.S. Army Corps of Engineers.
b. Identify the vegetative cover status of all areas on the property that are within 200
feet of the top of bank of streams, rivers, and open water, are wetlands or are within
150 feet of wetlands, and are flood areas and within 100 feet of flood areas.
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i. Vegetative cover status must be as identified on the metro vegetative cover map.
ii. The vegetative cover status of a property may be adjusted only if(a) the property
was developed prior to the time the regional program was approved; or (b) an
error was made at the time the vegetative cover status was determined. To assert
the latter type of error, applicants must submit an analysis of the vegetative cover
on their property using summer 2002 aerial photographs and the following
definition of vegetative cover types in Table 18.510.1.
Table 18.510.1
Definitions of Vegetative Cover Types
ype 1 Definition
Low structure vegetation Areas that are part of a contiguous area 1 acre or larger of grass,
or open soils meadow, croplands, or areas of open soils located within 300 feet of a
surface stream (low structure vegetation areas may include areas of
shrub vegetation less than 1 acre in size if they are contiguous with
areas of grass, meadow, croplands, orchards, Christmas tree farms,
holly farms, or areas of open soils located within 300 feet of a surface
stream and together form an area of 1 acre in size or larger).
Woody vegetation Areas that are part of a contiguous area 1 acre or larger of shrub or
open or scattered forest canopy(less than 60 percent crown closure)
located within 300 feet of a surface stream.
Forest canopy Areas that are part of a contiguous grove of trees 1 acre or larger in
area with approximately 60 percent or greater crown closure,
irrespective of whether the entire grove is within 200 feet of the
relevant water feature.
c. Determine whether the degree that the land slope upward from all streams, rivers, and
open water within 200 feet of the property is greater than or less than 25 percent
(using the vegetated corridor measurement methodology as provided in Clean Water
Services Design and Construction Standards; and
d. Identify the riparian habitat classes applicable to all areas on the property using Table
18.510.2 and Table 18.510.3.
Table 18.510.2
Method for Locating Boundaries of Class I and II Riparian Areas
Development/Vegetation Status[1]
Distance in Developed areas Low structure Woody vegetation Forest canopy
feet from (shrub and
not providing vegetation or open (closed to open
water feature vegetative cover soils scattered forest forest canopy)
canopy)
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Surface streams _
0-50 Class II Class I Class I Class I _
50-100 Class II [2] Class I Class I
100-150 Class II [2] Class II [2] Class II [2]
if slope>25 if slope>25
percent percent
150-200 Class II [2] Class II [2] Class II [2]
if slope>25 if slope>25 if slope>25
percent percent percent
Wetlands (Wetland feature itself is a Class I Riparian Area)
0-100 Class II [2] Class I Class I
100-150 Class II [2]
Flood Areas (Undeveloped portion of flood area is a Class I Riparian Area)
0-100 Class II [2] Class II [2]
[1] The vegetative cover type assigned to any particular area was based on 2 factors: the type of
vegetation observed in aerial photographs and the size of the overall contiguous area of
vegetative cover to which a particular piece of vegetation belonged. As an example of how
the categories were assigned, in order to qualify as a "forest canopy" the forested area had to
be part of a larger patch of forest land at least 1 acre in size.
[2] Areas that have been identified as habitats of concern, as designated on the Metro Habitats of
Concern Map, will be treated as Class I riparian habitat areas in all cases, subject to the
provision of additional information that establishes that they do not meet the criteria used to
identity habitats of concern as described in Metro's Technical Report for Fish and Wildlife.
Examples of habitats of concern include: Oregon white oak woodlands, bottomland
hardwood forests, wetlands, native grasslands, riverine islands or deltas, and important
wildlife migration corridors.
Table 18.510.3
Tualatin Basin "Limit"Decision [1]
Conflicting Use Category
Resource Future Urban
High Intensity Non-Urban
Category Urban Other Urban (2002 and 2004 (outside UGB)
additions)
Class I & II Riparian Moderately Strictly Limit Strictly Limit N/A
inside vegetated corridor Limit
Class I & II Riparian Moderately Moderately Moderately Moderately
outside vegetated corridor Limit Limit Limit Limit
All other Resource Areas Lightly Limit Lightly Limit Lightly Limit Lightly Limit
Inner Impact Area Lightly Limit Lightly Limit Lightly Limit Lightly Limit
Outer Impact Area Lightly Limit Lightly Limit Lightly Limit Lightly Limit
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[1] Vegetated corridor standards are applied consistently throughout the District; in HIU areas
they supersede the "limit" decision.
2. Verifying boundaries of inventoried upland habitat was identified based on the existence
of contiguous patches of forest canopy, with limited canopy openings. The "forest
canopy" designation is made based on analysis of aerial photographs as part of
determining the vegetative cover status of land within the region. Upland habitat is as
identified on the Significant Habitat Areas Map unless corrected as provided in this
subsection.
a. The only allowed corrections to the vegetative cover status of a property area as
follows:
i. To correct errors made when the vegetative status of an area was determined
based on analysis of the aerial photographs used to inventory the habitat. The
perimeter of an area delineated as "forest canopy" on the Metro Vegetative Cover
Map may be adjusted to more precisely indicate the dripline of the trees within the
canopied area provided that no areas providing greater than 60 percent canopy
crown closure are de-classified from the "forest canopy" designation. To assert
such errors, applicants must submit an analysis of the vegetative habitat cover on
their property using the aerial photographs that were used to inventory the habitat
and the definitions of the different vegetative cover types provided in Table
18.510.1; and
ii. To remove tree orchards and Christmas tree farms from inventoried habitat;
provided, however, that Christmas tree farms where the trees were planted prior to
1975 and have not been harvested for sale as Christmas trees may not be removed
from the habitat inventory.
b. If the vegetative cover status of any area identified as upland habitat is corrected in
compliance with Subparagraph 18.510.110.B.2.a to change the status of an area
originally identified as "forest canopy," then such area will not be considered upland
habitat unless it remains part of a forest canopy opening less than 1 acre in area
completely surrounded by an area of contiguous forest canopy. (Ord. 18-23 §2; Ord.
18-21 §2; Ord. 17-22 §2) ■
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