HomeMy WebLinkAboutFISCHER PROPERTIES - FDP230010 - DOCUMENT MARKUPS - ROUND 2 - DRAINAGE REPORT
FINAL DRAINAGE REPORT
FISCHER PROPERTIES
FORT COLLINS, COLORADO
MARCH 15, 2023
NORTHERNENGINEERING.COM
970.221.4158
FORT COLLINS
GREELEY
This Drainage Report is consciously provided as a PDF.
Please consider the environment before printing this document in its entirety.
When a hard copy is necessary, we recommend double-sided printing.
NORTHERNENGINEERING.COM | 970.221.4158
FORT COLLINS | GREELEY
FINAL DRAINAGE REPORT: FISCHER PROPERTIES
12 | 16
water quality. In order to meet the water quality requirement, the existing impervious area of off-
site basins OS-2, OS-4 and OS-5 are proposed to be treated in exchange.
Rain Gardens/Underground Chambers
3. Rain Gardens A and B provides Low Impact Development (LID) for Basins 301, 302, 303, 304, OS-2
and OS-5. This rain garden was sized to provide 120% of the calculated 12-hour volume.
4. Stormtech Underground Chambers provides Low Impact Development (LID) for Basins 200-208 and
OS-4. This underground chamber system was sized to provide 120% of the calculated 12-hour
volume.
5. Overflow inlets will be provided in both rain gardens to pass storms greater than the WQCV to
Detention Pond 3.
6. An overflow weir is provided in the underground chambers to pass storms greater than the WQCV
into the detention portion of the underground chambers (Detention Pond 2).
7. The site is required to treat 75% of new impervious area with LID treatment. Due to site constraints
stated previously, Basins OF-1 and OF-2 are unable to be captured and treated for water quality. In
order to meet the water quality requirement, the existing impervious area of off-site basins OS-2,
OS-4 and OS-5 are proposed to be treated in exchange. This site treats 87.15% of the on-site
impervious area with LID and an additional 10,714 ft2 of offsite area for an effective percent of
impervious area treated of 94.64%.
Water Quality Pond
1. Pond 1 provide water quality for Basins 100-105 through a traditional 40-hour extended
detention basin. The WQCV for Pond 1 was sized to 120% of the calculated 40-hour
volume.
Total WQ Treatment
1. Using a combination of LID and Traditional Extended Detention Basins of both on-site
and off-site basins, this site is able to treat 106% of the required site impervious area.
LID Site Summary - New Impervious Area
Total Area of Current Development 234,073 ft2
Total On-site Impervious Area 143,103 ft2
75% Required Minimum Area to be Treated by LID 107,327 ft2
Total On-site Impervious Area Treated by LID 103,480 ft2
Percent On-site Impervious Treated by LID 72.31%
Additional Off-site Impervious Area Treated by LID 10,714 ft2
Percent Total Impervious Area Treated by LID 79.80%
Total Impervious Area Treated by Traditional WQ 36,977 ft2
Percent Impervious Treated by Traditional Water Quality 25.84%
Percent Impervious Area Treated by Traditional WQ or LID 105.64%
Table 3 - LID Summary
Vault ID
Required
Detention
Volume
by FAA
Method
(cf)
Flow,
100-yr
(cfs)
Chamber
Type
Chamber
Release
Ratea
(cfs)
Chamber
Volumeb
(cf)
Installed
Chamber w/
Aggregatec
(cf)
Minimum
No. of
Chambersd
Total
Release
Ratee
(cfs)
Required
Storage
Volume by
FAA Method
(cf)
Minimum
No. of
Chambersf
Provided
Number of
Chambers
Provided
Release
Rate (cfs)
Storage
Provided
within the
Chambersg
(cf)
Total
Installed
System
Volumeh
(cf)
Pond 2 12053 18.73 MC-3500 N/A 109.90 161.70 75 N/A N/A N/A 75 N/A 8243 12128
a. Release rate per chamber, limited by flow through geotextile with accumulated sediment.
b. Volume within chamber only, not accounting for void spaces in surrounding aggregate.
c. Volume includes chamber and void spaces (30%) in surrounding aggregate, per chamber unit.
d. Number of chambers required to provide full WQCV within total installed system, including aggregate.
e. Release rate per chamber times number of chambers.
f. Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage).
g. Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume.
h. System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV.
Chamber Detention Configuration Summary
FDCUDUD
NYLOPLAST
DO NOT POLLUTEDRAINS TOWATERWAYSDO NOT POLLUTE DRAINS TO WA
T
E
R
W
A
Y
S
NYLOPLAST DUCTILE IRON
NYLOPLAST
DO NOT POLLUTEDRAINS TOWATERWAYS
DO NOT POLLUTE DRAINS TO WA
T
E
R
W
A
Y
S
NYLOPLAST DUCTILE IRON
DS
DS
DS
DS
DS
DS
DS DS
DS
DS
DS DS
DS
DS
DS
DS
DS DS
DS DS DS DS DS
DS
DS
DS
DS
DS
DS
DS
DSDS
DS
DS
DS
DS
DS
DS
DS
DS
NYLOPLAST
DO NOT POLLUTEDRAINS TOWATERWAYS DO NOT POLLUTE DRAINS TO WA
T
E
R
W
A
Y
SNYLOPLAST DUCTILE IRON
XX
XXXXXXXX X
D
D
D
D
D
D
STSTSTST6" ABD
N
W
6" ABDN W
RAIN
GARDEN B
WQ DETENTION POND 3
100-YR WSEL = 5031.11
RAIN
GARDEN A
0.31 ac.
OS-2
0.46 ac.
200
0.80
305
0.93 ac.
OS-4
0.13 ac.
OS-1
0.40 ac.
OS-3
0.08 ac.
100
0.23 ac.
OF-1
0.04 ac.
OF-2
0.97 ac.
304
0.20 ac.
302
0.21 ac.
OS-5
0.09 ac.
303
0.37 ac.
300
0.21 ac.
301
0.18 ac.
201
0.26 ac.
202
0.07 ac.
203
0.02 ac.
204
0.28 ac.
205
0.27 ac.
206
0.21 ac.
207
0.12 ac.
208
0.26 ac.
101
0.05 ac.
102
0.02 ac.
103
0.06 ac.
104
0.14 ac.
105
200
300
OS-5
OS-1
OS-3
OS-4
OF
301
302
OS-2
201
202
203
204
205206
207
208
303
304
305
WQ DETENTION POND 1
100-yr WSEL = 5029.31
STORMTECH
CHAMBERS 2
DRAWN BY:
SCALE:
ISSUED:
FISCHER PROPERTIES
SHEET NO:
FORT COLLINS: 301 North Howes Street, Suite 100, 80521
GREELEY: 820 8th Street, 80631
E N G I N E E R N GI
EHTRON R N
970.221.4158
northernengineering.com
LID EXHIBIT
A. Boese
1in=100ft
03/09/23
PROPOSED STORM SEWER
PROPOSED CURB & GUTTER
PROPERTY BOUNDARY
PROPOSED INLET
ADESIGN POINT
DRAINAGE BASIN LABEL
DRAINAGE BASIN BOUNDARY
A
LEGEND:
( IN FEET )
1 inch = ft.
Feet0100100
100
RAIN GARDEN LIMITS
STORMTECH CHAMBERS
FOR DRAINAGE REVIEW ONLY
NOT FOR CONSTRUCTION
LID Site Summary - New Impervious Area
Total Area of Current Development 234,073 ft2
Total On-site Impervious Area 143,103 ft2
75% Required Minimum Area to be Treated by LID 107,327 ft2
Total On-site Impervious Area Treated by LID 103,480 ft2
Percent On-site Impervious Treated by LID 72.31%
Additional Off-site Impervious Area Treated by LID 10,714 ft2
Percent Total Impervious Area Treated by LID 79.80%
Total Impervious Area Treated by Traditional WQ 36,977
Percent Impervious Treated by Traditional Water Quality 25.84%
Percent Impervious Area Treated by Traditional WQ or LID 105.64%
Project Number:Project:
Project Location:
Calculations By:Date:
Sq. Ft. Acres
100 3,599 0.08 32%n/a Traditional 0 1,152
101 11,385 0.26 58%n/a Traditional 0 6,603
102 1,983 0.05 73%n/a Traditional 0 1,448
103 674 0.02 76%n/a Traditional 0 512
104 2,480 0.06 71%n/a Traditional 0 1,761
105 6,071 0.14 37%n/a Traditional 0 2,246
200 19,824 0.46 85%Stormtech 2 Stormtech 479 16,850
201 7,699 0.18 86%Stormtech 2 Stormtech 190 6,621
202 11,368 0.26 80%Stormtech 2 Stormtech 249 9,094
203 3,196 0.07 60%Stormtech 2 Stormtech 50 1,918
204 1,051 0.02 63%Stormtech 2 Stormtech 17 662
205 12,287 0.28 74%Stormtech 2 Stormtech 241 9,092
206 11,663 0.27 69%Stormtech 2 Stormtech 210 8,047
207 9,003 0.21 86%Stormtech 2 Stormtech 222 7,743
208 5,021 0.12 78%Stormtech 2 Stormtech 106 3,916
300 15,967 0.37 14%n/a Traditional 0 2,235
301 9,258 0.21 71%Rain Garden B Rain Garden 173 6,573
302 8,811 0.20 63%Rain Garden A Rain Garden 145 5,551
303 4,007 0.09 51%Rain Garden A Rain Garden 56 2,044
304* 42,279 0.97 60% 58/42 split Rain Garden A/B Rain Garden 666 25,367
305 34,809 0.80 61%n/a Traditional 0 21,233
OF-1 9,836 0.23 13%n/a n/a 0 1,279
OF-2 1,803 0.04 64%n/a n/a 0 1,154
Total On-site 234,073 5.37 143,103
OS-1 5,772 0.13 80%n/a n/a 0 4,617
OS-2* 13,395 0.31 26% 58/42 split Rain Garden A/B Rain Garden 124 3,483
OS-3 17,304 0.40 25%n/a n/a 0 4,326
OS-4 40,418 0.93 12%Stormtech 2 Stormtech 210 4,850
OS-5 9,158 0.21 26%Rain Garden A Rain Garden 84 2,381
Total Off-Site 86,047 1.98 19,657
Sq. Ft. Acres
Rain Garden A 54,267 1.25 49% 26,709
302, 303, 304*,
OS-2*, OS-5 Rain Garden 738 886
Rain Garden B 32,641 0.75 57% 18,690 301, 304*, OS-2* Rain Garden 495 594
Stormtech 2 121,530 2.79 57% 69,272
200, 201, 202,
203, 204, 205,
206, 207, 208, OS-
4 Stormtech 1,835 2,202
Total 208,438 4.79 114,671 3,682
Sq. Ft. Acres
WQ Pond 1 26,192 0.60 52% 13,620
100, 101, 102,
103, 104, 105 Standard 462 555
WQ Pond 3 50,776 1.17 46%23,357 300, 305 Standard 828 993
Total 76,968 1.77 36,977 1,548
234,073 ft2
143,103 ft2
107,327 ft2
103,480 ft2
72.31%
10,714 ft2
79.80%
36,977 ft2
25.84%
105.64%
Water Quality Treatment via Traditional Water Quality
LID Summary
AreaBasin ID WQ Treatment TypePercent
Impervious LID ID
Fischer Subdivision
3/9/2023
1382-002
Fort Collins, Colorado
A. Boese
Total
Impervious
Area (ft2)
Required
Volume (ft3)
LID Summary per Basin
Tributary Area Weighted %
Impervious
Impervious
Area (ft2)
Vol. w/20%
Increase per
Fort Collins
Manual (ft3)
Subbasin ID Treatment TypeWQ Treatment Volume per
UD-BMP (ft3)
Water Quality Treatment via LID
Percent Impervious Area Treated by Traditional WQ or LID
Total On-site Impervious Area Treated by LID
75% Required Minimum Area to be Treated by LID
Total Area of Current Development
Total On-site Impervious Area
Vol. w/20%
Increase per
Fort Collins
Manual (ft3)
Total Impervious Area Treated by Traditional WQ
Percent Impervious Treated by Traditional Water Quality
WQ Treatment
Tributary Area Weighted %
Impervious
LID Site Summary - New Impervious Area
Treatment Type Volume per
UD-BMP (ft3)
Additional Off-site Impervious Area Treated by LID
Percent On-site Impervious Treated by LID
Subbasin IDImpervious
Area (ft2)
Percent Total Impervious Area Treated by LID
Circular
D or Da,
Pipe
Diameter
(ft)
H or Ha,
Culvert
Height
(ft)
W,
Culvert
Width
(ft)
Yt/D Q/D1.5 Q/D2.5 Yt/H Q/WH0.5
Storm Line C 7.76 1.50 0.60 0.40 4.22 2.82 N/A N/A 4.60 2.82 1.10 1.54 Type L 2.00 6.00 1.5
Storm Line D 2.24 1.00 0.40 0.40 2.24 2.24 N/A N/A 5.40 2.24 0.56 2.14 Type L 3.00 4.00 1.5
Storm Line E 9.08 1.50 0.60 0.40 4.94 3.30 N/A N/A 4.20 3.30 1.47 4.00 Type L 5.00 6.00 1.5
Storm Line F 9.06 1.25 0.50 0.40 6.48 5.19 N/A N/A 2.30 5.19 1.19 2.59 Type L 3.00 5.00 1.5
Design
Discharge
(cfs)
Expansion
Factor
1/(2tanq)
(From
Figure
MD-23 or
MD-24)
Yt,
Tailwater
Depth
(ft)
Culvert Parameters
At=Q/V (ft)
Froude
Parameter
Q/D2.5
Max 6.0
or
Q/WH1.5
Max 8.0
Riprap
Type
(From
Figure
MD-21 or
MD-22)
By: Adam Boese
CALCULATE
Date: 02/23/2023
Project: 1382-002
Urban Drainage
pg MD-107
L=
1/(2tanq)*
[At/Yt)-W]
(ft)
INPUT
Storm
Line/Culvert
Label
OUTPUT
Spec
Length
of
Riprap
(ft)
Box Culvert
CALCULATIONS FOR RIPRAP PROTECTION AT PIPE OUTLETS
Circular
Pipe
(Figure MD-21)
Rectangular
Pipe
(Figure MD-22)Spec
Width
of
Riprap
(ft)
2*d50,
Depth
of
Riprap
(ft)
for L/2