HomeMy WebLinkAboutDrainage Reports - 02/06/2024City of Fort Collins Approved Plans
Approved by:
Date:
Dan Mogen
02/06/2024
South Campus Stormwater Master Plan
Colorado State University 015-0770
December 2015 i
Table of Contents
1.0 Introduction ........................................................................................................................ 1
1.1 Background .............................................................................................................. 1
1.2 Purpose and Scope .................................................................................................. 1
1.3 Previous Reports ...................................................................................................... 1
2.0 Hydrology .......................................................................................................................... 3
2.1 Model History ........................................................................................................... 3
2.2 Rainfall ..................................................................................................................... 3
3.0 Existing Conditions ............................................................................................................ 5
3.1 Effective Model ......................................................................................................... 5
3.2 Existing Conditions Model ........................................................................................ 6
3.3 Existing Detention Requirements ............................................................................. 9
4.0 Proposed Conditions ....................................................................................................... 12
4.1 Basin Description ....................................................................................................12
4.2 Detention Basin Alternative .....................................................................................14
4.2.1 Off-Line Detention Alternative ..........................................................................14
4.2.2 On-Line Detention Alternative ..........................................................................16
4.3 Water Quality Alternative .........................................................................................17
5.0 Recommendations ........................................................................................................... 19
List of Tables
Table 1: Fort Collins Intensity Duration Frequency Curves for Use with SWMM ......................... 4
Table 2: MODSWMM & EPA SWMM Peak Flow Comparison .................................................... 6
Table 3: Changes to Existing Condition...................................................................................... 8
Table 4: Converted Effective Model & Updated Existing Model Peak Flow Comparison ............ 9
Table 5: Required Onsite 100-Year Release Rates ...................................................................10
Table 6 Allowable Release Rate Pond Summary .....................................................................10
Table 7: Detention Pond Requirements Compared to Constructed Facilities ............................10
Table 8: Changes to Proposed Condition ..................................................................................14
Table 9: Required Water Quality and Detention Requirements .................................................15
Table 10: Off-Line Detention Alternative Estimated Cost ...........................................................16
Table 11: On-Line Detention Alternative Estimated Cost ...........................................................17
Table 12: Water Quality Requirements .....................................................................................18
Table 13: Water Quality Alternative Estimated Cost ..................................................................18
List of Figures
Exhibit 1: Study Area.................................................................................................................. 2
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List of Appendices
Appendix A Existing Conditions Analysis
Exhibit 2: Existing Conditions Basin Map
Exhibit 3: Existing Conditions SWMM Schematic
Appendix B Master Plan
Exhibit 4: Master Plan Basin Map
Exhibits 5A-5C: Master Plan SWMM Schematics
Exhibit 6: Off-line Detention Pond Alternative
Exhibit 7: On-line Detention Pond Alternative
Exhibit 8: Water Quality Pond Alternative
Appendix C Water Quality Calculations
Appendix D EPA SWMM Water Quality Model
EPA SWMM Input Files
EPA SWMM Output Files
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1.0 INTRODUCTION
1.1 Background
This report addresses the stormwater master plan improvements to the Colorado State
University (CSU) South Campus. The master plan study encompasses the area north of Drake
Road, west of the Burlington Northern Railroad, east of Research Boulevard and Centre
Avenue, and south of the Natural Resources Research Center. A vicinity map for this study area
is shown in Exhibit 1.
1.2 Purpose and Scope
Olsson Associates was retained to complete this Colorado State University South Campus
Stormwater Master Plan study, which was authorized by CSU.
The purpose of this study was to document the existing and future conditions, update the
hydrology for existing conditions, develop drainage alternatives and update hydrology for the
future campus layout, and provide a recommendation for drainage improvements.
1.3 Previous Reports
The following studies were reviewed as part of this project for comparison of developed
hydrology in similar areas:
CSU South Campus/ Veterinary Teaching Hospital Drainage Evaluation (Anderson
Consulting Engineer, Inc., 2001)
Tennis Court Parking Lot Final Drainage Report (Olsson Associates, 2015)
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
R
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
STUDY AREA
1
LEGEND
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2.0 HYDROLOGY
The study area was included in the Spring Creek Basin As-built model, which was prepared by
Anderson Consulting Engineers in 2008 using MODSWMM. For this study, the effective
MODSWMM model was updated to EPA SWMM 5.1.007 and the CSU drainage basins were
updated with more detailed existing conditions information. As part of the analysis, the existing
detention ponds at CSU were evaluated and the results were compared to the City of Fort
Collins criteria. Following the existing conditions analysis, Olsson Associates evaluated the
effects of proposed improvements on peak flows at CSU and recommend necessary drainage
improvements.
2.1 Model History
The City of Fort Collins provided the effective Spring Creek Basin As-built MODSWMM model.
This model represents master planning conditions in the basin, including the Physical Map
Revision (PMR) improvements at Rolland Moore Park, Taft Hill, and Spring Canyon Park. This
model was used as the basis for this study. The existing conditions model development process
is detailed in Section 3.0.
2.2 Rainfall
The 2- and 100-year precipitation values in the effective model were verified using the Rainfall
Intensity-Duration-Frequency Table in the Fort Collins Stormwater Criteria manual. The rainfall
values used in the effective model were found to be acceptable and were not changed for this
study. Only the 2- and 100-year rainfall events were required for this study. The table of rainfall
intensities can be found in Table 1.
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Table 1: Fort Collins Intensity Duration Frequency Curves for Use with SWMM
Duration 2-Year
lntensity
5-Year
lntensity
10-Year
lntensity
25-Year
lntensity
50-Year
lntensity
100-Year
lntensity
(min) (in/hr) (in/hr) (in/hr) (in/hr) (in/hr) (in/hr)
5 0.29 0.40 0.49 0.63 0.79 1.00
10 0.33 0.45 0.56 0.72 0.90 1.14
15 0.38 0.53 0.65 0.84 1.05 1.33
20 0.64 0.89 1.09 1.41 1.77 2.23
25 0.81 1.13 1.39 1.80 2.25 2.84
30 1.57 2. 19 2.69 3.48 4.36 5.49
35 2.85 3.97 4.87 6.30 7.90 9.95
40 1.18 1.64 2.02 2.61 3.27 4.12
45 0.71 0.99 1.21 1.57 1.97 2.48
50 0.42 0.58 0.71 0.92 1.16 1.46
55 0.35 0.49 0.60 0.77 0.97 1.22
60 0.30 0.42 0.52 0.67 0.84 1.06
65 0.20 0.28 0.39 0.62 0.79 1.00
70 0.19 0.27 0.37 0.59 0.75 0.95
75 0.18 0.25 0.35 0.56 0.72 0.91
80 0.17 0.24 0.34 0.54 0.69 0.87
85 0.17 0.23 0.32 0.52 0.66 0.84
90 0.16 0.22 0.31 0.50 0.64 0.81
95 0.15 0.21 0.30 0.48 0.62 0.78
100 0.15 0.20 0.29 0.47 0.60 0.75
105 0.14 0.19 0.28 0.45 0.58 0.73
110 0.14 0.19 0.27 0.44 0.56 0.71
115 0.13 0.18 0.26 0.42 0.54 0.69
120 0.13 0.18 0.25 0.41 0.53 0.67
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3.0 EXISTING CONDITIONS
As a baseline to determine necessary master plan improvements, an existing conditions model
was developed. To develop an existing conditions model, the effective as-built model was first
converted to EPA SWMM 5.1.007. The peak flows from the EPA SWMM 5.1.007 model were
then compared to the effective peak flows to see if calibration was warranted. Following this
analysis, the existing subbasin boundaries and percent impervious values were checked and
updated as needed to reflect existing conditions. A detailed description of the existing conditions
analysis is included herein.
3.1 Effective Model
To prepare the baseline existing model, the effective as-built MODSWMM model for the Spring
Creek Basin was first converted to EPA SWMM 5.1.007. The input file for the MODSWMM
model was modified to match the same format as a UDSWMMM 2000 model. Only minor
modifications to the input file were necessary to convert the model to a UDSWMM 2000 model.
The UDSWMM 2000 model was then converted to an EPA SWMM model using the Urban
Drainage and Flood Control District (UDFCD) CUHP SWMM Converter. The EPA SWMM
5.1.007 model was spot checked to verify input parameters were properly converted. Minor
corrections to the model were required at nodes where flooding was occurring. Primarily,
corrections were made at detention ponds and a few nodes where downstream conveyance
elements were inadequate for the flows received. For detention ponds, the rating curves for the
pond outlets were extrapolated out in order to replicate the higher release rates typically seen
when ponded depth increases on an orifice outlet. In cases where nodes were flooding and not
freely releasing flows, additional conveyance was added to ensure no inadvertent detention was
being modeled.
The peak flows from the EPA SWMM 5.1.007 model were then compared to the effective
MODSWMM peak flows in the study area, to see if calibration was necessary. The EPA SWMM
5.1.007 100-year peak flows compared well to the effective 100-year peak flows, with average
differences of – 2.0% to 3.2% in the study area. Because the peak flows from the EPA SWMM
5.1.007 model only had small percent differences as compared to the effective MODSWMM
model, no calibration was warranted. The effective MODSWMM peak flows, EPA SWMM
5.1.007 peak flows, and percent differences are shown in Table 2. An existing conditions
subbasin map and SWMM schematic is included as Exhibit 2 and Exhibit 3, in Appendix A.
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Table 2: MODSWMM & EPA SWMM Peak Flow Comparison
Design Point Notes
MODSWMM
Peak Flow
(cfs)
EPA
SWMM
5.1.007
Peak
Flow (cfs)
% Change
(MODSWMM
to EPA
SWMM 5.1
Peak Flow)
Q100 Q100 Q100
JUNCT_327 Spring Creek 2930.00 2961.38 1.1%
JUNCT_727 Spring Creek 3085.20 3129.67 1.4%
JUNCT_27 Spring Creek 3175.40 3220.46 1.4%
JUNCT_703 Spring Creek 3789.30 3849.31 1.6%
OUTLET_303 Detention Pond/ Spring Creek 1972.10 1957.75 -0.7%
JUNCT_321 Spring Creek 1972.70 1958.38 -0.7%
JUNCT_726 Area within BNRR Pond 663.30 668.51 0.8%
JUNCT_260 Bay Farm Rd. Ditch at swale 552.20 569.65 3.2%
JUNCT_261 Bay Farm Rd. Ditch at Spring
Creek 570.20 588.71 3.2%
OUTLET_50 Detention Pond at CSU
Veterinary Teaching Hospital 512.40 527.58 3.0%
OUTLET_362 Detention Pond south of the
Tennis Courts along Drake Rd. 1.50 1.47 -2.0%
OUTLET_289 CSU Tennis Courts Detention
Pond 4.50 4.46 -0.9%
3.2 Existing Conditions Model
The EPA SWMM 5.1.007 model was checked to see if it correctly reflected the existing
conditions in accordance with the standards and guidelines of the City of Fort Collins Storm
Drainage Manual. LiDAR production, completed by Ayers Associates in 2013 for the City of Fort
Collins, was used to verify and update basin boundaries. The LiDAR data includes one-foot
contours on the NAVD 88 datum. The evaluation of the model centered on CSU’s south
campus. Subbasins in the effective model outside of this area were not checked. The following
modifications were made to the CSU subbasins for the existing conditions model.
The subbasin boundaries of 61, 62, 65, 66, 67, 68, 89, and 125 did not reflect existing
conditions. The subbasin boundaries and EPA SWMM 5.1.007 subbasin parameters
were updated using the May 2013 topography provided by Fort Collins.
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Basin 126 was split into two subbasins, 126 and 126B, to match the study area
boundary. The subbasin parameters were modified accordingly.
The percent impervious values for subbasins 62, 66, 68, 89, 125, 126, and 126 B did not
reflect existing conditions. The existing percent impervious values were updated using
aerial imagery.
Subbasins 61, 89 and Pond 289 were updated with the design information from the
Tennis Court Parking Lot Final Drainage Report, prepared by Olsson Associates in
2015. The improvements were constructed by CSU in the summer of 2015.
Pond 362 was removed from the EPA SWMM 5.1.007 model because it did not reflect the
current existing conditions of the CSU South Campus study area. As a result of removing Pond
362 from the model, the outflow value of Pond 50 increased, which also increased the inflow
values for nodes 261 and 260.
A summary of the changes in area and percent imperviousness is included in Table 3. A
comparison of the EPA SWMM 5.1.007 model before and after updating the existing conditions
can be found in Table 4.
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Table 3: Changes to Existing Condition
Basin Property
Original
Value
(as of 2008)
Corrected Value**
(as of 2008)
Changed Value***
(as of 2013)
61
Area (acres) 20.4 21.4 21.9
% Impervious 90% 90% 90%
62
Area (acres) 5.9 6.0 4.2
% Impervious 70% 70% 2%
65
Area (acres) 6.5 6.7 6.7
% Impervious 8% 8% 8%
66
Area (acres) 17.8 16.8 22.7
% Impervious 55% 55% 65%
67*
Area (acres) 29.2 28.2 25.6
% Impervious 55% 55% 55%
68*
Area (acres) 11.5 11.1 16.0
% Impervious 55% 55% 30%
89
Area (acres) 25.4 24.7 16.0
% Impervious 90% 90% 61%
125
Area (acres) 22.6 22.5 23.1
% Impervious 51% 51% 65%
126
Area (acres) 72.6 78.7 51.7
% Impervious 25% 25% 19%
126B
Area (acres) N/A N/A 26.9
% Impervious N/A N/A 81%
Ditch Area (acres) 1.7 2.4 3.6
*The percent impervious value was not affected by the change in area.
**The areas in the effective model did not match the electronic files of the
effective subbasins. Because the electronic files were used as a basis for the
existing conditions, the total area of the electronic files and the existing
conditions match.
***Changed Value refers to the conditions of the subbasin in 2013 as
documented in the aerial imagery from LiDAR production by Ayers Associates
in 2013.
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Table 4: Converted Effective Model & Updated Existing Model Peak Flow Comparison
Design Point Notes
Converted
Effective
Peak Flow
(cfs)
Updated
Existing
Peak Flow
(cfs)
% Change
Q100 Q100 Q100
JUNCT_327 Spring Creek 2,961.38 2,961.90 0.0%
JUNCT_727 Spring Creek 3,129.67 3,146.53 0.5%
JUNCT_27 Spring Creek 3,220.46 3,218.72 -0.1%
JUNCT_703 Spring Creek 3,849.31 3,846.60 -0.1%
OUTLET_303 Detention Pond/ Spring Creek 1,957.75 1,927.99 -1.5%
JUNCT_321 Spring Creek 1,958.38 1,928.68 -1.5%
JUNCT_726 Area within BNRR Pond 668.51 659.62 -1.3%
JUNCT_260 Bay Farm Rd. Ditch at swale 569.65 594.33 4.3%
JUNCT_261 Bay Farm Rd. Ditch at Spring
Creek
588.71 613.41 4.2%
OUTLET_50 Detention Pond at CSU
Veterinary Teaching Hospital
527.58 555.94 5.4%
OUTLET_289 Tennis Courts Detention Pond 4.46 0.89 -80.0%
3.3 Existing Detention Requirements
Pond 303 and Pond 50 provide additional detention beyond what is required for CSU’s property
alone. To help determine master plan improvements, the existing detention volumes and
release rates were compared to the required detention volumes and release rates.
Pond 303, identified in Exhibit 2, in Appendix A, is predominantly inundated by the Spring Creek
100-year storm event. This area provides detention for a large area upstream, not just for CSU
south campus. In addition, Pond 50 also provides detention storage for offsite basins. To
determine what portion of the pond volumes are used for detention for the study area versus
offsite areas, the required onsite detention was determined by modifying the existing conditions
model to disconnect all off-site areas. Next, the 2-year undeveloped flow from the study area
was developed to determine a 100-year release rate for the developed basin based on City of
Fort Collins criteria. The undeveloped 2-year flow was determined by changing all of the
subbasins to a 2% imperviousness and converting all of the existing ponds to nodes so no
storage would be modeled. The required 100-year release rates, or the CSU 2-year historic
(undeveloped) peak flows, at each pond location is shown in Table 5.
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Table 5: Required Onsite 100-Year Release Rates
Pond CSU Tributary
Area (ac)
Required 100-Year
Release Rate (cfs)
50 33.6 1.98
289 16.0 0.96
303 166.0 5.65
To determine the detention required for the study area, per Fort Collins criteria, the existing
conditions model was modified to allow the offsite flows to pass through Ponds 50 and 303,
while detaining the developed 100-year flows to release at the 2-year historic flowrates. Pond
289 does not intercept any offsite basins so the release rate from Pond 289 is driven solely by
the historic 2-year flow. A summary of the 2-year historic flow, 100-year offsite flow, and total
allowable release rate at each pond is provided in Table 6.
Table 6 Allowable Release Rate Pond Summary
Pond
A: Historic 2-
year Flow Rate
(cfs)
B: Intercepted 100-
year Offsite
Developed Flows
(cfs)
Allowable Release Rate
(A + B)
(cfs)
50 1.98 702.91 704.89
289 0.96 0.00 0.96
303* 5.65 3,946.83 3,952.48
*The historic flows, intercepted flows, and allowable release rate for Pond 303 reported in Table
6 include the onsite and offsite flows from Pond 50 and Pond 289, as these ponds are tributary
to Pond 303. The offsite flows for Pond 303 also include flows from a portion of the CSU
Stadium project on the main campus, hydrographs 297, 298, 299, accounting for approximately
180.83 cubic feet per second (cfs)) of the total 3,946.83 cfs in offsite flows.
Table 7 summarizes the required release rates and detention volumes versus the as-
constructed condition release rates and detention volumes at each pond. Pond 50 and Pond
303 provide substantial excess detention that benefits the community as a whole.
Table 7: Detention Pond Requirements Compared to Constructed Facilities
Pond
Allowable
Release Rate
(cfs)
Required
Detention
(ac-ft)
Existing
Release Rate
(cfs)
Provided
Detention
(ac-ft)
50 704.89 5.48 549.72 21.96
289 0.96 3.90 0.89 3.91
303 3,952.48 13.84 1,956.85 337.1
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The area south of the New Mercer Ditch, which lies just north of the Natural Resource Research
Center, is currently undeveloped. Fort Collins stormwater criteria requires the developed 100-
year storm event flows be released at a 2-year historic flowrate, even if the site is entirely
pervious, which results in required detention to any property, developed or undeveloped.
Removing this area, which lies in Subbasin 126, from the onsite analysis reduces the overall
detention required in Pond 303 from 13.84 acre-feet (ac-ft) to 9.69 ac-ft. Ponds 50 and 289
would not be effected. Total detention required for the area south of New Mercer Ditch would be
19.07 ac-ft, as compared to the 23.22 ac-ft required for the entire study area identified in Exhibit
1.
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4.0 PROPOSED CONDITIONS
The “Medical Campus: Master Plan” (Master Plan), in Appendix B, shows the proposed site
layout for CSU’s South Campus. The Master Plan includes additional buildings, animal pens,
parking lots, and rearrangement of paved and landscaped areas.
To evaluate future drainage improvements with the Master Plan site layout, new drainage
basins were delineated, as shown in Exhibit 4, in Appendix B. The master plan SWMM
schematics are included as Exhibits 5A-5C, in Appendix B. The Anderson South Campus
Master Plan used 2-foot contours, as opposed to the one-foot contours used for this study. The
Master Plan subbasins, including existing facilities to remain, are described in Section 4.1
The analysis for the western portion of the campus, including the new tennis courts, provides
water quality for the southern portion of the campus west of the Larimer County Canal (LCC)
No. 2 and detention for the northern portion of the area west of the LCC No. 2. This condition
remains consistent whereas alternatives are proposed for the area east of the LCC No. 2.
Three drainage alternatives were then evaluated for the area east of LCC No. 2. The first
alternative includes three additional off-line detention ponds: Ponds 52, 53, and 54. These
ponds would collect runoff from tributary basins and discharge flows into the existing stormwater
channel. The second alternative includes the same detention ponds, but the ponds would be
constructed on-line (along the existing channel). The proposed detention ponds for both
detention alternatives would provide water quality storage and detain developed on-site flows
resulting from the Master Plan improvements, releasing flows at the 2-year historic flow rates.
The third alternative includes rerouting the existing channel into a meandering swale and
construction of three water quality ponds along the relocated channel. This alternative would not
provide any additional detention of onsite flows, although it would provide enhanced water
quality and a more aesthetically pleasing environment.
4.1 Basin Description
Subbasin 62 will consist of a parking lot, a proposed building, Pond 362, and landscaped areas.
The future percent imperviousness for this subbasin is 46%. Stormwater drains to the
southeast to Pond 362, which outlets into in a small swale to Pond 50, which is located in
Subbasin 66.
Subbasin 65 will consist of paved streets, a proposed parking lot, animal pens, the portion of
Pond 50 that is north of the paved road, and landscaped areas. The future percent
imperviousness for this subbasin is 36%. Stormwater drains to the east along the paved road to
Pond 50 which outlets into a swale that flows to the north.
Subbasin 65A will consist of paved streets, a portion of the proposed sheep barn, proposed
animal pens, and landscaped areas. The future percent imperviousness for this subbasin is
63%. Stormwater drains to the east along Booth Road to Pond 52, which is located in Subbasin
65C.
Subbasin 65C will consist of a portion of the proposed sheep barn and small animal barn, the
existing hay barn, proposed animal pens, paved areas, Pond 52, and landscaped areas. The
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future percent imperviousness for this subbasin is 28%. Stormwater drains to the east to Pond
52 which outlets into a swale that flows to the north.
Subbasin 66 will consist of parking lots, existing and proposed buildings, the portion of Pond 50
that is south of the paved road, and landscaped areas. The future percent imperviousness for
this subbasin is 67%. Stormwater drains to the south along Gillette Drive, until it reaches a curb
cut that directs flows into Pond 50 which outlets into a swale that flows to the north.
Subbasin 67 will consist of a paved roadway, existing and proposed buildings, proposed animal
pens, and landscaped areas. The future percent imperviousness for this subbasin is 68%.
Stormwater drains east along Niswender Road to a swale that flows to the north.
Subbasin 67A will consist of a paved roadway, a parking lot, existing and proposed buildings,
proposed animal pens, Pond 53, and landscaped areas. The future percent imperviousness for
this subbasin is 43%. Stormwater drains to the east to Pond 53 which outlets into a swale that
flows to the north.
Subbasin 67B will consist of a paved roadway, existing, and proposed buildings. The future
percent imperviousness for this subbasin is 97%. Stormwater will drain east in a proposed 30-
inch RCP to Pond 53, which is located in Subbasin 67A.
Subbasin 67C will consist of a parking lot, existing and proposed buildings, and landscaped
areas. The future percent imperviousness for this subbasin is 44%. Stormwater will drain to the
west toward Gillette Drive, which is located in Subbasin 66.
Subbasin 68 will consist of a paved roadway, a parking lot, existing and proposed buildings,
Pond 54, and landscaped areas. The future percent imperviousness for this subbasin is 63%.
Stormwater will drain to the east along a paved road to Pond 54 which outlets into a swale that
flows to the north to a 78-inch reinforced concrete pipe (RCP) that discharges to Spring Creek.
Subbasin 89 will consist of the CSU tennis courts, Detention Pond 289, parking lots, and
landscaped areas. The future percent impervious for this subbasin is 61%, which was calculated
based off of the Tennis Court Parking Lot Final Drainage Report, prepared by Olsson
Associates in 2015. Stormwater outlets Pond 289 to the east in an 18-inch RCP to Pond 54,
which is located in Subbasin 68.
A summary of the Master Plan subbasin areas and percent impervious compared to existing
conditions is shown in Table 8.
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Table 8: Changes to Proposed Condition
Basin Property
Existing
Conditions
Proposed
Conditions
62
Area (acres) 4.2 4.2
% Impervious 2% 46%
65
Area (acres) 6.7 5.7
% Impervious 8% 36%
65A
Area (acres) --- 3.0
% Impervious --- 63%
65C
Area (acres) --- 3.5
% Impervious --- 28%
66
Area (acres) 22.7 25.3
% Impervious 65% 67%
67
Area (acres) 25.6 5.3
% Impervious 55% 98%
67A
Area (acres) --- 5.8
% Impervious --- 43%
67B
Area (acres) --- 2.4
% Impervious --- 97%
67C
Area (acres) --- 4.8
% Impervious --- 44%
68*
Area (acres) 16.0 15.2
% Impervious 30% 63%
89
Area (acres) 16.0 16.0
% Impervious 61% 61%
4.2 Detention Basin Alternative
4.2.1 Off-Line Detention Alternative
The existing swale located on the east side of the project area drains stormwater from Pond 50
at the southeast corner of the South Campus north to Spring Creek. The first alternative for
stormwater improvements includes adding detention ponds prior to discharging into the existing
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swale, as shown in Exhibit 6, in Appendix B. Three detention ponds 52, 53, and 54, would be
added as off-line detention ponds that would outlet directly into the swale.
Proposed detention ponds will provide water quality capture volume. Due to the high nutrient
loading of the stormwater, it is also proposed to provide additional water quality by providing a
meandering bioswale to be constructed upstream of the detention ponds. This bioswale would
be offset approximately 5 feet from the proposed detention ponds. When the bioswale reaches
its capacity, stormwater will overflow to Detention Ponds 52, 53, and 54. A summary of the
detention and water quality pond volumes can be found in Table 9.
Table 9: Required Water Quality and Detention Requirements
Pond
Required
Detention
Volume (AC-FT)
WQCV
Required
(ac-ft)
Off-Line
Total
Required
Volume
(ac-ft)
52 1.31 0.15 1.46
53 3.14 0.48 3.62
54 3.47 0.48 3.95
362* 0.87 0.11 0.98
*Pond 362 will primarily be utilized for water quality with a maximum capacity of 0.38 ac-ft
Proposed Pond 362 is located in basin 62, which is in the southwest portion of the South
Campus. Due to site constraints, only 0.38 af-ft of volume can be achieved in Pond 362 given
the current layout of the proposed south campus buildings, sidewalks, and utilities. While this
volume does not provide adequate detention, it will provide water quality and limited detention.
The overflow will be routed to Pond 50.
The grading in the South Campus relative to elevations in the swale will cause some hydraulic
issues in the ponds. Tailwater in the swale may reduce the outflow rate in the ponds. Check
valves will be required to ensure flows do not back into the ponds from the swale. Should this
option be selected, refined modeling of the discharge relative to the pond size is required to
ensure the timing of the release enables the pond to drain appropriately during final design.
The construction costs of the evaluated improvements were estimated using unit costs obtained
from Urban Drainage and Flood Control District’s master planning cost estimator, UD-MP Cost,
Version 2.2. The detention pond unit cost includes excavation, trickle channels, forebays,
micropools, access roads, outlet structures, and revegetation. The estimated cost of this
alternative is shown in Table 10.
South Campus Stormwater Master Plan
Colorado State University 015-0770
December 2015 16
Table 10: Off-Line Detention Alternative Estimated Cost
Description Quantity Unit Unit Cost Total Cost
Detention/WQ Pond 52 (Complete-in-Place) 1.46 AC-FT $48,000 $70,080
Detention/WQ Pond 53 (Complete-in-Place) 3.62 AC-FT $48,000 $173,760
Detention/WQ Pond 54 (Complete-in-Place) 3.95 AC-FT $48,000 $189,600
Detention/WQ Pond 362 (Complete-in-Place) 0.38 AC-FT $48,000 $18,240
Bioswale (Complete-in-Place) 1 L.S. $24,000 $24,000
Dewatering 1 L.S. $5,000 $5,000
Mobilization (5%) 1 L.S. $23,784 $23,784
Traffic Control 1 L.S. $1,000 $1,000
Utility Coordination/Relocation 1 L.S. $5,000 $5,000
Stormwater Management/Erosion Control
(5%)
1 L.S. $23,784 $23,784
Subtotal Capital Improvement Costs $534,248
Engineering (15%) 1 L.S. $80,137 $80,137
Legal/Administrative (5%) 1 L.S. $26,712 $26,712
Contract Admin/Construction Management
(10%)
1 L.S. $53,425 $53,425
Contingency (25%) 1 L.S. $133,562 $133,562
Subtotal Other Costs $293,836
Total Capital Improvement Costs $828,084
4.2.2 On-Line Detention Alternative
If the detention ponds included in the off-line detention alternative were instead on-line ponds
along the existing swale, there would be significantly more developable land, as shown in
Exhibit 7, in Appendix B. On-line detention would slightly reduce the overall peak flow in the
swale; however, due to the difference in timing of the peak flow from the south campus tributary
basins and the peak flow for the outfall of Pond 50, the in-line ponds would not provide much
detention of the developed site and little to no water quality benefit. The net impact was a
reduction in peak flows of 10 cfs, as compared to existing conditions, at the downstream end of
the developed site. No water quality capture volume would be included in the ponds. Water
quality would only be addressed by meandering bioswales on the upstream side of the
detention ponds. The water quality and detention provided in this alternative do not justify the
increased developable land and this alternative is therefore not recommended.
The construction costs of the evaluated improvements were estimated using unit costs obtained
from Urban Drainage and Flood Control District’s master planning cost estimator, UD-MP Cost,
Version 2.2. The detention pond unit cost includes excavation, trickle channels, forebays,
micropools, access roads, outlet structures, and revegetation. The estimated cost of this
alternative is shown in Table 11.
South Campus Stormwater Master Plan
Colorado State University 015-0770
December 2015 17
Table 11: On-Line Detention Alternative Estimated Cost
Description Quantity Unit Unit Cost Total Cost
Detention Pond 52 (Complete-in-Place) 2.20 AC-FT $48,000 $105,600
Detention Pond 53 (Complete-in-Place) 1.56 AC-FT $48,000 $74,880
Detention Pond 54 (Complete-in-Place) 4.36 AC-FT $48,000 $209,280
Detention/WQ Pond 362 (Complete-in-
Place)
0.38 AC-FT $48,000 $18,240
Bioswale (Complete-in-Place) 1 L.S. $24,000 $24,000
Dewatering 1 L.S. $5,000 $5,000
Mobilization (5%) 1 L.S. $21,600 $21,600
Traffic Control 1 L.S. $1,000 $1,000
Utility Coordination/Relocation 1 L.S. $5,000 $5,000
Stormwater Management/Erosion
Control (5%)
1 L.S. $21,600 $21,600
Subtotal Capital Improvement Costs $486,200
Engineering (15%) 1 L.S. $72,930 $72,930
Legal/Administrative (5%) 1 L.S. $24,310 $24,310
Contract Admin/Construction
Management (10%)
1 L.S. $48,620 $48,620
Contingency (25%) 1 L.S. $121,550 $121,550
Subtotal Other Costs $267,410
Total Capital Improvement Costs $753,610
4.3 Water Quality Alternative
The final alternative for stormwater improvements addresses only water quality for the proposed
improvements on South Campus that lie east of LCC No. 2. The most significant impact of the
South Campus plan is the increased presence of animal manure to the storm system. To help
alleviate this loading, bioswales would be constructed to collect stormwater from the developed
facilities and convey it to water quality ponds. The water quality ponds would be located at the
same location as the proposed off-line detention pond alternative. The existing swale along the
eastern border would be realigned to have a more natural, meandering, alignment. This
alternative would not provide any additional detention of on-site flows; however, it would provide
enhanced water quality and a more aesthetically pleasing environment. This alternative is
shown on Exhibit 8, in Appendix B. A summary of the water quality storage pond volumes can
be found in Table 12. It should be noted that Pond 362 will provide limited detention volume as
well as water quality capture volume resulting in a total storage of 0.38 ac-ft.
South Campus Stormwater Master Plan
Colorado State University 015-0770
December 2015 18
Table 12: Water Quality Requirements
Pond WQCV Required
(ac-ft)
51 0.12
52 0.15
53 0.48
54 0.48
362 0.11
The construction costs of the evaluated improvements were estimated using unit costs obtained
from Urban Drainage and Flood Control District’s master planning cost estimator, UD-MP Cost,
Version 2.2. The water quality pond unit cost includes excavation, trickle channels, forebays,
micropools, access roads, outlet structures, and revegetation. The estimated cost of this
alternative is shown in Table 13.
Table 13: Water Quality Alternative Estimated Cost
Description Quantity Unit Unit Cost Total Cost
Water Quality Pond 50 (Complete-in-Place) 0.12 AC-FT $48,000 $5,760
Water Quality Pond 52 (Complete-in-Place) 0.15 AC-FT $48,000 $7,200
Water Quality Pond 53 (Complete-in-Place) 0.48 AC-FT $48,000 $23,040
Water Quality Pond 54 (Complete-in-Place) 0.48 AC-FT $48,000 $23,040
Detention/WQ Pond 362 (Complete-in-Place) 0.38 AC-FT $48,000 $18,240
Swale (Complete-in-Place) 12,000 CY $20 $240,000
Bioswale (Complete-in-Place) 1 L.S. $24,000 $24,000
Dewatering 1 L.S. $5,000 $5,000
Mobilization (5%) 1 L.S. $17,064 $17,064
Traffic Control 1 L.S. $1,000 $1,000
Utility Coordination/Relocation 1 L.S. $5,000 $5,000
Stormwater Management/Erosion Control
(5%)
1 L.S. $17,064 $17,064
Subtotal Capital Improvement Costs $386,408
Engineering (15%) 1 L.S. $57,961 $57,961
Legal/Administrative (5%) 1 L.S. $19,320 $19,320
Contract Admin/Construction Management
(10%)
1 L.S. $38,641 $38,641
Contingency (25%) 1 L.S. $96,602 $96,602
Subtotal Other Costs $212,524
Total Capital Improvement Costs $598,932
South Campus Stormwater Master Plan
Colorado State University 015-0770
December 2015 19
5.0 RECOMMENDATIONS
The water quality alternative is recommended to be implemented as part of the CSU South
Campus Master Plan. With the Master Plan improvements in place, the total outflow of Pond
303 would be 1,932 cfs, as compared to the effective outflow of 1,972 cfs. Pond 303
encompasses not only the Spring Creek floodplain, but also the FEMA designated floodway.
The effective water surface elevation at Pond 303 is 4995.12 (NGVD29 datum), or 4988.10
(NAVD88 datum). The proposed water surface elevation will be 4994.90 (NGVD29 datum), or
4997.88 (NAVD88 datum). Because the proposed water surface elevation is lower that the
effective, no CLOMR/LOMR will be required for the proposed improvements.
This alternative will better serve the watershed by providing additional water quality facilities
without negatively affecting the capacity of downstream infrastructure. The proposed stormwater
improvements will reduce the potential for pollutants entering Spring Creek.
APPENDIX A
EXISTING CONDITIONS ANALYSIS
Exhibit 2: Existing Conditions Basin Map
Exhibit 3: Existing Conditions SWMM Schematic
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
R
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
EXISTING CONDITIONS BASIN MAP
2
LEGEND
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
EXISTING CONDITIONS
SWMM SCHEMATIC 3R
APPENDIX B
MASTER PLAN
Exhibit 4: Master Plan Basin Map
Exhibits 5A-5C: Master Plan SWMM Schematics
Exhibit 6: Off-line Detention Pond Alternative
Exhibit 7: On-line Detention Pond Alternative
Exhibit 8: Water Quality Pond Alternative
CSURF-Controlled
Property
University-Controlled
Property
New/Future
Buildings
Existing
Buildings
LEGEND
LEGEND
CSURF-Controlled
Property
University-Controlled
Property
New/Future
Buildings
Existing
Buildings
N
WEST
DRAKE
ROAD
JENSEN ROAD
CENTRE
AVENUE
NISWENDER
ROAD
BOOTH
ROAD
CROSS
DRIVE
G I L E T T E D R I V E
R E S E A R C H B O U L E V A R D
PHEMISTER
ROAD
MASONTRAIL MAX BRT
MEDIC
AL
C
AMPUS:
MASTER
PLAN
UPDATE
FEB. 2015
MEDIC
AL
C
AMPUS:
MASTER
PLAN
UPDATE
EXISTING
FACILITIES
1.
Veterinar
y
Teaching
Hospital
2.
Diagnostic
Medicine
Center
3.
Equine
Orthopaedic
Research
Center
4.
Facilities
Carpentry
Shop
5.
Chill
Plant
6.
Hay
Barn
7.
Tennis
Courts
PROPOSED
FACILITIES
8.
Sheep
Barn
9.
Hay
Barn
10.
Small
Animal
Barn
11.
Institute
for
Biological
&
Translational
Therapies
12.
Equine
Hospital
13.
Second
Year
DVM
14.
Community
Practice
15.
Parking
16.
Relocated
Large
Animal
Program
17.
Stormwater
Detention/Treatment
18.
Cancer
Innovation
Center
19.
900-Space
Parking
Lot
(Summer
2015)
9
17
11
10
5
4
12
3
6
8
2
16
13
14
15
1
18
19
7
Facilities
Management
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
R
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
MASTER PLAN
BASIN MAP 4
LEGEND
NOTE: FOR THE OFF-LINE DETENTION POND ALTERNATIVE BASINS 65A,
65C, 67, 67A, 67B AND 68 ARE MODELED AS 2-YEAR EXISTING TO
REPLICATE THE HISTORIC FLOW RATES DISCHARGING FROM THE
OFF-LINE DETENTION PONDS INTO THE EXISTING SWALE AS REQUIRED
BY CITY OF FORT COLLINS CRITERIA.
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney BoulevardOFF-LINE DETENTION POND
MASTER PLAN
SWMM SCHEMATIC 5AR
NOTE: BASINS 65A, 65C, 67, 67A, 67B AND 68 ARE MODELED AS 2-YEAR
EXISTING TO REPLICATE THE HISTORIC FLOW RATES DISCHARGING
FROM THE OFF-LINE DETENTION PONDS INTO THE EXISTING SWALE AS
REQUIRED BY CITY OF FORT COLLINS CRITERIA.
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney BoulevardON-LINE DETENTION POND
MASTER PLAN
SWMM SCHEMATIC 5BR
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney BoulevardWATER QUALITY POND
MASTER PLAN
SWMM SCHEMATIC 5CR
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
R
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
OFF-LINE DETENTION POND
ALTERNATIVE 6
LEGEND
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
R
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
ON-LINE DETENTION POND ALTERNATIVE
7
LEGEND
POND 50
015-0770PROJECT NO:
DRAWN BY:
12/04/2015
FJS/MKD
EXHIBIT
R
TEL 970.461.7733
Loveland, CO 80538
Suite 160
5285 McWhinney Boulevard
WATER QUALITY POND ALTERNATIVE
8
LEGEND
APPENDIX C
WATER QUALITY CALCUL ATIONS
Project:
Basin ID:
WQCV Design Volume (Input):
Catchment Imperviousness, Ia =36.0 percent
Catchment Area, A =5.70 acres Diameter of holes, D =inches
Depth at WQCV outlet above lowest perforation, H =1 feet Number of holes per row, N =
Vertical distance between rows, h =4.00 inches OR
Number of rows, NL =4.00
Orifice discharge coefficient, Co =0.67 Height of slot, H =inches
Slope of Basin Trickle Channel, S =0.004 ft / ft Width of slot, W =inches
Time to Drain the Pond =40 hours
Watershed Design Information (Input):1
Percent Soil Type A =%
Percent Soil Type B =%
Percent Soil Type C/D =100 %
Outlet Design Information (Output):
Water Quality Capture Volume, WQCV =0.217 watershed inches
Water Quality Capture Volume (WQCV) =0.103 acre-feet 0.00
Design Volume (WQCV / 12 * Area * 1.2) Vol =0.124 acre-feet
Outlet area per row, Ao =0.42 square inches
Total opening area at each row based on user-input above, Ao =0.00 square inches
Total opening area at each row based on user-input above, Ao =0.000 square feet
3
Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 S
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Area
Row 19
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Area
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Area
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Area
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Area
Row 23
Override
Area
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Central Elevations of Rows of Holes in feet
Collection Capacity for Each Row of Holes in cfs
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
WQV-POND51.xls, WQCV 12/22/2015, 4:46 PM
Project:
Basin ID:
WQCV Design Volume (Input):
Catchment Imperviousness, Ia =45.4 percent
Catchment Area, A =6.05 acres Diameter of holes, D =inches
Depth at WQCV outlet above lowest perforation, H =1 feet Number of holes per row, N =
Vertical distance between rows, h =4.00 inches OR
Number of rows, NL =4.00
Orifice discharge coefficient, Co =0.67 Height of slot, H =inches
Slope of Basin Trickle Channel, S =0.004 ft / ft Width of slot, W =inches
Time to Drain the Pond =40 hours
Watershed Design Information (Input):1
Percent Soil Type A =%
Percent Soil Type B =%
Percent Soil Type C/D =100 %
Outlet Design Information (Output):
Water Quality Capture Volume, WQCV =0.254 watershed inches
Water Quality Capture Volume (WQCV) =0.128 acre-feet 0.00
Design Volume (WQCV / 12 * Area * 1.2) Vol =0.153 acre-feet
Outlet area per row, Ao =0.51 square inches
Total opening area at each row based on user-input above, Ao =0.00 square inches
Total opening area at each row based on user-input above, Ao =0.000 square feet
3
Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 S
Flow
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Row 2
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Area
Row 3
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Area
Row 4
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Area
Row 5
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Area
Row 6
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Area
Row 7
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Area
Row 8
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Area
Row 9
Override
Area
Row 10
Override
Area
Row 11
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Area
Row 12
Override
Area
Row 13
Override
Area
Row 14
Override
Area
Row 15
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Area
Row 16
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Area
Row 17
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Area
Row 18
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Area
Row 19
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Area
Row 20
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Area
Row 21
Override
Area
Row 22
Override
Area
Row 23
Override
Area
Row 24
Central Elevations of Rows of Holes in feet
Collection Capacity for Each Row of Holes in cfs
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
WQV-POND52.xls, WQCV 12/22/2015, 4:45 PM
Project:
Basin ID:
WQCV Design Volume (Input):
Catchment Imperviousness, Ia =74.2 percent
Catchment Area, A =13.50 acres Diameter of holes, D =inches
Depth at WQCV outlet above lowest perforation, H =1 feet Number of holes per row, N =
Vertical distance between rows, h =4.00 inches OR
Number of rows, NL =4.00
Orifice discharge coefficient, Co =0.67 Height of slot, H =inches
Slope of Basin Trickle Channel, S =0.004 ft / ft Width of slot, W =inches
Time to Drain the Pond =40 hours
Watershed Design Information (Input):1
Percent Soil Type A =%
Percent Soil Type B =%
Percent Soil Type C/D =100 %
Outlet Design Information (Output):
Water Quality Capture Volume, WQCV =0.353 watershed inches
Water Quality Capture Volume (WQCV) =0.397 acre-feet 0.00
Design Volume (WQCV / 12 * Area * 1.2) Vol =0.476 acre-feet
Outlet area per row, Ao =1.50 square inches
Total opening area at each row based on user-input above, Ao =0.00 square inches
Total opening area at each row based on user-input above, Ao =0.000 square feet
3
Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 S
Flow
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Row 3
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Row 4
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Area
Row 5
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Area
Row 6
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Area
Row 7
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Area
Row 8
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Area
Row 9
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Area
Row 10
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Area
Row 11
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Area
Row 12
Override
Area
Row 13
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Area
Row 14
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Area
Row 15
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Area
Row 16
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Area
Row 17
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Area
Row 18
Override
Area
Row 19
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Area
Row 20
Override
Area
Row 21
Override
Area
Row 22
Override
Area
Row 23
Override
Area
Row 24
Central Elevations of Rows of Holes in feet
Collection Capacity for Each Row of Holes in cfs
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
WQV-POND53.xls, WQCV 12/22/2015, 4:47 PM
Project:
Basin ID:
WQCV Design Volume (Input):
Catchment Imperviousness, Ia =63.0 percent
Catchment Area, A =15.20 acres Diameter of holes, D =inches
Depth at WQCV outlet above lowest perforation, H =1 feet Number of holes per row, N =
Vertical distance between rows, h =4.00 inches OR
Number of rows, NL =4.00
Orifice discharge coefficient, Co =0.67 Height of slot, H =inches
Slope of Basin Trickle Channel, S =0.004 ft / ft Width of slot, W =inches
Time to Drain the Pond =40 hours
Watershed Design Information (Input):1
Percent Soil Type A =%
Percent Soil Type B =%
Percent Soil Type C/D =100 %
Outlet Design Information (Output):
Water Quality Capture Volume, WQCV =0.316 watershed inches
Water Quality Capture Volume (WQCV) =0.400 acre-feet 0.00
Design Volume (WQCV / 12 * Area * 1.2) Vol =0.480 acre-feet
Outlet area per row, Ao =1.52 square inches
Total opening area at each row based on user-input above, Ao =0.00 square inches
Total opening area at each row based on user-input above, Ao =0.000 square feet
3
Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 S
Flow
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Area
Row 23
Override
Area
Row 24
Central Elevations of Rows of Holes in feet
Collection Capacity for Each Row of Holes in cfs
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
WQV-POND54.xls, WQCV 12/22/2015, 4:47 PM
Project:
Basin ID:
WQCV Design Volume (Input):
Catchment Imperviousness, Ia =46.0 percent
Catchment Area, A =4.20 acres Diameter of holes, D =inches
Depth at WQCV outlet above lowest perforation, H =1 feet Number of holes per row, N =
Vertical distance between rows, h =4.00 inches OR
Number of rows, NL =4.00
Orifice discharge coefficient, Co =0.67 Height of slot, H =inches
Slope of Basin Trickle Channel, S =0.005 ft / ft Width of slot, W =inches
Time to Drain the Pond =40 hours
Watershed Design Information (Input):1
Percent Soil Type A =%
Percent Soil Type B =%
Percent Soil Type C/D =100 %
Outlet Design Information (Output):
Water Quality Capture Volume, WQCV =0.256 watershed inches
Water Quality Capture Volume (WQCV) =0.090 acre-feet 0.00
Design Volume (WQCV / 12 * Area * 1.2) Vol =0.107 acre-feet
Outlet area per row, Ao =0.36 square inches
Total opening area at each row based on user-input above, Ao =0.00 square inches
Total opening area at each row based on user-input above, Ao =0.000 square feet
3
Row 1 Row 2 Row 3 Row 4 Row 5 Row 6 Row 7 Row 8 Row 9 Row 10 Row 11 Row 12 Row 13 Row 14 Row 15 Row 16 Row 17 Row 18 Row 19 Row 20 Row 21 Row 22 Row 23 Row 23 S
Flow
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Override
Area
Row 1
Override
Area
Row 2
Override
Area
Row 3
Override
Area
Row 4
Override
Area
Row 5
Override
Area
Row 6
Override
Area
Row 7
Override
Area
Row 8
Override
Area
Row 9
Override
Area
Row 10
Override
Area
Row 11
Override
Area
Row 12
Override
Area
Row 13
Override
Area
Row 14
Override
Area
Row 15
Override
Area
Row 16
Override
Area
Row 17
Override
Area
Row 18
Override
Area
Row 19
Override
Area
Row 20
Override
Area
Row 21
Override
Area
Row 22
Override
Area
Row 23
Override
Area
Row 24
Central Elevations of Rows of Holes in feet
Collection Capacity for Each Row of Holes in cfs
STAGE-DISCHARGE SIZING OF THE WATER QUALITY CAPTURE VOLUME (WQCV) OUTLET
WQV-POND362.xls, WQCV 12/22/2015, 4:46 PM
APPENDIX D
EPA SWMM WATER QUALITY MODEL
INPUT AND OUTPUT FILES
EPA SWMM Input
EPA SWMM Output