Report Fi 'is`►i I "y•e
`,� AUG x 2019 . )-7-2,0 l9 - OCO l °t
CleanWater\ Services ct��'of riGAFa 73O darinoviA
Our commitment is clear. "IliftlearapNS Ate Number
AMENDED Service Provider Letter 16-001563
This form and the attached conditions will serve as your Service Provider Letter in accordance
with Clean Water Services Design and Construction Standards (R&O 19-5).
Jurisdiction: City of Tigard Review Type: Tier 2 Analysis
SPL Original Date: June 8,2016
Site Address 12105 SW 72nd AVE SPL Amendment Date: August 27,2019
/Location: Tigard, OR 97223 SPL Expiration Date: August 26,2021
Applicant Information: Owner Information:
Name Name
Company BASE CAMP 1, LLC Company BASE CAMP 1, LLC
Address 2911 TENNYSON AVE, SUITE 400 Address 2911 TENNYSON AVE, SUITE 400
EUGENE, OR 97408 EUGENE,OR 97408
Phone/Fax Phone/Fax
E-mail: E-mail:
Tax lot ID Development Activity
2S101BA00300,400,402 Base Camp I Office Building
Pre-Development Site Conditions: Post Development Site Conditions:
Sensitive Area Present: I 1 On-Site I I Off-Site Sensitive Area Present: I X1 On-Site Ti Off-Site
Vegetated Corridor Width: 50 _ Vegetated Corridor Width: Variable
Vegetated Corridor Condition: Degraded
Enhancement of Remaining
Vegetated Corridor Required: Square Footage to be enhanced: 15,700
Encroachments into Pre-Development Vegetated Corridor:
Type and location of Encroachment: Square Footage:
Building and Parking(Permanent Encroachment: Mitigation Required) 3,900
Construction Access(Temporary Encroachment: Mitigation/Planting-in place) 1,800
Mitigation Requirements:
Type/Location Sq. Ft./Ratio/Cost
On-site 2S101BA00300 400/1:1
Off-site 1N206CB04000(McKay Fields) 5,226/1.5:1
Public Benefit Mitigation IN206CB04000(McKay Fields) 1,800
X Conditions Attached ❑X Development Figures Attached (2) ID Planting Plan Attached I IGeotech Report Required
This Service Provider Letter does NOT eliminate the need to evaluate and protect water quality
sensitive areas if they are subsequently discovered on your property.
Page lcf6
Number CWS File ( 16401563
TiER 2 ALTERNATIVES ANALYSIS CRITERIA
The proposed project will result in encroachment exceeding 30%of the depth of the 50-foot wide vegetated corridor,
requiring a Tier 2 Alternatives Analysis.The project will meet all of the Tier 2 criteria outlined in CWS'R&O Design and
Construction Standards. Details are described below.
3.07.4.c.1 The proposed encroachment area is mitigated in accordance with Section 3.08.
The project requires mitigation for a total of 0.09 acres of permanent vegetated corridor impact.To mitigate for the
impacts,the applicant is proposing both on and off site mitigation. On site mitigation will include 0.01 acres of
replacement vegetated corridor mitigation.The existing condition of the replacement mitigation area is in degraded
condition and will be enhanced to good condition.
The project will require 0.12 acres(5,226 square feet)of off-site replacement vegetated corridor mitigation(based on
1.5:1 off-site replacement ratio).The off-site mitigation area is located at the McKay Fields site,which is situated off of
West Union Road in North Plains(see attached Figure 10).The off-site replacement mitigation area is located
continuous and adjacent to an existing 50-foot wide vegetated corridor associated with McKay Creek, previously
permitted under CWS File No.2013-001827.The mitigation meets the requirements set forth in Section 3.08 of CWS'
R&O Design and Construction Standards.The off-site mitigation area includes approximately 1,800 square feet of
additional mitigation area to serve as public benefit mitigation.
3.07.4.c.2 The replacement mitigation protects the functions and values of the Vegetated Corridor and Sensitive Area.
The on-site and off-site replacement mitigation areas are continuous with the existing 50-foot vegetated corridor.The
existing condition of the on-site replacement mitigation area was determined to be in degraded condition.The
installation of native trees and shrubs will increase structural diversity,resulting in increased functional capacities.The
native plantings will also provide thermal regulation to the water temperature in the nearby tributary to Red Rock Creek
(onsite)and McKay Creek(offsite),as well as create riparian habitat and nutrient recycling for the organisms in the
riparian areas.Therefore, the replacement mitigation proposed would protect as well as improve the functions and
values of the vegetated corridor and the associated sensitive areas.
3.07.4.c.3 Enhancement of the replacement area,if not already in Good Corridor Condition, and either the remaining
Vegetated Corridor on the site or the first 50 feet of width closest to the resource, whichever is less, to a Good Corridor
Condition.
The site will have approximately 0.33 acres of remaining on-site degraded condition vegetated corridor.The remaining
0.33 acres, in addition to the 0.04 acres of on-site replacement vegetated corridor mitigation area,will be enhanced to
good condition,per CWS standards,per the attached Planting Specification Tables(Appendix E).The Site Plan also
includes planting the 0.05 acres of temporarily disturbed vegetated corridor to good condition.
3.07.4.c.5 Location of development and site planning minimizes incursion into the Vegetated
Corridor.
The proposed layout provides the least amount of vegetated corridor impact possible while achieving the project's
goals.The City is requiring a sidewalk through the site to provide pedestrian connectivity from SW Dartmouth Street to
SW 72nd Avenue. Due to topographic constraints,the location of the sidewalk requires the building to be moved to the
north,closer to the vegetated corridor. Site topography also pushes the building location towards the northern,flatter
portion of the site,as the City is requiring the building entrance to be at street grade.The Project Architect incorporated
an undesirable jag into the building to reduce vegetated corridor encroachment closest to the on-site wetland boundary.
The remaining encroachment from the building is necessary to accommodate the minimum building size. Retaining
walls have been incorporated to minimize vegetated corridor encroachment.The applicant reduced the size of the
proposed parking area and shifted the building to the south in order to maintain a minimum 25-foot wide vegetated
corridor.Therefore,the proposed Site Plan provides the least practical incursion into vegetated corridor.
3.07.4.c.6 No practicable alternative to the location of the development exists that will not disturb the Sensitive Area or
Vegetated Corridor.
There is no practical alternative layout that would avoid vegetated corridor encroachment.The medical building requires
a one-story facility.The applicant has specific requirements regarding level parking for patients and staff,with the
minimal acceptable parking shown on the Site Plan and optimal parking levels exceeding that amount. In addition to the
applicant's expressed parking requirements,it is the expert opinion of the Project Architect,who has designed multiple
buildings for the specific type of medical use proposed,that the number of parking spaces shown are the minimum
required for this type of user. Substantial(both in length and height)retaining walls at the top and bottom of the site
have been incorporated to minimize vegetated corridor encroachment.
Page 2 or 6
CWS File 16-001563
Number
In order to comply with Clean Water Services water quality protection
requirements the project must comply with the following conditions:
1. No structures, development, construction activities,gardens, lawns, application of chemicals,
uncontained areas of hazardous materials as defined by Oregon Department of Environmental
Quality, pet wastes, dumping of materials of any kind, or other activities shall be permitted
within the sensitive area or Vegetated Corridor which may negatively impact water quality,
except those allowed in R&O 19-5,Chapter 3.
2. Prior to any site clearing, grading or construction the Vegetated Corridor and water quality
sensitive areas shall be surveyed, staked,and temporarily fenced per approved plan. During
construction the Vegetated Corridor shall remain fenced and undisturbed except as allowed by
R&O 19-5,Section 3.06.1 and per approved plans.
3. If there is any activity within the sensitive area,the applicant shall gain authorization for
the project from the Oregon Department of State Lands(DSL)and US Army Corps of
Engineers(USACE). The applicant shall provide Clean Water Services or its designee
(appropriate city)with copies of all DSL and USACE project authorization permits.No
wetland impacts proposed for this project.
4. An approved Oregon Department of Forestry Notification is required for one or more trees
harvested for sale,trade, or barter, on any non-federal lands within the State of Oregon.
5. Appropriate Best Management Practices(BMP's)for Erosion Control, in accordance with Clean
Water Services' Erosion Prevention and Sediment Control Planning and Design Manual, shall
be used prior to, during, and following earth disturbing activities.
6. Prior to construction, a Stormwater Connection Permit from Clean Water Services or its
designee is required pursuant to Ordinance 27, Section 4.B.
7. Activities located within the 100-year floodplain shall comply with R&O 19-5, Section 5.10.
8. Removal of native,woody vegetation shall be limited to the greatest extent practicable.
9. The water quality swale and detention pond shall be planted with Clean Water Services
approved native species, and designed to blend into the natural surroundings.
10. Should final development plans differ significantly from those submitted for review by
Clean Water Services,the applicant shall provide updated drawings,and if necessary,
obtain a revised Service Provider Letter.
11. The Vegetated Corridor width for sensitive areas within the project site shall be a minimum of
50 feet wide,as measured horizontally from the delineated boundary of the sensitive area.
12. For Vegetated Corridors up to 50 feet wide,the applicant shall enhance the entire
Vegetated Corridor to meet or exceed good corridor condition as defined in R&O 19-5,
Section 3.14.2,Table 3-3.
13. Removal of invasive non-native species by hand is required in all Vegetated Corridors rated
"good." Replanting is required in any cleared areas larger than 25 square feet using low
impact methods. The applicant shall calculate all cleared areas larger than 25 square feet prior
to the preparation of the required Vegetated Corridor enhancement/restoration plan.
14, Prior to any site clearing, grading or construction,the applicant shall provide Clean Water
Services with a Vegetated Corridor enhancement/restoration plan. Enhancement/restoration of
the Vegetated Corridor shall be provided in accordance with R&O 19-5, Appendix A,and shall
include planting specifications for all Vegetated Corridor, including any cleared areas larger
than 25 square feet in Vegetated Corridor rated"good."
15. Prior to installation of plant materials, all invasive vegetation within the Vegetated Corridor shall
be removed per methods described in Clean Water Services'Integrated Vegetation and Animal
Management Guidance,2003. During removal of invasive vegetation care shall be taken to
minimize impacts to existing native tree and shrub species.
Page 3 of 8
CWS Fila 46401563
Number
16. Clean Water Services shall be notified 72 hours prior to the start and completion of
enhancement/restoration activities. Enhancement/restoration activities shall comply with the
guidelines provided in Planting Requirements (R&0 19-5,Appendix A).
17. Maintenance and monitoring requirements shall comply with R&O 19-5,Section 2.12.2, if
at any time during the warranty period the landscaping falls below the 80%survival
level,the owner shall reinstall all deficient planting at the next appropriate planting
opportunity and the two year maintenance period shall begin again from the date of
replanting.
18. Performance assurances for the Vegetated Corridor shall comply with R&O 19-5,Section
2.07.2,Table 2-1 and Section 2.11,Table 2-2.
19. Clean Water Services will require an easement over the on-site Vegetated Corridor and
the mitigated Vegetated Corridor on tax lot 1 N206CB04000 conveying storm and surface
water management to Clean Water Services or the City that would prevent the owner of
the Vegetated Corridor from activities and uses inconsistent with the purpose of the
corridor and any easements therein.
20. Final construction plans shall include landscape plans. In the details section of the plans,
a description of the methods for removal and control of exotic species, location,distribution,
condition and size of plantings,existing plants and trees to be preserved, and installation
methods for plant materials is required. Plantings shall be tagged for dormant season
identification and shall remain on plant material after planting for monitoring purposes.
21. A Maintenance Plan shall be included on final plans including methods, responsible party
contact information, and dates(minimum two times per year, by June 1 and September 30).
22. Final construction plans shall clearly depict the location and dimensions of the sensitive
area and the Vegetated Corridor(indicating good, marginal,or degraded condition).
Sensitive area boundaries shall be marked in the field.
23. Protection of the Vegetated Corridors and associated sensitive areas shall be provided by the
installation of permanent fencing and signage between the development and the outer limits of
the Vegetated Corridors. Fencing and signage details to be included on final construction
plans.
This Service Provider Letter is not valid unless CWS-approved site plan is attached.
Please call(503)681-3667 with any questions.
Stela/ 8421,1 p' ..
Stacy Benjamin -"f _
Environmental Plan Review
Attachments (2)
Page 4 of 6