HomeMy WebLinkAboutWARREN FEDERAL CREDIT UNION - FDP - FDP160011 - REPORTS - DRAINAGE REPORTPage 2
PROPOSED DEVELOPMENT
The drainage for this site has been designed to be less than the maximum allowable runoff from each basin
as stated in the Overall Rigden Farm drainage plan. Table 1 compares the actual runoff versus the allowable
runoff from the Northwest Roads Ultimate Drainage Plan. Runoff from the four basins (A, B1, B2 and C)
are to follow the intent of that plan and are to be collected in storm inlets and piped to the North Tributary
Storm Sewer in Drake Road. Please refer to the attachments for the hydrologic calculations of the 10 and
100 year storm events that were performed utilizing the Rational Method.
Table 1. Comparison of Flows.
Rigden Farms Northwest Roads Warren Federal Credit Union Subdivision
Basin ID
Contributing
Area
(Acres)
100-yr
Design
Runoff
(cfs)
Basin ID
Contributing
Area
(Acres)
100-yr
Design
Runoff
(cfs)
103b 0.93 9.3 A 0.51 5.1
103a 1.15 11.4 B1 0.44 3.8
B2 0.65 6.0
C 0.40 3.9
Totals 2.08 20.7 2.01 18.8
103b 0.93 9.3 A 0.51 5.1
103a 1.15 11.4 B1, B2, C 1.49 13.7
BASIN DESCRIPTIONS
The site is divided into four basins: A, B1, B2 and C.
Basin A is 0.51 acres and is comprised of drainage from the roof of Lot 3 and on-site sidewalks and
landscape areas. Water will flow from the roof drains into the proposed drainage system that ties into an
existing stub from the existing storm system in Limon Drive. Water from the proposed sidewalk along
Limon Drive will sheet flow into the curb and gutter of Limon Drive where it will then be collected by the
existing inlet in Limon Drive.
Basin B1 is 0.44 acres and is comprised of the eastern portion of the Tract A parking lot, on-site sidewalks
and landscape areas. Water will flow into the proposed parking lot, across pervious pavers and into the
proposed Type C sump inlet at design point B1. From the inlet, water will be transported via storm drain
pipe to the existing storm drain system in Iowa Drive. Water from the proposed sidewalk along Iowa Drive
will sheet flow into the curb and gutter of Iowa Drive where it will then be collected by the existing inlet in
Iowa Drive.
Basin B2 is 0.65 acres and is comprised of the western portion of the Tract A parking lot, on-site sidewalks
and landscape areas. Water will flow into the proposed parking lot, across pervious pavers and into the
proposed Type C sump inlet at design point B2. From the inlet, water will be transported via storm drain
Page 3
pipe to the existing storm drain system in Iowa Drive. Water from the proposed sidewalk along Iowa Drive
will sheet flow into the curb and gutter of Iowa Drive where it will then be collected by the existing inlet in
Iowa Drive.
Basin C is 0.40 acres and is the comprised drainage from Lots 1 and 2. It was assumed to have a percent
imperviousness of 73 percent with assumed areas for roof and sidewalk. Water from Lots 1 and 2 will flow
be routed into the proposed manhole at design point C. From this point water will be transported via storm
drain pipe to the existing storm drain system in Iowa Drive.
Please refer to the attachments for Warren Federal Credit Union Drainage Plan that depicts the drainage
basins.
The original design used a percent imperviousness of 90 percent. The weighted percent imperviousness of
the proposed plan is calculated to be 73 percent. Therefore, the site is in substantial conformance with the
previously approved Final Drainage Reports.
Hydraulic calculations for sizing the proposed stormwater inlets and pipe discussed in Basins A, B1, B2 and
C have been completed using area inlet spreadsheets and StormCAD hydraulic modeling software.
Calculations are attached and show that the storm systems in Iowa and Limon Drives have capacity.
FOUR STEP LOW IMPACT DEVELOPMENT PROCESS
With the development of the site, the design team has followed the four step low impact development
process outlined in Urban Drainage. Water quality is required for the site and is provided by an existing
off-site water quality and detention pond. In addition to water quality, Low Impact Development (LID)
criteria must be met.
It is required that no less than fifty percent of any newly added impervious area must be treated using one or
a combination of LID techniques. For Lots 1, 2, 3 and Tract A, 51% of newly added impervious area is
treated by pervious pavers LID technique. It is also required that no less than twenty five percent of any
newly added pavement areas must be treated using a permeable pavement technology. For Lots 1, 2, 3 and
Tract A, 25% of newly added pavement is pervious pavers. Please refer to the attachments for LID
calculations. Please note, calculation includes assumed roof and sidewalk area for Lots 1 and 2.
Page 4
Table 2. LID Compliance.
An erosion control plan will be implemented during construction that will address source control and
unwanted materials (hazardous materials, sediment) from entering the downstream storm systems. The
contractor will be responsible for implementing the erosion control plan and adequately addressing any
spills or clean up on site.
The proposed redevelopment has improved upon the existing conditions by providing off site water quality
and detention and onsite LID treatment. The site has been designed with provisions for safe and efficient
control of stormwater runoff in a manner that will not adversely affect the downstream storm system and
will improve water quality. Overall, it is evident that the proposed redevelopment will have a positive
impact on the overall stormwater management system.
Page 5
STANDARD OPERATING PROCEDURES
Pervious Pavers Maintenance Plan
Routine Maintenance Table (Summary from Chapter 6 of UDFCD)
Required Action Maintenance Objective Frequency of Action
Debris Removal, Sweeping, and
Vacuuming
Remove debris with regular
sweeping of the pavement surface,
typically performed with a broom
sweeper. Removing solids from
void spaces will require a vacuum
or regenerative air
Sweeper.
Routine – Sweeping should be
performed weekly to monthly
depending on the season.
Frequency of vacuuming is site
specific but recommended twice
annually to maintain infiltration
rates.
Snow Removal
Conventional plowing operations
should be used for snow removal.
Do not use sand or deicing liquids
on permeable pavement systems.
If sand is accidentally used, use a
vacuum sweeper to remove it
Non-routine – Performed as
needed after winter storm events.
Full or Partial Replacement of
Pavement or Infill Material
Concrete pavers, when installed
correctly, should have a long
service life. Follow industry
guidelines for installation and
replacement after underground
repairs. If the surface is
completely clogged, restoration of
infiltration can be achieved by
removing the first ½ to 1 inch of
soiled aggregate infill material
with a vacuum sweeper. Replace
with clean aggregate infill
material using a push broom.
Non-routine – Performed as
needed when surface infiltration
becomes completely clogged or
when individual pavers require a
repair.
Inspections Inspect to ensure that the facility
continues to function as initially
intended.
Routine – Inspect pavement
condition at least annually, either
during a rain event or with a
garden hose to ensure that water
infiltrates into the surface.
Systematic measurement of
surface infiltration can be
Page 6
Storm Drain Lines Maintenance Plan
Routine Maintenance Table
Required Action Maintenance Objective Frequency of Action
Debris Removal from Inlets
and Catch Basins
Remove debris and trash from
inlets to prevent them from
continuing downstream or
clogging and reducing the
flow capacity of the system.
Non-routine – Remove debris
as needed after storm events or
seasonally such as during the
Fall with heavy amounts of
leaves and twigs entering the
system.
Debris Removal from Storm
Pipes
Ensure the pipe systems
function as intended. Reduced
capacities in the pipes will
cause the system to back up
and increase the frequency of
surface flooding that could
damage property.
Non-routine – Pipe cleaning is
recommended as needed based
on the results of inspections or
when the system is no longer
able to regularly convey
routine storm flows from the
site.
Inspection Use a video camera to inspect
the condition of the storm
drain pipes looking for
sediment buildup and
structural integrity. Clean out
pipes as needed. If the
integrity of the pipe is
compromised, then repair the
damaged section(s).
Routine – Visually Inspect
pipes and inlets at least
annually or after major storm
events. Every 2-5 years the
pipes should be inspected with
a video camera.
If you have any questions or comments please contact me at (970) 460-8471.
Sincerely,
Michael Oberlander, P.E., LEED AP
Colorado Professional Engineer 34288
Attachments
SUMMARY
DRAINAGE SUMMARY TABLE
Design Tributary Area C (10) C (100) tc (10) tc (100) Q(10)tot Q(100)tot
Sub-basin 10 and 100 year storm
Point (ac) (min) (min) (cfs) (cfs)
a A 0.51 0.83 1.00 5.0 5.0 2.1 5.1 Existing Storm System in Limon Drive
b1 B1 0.44 0.70 0.88 5.0 5.0 1.5 3.8 Type C Sump Inlet
b2 B2 0.65 0.74 0.92 5.0 5.0 2.4 6.0 Type C Sump Inlet
c C 0.40 0.80 1.00 5.0 5.0 1.5 3.9 Existing Storm System in Illinois Drive
Page 1
Interwest Consulting Group
RUNOFF COEFFICIENTS & % IMPERVIOUS
LOCATION: Warren Federal Credit Union
PROJECT NO: 1219-048-00
COMPUTATIONS BY: es
DATE: 11/3/2015
Recommended Runoff Coefficients from Table RO-11 of City of Fort Collins Stormwater Code, Volume I
Recommended % Impervious from Table RO-3 Urban Storm Drainage Criteria Manual, Volume I
Type B Soils Runoff %
coefficient Impervious
C
Streets, parking lots (asphalt): 0.95 100
Sidewalks (concrete): 0.95 96
Roofs: 0.95 90
Gravel or Pavers: 0.50 40
Landscape Areas (Flat, Sandy) : 0.15 0
Landscape Areas (Steep, Sandy) : 0.20 0
SUBBASIN TOTAL TOTAL ROOF PAVED PAVERS SIDEWALK LANDSCAPE RUNOFF %
DESIGNATION AREA AREA AREA AREA AREA AREA AREA COEFF. Impervious REMARKS
(ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C)
A 0.51 22,350 12,959 0 0 5,925 3,466 0.83 78
B1 0.44 19,093 0 10,977 2,828 933 4,355 0.70 68
B2 0.65 28,470 0 13,977 5,427 4,590 4,475 0.74 72
C 0.40 17,318 13,000 0 0 1,000 3,318 0.80 73 Assmumption for Future
TOTAL 2.00 87,230 25,959 24,954 8,255 12,447 15,615 0.76 73
Equations
- Calculated C coefficients & % Impervious are area weighted
C = Σ (Ci Ai) / At
Ci = runoff coefficient for specific area, Ai
Ai = areas of surface with runoff coefficient of Ci
n = number of different surfaces to consider
At = total area over which C is applicable; the sum of all Ai's
3-2-16 FC FLOW.xls
Interwest Consulting Group
STANDARD FORM SF-2
TIME OF CONCENTRATION - 2 and 10 YR
LOCATION: Warren Federal Credit Union
PROJECT NO: 1219-048-00
COMPUTATIONS BY: es
DATE: 11/3/2015
2 and 10-yr storm Cf = 1.00 from Table RO-12 of City of Fort Collins Stormwater Code, Volume I
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
a A 0.51 0.83 15 2.0 1.6 131 1.0 0.016 2.0 1.1 2.7 146 10.8 5.0
b1 B1 0.44 0.70 10 2.0 1.9 130 1.0 0.016 2.0 1.1 3.0 140 10.8 5.0
b2 B2 0.65 0.74 10 2.0 1.7 100 1.0 0.016 2.0 0.8 2.5 110 10.6 5.0
c C 0.40 0.80 20 2.0 2.0 0 2.0 0.016 2.8 0.0 2.0 20 10.1 5.0
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
3-2-16 FC FLOW.xls
Interwest Consulting Group
STANDARD FORM SF-2
TIME OF CONCENTRATION - 100 YR
LOCATION: Warren Federal Credit Union
PROJECT NO: 1219-048-00
COMPUTATIONS BY: es
DATE: 11/3/2015
100-yr storm Cf = 1.25 from Table RO-12 of City of Fort Collins Stormwater Code, Volume I
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
A A 0.51 0.83 1.00 15 2.0 0.6 131 1.0 0.016 2.0 1.1 1.7 146 10.8 5.0
b1 B1 0.44 0.70 0.88 10 2.0 1.1 130 1.0 0.016 2.0 1.1 2.1 140 10.8 5.0
b2 B2 0.65 0.74 0.92 10 2.0 0.8 100 1.0 0.016 2.0 0.8 1.7 110 10.6 5.0
C C 0.40 0.80 1.00 20 2.0 0.7 0 2.0 0.016 2.8 0.0 0.7 20 10.1 5.0
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
3-2-16 FC FLOW.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 2-Yr Storm)
LOCATION: Warren Federal Credit Union
PROJECT NO: 1219-048-00
COMPUTATIONS BY: es
DATE: 11/3/2015
2 yr storm, Cf = 1.00
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C Cf tc i Q (2) from Q (2) Q(2)tot
Sub-basin Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
A A 0.51 0.83 5.0 2.85 1.2 1.2
B1 B1 0.44 0.70 5.0 2.85 0.9 0.9
B2 B2 0.65 0.74 5.0 2.85 1.4 1.4
C C 0.40 0.80 5.0 2.85 0.9 0.9
Q = Cf C iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 24.221 / (10+ tc)0.7968
3-2-16 FC FLOW.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 10-Yr Storm)
LOCATION: Warren Federal Credit Union
PROJECT NO: 1219-048-00
COMPUTATIONS BY: es
DATE: 11/3/2015
10 yr storm, Cf = 1.00
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C Cf tc i Q (10) from Q (10) Q(10)tot
Sub-basin Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
A A 0.51 0.83 5.0 4.87 2.1 2.1
B1 B1 0.44 0.70 5.0 4.87 1.5 1.5
B2 B2 0.65 0.74 5.0 4.87 2.4 2.4
C C 0.40 0.80 5.0 4.87 1.5 1.5
Q = Cf C iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 41.44 / (10+ tc)0.7974
3-2-16 FC FLOW.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 100-Yr Storm)
LOCATION: Warren Federal Credit Union
PROJECT NO: 1219-048-00
COMPUTATIONS BY: es
DATE: 11/3/2015
100 yr storm, Cf = 1.25
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Des. Area A C Cf tc i Q (100) from Q (100) Q(100)tot
Design
Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
A A 0.51 1.00 5.0 9.95 5.1 5.1
B1 B1 0.44 0.88 5.0 9.95 3.8 3.8
B2 B2 0.65 0.92 5.0 9.95 6.0 6.0
C C 0.40 1.00 5.0 9.95 3.9 3.9
Q = C iA
Q = peak discharge (cfs)
C = runoff coefficient
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 84.682 / (10+ tc)
0.7975
3-2-16 FC FLOW.xls
Conduit FlexTable: Combined Pipe/Node Report
Energy Grade
Line (In)
(ft)
Hydraulic
Grade Line
(Out)
(ft)
Hydraulic
Grade Line
(In)
(ft)
Slope
(Calculated)
(ft/ft)
Invert
(Stop)
(ft)
Invert
(Start)
(ft)
Velocity
(ft/s)
Flow
(cfs)
Diameter
(in)
Length Material
(Unified)
(ft)
Stop
Node
Start
Node
Label
24.0 13.70 4.36 28.13 28.65 -0.003 31.39 30.69 31.68
Concret
e
B1 190.5
EX
INLET
IN
IOWA
P1
18.0 9.90 5.60 28.65 28.89 -0.005 31.99 31.54 32.47
Concret
e
P2 B1 B2 50.5
15.0 3.90 3.18 29.14 29.68 -0.005 32.64 32.23 32.79
Concret
e
P3 B2 C 112.0
Energy
Grade Line
(Out)
(ft)
30.99
32.02
32.39
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FlexTable: Catch Basin Table
Energy Grade
Line (Out)
(ft)
Energy Grade
Line (In)
(ft)
Hydraulic Grade
Line (Out)
(ft)
Hydraulic Grade
Line (In)
(ft)
Flow (Additional
Carryover)
(cfs)
Elevation
(Invert)
(ft)
Elevation (Rim)
(ft)
Elevation
(Ground)
(ft)
ID Label
28 B1 33.40 33.40 28.65 3.80 31.54 31.39 32.02 31.68
29 B2 33.22 33.22 28.89 6.00 32.23 31.99 32.39 32.47
30 C 36.00 36.00 29.68 3.90 32.64 32.64 32.79 32.79
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2/23/2016
Bentley StormCAD V8i (SELECTseries 3)
Storm B.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
FlexTable: Outfall Table
Energy Grade
Line
(ft)
Flow (Total Out)
(cfs)
Hydraulic Grade
(ft)
Elevation (User
Defined Tailwater)
(ft)
Elevation
(Invert)
(ft)
Set Rim to
Ground
Elevation?
Elevation
(Ground)
(ft)
Label
32.40 False 27.80 30.69 30.69 13.70 30.69
EX
INLET
IN
IOWA
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Bentley StormCAD V8i (SELECTseries 3)
Storm B.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
Profile Report
Engineering Profile - Profile - 1 (Storm B.stsw)
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
+1-203-755-1666
2/23/2016
Bentley StormCAD V8i (SELECTseries 3)
Storm B.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
Conduit FlexTable: Combined Pipe/Node Report
Energy Grade
Line (In)
(ft)
Hydraulic
Grade Line
(Out)
(ft)
Hydraulic
Grade Line
(In)
(ft)
Slope
(Calculated)
(ft/ft)
Invert
(Stop)
(ft)
Invert
(Start)
(ft)
Velocity
(ft/s)
Flow
(cfs)
Diameter
(in)
Length Material
(Unified)
(ft)
Stop
Node
Start
Node
Label
18.0 5.10 11.20 28.13 30.30 -0.058 31.17 30.69 31.53
Concret
e
MH-2 37.4
EX MH
IN
LIMON
P1
P2 MH-2 MH-1 83.0 PVC 12.0 5.10 6.49 30.30 31.13 -0.010 32.36 31.35 33.01
P3 MH-1 A 48.0 PVC 12.0 5.10 6.49 31.13 31.61 -0.010 33.26 32.68 33.92
Energy
Grade Line
(Out)
(ft)
30.82
32.00
33.34
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
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2/17/2016
Bentley StormCAD V8i (SELECTseries 3)
Storm A.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
FlexTable: Catch Basin Table
Energy Grade
Line (Out)
(ft)
Energy Grade
Line (In)
(ft)
Hydraulic Grade
Line (Out)
(ft)
Hydraulic Grade
Line (In)
(ft)
Flow (Additional
Carryover)
(cfs)
Elevation
(Invert)
(ft)
Elevation (Rim)
(ft)
Elevation
(Ground)
(ft)
ID Label
30 A 36.00 36.00 31.61 5.10 33.26 33.26 33.92 33.92
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Storm A.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
FlexTable: Manhole Table
Energy Grade
Line (Out)
(ft)
Energy Grade
Line (In)
(ft)
Hydraulic Grade
Line (In)
(ft)
Hydraulic Grade
Line (Out)
(ft)
Flow (Total
Out)
(cfs)
Elevation
(Invert)
(ft)
Bolted
Cover?
Elevation (Rim)
(ft)
Elevation
(Ground)
(ft)
Label
MH-1 35.56 35.56 False 31.13 5.10 32.36 32.68 33.34 33.01
MH-2 35.75 35.75 False 30.30 5.10 31.17 31.35 32.00 31.53
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
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2/17/2016
Bentley StormCAD V8i (SELECTseries 3)
Storm A.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
FlexTable: Outfall Table
Energy Grade
Line
(ft)
Flow (Total Out)
(cfs)
Hydraulic Grade
(ft)
Elevation (User
Defined Tailwater)
(ft)
Elevation
(Invert)
(ft)
Set Rim to
Ground
Elevation?
Elevation
(Ground)
(ft)
Label
34.00 True 27.10 30.69 30.69 5.10 30.69
EX MH
IN
LIMON
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Bentley StormCAD V8i (SELECTseries 3)
Storm A.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
Profile Report
Engineering Profile - Profile - 1 (Storm A.stsw)
27 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA Page 1 of 1
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Bentley StormCAD V8i (SELECTseries 3)
Storm A.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
New Impervious Area 60,266 acre/sq. ft.
Required Minimum Impervious Area to be Treated 30,133 acre/sq. ft.
Ratio
Area of Paver Section #1 (Basin B1) 2,828 acre/sq. ft.
Pavement area for Paver Section #1 (up to 3:1 is permited) 10,977 acre/sq. ft. 3.9
Impervious Area Treated by LID Treatment Method #1 (Pervious Pavement System) 11,910 acre/sq. ft. 4.2
Area of Paver Section #2 (Basin B2) 5,427 acre/sq. ft.
Pavement area for Paver Section #2 (up to 3:1 is permited) 13,977 acre/sq. ft. 2.6
Impervious Area Treated by LID Treatment Method #1 (Pervious Pavement System) 18,567 acre/sq. ft. 3.4
Total Impervious Area Treated 30,477 acre/sq. ft.
Actual % On-Site Treated by LID 51 %
New Pavement Area 33,209 acre/sq. ft.
Required Minimum Area of Porous Pavement 8,302 acre/sq. ft.
Area of Paver Section #1 2,828 acre/sq. ft.
Area of Paver Section #2 5,427 acre/sq. ft.
Total Porous Pavement Area 8,255 acre/sq. ft.
Actual % of Porous Pavement Provided 25 %
50% On-Site Treatment by LID Requirement
25% Porous Pavement Requirement
LID Table
New Impervious Area 60,266 acre/sq. ft.
Required Minimum Impervious Area to be Treated 30,133 acre/sq. ft.
Ratio
Area of Paver Section #1 (Basin B1) 2,828 acre/sq. ft.
Pavement area for Paver Section #1 (up to 3:1 is permited) 10,977 acre/sq. ft. 3.9
Impervious Area Treated by LID Treatment Method #1 (Pervious Pavement System) 11,910 acre/sq. ft. 4.2
Area of Paver Section #2 (Basin B2) 5,427 acre/sq. ft.
Pavement area for Paver Section #2 (up to 3:1 is permited) 13,977 acre/sq. ft. 2.6
Impervious Area Treated by LID Treatment Method #1 (Pervious Pavement System) 18,567 acre/sq. ft. 3.4
Total Impervious Area Treated 30,477 acre/sq. ft.
Actual % On-Site Treated by LID 51 %
New Pavement Area 33,209 acre/sq. ft.
Required Minimum Area of Porous Pavement 8,302 acre/sq. ft.
Area of Paver Section #1 2,828 acre/sq. ft.
Area of Paver Section #2 5,427 acre/sq. ft.
Total Porous Pavement Area 8,255 acre/sq. ft.
Actual % of Porous Pavement Provided 25 %
50% On-Site Treatment by LID Requirement
25% Porous Pavement Requirement
LID Table
+1-203-755-1666
2/23/2016
Bentley StormCAD V8i (SELECTseries 3)
Storm B.stsw Bentley Systems, Inc. Haestad Methods Solution Center [08.11.03.84]
accomplished using ASTM C1701
Standard Test Method for
Infiltration Rate of In Place
Pervious Concrete