Report (150) ti�3� S�v T4 Qd St.
Dirksen Nature Park la 9 2 01 e
City of Tigard, Oregon CItY of 11GARD
City Project No. 92016 WILDING DMSION
Preliminary Storm Water Management Report
Prepared for:
City of Tigard, Oregon
Prepared by:
WH Pacific
9755 SW Barnes Road, Suite 300
Portland, Oregon 97225
Drainage Engineer (Offsite) Street Drainage Engineer (Onsite) Park
Jason T. Truong, P.E. Monte S. Higbee, P.E.
Original: July 8, 2013
Preliminary Storm Water Management Report
S.W. Tigard Street & Dirksen Nature Park Improvements
TABLE OF CONTENTS
1. INTRODUCTION AND PURPOSE 1
2. PROJECT LOCATION AND DESCRIPTION 1
3. EXISTING CONDITIONS 1
4. DRAINAGE ANALYSIS AND DESIGN 2
5. WATER QUALITY DESIGN 2
6. CONVEYANCE SYSTEM DESIGN 3
7. CONCLUSIONS 5
APPENDIX 1
• Figure 1 -Water Quality Map(Offsite)
• Figure 2—Water Quality Map(Onsite)
• LIDA Sizing Forms
• Gutter Spread Calculations
Preliminary Storm Water Management Report
S.W. Tigard Street & Dirksen Nature Park Improvements
1. INTRODUCTION AND PURPOSE
The intent of this report is to document the design criteria, analysis techniques and minimum
standards used in the design of the storm water management facilities for roadway
improvements to SW Tigard Street and site improvements for the Dirksen Nature Park in the
City of Tigard, Oregon. The storm water management report will therefore document the
following:
• Existing conditions
• Drainage analysis and design
• Water quality and quantity design
• Conveyance system design
• Conclusions
2. PROJECT LOCATION AND DESCRIPTION
Tigard Street(Offsite)
The project will begin approximately 180 feet west of Twin Park PI and end on the west side
of the Fanno Creek bridge. The project improvements consist of roadway widening on the
south side of Tigard Street to provide on-street parking. The existing pavement of Tigard
Street will be left undisturbed and saw cut will be done at the edge of existing pavement in
preparation for the widened pavement section. Other improvements include limited storm
drainage system, water quality system, illumination, retaining wall, utility undergrounding,
and landscaping. The total length of project improvements on SW Tigard Street is
approximately 1,800 feet(0.34 miles). See project vicinity map.
Dirksen Nature Park (Onsite)
The existing park is located adjacent to the south side of Tigard Street and spans the
proximity of the Tigard Street Improvements limit. The total park area is 48.88 acres. The
total disturbed area is 5.2 acres.
The improvements to the park include adding a new parking lot off Tigard Street, smoothing
out the grades of the existing ball field and improve its drainage, adding new hard and soft
pedestrian paths for connectivity throughout the park. There is also a new
concession/restroom building proposed. The park improvements will trigger half street
improvements for Tigard Street, along the park frontage is described above.
3. EXISTING CONDITIONS
Land Use and Existing Features (Offsite)
Tigard Street is classified as a Neighborhood Route street according to the City of Tigard
Transportation System Plan. The project corridor is nearly fully developed with residential
on the north side of Tigard Street. The south side of the project corridor borders the existing
Dirksen Nature Park on city property. This section of the roadway has intermittent curb and
sidewalk on the north side while the south side of the roadway is limited gravel shoulder.
Drainage Basins and Flow Paths (Offsite)
The topography of the project corridor slopes gently in a north to south direction. Tigard
Street longitudinal slope is west to east with a natural crest point between Twin Park PI and
Page 1
Preliminary Storm Water Management Report
S.W. Tigard Street & Dirksen Nature Park improvements
Cornell PI. The street crown serves as the drainage basin divide line where drainage from
the existing subdivisions remains on the north side of the roadway. The runoff on this side
of the road is conveyed by the existing drainage system and daylights to Fanno Creek at the
east end of the project. Runoff from the south side of the roadway currently sheet flows off
the pavement and shoulder where it infiltrates into the park area and eventually may reach
Fanno Creek.
Dirksen Nature Park(Onsite)
The park mainly consists of pervious areas made up of grass, natural forest and wetland
areas. There is an existing paved path called the Fanno Creek Trail which runs through the
park from Tiedeman Ave to Tigard Street.
4. DRAINAGE ANALYSIS AND DESIGN
The design is based upon the City of Tigard Design Standards which follows the
CleanWater Services (CWS) Design and Construction Standards for Sanitary Sewer and
Surface Water Management dated June 2007.
Water quantity requirement is exempt for Tigard Street and Dirksen Nature Park
improvements due to the project proximity with Fanno Creek. Water quality requirements
will be designed per Section 4.05 of the CWS design manual and the method of treatment is
detailed in Section 5 of this report.
5. WATER QUALITY DESIGN
Water quality treatment design is per the requirements of Section 4.05 of the CleanWater
Services Design and Construction Standards, which requires all new developments that
create new impervious surfaces to construct or fund permanent water quality facilities to
reduce contaminants entering the storm or surface water system. The storm water quality
system is to remove 65% of the total phosphorous from the runoff. The allowable methods
of treatment per Section 4.05.3 c. are:
1. Vegetated swales (Per Section 4.06.2)
2. Extended dry detention (Per Section 4.06.3)
3. Constructed water quality wetland(Per Section 4.06.4)
4. Proprietary treatment systems meeting the requirements of Section 4.05.8
5. Low impact development approaches per(Per Section 4.07)
Tigard Street(Offsite)
The water quality treatment method for this project is through the use of Low Impact
Development Approach facilities (LIDA). Four infiltration planters and a LIDA swale will be
used along the south curb side of Tigard Street to provide treatment for the new impervious
created from the roadway widening. In addition, these water quality facilities have also been
sized to treat existing impervious from the roadway draining to them. This is done to
mitigate for the new impervious areas created from the Dirksen Nature Park that will not
receive treatment due to on-site constraints. The total over treatment of this project to
mitigate for Dirksen Nature Park untreated impervious areas is approximately 20,154 sf.
Table 1 below summarizes the water quality mitigation required and their proposed
locations. See Appendix 1, Figure 1 for facility locations. See LIDA sizing forms for detail
facility calculations in Appendix 1.
Page 2
Preliminary Storm Water Management Report
S.W. Tigard Street & Dirksen Nature Park Improvements
Table 1 —Water Quality Treatment (Offsite)
Facility Impervious
Treatment Area
Facility Type & Size Mitigation Impervious Area Project Excess
Location (SF) Required (SF) Treated (SF) (SF)
Infiltration
Planter
Sta. 29+00 (467 SF) 1,468 5,111 3,643
LIDA Swale
Sta. 36+00 (640 SF) 3,135 8,427 5,292
Infiltration
Planter
Sta. 39+00 (450 SF) 2,270 6,033 3,763
Infiltration
Planter
Sta. 42+50 (450 SF) 2,403 6,457 4,054
Infiltration
Planter
Sta. 45+50 (450 SF) 2,622 6,024 3,402
Total 20,154
Dirksen Nature Park(Onsite)
Stormwater treatment for this project will be provided for the new impervious areas in
several ways. The new parking lot will receive treatment through the use of a Low Impact
Development Approach (LIDA)facility. The CWS LIDA facility that best fit the parking lot
treatment is a Vegetated Filter Strip. Due to existing grades, wetlands and wetland buffers,
the remaining impervious areas are currently not designed with stormwater treatment
facilities. In-lieu of direct treatment for the impervious park areas, the plan is to over treat
the Tigard Street improvements to make up for most of the untreated park areas. Although
untreated by conventional BMP practice, the multi-use path off of the Tigard Street will
receive some treatment as it sheet flows across the grassy park area with gradual slope of
6%to 8%toward the existing buffers/wetlands. The total impervious area created onsite is
43,845 sf. There is approximately 1,535 sf of impervious removal at the existing west
parking lot due to reconfigured striping. Onsite LIDA facility treats 15,355 sf. The offsite
LIDA facilities mitigate 20,154 sf for the untreated impervious of Dirksen Nature Park as
noted above. Therefore, the total treatment and mitigation provided with this project is
37,044 sf. This will leave 6,801 sf of new impervious area within the park that will not have
treatment accounted for. Table 2 below summarizes the water quality mitigation required
and their proposed locations. See Appendix 1, Figure 2 for facility locations. See LIDA
sizing forms for detail facility calculations in Appendix 1.
Page 3
Preliminary Storm Water Management Report
S.W. Tigard Street & Dirksen Nature Park Improvements
Table 2—Water Quality Treatment(Onsite)
Facility Impervious
Impervious Treatment Area Impervious
Area Type & Size Mitigation Impervious Area Area Untreated
Location (SF) Required (SF) Treated (SF) (SF)
Vegetated 3,622
West Parking Filter Strip plus removal of
Lot (394 SF) 3,622 1,535 0
Vegetated
East Parking Filter Strip
Lot (1,150 SF) 11,733 11,733 0
24,390
(See offsite
Conc. Paths None 24,390 0 mitigation)
Concession/
Restroom &
Amenities None 4,100 0 4,100
Total 28,490
6. CONVEYANCE SYSTEM DESIGN
Tigard Street(Offsite)
There is limited storm drainage system on this project as the LIDA method was determined
the best BMP to treat stormwater runoff. Runoff from the pavement will enter the LIDA
facilities along the project corridor to receive treatment. The facilities are designed to have
ponding depths of 4 inches to allow the runoff to percolate into the ground. In the event that
the volume of runoff exceeds the infiltration capacity and volume available within the
facilities, overflow structures have been provided in the facilities to convey the runoff and
daylight to the existing nearby wetland areas. Due to the small impervious area entering
each facility, we do not anticipate large volume of overflow leaving the facility. Nonetheless,
we have designed a minimum 10" diameter pipe to convey the overflow runoff from the
facility. The drainage pipes were also designed to have a minimum free flow velocity of
3 ft/s. Spacing of the LIDA facilities have been designed such that flows along the curb do
not exceed 4 inches or extend into the travel lane. The LIDA facility at Sta. 36+00 has been
selected and analyzed to determine if these conditions have been met. The analysis shows
that flow is 1.8 inches at the curb and the spread (7.5 feet) is contained within the
parking/shoulder area. See gutter spread calculations in Appendix 1.
Dirksen Nature Park(Onsite)
There is no proposed storm drainage piping for this project as the LIDA method was chosen
to treat onsite stormwater runoff. The majority of impervious is at the east and west parking
lots where runoff will sheet flow across the LIDA facilities and eventually enter the wetland
areas. Runoff from the multi-used path will sheet flow across the grassy park area and
either infiltrate into the soil or eventually make its way to the buffers/wetland areas.
Page 4
Preliminary Storm Water Management Report
S.W. Tigard Street & Dirksen Nature Park Improvements
7. CONCLUSIONS
Tigard Street(Offsite)
The drainage and water quality analyses for this project were designed to the jurisdictional
requirements of the City of Tigard Design Standards which follows CleanWater Services
Design and Construction Standards for Sanitary Sewer and Surface Water Management.
The project uses LIDA facilities to mitigate for the new impervious created from the roadway
widening. Four infiltration planters and a LIDA swale are proposed along Tigard Street to
provide treatment to the new impervious area. The facilities have also been sized to treat
the runoff from the existing pavement draining to the project. This is done to mitigate for the
new impervious areas created from the Dirksen Nature Park that will not receive treatment
due to on-site constraints. The total over treatment of this project to mitigate for Dirksen
Nature Park untreated impervious area is approximately 20,154 sf.
The LIDA facilities for this project have been designed to provide a maximum ponding depth
of 4 inches to allow the runoff to percolate into the ground. The spacing of these facilities
has been designed such that flows along the curb do not exceed 4 inches or extend into the
travel lane. The overflow piping system has been included to convey the runoff exceeding
the percolation and volume capacity within these facilities. The drainage system was
designed to have a minimum free flow velocity of 3 ft/s. Therefore, this project meets the
requirements of the CleanWater Services Design and Construction Standards for Sanitary
Sewer and Surface Water Management.
Dirksen Nature Park(Onsite)
The drainage and water quality analyses for this project were designed to the jurisdictional
requirements of the City of Tigard Design Standards which follows CleanWater Services
Design and Construction Standards for Sanitary Sewer and Surface Water Management.
The project uses LIDA facilities to mitigate for the new impervious created onsite. Two
vegetated filter strips are proposed to provide treatment to the east and west parking lots.
The project also proposes to remove a portion of the existing west parking lot and
reconfigure the striping. Through the use of LIDA facilities, removal of a portion of the west
parking lot, and the over treatment of Tigard Street improvements, the project will mitigate
for a total of 37,044 sf of impervious from a total of 43,845 sf created. This will leave 6,801
sf of new impervious area that will not have treatment accounted for. However, due to the
layout of the multi-use path and the gradual slope of the park, runoff from the path will
receive some treatment as it sheet flows across the grassy park area with slopes ranging
from 6%to 8% toward the existing buffers/wetland. Therefore, this project utilizes the BMP
technique to provide treatment for the new impervious area to the maximum extent
practicable.
Page 5
APPENDIX 1
• Figure 1 -Water Quality Map(Offsite)
• Figure 2 -Water Quality Map(Onsite)
• LIDA Sizing Forms
• Gutter Spread Calculations
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Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park - Tigard Street
Project Location: Sta. 29+00 (offsite)
Contact Name/Title/Company: Jason T. uong/w}Paci f is
Phone/e-mail:
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): 0. 1.2 ac 5, 111 SF
Total Existing Impervious Area (sq.ft.): 3, 643
Proposed New Impervious Area (sq.ft.): 1, 468
Impervious Area Requiring Treatment (sq.ft.) 1, 468
•
(Refer to Design&Construction Standards Chapter 4 for
instructions to calculate this area,which will be less than or
equal to the new plus existing site impervious area.)
STEP 2: Deduct Impervious Area LIDA Credits
Porous Pavement (sq. ft.): i o
Green Roof(sq. ft.):
Other Credits as approved.(sq. ft.): _._
Total Credits (sq. ft.):.` L.
Remaining Impervious area (sq. ft.)
(Total from Step 1 —Total Credits):
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
area treated Factor (sq.ft.) (IA x SF)
(sq.ft.)
Infiltration Planters/Rain 0.06 312 (Required)
Garden ' 5, 111 467 (Provided)
Flow-through Planter 0.06
LIDA Swale 0.06
Vegetated Filter Strip 0.06
Total Impervious 5 111 ('"Must equal total from Step 2 or additional LIDA
Area treated (sq.ft.) facilities or Water Quality Facilities must be
added.)
1 ;(m ,?`;'s'De ' ,?rr 6tit,'i'7.�-',;ro r�.S '. ,c:�"!otD Cle2nWatcr�Ser\ices
Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park - Ticiard Street
Project Location: .Sta. 36+00 (offsite) _.._..__ ._...._m... ,,. ._..._...._.___.__.
Contact Name/Title/Company: Jason Truong/wxPacific
Phone/e-mail _._._.w.,...,.__:._..__w.....w...u_._..._..._..,....._._....__._.__...__._.__._...__._..._..____......_____._.._.
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): o .19 ac 8, 427 SF.
Total Existing Im ,ervious Areas ft 5,292
Proposed New Impervious Area (sq.ft.): 3, 135
p p _:
Impervious Area Requiring Treatment (sq.ft.) 3. 135
(Refer.to Design&Construction Standards Chapter 4.for
instructions to calculate this area,which will be less than or
equal to the new plus existing site impervious area.)
STEP 2: Deduct Impervious Area LIDA Credits .
Porous Pavement (sq. ft.):
m V o�nrcY
Green Roof(sq. ft )
Other Credits as approved (sq. ft):
Total Credits (sq. ft.):
Remaining Impervious area (sq. ft.) 3� 135 f
(Total from Step 1 Total Credits):
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
area treated Factor (sq.ft.) (IA x SF)
(sq.ft.)
Infiltration Planters/Rain 0.06
Garden
Flow-through Planter 0.06
LIDA Swale • 8, 427 0.06 640 (Provided)
Vegetated Filter Strip 0.06
Total Impervious8, 427 (*Must equal total from Step 2 or additional LIDA
Area treated (sq.ft.) facilities or Water Quality Facilities must be
added.)
16 t t':Ir'!: ?i ar,: i~ t!t_'t.':lie!? I;j"r%?Q<i�'c.;}?' .hr ?r,ni%
- Cleanl?�ater ScrGiccs
Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park - Tigard Street
Project Location:
Contact Name/Title/Company: Jason Truong/wHPaca.fic
Phone/e-mail: _....
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): 0 . 14 ac 6, 033 SF `
Total Existing Impervious Area (sq.ft.): • 3, 763
Proposed New Impervious'Area (sq.ft.): 2, 270
Impervious Area Requiring Treatment (sq.ft.) 2, 270
• (Refer to Design&Construction Standards Chapter 4 for
instructions to calculate this area,which will be less than or •
equal to the new plus existing site impervious area.)
STEP 2: Deduct impervious Area LIDA Credits
• Porous Pavement (sq. ft-): • °.,_
Green Roof(sq ft.):
Other Credits as approved (sq. ft.):
Total Credits (sq. ft.):
Remaining Impervious area (sq. ft.) ,;,..-_ -__..rt:.
(Total from Step 1 Total Credits): 2, 270
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
area treated Factor (sq.ft.) (IA x SF)
• (sq.ft.)
Infiltration Planters/Rain 0 06 362 (Required)
Garden 6, 033 450 (Provided)
Flow-through Planter 0.06
LIDA Swale 0.06
Vegetated Filter Strip 0.06
Total Impervious 6 033 ("Must equal total from Step 2 or additional LIDA
Area treated (sq.ft.) facilities or Water Quality Facilities must be
added.)
16 7 t r t,rc1 S. r . .
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Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park - Tigard Street
Project Location: Sta. 42+50 (Offsite) _.._. ._.._...._....__._.
Contact Name/Title/Company: ;Jason Truon_g/WEPac.fic__._.m.__ ._..._._.__. n.�.n_... ...
Phone/e-mail:
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): 0.15 ac 6,457 SF
Total Existing Impervious Area (sq.ft.): 4, 054
Proposed New Impervious Areas ft2, 403
Impervious Area Requiring Treatment (sq.ft.) 2, 403
(Refer to Design&Construction Standards Chapter 4 for
instructions to calculate this area,whichwill be less than or
equal to the new plus existing site impervious area) .:,
STEP 2: Deduct Impervious Area LIDA Credits
Porous Pavement(sq. ft.): } . .._. ._..... ....
Green Roof(sq. ft.):
Other Credits as approved (sq. ft.):
Total Credits (sq. ft.) __..__._..
Remaining Impervious area (sq. ft.)
(Total from Step 1 Total Credits):
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
area treated Factor (sq.ft.) (IA x SF)
(sq.ft.)
Infiltration Planters/Rain 0.06 387 (Required)
Garden 6, 457 450 (Provided)
Flow-through Planter 0.06
LIDA Swale 0.06
Vegetated Filter Strip 0.06
Total Impervious 6, 457 (*Must equal total from Step 2 or additional LIDA
Area treated (sq.ft.) facilities or Water Quality Facilities must be
added.)
Wi? ':i�.,=G<`ns,,elooment Approache. +tlf?uloC. CleanWateS Scn•iccs
Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park Tigard Street
Project Location: S.ta_...._.45+50 (Offsite)
Contact Name/Title/Company: Jason Truong/WHPacific
Phone/e-mail: __..___......._.._.._.__..____..._..,... _.....v,
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): 0. 14 ac 6, 024 SF
Total Existing Impervious Area (sq.ft.): 3, 402
Proposed New Impervious Area (sq.ft.): 2, 622
Impervious Area Requiring Treatment (sq.ft.) 2, 622
(Refer to Design&Construction Standards Chapter 4 for
instructions to calculate this area,which will be less than or
equal to the newplus existing site impervious area.)
STEP 2: Deduct Impervious Area LIDA Credits
Porous Pavement (sq. ft.): _...o_.....__
Green Roof(sq. ft.):
Other Credits as approved (sq. ft.): .w�_
'Total. Credits (sq. ft.):
Remaining Impervious area (sq. ft.)
� 2, 622 ,
(Total from Step 1 Total Credits): _ . ,_. .:
•
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
area treated Factor (sq.ft.) (IA x SF)
(sq.ft.)
Infiltration Planters/Rain 0.06 361 (Required)
Garden 6, 024 450 (Provided)
Flow-through Planter 0.06
LIDA Swale 0.06
Vegetated Filter Strip 0.06
Total Impervious 6, 024 (`Must equal total from Step 2 or additional LIDA
facilities or Water Quality Facilities must be
Area treated (sq.ft.) added.)
16 i!?M?P6 Deve?i: :merii!AptproiTc: -.5 Hal iL=boo'h` aeanWatc;$Services
Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park
Project Location: West Parking Lot
Contact Name/Title/Company: ,Monte Higbee/WHPacific
Phone/e-mail:
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): 0. os ac 3, 622 SF
' Total Existing Impervious Area (sq.ft.): 0
Proposed New Impervious Area (sqft.): • 3, 622
Impervious Area.Requiring Treatment (sq ft.) 3, 622
(Refer to Design&Construction Standards Chapter 4 for
instructions to calculate this area,which will be less than or.
equal to the new plus existing site impervious area.)
STEP 2: Deduct Impervious Area LIDA Credits
Porous Pavement (sq. ft.): 0
__
Green Roof(sq. ft.):. .___... _.-._.
Other Credits es approved (sq. ft.):
Total Credits (sq. ft.): . _
Remaining Impervious area (sq. ft.) .......
f
3,, §„..a,2
(Total from Step I =Total Credits): .t,.n ,
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
area treated Factor (sq.ft_) (IA x SF)
(sq.ft.)
Infiltration Planters/Rain 0.06
Garden
Flow-through Planter 0.06
LIDA Swale 0.06 }
ired
Vegetated Filter Strip 3, 622 0.06 394 (217 (RequiredPiuv )
ed)
Total Impervious (*Must equal total from Step 2 or additional LIDA
3, 622 facilities or Water Quality Facilities must be
Area treated (sq.ft.) added.)
16 Low i.; d, i(E,l%`p;.Y_.nx cr'-'?fl rl' ^! ib 1-"1'1.ii r ' Clea Wate_Services
Clean Water Services LIDA Sizing Form
Project Title: Dirksen Nature Park
Project Location: East Parking, L .
Contact Name/Title/Company: Monte Higbee/WHPacific
Phone/e-mail: _._..._..__._.._.. _.._..__............._.__.._ „-_.. ..._,_._._w... ,_.._._.___.___._.._._..__..._._,.._..,__
STEP 1: Determine Impervious Area Requiring Treatment
Total Site Area (acres): 0.27 ac 11, 733 SF,
Total Existing impervious Area (sq.ft ) 0
Proposed New Impervious Area (sq.ft.):) 111733 •
Impervious Area Requiring Treatment (sq.ft.) 11, 733
• (Refer to Design&Construction Standards Chapter 4 for
instructions to calculate this area,which will be less than or
equal to the new plus existing site impervious area.)
STEP 2:..:Deduct Impervious Area LIDA Credits
Porous Pavement (sq. ft.): _�.._ `
Green Roof(sq. ft ) ._.___..._ x
Other Credits as approved (sq. ft.): .. ._Y_... ._
Total Credits (sq. ft.);
Remaining Impervious area (sq. ft.)
'(Tota! from.Step 1 Total Credits): s 11, 733
STEP 3: Size LIDA Facilities for Remaining Impervious Area
IA: Impervious SF, Sizing LIDA facility size
• area treated Factor (sq.ft.) (IA x SF)
(sq.ft.)
Infiltration Planters/Rain 0.06
Garden
Flow-through Planter 0.06
LIDA Swale 0.06
Vegetated Filter Strip 11, 733 0.06 703 (Required)1, 150 (Pr ovide-d)
Total Impervious 11, 733 (`Must equal total from Step 2 or additional LIDA
Area treated (sq.ft.) facilities or Water Quality Facilities must be
added.)
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Hydrograph Report
Hydraflow Ffydrographs Extension forAutoCAD®Civil 3D®2009 by Autodesk, Inc.v6.066 Monday,Jun 24,2013
Hyd. No. 1
Area @ Lida Swale - Sta. 36+00
Hydrograph type = SBUH Runoff Peak discharge = 0.174 cfs
Storm frequency = 25 yrs Time to peak = 7.90 hrs
Time interval = 2 min Hyd. volume = 2,528 cuft
Drainage area = 0.190 ac Curve number = 98
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = USER Time of conc. (Tc) = 5.00 min
Total precip. = 3.90 in Distribution = Type IA
Storm duration = 24 hrs Shape factor = NIA
Area @ Lida Swale -Sta. 36+00
Q (cfs) Hyd. No. 1 —25 Year Q(cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 ! 0.10
0.05 0.05
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Hyd No. 1 Time(hrs)
Channel Report
Ftydraflow Express Extension for AutoCAD®Civil 3Dct 2009 by Autodesk,Inc. Monday,Jun 24 2013
Gutter Spread @ Sta. 36+00
Gutter Highlighted
Cross SI, Sx (ft/ft) = 0.02 Depth (ft) = 0.15
Cross SI, Sw (ft/ft) = 0.02 Q (cfs) = 0.170
Gutter Width (ft) = 1.50 Area (sqft) = 0.56
Invert Elev (ft) = 189.51 Velocity (ft/s) = 0.30
Slope (%) = 0.03 Wetted Perim (ft) = 7.65
N-Value = 0.013 Crit Depth, Yc (ft) = 0.08
Spread Width (ft) = 7.50
Calculations EGL(ft) = 0.15
Compute by: Known Q
Known Q (cfs) = 0.17
Elev (ft) Section Depth (ft)
191.00 1.49
sEE `'Yet SAL i o+ t x .Y 5 'c N
190.50
P srt f 4401 .it''`.r LAN 1 0.99
, 42'
190.00
_:_..___._ 0.49
189.50 —0.01
189.00 —0.51
0 5 10 15 20 25 30 35
Reach (ft)