HomeMy WebLinkAboutReports - Drainage - 07/02/2025FINAL DRAINAGE REPORT
FOR LIBERTY COMMON JUNIOR HIGH
Lots 4, 5, 8 & 9, Prospect Industrial Park
FORT COLLINS, CO
Prepared for:
NEENAN ARCHISTRUCTION
3325 S. Timberline Road, Suite 100
Fort Collins, CO 80525
Contact: Shelby Hinchliff
Phone: 970.218.9607
Prepared by:
ELEVATION CONSULTING GROUP, LTD.
P.O. Box 280869
Lakewood, CO 80226
Contact: Lincoln Thomas, P.E.
Phone: 303.204.5065
JN: 2024020
July 2, 2025
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 2
ENGINNER’S CERTIFICATION
I hereby attest that this report for the final drainage design for the Liberty Common
Junior High was prepared by me or under my direct supervision, in accordance with the
provisions of the Fort Collins Stormwater Criteria Manual. I understand that the City of
Fort Collins does not and will not assume liability for drainage facilities designed by
others.
_______________________________________
Lincoln J. Thomas, PE
State of Colorado No. 42350
For and on behalf of Elevation Consulting
7/02/25
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 3
TABLE OF CONTENTS
1 General Location and Existing Site Information ........................................................ 4
2 Master Drainage Basin Information ............................................................................ 7
3 Project Description...................................................................................................... 8
4 Drainage Design Criteria ............................................................................................ 9
4.1 Regulations ......................................................................................................... 9
4.2 Four-Step Process ............................................................................................... 9
4.3 Hydrologic Criteria ........................................................................................... 10
4.4 Hydraulic Criteria ............................................................................................. 10
4.5 Low Impact Development................................................................................. 10
5 Variance Requests ..................................................................................................... 11
6 Erosion Control ......................................................................................................... 11
7 Conclusions ............................................................................................................... 11
8 References ................................................................................................................. 12
Appendices ........................................................................................................................ 13
APPENDIX A – Hydrologic Computations
APPENDIX B – Hydraulic Computations
APPENDIX C – Referenced Information
APPENDIX D – Drainage Map
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 4
1 General Location and Existing Site Information
Liberty Common Junior High (Site) is located within Section 20, Township 7 North,
Range 68 West of the 6th P.M. The following public roadways bound the Site, Sharp
Point Drive to the northeast, March Court to the northwest and Canton Court to the
southeast. Riverbend Court a former public right-of-way bisecting the Site has be
vacated per Ordinance No. 004, 2025 and is now part of the Site. Liberty Common
Elementary School is located to the northwest and southwest of the Site; 2601 Riverbend
Court, 2609 Riverbend Court and 2600 Canton Court, existing commercial buildings, are
also located to the southwest of the Site; Merganser Pond is located to the northeast of the
Site; 2619 Canton Court, and existing multi-tenant building is located to the southeast of
the Site, see vicinity map below.
Figure 1-1
Vicinity Map
The Site is located within the Cache La Poudre Master Basin per Figure 2.0-1 of the Fort
Collins Stormwater Criteria Manual (FCSCM).
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 5
There are no major drainageways through the Site. Per Flood Insurance Rate Map
(FIRM) Map No. 08069C0984H and 08069C0992G, the Site is located in Zone X and not
within a regulatory floodplain of Cache La Poudre River.
There are no major irrigation facilities within or adjacent to the Site.
Per the NRCS Soils Map in Appendix C, soils for this drainage study consist of Loveland
clay loam, Caruso clay loam and Table Mountain loam. NRCS hydrologic soils group C
has been used for the hydrology calculations for this drainage study.
The Site is 4.05 acres, including the vacated right-of-way for Riverbend Court. Current
improvements within the Site consist of 1825 Sharp Point Drive, an existing multi-tenant
office building and parking lot; Riverbend Court, an existing cul-de-sac; and 1901 Sharp
Point Drive, an existing multi-tenant office building and parking lot. A drainage area of
8.95 acres has been analyzed for the existing condition in this Drainage Report and is
divided into 19 existing sub-basins.
Basin EX1 (0.73 ac) is located behind the 1825 Sharp Point Drive building. The basin
consists of hardscape and landscaping. Runoff sheet flows to three area inlets within the
parking lot and conveyed via (3) 12-inch storm sewer pipes under the building to an inlet
(Design Point 3) on the front side of the building which outfalls to Merganser Pond.
(Q2=1.8 cfs, Q100=7.3 cfs). In the event the inlets becomes plugged, emergency
overflow path is at the southwest corner of the 1825 Sharp Point Drive building and into
Basin EX3.
Basin EX2 (0.44 ac) is located to the north of Basin EX1. The basin consists of the 1825
Sharp Point Drive building roof. Runoff is collected and routed through internal drains to
the (3) 12-inch storm sewer pipes under the building and routed to an inlet (Design Point
3) on the front side of the building which outfalls to Merganser Pond. (Q2=1.2 cfs,
Q100=4.4 cfs).
Basin EX3 (0.09 ac) is located to the west of the 1825 Sharp Point Drive building. The
basin consists of hardscape and landscaping. Runoff sheet flows to a swale and drainage
channel and is conveyed to the parking lot on the front side of the building, collected in
an inlet (Design Point 3) and conveyed to Merganser Pond. (Q2=0.1 cfs, Q100=0.4 cfs).
Basin EX4 (0.54 ac) is located in front of the 1825 Sharp Point Drive building. The basin
consists of hardscape and landscaping. Runoff sheet flows to an inlet (Design Point 3)
and conveyed to Merganser Pond. (Q2=1.1 cfs, Q100=4.9 cfs). In the event the inlet
becomes plugged, emergency overflow path is to the north and into Sharp Point Drive.
Basin EX5 (0.58 ac) is located to the east of 1825 Sharp Point Drive. The basin consists
of hardscape and landscaping. Runoff sheet flows to the vacated Riverbend Court curb
and gutter and is conveyed to Sharp Point Drive right-of-way, collected by a sump curb
inlet which outfalls to Merganser Pond. (Q2=1.0 cfs, Q100=4.9 cfs).
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
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Basin EX6 (0.28 ac) is located behind the 1901 Sharp Point Drive building. The basin
consists of hardscape and landscaping. Runoff sheet flows to an area inlet (Design Point
5) within the parking lot and conveyed via a 12-inch storm sewer pipe under the building
to an inlet (Design Point 8) on the front side of the building which outfalls to Merganser
Pond. (Q2=0.7 cfs, Q100=2.8 cfs). In the event the inlet becomes plugged, emergency
overflow path is at the southeast corner of the 1901 Sharp Point Drive building and into
Basin EX9.
Basin EX7 (0.33 ac) is located behind the 1901 Sharp Point Drive building. The basin
consists of hardscape and landscaping. Runoff sheet flows to an area inlet (Design Point
4) within the parking lot and conveyed via a 12-inch storm sewer pipe under the building
to an inlet (Design Point 8) on the front side of the building which outfalls to Merganser
Pond. (Q2=0.9 cfs, Q100=3.3 cfs). In the event the inlet becomes plugged, emergency
overflow path is at the southeast corner of the 1901 Sharp Point Drive building and into
Basin EX9.
Basin EX8 (0.23 ac) is located to the north of Basin EX6. The basin consists of a portion
of the 1901 Sharp Point Drive building roof. Runoff is collected and routed through
internal drains to an external drain on the east side of the building where a concrete
drainage channel conveys flows to the parking lot on the front side of the building.
Flows are collected via parking lot inlet (Design Point 8) and conveyed to Merganser
Pond. (Q2=0.6 cfs, Q100=2.3 cfs).
Basin EX9 (0.04 ac) is located to the east of Basin EX8. The basin consists of hardscape
and landscaping. Runoff sheet flows to drainage channels and is conveyed to the parking
lot on the front side of the building. Flows are collected via parking lot inlet (Design
Point 8) and conveyed to Merganser Pond. (Q2=0.0 cfs, Q100=0.1 cfs).
Basin EX10 (0.56 ac) is located in front of the 1901 Sharp Point Drive building. The
basin consists of hardscape and landscaping. Runoff sheet flows to an inlet (Design Point
8) and conveyed to Merganser Pond. (Q2=1.1 cfs, Q100=4.9 cfs). In the event the inlet
becomes plugged, emergency overflow path is to the north and into Sharp Point Drive.
Basin EX11 (0.23 ac) is located to the north of Basin EX7. The basin consists of a
portion of the 1901 Sharp Point Drive building roof. Runoff is collected and routed
through internal drains to an external drain on the west side of the building where it
discharges to the vacated Riverbend Court curb and gutter and is conveyed to Sharp Point
Drive right-of-way, collected by a sump curb inlet which outfalls to Merganser Pond.
(Q2=0.6 cfs, Q100=2.3 cfs).
Basin OS1 (1.61 ac) is an offsite basin located to the south of Basin EX1 and consists of a
portion of the Liberty Common Elementary school track and field. Land uses are
hardscape, gravel and landscaping. Runoff is collected via trench drain or underdrains
and routed to a junction structure in the eastern portion of the field where it discharges to
the vacated Riverbend Court curb and gutter and is conveyed to Sharp Point Drive right-
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 7
of-way, collected by a sump curb inlet which outfalls to Merganser Pond. (Q2=1.6 cfs,
Q100=6.9 cfs).
Basin OS2 (1.45 ac) is an offsite basin located adjacent to OS1 and consists of the
remaining portion of the Liberty Common Elementary school track and field. Land uses
are hardscape, gravel and landscaping. Runoff is collected via trench drain or
underdrains and routed to a junction structure in the eastern portion of the field where it
discharges to the vacated Riverbend Court curb and gutter and is conveyed to Sharp Point
Drive right-of-way, collected by a sump curb inlet which outfalls to Merganser Pond.
(Q2=1.3 cfs, Q100=5.9 cfs).
Basin OS3 (1.24 ac) is an offsite basin located to the south of Basin EX7. Land uses are
industrial. Runoff sheet flows to a concrete drainage channel within the basin and is
conveyed to the area inlet within Basin EX7 (Design Point 4) and onto Merganser Pond
via the 1901 Sharp Point Drive storm sewer system. (Q2=3.0 cfs, Q100=11.2 cfs).
Basin OS4 (0.54 ac) is an offsite basin located to the south of Basin EX6. Land uses are
industrial. Runoff sheet flows to a concrete drainage channel within the basin and is
conveyed to the area inlet within Basin EX6 (Design Point 5) and onto Merganser Pond
via the 1901 Sharp Point Drive storm sewer system. (Q2=1.3 cfs, Q100=5.4 cfs).
Basin OS5 (0.01 ac) is an offsite basin located to the east of Basin EX6. Land uses are
landscape. Runoff sheet flows to the area inlet within Basin EX6 (Design Point 5) and
onto Merganser Pond via the 1901 Sharp Point Drive storm sewer system. (Q2=0.0 cfs,
Q100=0.0 cfs).
Basin OS6 (0.01 ac) is an offsite basin located to the north of Basin EX10. Land uses are
landscape. Runoff sheet flows to the area inlet within Basin EX10 (Design Point 8) and
onto Merganser Pond via the 1901 Sharp Point Drive storm sewer system. (Q2=0.0 cfs,
Q100=0.0 cfs).
Basin OS7 (0.02 ac) is an offsite basin located to the west of Basin EX1. Land uses are
hardscape and landscape. Runoff sheet flows to the area inlet within Basin EX1 and onto
Merganser Pond via the 1825 Sharp Point Drive storm sewer system. (Q2=0.0 cfs,
Q100=0.1 cfs).
Basin OS8 (0.02 ac) is an offsite basin located to the north of Basin EX4. Land uses are
landscape. Runoff sheet flows to the area inlet within Basin EX4 (Design Point 3) and
onto Merganser Pond via the 1825 Sharp Point Drive storm sewer system. (Q2=0.0 cfs,
Q100=0.1 cfs).
2 Master Drainage Basin Information
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 8
The Site is located within the Cache La Poudre River watershed. Per the City’s website,
the Master Plan update for the watershed is currently underway. Site is not identified on
the Cache La Poudre River Problem Identification Map or Flooding Solution Map.
3 Project Description
The majority of the existing improvements are to remain. Construction includes minor
parking lot improvements, utility services, landscaping and 17,240 s.f. building addition
between 1825 and 1901 Sharp Point Drive buildings. The proposed construction
activities associated with this report are grading, paving, utility, storm drainage
improvements and vertical construction with the total area of these proposed grading
activities being 1.33 acres. The existing grades are flat to steep ranging from less than
1% to 24%.
The overall drainage area of 8.95 acres did not change with the post development
analysis, 2 new sub-basins were created as well as modifications to 8 existing sub-basins.
Basin C2 ( 0.90 ac) is located in between 1825 and 1901 Sharp Point Drive buildings. Land
uses are rooftop, landscape and hardscape. Surface runoff will be conveyed overland to
Rain Garden #1 and routed through the Site storm sewer system to Merganser Pond.
Building runoff will be piped via the Site storm sewer system to the Rain Garden #1 and
routed through the Site storm sewer system to Merganser Pond. (Q2=1.6 cfs, Q100=6.9
cfs).
Basin C3 ( 0.07 ac) is located to the north of Basin C2. Land uses are landscape and
hardscape. Runoff sheet flows to Sharp Point Drive right-of-way, collected by a sump
curb inlet which outfalls to Merganser Pond. (Q2=0.0 cfs, Q100=0.2 cfs).
Basin EX1-A (0.96 ac) Land uses are not being changed, but basin area and composite
imperviousness are being modified with Site improvements. Runoff will continue to
sheet flow to three existing area inlets within the parking lot and conveyed via (3) 12-
inch storm sewer pipes under the building to an inlet (Design Point 3) on the front side of
the building which outfalls to Merganser Pond. (Q2=2.2 cfs, Q100=9.6 cfs). Emergency
overflow path will not change and continue to be into Basin EX3.
Basin EX2-A (0.44 ac) is located to the north of Basin EX1-A. The basin area and land
use have not been changed. Runoff will now be collected and routed through internal
drains to (2) new external roof drains on the March Court side of the building. Runoff
sheet flows to a swale and drainage channel within Basin EX-3 and is conveyed to the
parking lot on the front side of the building, collected in the existing inlet (Design Point
3) and conveyed to Merganser Pond. (Q2=1.2 cfs, Q100=4.4 cfs).
Basin EX4-A (0.48 ac) Land uses are not being changed, but basin area and composite
imperviousness are being modified with Site improvements. Runoff will continue to
sheet flow to an existing inlet within the parking lot (Design Point 3) and be conveyed to
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 9
Merganser Pond. (Q2=1.0 cfs, Q100=4.5 cfs). Emergency overflow path will not change
and continue to be into Sharp Point Drive.
Basin EX7-A (0.33 ac) Site improvements do not modify the Basin area or land uses, but
there is a change in composite imperviousness. Runoff will continue to sheet flow to an
area inlet (Design Point 4) within the parking lot and conveyed via a 12-inch storm sewer
pipe under the building to an inlet (Design Point 8) on the north side of the building
which outfalls to Merganser Pond. (Q2=0.8 cfs, Q100=3.3 cfs). Emergency overflow
path will not change and continue to be into Basin EX9.
Basin EX10-A (0.23 ac) ) Land uses are not being changed, but basin area and composite
imperviousness are being modified with Site improvements. Runoff will now be
conveyed overland to Rain Garden #2 and routed through the Site storm sewer system to
Merganser Pond. (Q2=0.1 cfs, Q100=1.0 cfs). Emergency overflow path will not change
and continue to be into Sharp Point Drive.
Basin OS1-A (1.61 ac) Land uses, basin area and composite imperviousness are not being
modified with Site improvements. Runoff will now discharge to the March Court curb
and gutter, conveyed to Sharp Point Drive right-of-way, collected by a sump curb inlet
which outfalls to Merganser Pond. (Q2=1.6 cfs, Q100=6.9 cfs).
Basin OS2-A (1.44 ac) Land uses, basin area and composite imperviousness are not being
modified with Site improvements. Runoff will now discharge to the March Court curb
and gutter, conveyed to Sharp Point Drive right-of-way, collected by a sump curb inlet
which outfalls to Merganser Pond. (Q2=1.3 cfs, Q100=5.9 cfs).
Basin OS7-A (0.02 ac) Land uses, basin area and composite imperviousness are not being
modified with Site improvements. Runoff will now discharge to the March Court curb
and gutter, conveyed to Sharp Point Drive right-of-way, collected by a sump curb inlet
which outfalls to Merganser Pond. (Q2=0.0 cfs, Q100=0.1 cfs).
4 Drainage Design Criteria
4.1 Regulations
This drainage report was prepared in accordance with the Fort Collins Stormwater Citeria
Manual (FCSCM).
4.2 Four-Step Process
Site complies with the City’s four step process to minimize adverse impacts of
urbanization. Step 1 – Employing runoff reduction practices; new Site imperviousness,
73%, will not exceed existing conditions, 80%, therefore reducing runoff volume. Step 2
– Implementing best management practice (BMPs) that provide a water quality capture
volume with slow release and/or infiltration; new rain gardens will be constructed as part
of the project to provide WQCV for modified areas of the Site. Step 3 – Stabilizing
streams; there are no drainageways on or adjacent to the Site, therefore Step 3 is not
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 10
applicable to this project. Step 4 – Implementing site specific and other source control
BMPs; Site use of a school facility will minimize risk for illicit discharges from material
storage, vehicle maintenance and manufacturing as these site activities are not generally
associated with a school facility. Good housekeeping practices will be implemented to
control the potential for illicit discharges from the Site.
4.3 Hydrologic Criteria
The minor storm was calculated for the 2-year recurrence interval and the major storm
was calculated at the 100-year recurrence interval. The Rational Method was used for
determining peak runoff rate. Runoff coefficients were calculated for each sub basin
using values from the FCSCM Tables 3.2-1, 3.2-2 and 3.2-3.
The developed time of concentration for the basins were calculated using FCSCM
Equation 5-3. The initial overland flow time was calculated using FCSCM Equation 3.3-
2. Channelized flow time was calculated using Manning’s Equation for velocity and
FCSCM Equation 5-5. The maximum total time of concentration for the most upstream
basins were calculated using FCSCM Equation 3.3-5. The project design rainfall
intensities were determined using FCSCM Table 3.4-1.
Rain Garden Water Quality Capture Volume (WQCV) was calculated using FCSCM
Equation 7-1 and 7-2 with a drain time of 12 hours. Additional 20% storage volume
listed in equation 7-2 was removed for Low Impact Development (LID) systems.
Complete calculations are included in Appendix A.
4.4 Hydraulic Criteria
All new Site storm sewers will be private and sized to convey the 100-year storm event.
Inlets were sized to capture runoff using the software from Mile High Flood District
(MHFD). StormCAD and Flowmaster, software programs developed by Bentley
Systems, were used to determine storm sewer hydraulic gradelines, velocities and
capacities as well as roadway
Pipe hydraulic calculations show the existing 1825 Sharp Point storm system has capacity
for the increased runoff from basin EX1-A, pipe HGL and EGL are still contained within
the pipes.
Open channel flow calculations for March Court show the street has conveyance capacity
for the redirected runoff from the Liberty Common Elementary school track and field
without overtopping curb.
4.5 Low Impact Development
Proposed improvements will modify 1.33 acres of the Site. 917 cubic feet of WQCV is
needed for this disturbed area in order to meet City’s Low Impact Development
requirements. Rain Gardens 1 & 2 will provide 1,292 cubic feet of WQCV, therefore
exceeding the minimum requirements. Refer to Stormwater Quality Exhibit in Appendix
A.
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 11
5 Variance Requests
No variances associated with drainage are being requested.
6 Erosion Control
Erosion Control Plan and Erosion Control Report in compliance with the Fort Collins
Stormwater Criteria Manual will be submitted as part of the permitting for this project.
7 Conclusions
The Site is designed in compliance with the Fort Collins Stormwater Criteria Manual.
Site runoff to the existing 1901 Sharp Point Drive storm sewer system has been reduced.
Site runoff to the existing 1825 Sharp Point Drive storm sewer system has been slightly
increased, but existing system has capacity for the increased flows. Stormwater runoff
being conveyed underneath either of the existing buildings has not been increased with
the proposed improvements. Total runoff from the Site to Merganser Pond has been
reduced per Design Flow Comparison below, therefore proposed Site improvements
should not negatively impact downstream properties.
Design Flow Comparison Table
Pre Development Post Development
Design Point Q2 (cfs) Q100 (cfs) Design
Point
Q2 (cfs) Q100 (cfs)
3 3.8 17.1 3 4.2 18.8
8 7.1 28.0 8 7.1 27.3
9 4.2 18.2 9 3.0 13.0
TOTAL 15.1 63.3 14.3 59.1
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 12
8 References
1 Fort Collins Stormwater Criteria Manual; City of Fort Collins; December 2018.
2 Mile High Flood District Storm Drainage Criteria Manual Volumes 1, 2 & 3; Mile
High Flood District; November 2010.
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 13
Appendices
APPENDIX A – Hydrologic Analyses
APPENDIX B – Hydraulic Analyses
APPENDIX C – Referenced Information
APPENDIX D – Drainage Map
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 14
APPENDIX A
HYDROLOGIC COMPUTATIONS
% Impervious1 C2 2-YR
100% 0.95 100-YR
90% 0.95
Gravel 40% 0.50
2% 0.20
2% 0.25
2% 0.35
90% 0.95
Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) %
EX1 0.73 0.63 86.3% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.10 13.7% 0.00 0.0% 0 0.0% 100.00% 87% 0.85 0.85 1.00
EX2 0.44 0.00 0.0% 0.44 100.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0 0.0% 100.00% 90% 0.95 0.95 1.00
EX3 0.09 0.01 11.1% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.08 88.9% 0.00 0.0% 0.00 0.0% 100.00% 13% 0.33 0.33 0.41
EX4 0.54 0.37 68.5% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.17 31.5% 0.00 0.0% 0.00 0.0% 100.00% 69% 0.73 0.73 0.91
EX5 0.58 0.45 77.6% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.13 22.4% 0.00 0.0% 0.00 0.0% 100.00% 78% 0.79 0.79 0.99
EX6 0.28 0.27 96.4% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 3.6% 0.00 0.0% 0.00 0.0% 100.00% 97% 0.93 0.93 1.00
EX7 0.33 0.32 97.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 3.0% 0.00 0.0% 0.00 0.0% 100.00% 97% 0.93 0.93 1.00
EX8 0.23 0.00 0.0% 0.23 100.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 90% 0.95 0.95 1.00
EX9 0.04 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.04 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
EX10 0.56 0.36 64.3% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.20 35.7% 0.00 0.0% 0.00 0.0% 100.00% 65% 0.70 0.70 0.88
EX11 0.23 0.00 0.0% 0.23 100.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 90% 0.95 0.95 1.00
Subtotal 4.05 2.41 59.5%0.90 22.2%0.00 0.0%0.00 0.0%0.74 18.3%0.00 0.0%0.00 0.0%100.00%80%0.82 0.82 1.00
OS1 1.61 0.54 33.5% 0.00 0.0% 0.26 16.1% 0.81 50.3% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 41% 0.50 0.50 0.63
OS2 1.45 0.46 31.7% 0.00 0.0% 0.18 12.4% 0.81 55.9% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 38% 0.48 0.48 0.59
OS3 1.24 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 1.24 100.0% 100.00% 90% 0.95 0.95 1.00
OS4 0.54 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.54 100.0% 100.00% 90% 0.95 0.95 1.00
OS5 0.01 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
OS6 0.01 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
OS7 0.02 0.01 50.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 50.0% 0.00 0.0% 0.00 0.0% 100.00% 51% 0.60 0.60 0.75
OS8 0.02 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.02 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
Subotal 4.90 1.01 20.6%0.00 0.0%0.44 9.0%1.62 33.1%0.05 1.0%0.00 0.0%1.78 36.3%100.00%58%0.65 0.65 0.82
Total 8.95 3.42 38.2%0.90 10.1%0.44 4.9%1.62 18.1%0.79 8.8%0.00 0.0%1.78 19.9%100.00%68%0.73 0.73 0.91
1. From Tables 4.1-2 and 4.1-3 in the Fort Collins Stormwater Criteria Manual
2. From Tables 3.2-1 and 3.2-2 in the Fort Collins Stormwater Criteria Manual
3. From Table 3.2-3 in the Fort Collins Stormwater Criteria Manual
4. From Equation 5-2 in the Fort Collins Stormwater Criteria Manual
Industrial Land Use
% Check
Land Use Area per Sub-Basin
Lawns, Clayey Soil,
Steep Slope >7%
Lawns, Clayey Soil,
Avg Slope 2-7%
1.00
1.25
Asphalt, Concrete Rooftop Gravel
Global Parameters
Composite
C Coefficient4 Industrial Land Use
Rooftop
Asphalt, Concrete
Lawns, Clayey Soil, Avg Slope 2-7%
Subbasin Total Area (acres)Composite
Imperviousness
Lawns, Clayey Soil, Steep Slope >7%
Frequency Adjustment Factors (C F)3
2-YR 100-YR
Lawns, Clayey Soil, Flat
Slope <2%
Pre-Development C Value Calculations
Liberty Common Junior High
Fort Collins, Colorado
Land Use
Lawns, Clayey Soil, Flat Slope <2%
C*CF (1.00 MAX)
Tc Check 6
Su
b
-
B
a
s
i
n
Ar
e
a
Cx
C
F
(2
-
Y
R
)
Cx
C
F
(1
0
0
-
Y
R
)
Le
n
g
t
h
(2
0
0
'
m
a
x
)
Sl
o
p
e
ti (
2
-
Y
R
)
ti (
1
0
0
-
Y
R
)
Le
n
g
t
h
Sl
o
p
e
Ve
l
o
c
i
t
y
3
Tt=L
/
V
x
6
0
To
t
a
l
Le
n
g
t
h
Tc =
T
i+T
t
(2
-
Y
R
)
Tc =
T
i+T
t
(1
0
0
-
Y
R
)
Tc =
(L
/
1
8
0
)
+1
0
Fi
n
a
l
T
c
(2
-
Y
R
)
Fi
n
a
l
T
c
(1
0
0
-
Y
R
)
acres ft % min. min. ft % fps Tc min min min min min min
EX1 0.73 0.85 1.00 110 2.7% 3.5 1.4 110 3.5 1.4 10.6 5.0 5.0
EX2 0.44 0.95 1.00 5.0 5.0
EX3 0.09 0.33 0.41 13 10.0% 2.4 2.2 215 1.4% 1.3 2.8 228 5.2 4.9 11.3 5.2 5.0
EX4 0.54 0.73 0.91 10 10.0% 1.0 0.5 265 1.1% 1.1 3.9 275 4.9 4.4 11.5 5.0 5.0
EX5 0.58 0.79 0.99 42 3.0% 2.6 0.9 287 0.4% 0.7 6.9 329 9.5 7.9 11.8 9.5 7.9
EX6 0.28 0.93 1.00 73 2.8% 2.0 1.1 47 1.3% 1.2 0.6 120 2.6 1.8 10.7 5.0 5.0
EX7 0.33 0.93 1.00 61 4.1% 1.6 0.9 59 1.6% 1.4 0.7 120 2.3 1.6 10.7 5.0 5.0
EX8 0.23 0.95 1.00 5.0 5.0
EX9 0.04 0.25 0.31 5.0 5.0
EX10 0.56 0.70 0.88 28 6.6% 2.1 1.2 102 2.3% 1.7 1.0 130 3.1 2.2 10.7 5.0 5.0
EX11 0.23 0.95 1.00 5.0 5.0
OS1 1.61 0.50 0.63 88 1.0% 10.5 8.3 535 0.5% 0.2 44.3 623 54.8 52.6 13.5 13.5 13.5
OS2 1.45 0.48 0.59 95 1.0% 11.4 9.2 535 0.5% 0.2 44.3 630 55.7 53.5 13.5 13.5 13.5
OS3 1.24 0.95 1.00 22 2.0% 1.0 0.7 387 1.0% 1.1 5.9 409 7.0 6.6 12.3 7.0 6.6
OS4 0.54 0.95 1.00 22 2.0% 1.0 0.7 391 1.0% 1.1 6.0 413 7.0 6.7 12.3 7.0 6.7
OS5 0.01 0.25 0.31 5.0 5.0
OS6 0.01 0.25 0.31 5.0 5.0
OS7 0.02 0.60 0.75 5.0 5.0
OS8 0.02 0.25 0.31 5.0 5.0
Notes:
2. Ti =[1.87(1.1-CxCF)L0.5]/S1/3.
C=Runoff Coefficient
Cf=Frequency Adjustment Factor
L=Length of Overland Flow, feet
S=Slope, percent
3. V=(1.49/n)R2/3S1/2
V=velocity Land Use n 4' pan 0.04
n=Roughness Coefficient
Pervious
Surface 0.25
field
underdrain 0.33
R=Hydraulic Radius, feet
Impervious
Surface 0.016
S=Longitudinal Slope, feet/feet
4. Tt=L/(Vx60)
5. Tc =Ti+Tt
6. Tc=(L/180)+10
7. From Table 4.1-1 in the Fort Collins Stormwater Criteria Manual
Travel Time (t t)4
STANDARD FORM SF-2
TIME OF CONCENTRATION
Date:
Development:
Total Time of
Concentration (T C)5
2/22/2025
Liberty Common Junior High
Subbasin Data Initial/Overland Time (t i)2
Calculated By:
Time of Concentration, T c
LJT
Final T c
(4) 4-inch pipes
assuming full
Tc is the lesser of the values of equations 5. and
6., min Tc = 5.0 minutes
1. Flows calculated using the rational method, based on the methods
provided in Chapter 5 (Hydrology Standards) of the Fort Collins Stormwater
Criteria Manual
Hydraulic Radius, R
assuming full pan
Roughness
Coefficients 7
Calculated By: LJT Job #: 2024020
Date: 2/22/2025 Project: Liberty Common Junior High
Design Storm:2-Year Storm
Area Area Coeff Tc C*A I Q Tc Sum C*A I Q Slope Street Q Design Q Slope PIPE L VEL Tt Q add'l Q tot
Design (ac)C (min)(ac)(cfs)(min)(ac)in/hr cfs %cfs cfs %SIZE ft ft/sec min
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
OS1 1.61 0.50 13.5 0.81 1.95 1.6
OS2 1.45 0.48 13.5 0.69 1.95 1.3
1 13.5 1.49 1.95 2.9
OS7 0.02 0.60 5.0 0.01 2.85 0.0
EX1 0.73 0.85 5.0 0.62 2.85 1.8
EX2 0.44 0.95 5.0 0.42 2.85 1.2
2 5.0 1.05 2.61 2.7
EX3 0.09 0.33 5.2 0.03 2.81 0.1
EX4 0.54 0.73 5.0 0.39 2.85 1.1
OS8 0.02 0.25 5.0 0.01 2.85 0.0
3 5.2 1.48 2.59 3.8
OS3 1.24 0.95 7.0 1.18 2.52 3.0
EX7 0.33 0.93 5.0 0.31 2.85 0.9
4 7.0 1.48 2.45 3.6
OS4 0.54 0.95 7.0 0.51 2.49 1.3
OS5 0.01 0.25 5.0 0.00 2.85 0.0
EX6 0.28 0.93 5.0 0.26 2.85 0.7
5 7.0 0.77 2.45 1.9
6 7.0 2.26 2.45 5.5
EX8 0.23 0.95 5.0 0.22 2.85 0.6
EX9 0.04 0.25 5.0 0.01 2.85 0.0
7 5.0 0.23 2.61 0.6
EX10 0.56 0.70 5.0 0.39 2.85 1.1
OS6 0.01 0.25 5.0 0.00 2.85 0.0
8 7.0 2.88 2.45 7.1
EX5 0.58 0.79 9.5 0.46 2.25 1.0
EX11 0.23 0.95 5.0 0.22 2.85 0.6
9 13.5 2.17 1.95 4.2
Standard Form SF-3
Storm Drainage System Design
(Rational Method Procedure)
STREET DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE TRAVEL TIME
Calculated By: LJT Job #: 2024020
Date: 2/22/2025 Project: Liberty Common Junior High
Design Storm:100-Year Storm
Area Area Coeff Tc C*A I Q Tc Sum C*A I Q Slope Street Q Design Q Slope PIPE L VEL Tt Q add'l Q tot
Design (ac)C (min)(ac)(cfs)(min)(ac)in/hr cfs %cfs cfs %SIZE ft ft/sec min
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
OS1 1.61 0.63 13.5 1.01 6.82 6.9
OS2 1.45 0.59 13.5 0.86 6.82 5.9
1 13.5 1.87 6.82 12.7
OS7 0.02 0.75 5.0 0.02 9.95 0.1
EX1 0.73 1.00 5.0 0.73 9.95 7.3
EX2 0.44 1.00 5.0 0.44 9.95 4.4
2 5.0 1.19 9.95 11.8
EX3 0.09 0.41 5.0 0.04 9.95 0.4
EX4 0.54 0.91 5.0 0.49 9.95 4.9
OS8 0.02 0.31 5.0 0.01 9.95 0.1
3 5.0 1.72 9.95 17.1
OS3 1.24 1.00 6.6 1.24 8.99 11.2
EX7 0.33 1.00 5.0 0.33 9.95 3.3
4 6.6 1.57 8.99 14.1
OS4 0.54 1.00 6.7 0.54 9.95 5.4
OS5 0.01 0.31 5.0 0.00 9.95 0.0
EX6 0.28 1.00 5.0 0.28 9.95 2.8
5 6.7 0.82 9.95 8.2
6 6.7 2.39 8.96 21.5
EX8 0.23 1.00 5.0 0.23 9.95 2.3
EX9 0.04 0.31 5.0 0.01 9.95 0.1
7 5.0 0.24 9.95 2.4
EX10 0.56 0.88 5.0 0.49 9.95 4.9
OS6 0.01 0.31 5.0 0.00 9.95 0.0
8 6.7 3.13 8.96 28.0
EX5 0.58 0.99 7.9 0.58 8.44 4.9
EX11 0.23 1.00 5.0 0.23 9.95 2.3
9 13.5 2.67 6.82 18.2
Standard Form SF-3
Storm Drainage System Design
(Rational Method Procedure)
STREET DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE TRAVEL TIME
% Impervious1 C2 2-YR
100% 0.95 100-YR
90% 0.95
Gravel 40% 0.50
2% 0.20
2% 0.25
2% 0.35
90% 0.95
Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) % Area (acres) %
C2 0.9 0.05 5.6% 0.62 68.9% 0.00 0.0% 0.00 0.0% 0.23 25.6% 0.00 0.0% 0.00 0.0% 100.00% 68% 0.77 0.77 0.96
C3 0.07 0 0.0% 0 0.0% 0.00 0.0% 0.00 0.0% 0.07 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
EX1-A 0.96 0.76 79.2% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.20 20.8% 0.00 0.0% 0.00 0.0% 100.00% 80% 0.80 0.80 1.00
EX2-A 0.44 0.00 0.0% 0.44 100.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 90% 0.95 0.95 1.00
EX3 0.09 0.01 11.1% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.08 88.9% 0.00 0.0% 0.00 0.0% 100.00% 13% 0.33 0.33 0.41
EX4-A 0.48 0.34 70.8% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.14 29.2% 0.00 0.0% 0.00 0.0% 100.00% 71% 0.75 0.75 0.93
EX6 0.28 0.27 96.4% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 3.6% 0.00 0.0% 0.00 0.0% 100.00% 97% 0.93 0.93 1.00
EX7-A 0.33 0.30 90.9% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.03 9.1% 0.00 0.0% 0.00 0.0% 100.00% 91% 0.89 0.89 1.00
EX8 0.23 0.00 0.0% 0.23 100.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 90% 0.95 0.95 1.00
EX9 0.04 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.04 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
EX10-A 0.23 0.03 13.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.20 87.0% 0.00 0.0% 0.00 0.0% 100.00% 15% 0.34 0.34 0.43
Subtotal 4.05 1.76 43.5%1.29 31.9%0.00 0.0%0.00 0.0%1.00 24.7%0.00 0.0%0.00 0.0%100.00%73%0.78 0.78 0.97
OS1-A 1.61 0.54 33.5% 0.00 0.0% 0.26 16.1% 0.81 50.3% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 41% 0.50 0.50 0.63
OS2-A 1.45 0.46 31.7% 0.00 0.0% 0.18 12.4% 0.81 55.9% 0.00 0.0% 0.00 0.0% 0.00 0.0% 100.00% 38% 0.48 0.48 0.59
OS3 1.24 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 1.24 100.0% 100.00% 90% 0.95 0.95 1.00
OS4 0.54 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.54 100.0% 100.00% 90% 0.95 0.95 1.00
OS5 0.01 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
OS6 0.01 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
OS7-A 0.02 0.01 50.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.01 50.0% 0.00 0.0% 0.00 0.0% 100.00% 51% 0.60 0.60 0.75
OS8 0.02 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.00 0.0% 0.02 100.0% 0.00 0.0% 0.00 0.0% 100.00% 2% 0.25 0.25 0.31
Subotal 4.90 1.01 20.6%0.00 0.0%0.44 9.0%1.62 33.1%0.05 1.0%0.00 0.0%1.78 36.3%100.00%58%0.65 0.65 0.82
Total 8.95 2.77 30.9%1.29 14.4%0.44 4.9%1.62 18.1%1.05 11.7%0.00 0.0%1.78 19.9%100.00%64%0.71 0.71 0.89
1. From Tables 4.1-2 and 4.1-3 in the Fort Collins Stormwater Criteria Manual
2. From Tables 3.2-1 and 3.2-2 in the Fort Collins Stormwater Criteria Manual
3. From Table 3.2-3 in the Fort Collins Stormwater Criteria Manual
4. From Equation 5-2 in the Fort Collins Stormwater Criteria Manual
Frequency Adjustment Factors (C F)3
2-YR 100-YR
Lawns, Clayey Soil, Flat
Slope <2%
Post-Development C Value Calculations
Liberty Common Junior High
Fort Collins, Colorado
Land Use
Lawns, Clayey Soil, Flat Slope <2%
C*CF (1.00 MAX)
Global Parameters
Composite
C Coefficient4 Industrial Land Use
Rooftop
Asphalt, Concrete
Lawns, Clayey Soil, Avg Slope 2-7%
Subbasin Total Area (acres)Composite
Imperviousness
Lawns, Clayey Soil, Steep Slope >7%
Industrial Land Use
% Check
Land Use Area per Sub-Basin
Lawns, Clayey Soil,
Steep Slope >7%
Lawns, Clayey Soil,
Avg Slope 2-7%
1.00
1.25
Asphalt, Concrete Rooftop Gravel
Tc Check6
Su
b
-
B
a
s
i
n
Ar
e
a
Cx
C
F
(2
-
Y
R
)
Cx
C
F
(1
0
0
-
Y
R
)
Le
n
g
t
h
(2
0
0
'
m
a
x
)
Sl
o
p
e
ti (
2
-
Y
R
)
ti (
1
0
0
-
Y
R
)
Le
n
g
t
h
Sl
o
p
e
Ve
l
o
c
i
t
y
3
Tt=L
/
V
x
6
0
To
t
a
l
Le
n
g
t
h
Tc =
T
i+T
t
(2
-
Y
R
)
Tc =
T
i+T
t
(1
0
0
-
Y
R
)
Tc =
(L
/
1
8
0
)
+1
0
Fi
n
a
l
T
c
(2
-
Y
R
)
Fi
n
a
l
T
c
(1
0
0
-
Y
R
)
acres ft % min. min. ft % fps Tc min min min min min min
C2 0.90 0.77 0.96 186 1.0% 8.4 3.5 44 4.4% 0.6 1.2 230 9.6 4.7 11.3 9.6 5.0
C3 0.07 0.25 0.31 5.0 5.0
EX1-A 0.96 0.80 1.00 71 2.3% 3.5 1.2 166 1.0% 1.1 2.5 237 6.1 3.7 11.3 6.1 5.0
EX2-A 0.44 0.95 1.00 5.0 5.0
EX3 0.09 0.33 0.41 13 10.0% 2.4 2.2 215 1.4% 1.3 2.8 228 5.2 4.9 11.3 5.2 5.0
EX4-A 0.48 0.75 0.93 10 10.0% 1.0 0.5 265 1.1% 1.1 3.9 275 4.8 4.3 11.5 5.0 5.0
EX6 0.28 0.93 1.00 73 2.8% 2.0 1.1 47 1.3% 1.2 0.6 120 2.6 1.8 10.7 5.0 5.0
EX7-A 0.33 0.89 1.00 61 4.1% 1.9 0.9 59 1.6% 1.4 0.7 120 2.7 1.6 10.7 5.0 5.0
EX8 0.23 0.95 1.00 5.0 5.0
EX9 0.04 0.25 0.31 5.0 5.0
EX10-A 0.23 0.34 0.43 85 2.0% 10.4 9.2 85 10.4 9.2 10.5 10.4 9.2
OS1-A 1.61 0.50 0.63 88 1.0% 10.5 8.3 535 0.5% 0.2 44.3 623 54.8 52.6 13.5 13.5 13.5
OS2-A 1.45 0.48 0.59 95 1.0% 11.4 9.2 535 0.5% 0.2 44.3 630 55.7 53.5 13.5 13.5 13.5
OS3 1.24 0.95 1.00 22 2.0% 1.0 0.7 387 1.0% 1.1 5.9 409 7.0 6.6 12.3 7.0 6.6
OS4 0.54 0.95 1.00 22 2.0% 1.0 0.7 391 1.0% 1.1 6.0 413 7.0 6.7 12.3 7.0 6.7
OS5 0.01 0.25 0.31 5.0 5.0
OS6 0.01 0.25 0.31 5.0 5.0
OS7-A 0.02 0.60 0.75 5.0 5.0
OS8 0.02 0.25 0.31 5.0 5.0
Notes:
2. Ti =[1.87(1.1-CxCF)L0.5]/S1/3.
C=Runoff Coefficient
Cf=Frequency Adjustment Factor
L=Length of Overland Flow, feet
S=Slope, percent
3. V=(1.49/n)R2/3S1/2
V=velocity Land Use n 4' pan 0.04
n=Roughness Coefficient
Pervious
Surface 0.25
field
underdrain 0.33
R=Hydraulic Radius, feet
Impervious
Surface 0.016
S=Longitudinal Slope, feet/feet
4. Tt=L/(Vx60)
5. Tc =Ti+Tt
6. Tc=(L/180)+10
7. From Table 4.1-1 in the Fort Collins Stormwater Criteria Manual
Tc is the lesser of the values of equations 5. and
6., min Tc = 5.0 minutes
1. Flows calculated using the rational method, based on the methods
provided in Chapter 5 (Hydrology Standards) of the Fort Collins Stormwater
Criteria Manual
STANDARD FORM SF-2
TIME OF CONCENTRATION
Date:
Development:
Initial/Overland Time (ti)2
Time of Concentration, Tc
Liberty Common Junior High
Subbasin Data
Calculated By:
Total Time of
Concentration (TC)5
3/6/2025
Travel Time (tt)4 Final Tc
LJT
Hydraulic Radius, R
assuming full pan
Roughness
Coefficients7
(4) 4-inch pipes
assuming full
Calculated By: LJT Job #: 2024020
Date: 3/6/2025 Project: Liberty Common Junior High
Design Storm:2-Year Storm
Area Area Coeff Tc C*A I Q Tc Sum C*A I Q Slope Street Q Design Q Slope PIPE L VEL Tt Q add'l Q tot
Design (ac)C (min)(ac)(cfs)(min)(ac)in/hr cfs %cfs cfs %SIZE ft ft/sec min
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
OS1-A 1.61 0.50 13.5 0.81 1.95 1.6
OS2-A 1.45 0.48 13.5 0.69 1.95 1.3
OS7-A 0.02 0.60 5.0 0.01 2.85 0.0
1 13.5 1.51 1.95 2.9
EX1-A 0.96 0.80 6.1 0.77 2.66 2.1
EX2-A 0.44 0.95 5.0 0.42 2.85 1.2
EX3 0.09 0.33 5.2 0.03 2.81 0.1
EX4-A 0.48 0.75 5.0 0.36 2.85 1.0
OS8 0.02 0.25 5.0 0.01 2.85 0.0
3 6.1 1.58 2.66 4.2
OS3 1.24 0.95 7.0 1.18 2.52 3.0
EX7-A 0.33 0.89 5.0 0.29 2.85 0.8
4 7.0 1.47 2.52 3.7
OS4 0.54 0.95 7.0 0.51 2.52 1.3
OS5 0.01 0.25 5.0 0.00 2.85 0.0
EX6 0.28 0.93 5.0 0.26 2.85 0.7
5 7.0 0.77 2.52 2.0
6 7.0 2.25 2.52 5.7
EX8 0.23 0.95 5.0 0.22 2.85 0.6
EX9 0.04 0.25 5.0 0.01 2.85 0.0
7 5.0 0.23 2.85 0.7
C2 0.90 0.77 9.6 0.69 2.24 1.6
EX10-A 0.23 0.34 10.4 0.08 2.18 0.2
OS6 0.01 0.25 5.0 0.00 2.85 0.0
8 10.4 3.25 2.18 7.1
C3 0.07 0.25 5.0 0.02 2.85 0.0
9 13.5 1.52 1.95 3.0
Standard Form SF-3
Storm Drainage System Design
(Rational Method Procedure)
STREET DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE TRAVEL TIME
Calculated By: LJT Job #: 2024020
Date: 3/6/2025 Project: Liberty Common Junior High
Design Storm:100-Year Storm
Area Area Coeff Tc C*A I Q Tc Sum C*A I Q Slope Street Q Design Q Slope PIPE L VEL Tt Q add'l Q tot
Design (ac)C (min)(ac)(cfs)(min)(ac)in/hr cfs %cfs cfs %SIZE ft ft/sec min
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
OS1-A 1.61 0.63 13.5 1.01 6.82 6.9
OS2-A 1.45 0.59 13.5 0.86 6.82 5.9
OS7-A 0.02 0.75 5.0 0.02 9.95 0.1
1 13.5 1.88 6.82 12.8
EX1-A 0.96 1.00 5.0 0.96 9.95 9.6
EX2-A 0.44 1.00 5.0 0.44 9.95 4.4
EX3 0.09 0.41 5.0 0.04 9.95 0.4
EX4-A 0.48 0.93 5.0 0.45 9.95 4.5
OS8 0.02 0.31 5.0 0.01 9.95 0.1
3 5.0 1.89 9.95 18.8
OS3 1.24 1.00 6.6 1.24 8.99 11.2
EX7-A 0.33 1.00 5.0 0.33 9.95 3.3
4 6.6 1.57 8.99 14.1
OS4 0.54 1.00 6.7 0.54 8.96 4.8
OS5 0.01 0.31 5.0 0.00 9.95 0.0
EX6 0.28 1.00 5.0 0.28 9.95 2.8
5 6.7 0.82 8.96 7.4
6 6.7 2.39 8.96 21.5
EX8 0.23 1.00 5.0 0.23 9.95 2.3
EX9 0.04 0.31 5.0 0.01 9.95 0.1
7 5.0 0.24 9.95 2.4
C2 0.90 0.77 5.0 0.69 9.95 6.9
EX10-A 0.23 0.43 9.2 0.10 7.96 0.8
OS6 0.01 0.31 5.0 0.00 9.95 0.0
8 9.2 3.43 7.96 27.3
C3 0.07 0.31 5.0 0.02 9.95 0.2
9 13.5 1.90 6.82 13.0
Standard Form SF-3
Storm Drainage System Design
(Rational Method Procedure)
STREET DESIGN POINT
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE TRAVEL TIME
JOB #:2024020
DATE:4/22/2025
PROJECT: Liberty Common Junior High
SUBJECT: Rain Garden #1
Drainage Area=0.90 acres
719 cf
Available Volume =990
SEDIMENT BASIN VOLUME SUMMARY
Contour Total Area H Volume Cumulative Cumulative
Elev Volume Volume
(ft)(ft2)(ft)(ft3)(ft3)ac-ft
4892.5 603 0
1.0 990
4893.5 1436 990 0.023
Required WQCV=
JOB #:2024020
DATE:4/22/2025
PROJECT: Liberty Common Junior High
SUBJECT: Rain Garden #2
Drainage Area=0.51 acres
297 cf
Available Volume =302
SEDIMENT BASIN VOLUME SUMMARY
Contour Total Area H Volume Cumulative Cumulative
Elev Volume Volume
(ft)(ft2)(ft)(ft3)(ft3)ac-ft
4892.5 175 0
1.0 302
4893.5 450 302 0.007
Required WQCV=
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 15
APPENDIX B
HYDRAULIC COMPUTATIONS
Worksheet for March Court DP1 flow
Project Description
Manning
FormulaFriction Method
Normal DepthSolve For
Input Data
ft/ft0.008Channel Slope
cfs12.80Discharge
Section Definitions
Elevation
(ft)
Station
(ft)
4,897.950+00.0
4,897.880+04.0
4,897.410+04.5
4,897.530+06.5
4,897.920+22.5
4,897.290+38.5
4,897.150+40.5
4,897.620+41.0
4,897.720+44.0
Roughness Segment Definitions
Roughness CoefficientEnding StationStart Station
0.016(0+44.0, 4,897.72)(0+00.0, 4,897.95)
Options
Pavlovskii's
Method
Current Roughness Weighted
Method
Pavlovskii's
Method
Open Channel Weighting
Method
Pavlovskii's
Method
Closed Channel Weighting
Method
Results
in6.8Normal Depth
0.016Roughness Coefficient
ft4,897.71Elevation
4,897.15 to
4,897.95 ftElevation Range
ft²4.8Flow Area
ft26.25Wetted Perimeter
in2.2Hydraulic Radius
ft25.92Top Width
in6.8Normal Depth
in6.9Critical Depth
ft/ft0.007Critical Slope
ft/s2.67Velocity
Page 1 of 227 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
3/3/2025
FlowMaster
[10.03.00.03]
Bentley Systems, Inc. Haestad Methods Solution
CenterUntitled1.fm8
Worksheet for March Court DP1 flow
Results
ft0.11Velocity Head
ft0.67Specific Energy
1.096Froude Number
SupercriticalFlow Type
GVF Input Data
in0.0Downstream Depth
ft0.00Length
0Number Of Steps
GVF Output Data
in0.0Upstream Depth
N/AProfile Description
ft0.00Profile Headloss
ft/sInfinityDownstream Velocity
ft/sInfinityUpstream Velocity
in6.8Normal Depth
in6.9Critical Depth
ft/ft0.008Channel Slope
ft/ft0.007Critical Slope
Page 2 of 227 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
3/3/2025
FlowMaster
[10.03.00.03]
Bentley Systems, Inc. Haestad Methods Solution
CenterUntitled1.fm8
Cross Section for March Court DP1 flow
Project Description
Manning
FormulaFriction Method
Normal DepthSolve For
Input Data
ft/ft0.008Channel Slope
in6.8Normal Depth
cfs12.80Discharge
Page 1 of 127 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
3/3/2025
FlowMaster
[10.03.00.03]
Bentley Systems, Inc. Haestad Methods Solution
CenterUntitled1.fm8
Project:
Basin ID:
Design Information (Input):
Circular Opening:Diameter Dia. =ft.
OR
Rectangular Opening:Width W =2.00 ft.
Length L =2.00 ft.
Percentage of Open Area After Trash Rack Reduction % open =50.00 %
Orifice Coefficient Co =0.67
Weir Coefficient Cw =3.00
Orifice Elevation Eo =4894.88 ft.
Calculation of Collection Capacity:
Net Opening Area (after Trash Rack Reduction)Ao =2.00 sq. ft.
Perimeter as Weir Length Lw =8.00 ft.
Enter water surface elevations in ascending order.
Water Weir Orifice Collection
Surface Flow Flow Capacity
Elevation cfs cfs cfs
ft
(input) (output) (output) (output)
start 4895.00 1.00 3.73 1.00
4895.10 2.48 5.04 2.48
4895.20 4.34 6.08 4.34
Collection Capacity of Horizontal Orifice (Inlet Control)
Liberty Common Junior High
1825 Sharp Point Inlet (south parking lot)
3/3/2025, 1:18 PMInlet Capacity Calc.xls, Existing
3 inlets=13.02 cfs > 9.6 cfs for
Basin EX1-A
Project:
Basin ID:
Design Information (Input):
Circular Opening:Diameter Dia. =ft.
OR
Rectangular Opening:Width W =1.35 ft.
Length L =1.98 ft.
Percentage of Open Area After Trash Rack Reduction % open =50.00 %
Orifice Coefficient Co =0.67
Weir Coefficient Cw =3.00
Orifice Elevation Eo =4894.63 ft.
Calculation of Collection Capacity:
Net Opening Area (after Trash Rack Reduction)Ao =1.34 sq. ft.
Perimeter as Weir Length Lw =6.66 ft.
Enter water surface elevations in ascending order.
Water Weir Orifice Collection
Surface Flow Flow Capacity
Elevation cfs cfs cfs
ft
(input) (output) (output) (output)
start 4894.70 0.37 1.90 0.37
4894.80 1.40 2.96 1.40
4894.90 2.80 3.73 2.80
Collection Capacity of Horizontal Orifice (Inlet Control)
Liberty Common Junior High
Design Point 7 Area Inlet
3/3/2025, 1:23 PMInlet Capacity Calc.xls, Existing
> DP7 Q100 = 2.4 cfs
2 year storm: Conduit Table
Energy Grade
Line (Out)
(ft)
Energy Grade
Line (In)
(ft)
Hydraulic Grade
Line (Out)
(ft)
Hydraulic Grade
Line (In)
(ft)
Flow /
Capacity
(Design)
(%)
Capacity (Full
Flow)
(cfs)
Depth (Out)
(ft)
Velocity
(ft/s)
Flow
(cfs)
Manning's nDiameter
(in)
Section
Type
Slope
(Calculated)
(ft/ft)
Length
(Scaled)
(ft)
Invert (Stop)
(ft)
Stop
Node
Invert
(Start)
(ft)
Start
Node
Label
4,891.224,893.244,891.194,893.1117.54.280.624.090.750.01112.0Circle0.010211.34,890.57CB-44,892.75CB-1CO-1
4,891.224,893.054,891.194,892.9217.44.120.623.940.720.01112.0Circle0.010208.44,890.57CB-44,892.57CB-2CO-2
4,891.224,893.264,891.194,893.1317.44.290.624.100.750.01112.0Circle0.010212.04,890.57CB-44,892.77CB-3CO-3
4,890.714,891.464,890.274,891.1920.021.430.615.334.290.01324.0Circle0.00989.14,889.66O-14,890.46CB-4CO-4
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203-755-16663/3/2025
StormCAD
[10.03.04.53]Bentley Systems, Inc. Haestad Methods Solution Center2024020 - PROPOSED STORM MODEL 5 year.stsw
1825 SHARP POINT STORM
Profile Report
Engineering Profile - Profile - 1 (2024020 - PROPOSED STORM MODEL 2
year.stsw)
4,885.00
4,890.00
4,895.00
-0+50 0+00 0+50 1+00 1+50 2+00 2+50 3+00 3+50
Station (ft)
El
e
v
a
t
i
o
n
(
f
t
)
Element ID\Label
Length (Unified) (ft)
Rise (Unified) (ft)\Material
Flow (cfs)
Slope (Calculated) (ft/ft)
Element ID\Label
Elevation (Ground) (ft)
Elevation (Invert) (ft)
Station (ft)
57\CO-1 58\CO-4
211.3 89.1
1.00\ 2.00\
0.75 4.29
0.010 0.009
54\CB-1 55\CB-4 56\O-1
4,894.88 4,894.38 4,889.66
4,892.75 4,890.46 4,889.66
0+00 2+11 3+00
CB-1
Rim: 4,894.88 ft
Invert: 4,892.75 ft
CB-4
Rim: 4,894.38 ft
Invert: 4,890.46 ft
O-1
Rim: 4,889.66 ft
Invert: 4,889.66 ft
CO-4: 89.1 ft @ 0.009 ft/ftCircle - 24.0 in
CO-1: 211.3 ft @ 0.010 ft/ftCircle - 12.0 in
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT
06787 USA +1-203-755-1666
3/3/2025
StormCAD
[10.03.04.53]
Bentley Systems, Inc. Haestad Methods Solution
Center
2024020 - PROPOSED STORM MODEL 5
year.stsw
1825 SHARP POINT STORM
Profile Report
Engineering Profile - Profile - 2 (2024020 - PROPOSED STORM MODEL 2
year.stsw)
4,885.00
4,890.00
4,895.00
-0+50 0+00 0+50 1+00 1+50 2+00 2+50 3+00
Station (ft)
El
e
v
a
t
i
o
n
(
f
t
)
Element ID\Label
Length (Unified) (ft)
Rise (Unified) (ft)\Material
Flow (cfs)
Slope (Calculated) (ft/ft)
Element ID\Label
Elevation (Ground) (ft)
Elevation (Invert) (ft)
Station (ft)
62\CO-2 58\CO-4
208.4 89.1
1.00\ 2.00\
0.72 4.29
0.010 0.009
61\CB-2 55\CB-4 56\O-1
4,894.81 4,894.38 4,889.66
4,892.57 4,890.46 4,889.66
0+00 2+08 2+98
CB-4
Rim: 4,894.38 ft
Invert: 4,890.46 ft
CB-2
Rim: 4,894.81 ft
Invert: 4,892.57 ft
O-1
Rim: 4,889.66 ft
Invert: 4,889.66 ft
CO-2: 208.4 ft @ 0.010 ft/ftCircle - 12.0 in CO-4: 89.1 ft @ 0.009 ft/ftCircle - 24.0 in
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT
06787 USA +1-203-755-1666
3/3/2025
StormCAD
[10.03.04.53]
Bentley Systems, Inc. Haestad Methods Solution
Center
2024020 - PROPOSED STORM MODEL 5
year.stsw
1825 SHARP POINT STORM
Profile Report
Engineering Profile - Profile - 3 (2024020 - PROPOSED STORM MODEL 2
year.stsw)
4,885.00
4,890.00
4,895.00
-0+50 0+00 0+50 1+00 1+50 2+00 2+50 3+00 3+50
Station (ft)
El
e
v
a
t
i
o
n
(
f
t
)
Element ID\Label
Length (Unified) (ft)
Rise (Unified) (ft)\Material
Flow (cfs)
Slope (Calculated) (ft/ft)
Element ID\Label
Elevation (Ground) (ft)
Elevation (Invert) (ft)
Station (ft)
60\CO-3 58\CO-4
212.0 89.1
1.00\ 2.00\
0.75 4.29
0.010 0.009
59\CB-3 55\CB-4 56\O-1
4,894.80 4,894.38 4,889.66
4,892.77 4,890.46 4,889.66
0+00 2+12 3+01
CB-3
Rim: 4,894.80 ft
Invert: 4,892.77 ft
CB-4
Rim: 4,894.38 ft
Invert: 4,890.46 ft
O-1
Rim: 4,889.66 ft
Invert: 4,889.66 ft
CO-4: 89.1 ft @ 0.009 ft/ftCircle - 24.0 in
CO-3: 212.0 ft @ 0.010 ft/ftCircle - 12.0 in
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT
06787 USA +1-203-755-1666
3/3/2025
StormCAD
[10.03.04.53]
Bentley Systems, Inc. Haestad Methods Solution
Center
2024020 - PROPOSED STORM MODEL 5
year.stsw
1825 SHARP POINT STORM
100 year storm: Conduit Table
Energy Grade
Line (Out)
(ft)
Energy Grade
Line (In)
(ft)
Hydraulic Grade
Line (Out)
(ft)
Hydraulic Grade
Line (In)
(ft)
Flow /
Capacity
(Design)
(%)
Capacity
(Full Flow)
(cfs)
Depth (Out)
(ft)
Velocity
(ft/s)
Flow
(cfs)
Manning's nDiameter
(in)
Section
Type
Slope
(Calculated)
(ft/ft)
Length
(Scaled)
(ft)
Invert (Stop)
(ft)
Stop
Node
Invert
(Start)
(ft)
Start
Node
Label
4,892.264,893.904,892.004,893.5275.04.281.435.973.210.01112.0Circle0.010211.34,890.57CB-44,892.75CB-1CO-1
4,892.264,893.724,892.004,893.3477.84.121.435.803.210.01112.0Circle0.010208.44,890.57CB-44,892.57CB-2CO-2
4,892.264,893.924,892.004,893.5474.84.291.435.993.210.01112.0Circle0.010212.04,890.57CB-44,892.77CB-3CO-3
4,891.994,892.774,891.084,892.0085.021.431.427.6618.230.01324.0Circle0.00989.14,889.66O-14,890.46CB-4CO-4
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203-755-16663/3/2025
StormCAD
[10.03.04.53]Bentley Systems, Inc. Haestad Methods Solution Center2024020 - PROPOSED STORM MODEL.stsw
1825 SHARP POINT STORM
Profile Report
Engineering Profile - Profile - 1 (2024020 - PROPOSED STORM
MODEL.stsw)
4,885.00
4,890.00
4,895.00
-0+50 0+00 0+50 1+00 1+50 2+00 2+50 3+00 3+50
Station (ft)
El
e
v
a
t
i
o
n
(
f
t
)
Element ID\Label
Length (Unified) (ft)
Rise (Unified) (ft)\Material
Flow (cfs)
Slope (Calculated) (ft/ft)
Element ID\Label
Elevation (Ground) (ft)
Elevation (Invert) (ft)
Station (ft)
57\CO-1 58\CO-4
211.3 89.1
1.00\ 2.00\
3.21 18.23
0.010 0.009
54\CB-1 55\CB-4 56\O-1
4,894.88 4,894.38 4,889.66
4,892.75 4,890.46 4,889.66
0+00 2+11 3+00
CB-1
Rim: 4,894.88 ft
Invert: 4,892.75 ft
CB-4
Rim: 4,894.38 ft
Invert: 4,890.46 ft
O-1
Rim: 4,889.66 ft
Invert: 4,889.66 ft
CO-4: 89.1 ft @ 0.009 ft/ftCircle - 24.0 in
CO-1: 211.3 ft @ 0.010 ft/ftCircle - 12.0 in
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT
06787 USA +1-203-755-1666
3/3/2025
StormCAD
[10.03.04.53]
Bentley Systems, Inc. Haestad Methods Solution
Center2024020 - PROPOSED STORM MODEL.stsw
1825 SHARP POINT STORM
Profile Report
Engineering Profile - Profile - 2 (2024020 - PROPOSED STORM
MODEL.stsw)
4,885.00
4,890.00
4,895.00
-0+50 0+00 0+50 1+00 1+50 2+00 2+50 3+00
Station (ft)
El
e
v
a
t
i
o
n
(
f
t
)
Element ID\Label
Length (Unified) (ft)
Rise (Unified) (ft)\Material
Flow (cfs)
Slope (Calculated) (ft/ft)
Element ID\Label
Elevation (Ground) (ft)
Elevation (Invert) (ft)
Station (ft)
62\CO-2 58\CO-4
208.4 89.1
1.00\ 2.00\
3.21 18.23
0.010 0.009
61\CB-2 55\CB-4 56\O-1
4,894.81 4,894.38 4,889.66
4,892.57 4,890.46 4,889.66
0+00 2+08 2+98
CB-4
Rim: 4,894.38 ft
Invert: 4,890.46 ft
CB-2
Rim: 4,894.81 ft
Invert: 4,892.57 ft
O-1
Rim: 4,889.66 ft
Invert: 4,889.66 ft
CO-2: 208.4 ft @ 0.010 ft/ftCircle - 12.0 in CO-4: 89.1 ft @ 0.009 ft/ftCircle - 24.0 in
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT
06787 USA +1-203-755-1666
3/3/2025
StormCAD
[10.03.04.53]
Bentley Systems, Inc. Haestad Methods Solution
Center2024020 - PROPOSED STORM MODEL.stsw
1825 SHARP POINT STORM
Profile Report
Engineering Profile - Profile - 3 (2024020 - PROPOSED STORM
MODEL.stsw)
4,885.00
4,890.00
4,895.00
-0+50 0+00 0+50 1+00 1+50 2+00 2+50 3+00 3+50
Station (ft)
El
e
v
a
t
i
o
n
(
f
t
)
Element ID\Label
Length (Unified) (ft)
Rise (Unified) (ft)\Material
Flow (cfs)
Slope (Calculated) (ft/ft)
Element ID\Label
Elevation (Ground) (ft)
Elevation (Invert) (ft)
Station (ft)
60\CO-3 58\CO-4
212.0 89.1
1.00\ 2.00\
3.21 18.23
0.010 0.009
59\CB-3 55\CB-4 56\O-1
4,894.80 4,894.38 4,889.66
4,892.77 4,890.46 4,889.66
0+00 2+12 3+01
CB-3
Rim: 4,894.80 ft
Invert: 4,892.77 ft
CB-4
Rim: 4,894.38 ft
Invert: 4,890.46 ft
O-1
Rim: 4,889.66 ft
Invert: 4,889.66 ft
CO-4: 89.1 ft @ 0.009 ft/ftCircle - 24.0 in
CO-3: 212.0 ft @ 0.010 ft/ftCircle - 12.0 in
Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT
06787 USA +1-203-755-1666
3/3/2025
StormCAD
[10.03.04.53]
Bentley Systems, Inc. Haestad Methods Solution
Center2024020 - PROPOSED STORM MODEL.stsw
1825 SHARP POINT STORM
New Addition roof drain
Project Description
Manning
FormulaFriction Method
Normal DepthSolve For
Input Data
0.011Roughness Coefficient
ft/ft0.010Channel Slope
in12.0Diameter
cfs2.61Discharge
Results
in6.8Normal Depth
ft²0.5Flow Area
ft1.7Wetted Perimeter
in3.2Hydraulic Radius
ft0.99Top Width
in8.3Critical Depth
%57.0Percent Full
ft/ft0.006Critical Slope
ft/s5.65Velocity
ft0.50Velocity Head
ft1.07Specific Energy
1.457Froude Number
cfs4.53Maximum Discharge
cfs4.21Discharge Full
ft/ft0.004Slope Full
SupercriticalFlow Type
GVF Input Data
in0.0Downstream Depth
ft0.0Length
0Number Of Steps
GVF Output Data
in0.0Upstream Depth
N/AProfile Description
ft0.00Profile Headloss
%0.0Average End Depth Over Rise
%57.0Normal Depth Over Rise
ft/sInfinityDownstream Velocity
ft/sInfinityUpstream Velocity
in6.8Normal Depth
in8.3Critical Depth
ft/ft0.010Channel Slope
ft/ft0.006Critical Slope
Page 1 of 127 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
4/22/2025
FlowMaster
[10.03.00.03]
Bentley Systems, Inc. Haestad Methods Solution
Centerpipe capacities.fm8
Design Point 7 outfall pipe
Project Description
Manning
FormulaFriction Method
Normal DepthSolve For
Input Data
0.011Roughness Coefficient
ft/ft0.005Channel Slope
in12.0Diameter
cfs2.40Discharge
Results
in8.2Normal Depth
ft²0.6Flow Area
ft1.9Wetted Perimeter
in3.5Hydraulic Radius
ft0.93Top Width
in8.0Critical Depth
%68.0Percent Full
ft/ft0.005Critical Slope
ft/s4.22Velocity
ft0.28Velocity Head
ft0.96Specific Energy
0.952Froude Number
cfs3.20Maximum Discharge
cfs2.98Discharge Full
ft/ft0.003Slope Full
SubcriticalFlow Type
GVF Input Data
in0.0Downstream Depth
ft0.0Length
0Number Of Steps
GVF Output Data
in0.0Upstream Depth
N/AProfile Description
ft0.00Profile Headloss
%0.0Average End Depth Over Rise
%54.1Normal Depth Over Rise
ft/sInfinityDownstream Velocity
ft/sInfinityUpstream Velocity
in8.2Normal Depth
in8.0Critical Depth
ft/ft0.005Channel Slope
ft/ft0.005Critical Slope
Page 1 of 127 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
3/3/2025
FlowMaster
[10.03.00.03]
Bentley Systems, Inc. Haestad Methods Solution
Centerpipe capacities.fm8
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 16
APPENDIX C
REFERENCED INFORMATION
FORT COLLINS STORMWATER CRITERIA MANUAL Preface
2.0 Purpose
2.0 Purpose
Page 2
In addition, this Manual recognizes the various Master Drainage Plans that have been developed for all
the major drainage basins within and around Fort Collins. Each Master Drainage Plan provides detailed
analysis and selected plan improvement guidance for major stormwater infrastructure needs
throughout Fort Collins and its GMA, see Figure 2.0-1 below. This Manual directs users to apply
allowable release rates for storm drainage that have been established by the various Master Drainage
Plans and to incorporate any selected plan improvements (where appropriate) into their design. This
Manual does not provide direction or requirements for Master Drainage Plan updates.
Figure 2.0-1. Master Drainage Basin Map with City Limits and GMA
National Flood Hazard Layer FIRMette
0 500 1,000 1,500 2,000250
Feet
Ü
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
SPECIAL FLOOD
HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or Depth Zone AE, AO, AH, VE, AR
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mile Zone X
Future Conditions 1% Annual
Chance Flood Hazard Zone X
Area with Reduced Flood Risk due to
Levee. See Notes.Zone X
Area with Flood Risk due to Levee Zone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood Hazard Zone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 10/28/2024 at 9:00 PM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.
Legend
OTHER AREAS OF
FLOOD HAZARD
OTHER AREAS
GENERAL
STRUCTURES
OTHER
FEATURES
MAP PANELS
8
B 20.2
The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
105°2'1"W 40°33'58"N
105°1'23"W 40°33'31"N
Basemap Imagery Source: USGS National Map 2023
SITE
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/2/2025
Page 1 of 4
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497350 497390 497430 497470 497510 497550 497590 497630 497670 497710
497350 497390 497430 497470 497510 497550 497590 497630 497670 497710
40° 33' 48'' N
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40° 33' 48'' N
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40° 33' 40'' N
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40° 33' 40'' N
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N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 50 100 200 300
Feet
0 25 50 100 150
Meters
Map Scale: 1:1,760 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 19, Aug 29, 2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 2, 2021—Aug 25,
2021
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/2/2025
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
22 Caruso clay loam, 0 to 1
percent slope
D 2.4 31.5%
64 Loveland clay loam, 0 to
1 percent slopes
C 5.0 64.2%
105 Table Mountain loam, 0
to 1 percent slopes
B 0.3 4.3%
Totals for Area of Interest 7.8 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/2/2025
Page 3 of 4
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
3/2/2025
Page 4 of 4
SITE
SITE
Final Drainage Report Liberty Common Junior High
Fort Collins, Colorado
Elevation Consulting 17
APPENDIX D
DRAINAGE MAP
LOT 1
VIPONT AT PROSPECT
PARK EAST
LOT 3
PROSPECT
INDUSTRIAL PARK
LOT 11
PROSPECT
INDUSTRIAL PARK
LOT 12
PROSPECT
INDUSTRIAL PARK
LOT 6
PROSPECT
INDUSTRIAL PARK
LOT 2
PROSPECT
INDUSTRIAL PARK
LOT 10
PROSPECT
INDUSTRIAL PARK
LOT 7
PROSPECT
INDUSTRIAL PARK
LOT 3
PROSPECT
INDUSTRIAL PARK
LOT 6
PROSPECT
INDUSTRIAL PARK
LOT 2
PROSPECT
INDUSTRIAL PARK
LOT 1
VIPONT AT PROSPECT
PARK EAST
LOT 7
PROSPECT
INDUSTRIAL PARK
LOT 17
PROSPECT
INDUSTRIAL PARK
LOT 18
PROSPECT
INDUSTRIAL PARK
LOT 19
PROSPECT
INDUSTRIAL PARK
LOT 20
PROSPECT
INDUSTRIAL PARK
LOT 21
PROSPECT
INDUSTRIAL PARK
LOT 22
PROSPECT
INDUSTRIAL PARK
LOT 1
VIPONT AT PROSPECT
PARK EAST
LOT 3
PROSPECT
INDUSTRIAL PARK
LOT 11
PROSPECT
INDUSTRIAL PARK
LOT 12
PROSPECT
INDUSTRIAL PARK
LOT 6
PROSPECT
INDUSTRIAL PARK
LOT 2
PROSPECT
INDUSTRIAL PARK
LOT 10
PROSPECT
INDUSTRIAL PARK
LOT 7
PROSPECT
INDUSTRIAL PARK
LOT 1
VIPONT AT PROSPECT
PARK EAST
LOT 3
PROSPECT
INDUSTRIAL PARK
LOT 11
PROSPECT
INDUSTRIAL PARK
LOT 12
PROSPECT
INDUSTRIAL PARK
LOT 6
PROSPECT
INDUSTRIAL PARK
LOT 2
PROSPECT
INDUSTRIAL PARK
LOT 10
PROSPECT
INDUSTRIAL PARK
LOT 7
PROSPECT
INDUSTRIAL PARK
LOT 3
PROSPECT
INDUSTRIAL PARK
LOT 6
PROSPECT
INDUSTRIAL PARK
LOT 2
PROSPECT
INDUSTRIAL PARK
LOT 1
VIPONT AT PROSPECT
PARK EAST
LOT 3
PROSPECT
INDUSTRIAL PARK
LOT 6
PROSPECT
INDUSTRIAL PARK
LOT 2
PROSPECT
INDUSTRIAL PARK
LOT 1
VIPONT AT PROSPECT
PARK EAST
LOT 17
PROSPECT
INDUSTRIAL PARK
LOT 18
PROSPECT
INDUSTRIAL PARK
LOT 19
PROSPECT
INDUSTRIAL PARK
LOT 20
PROSPECT
INDUSTRIAL PARK
LOT 21
PROSPECT
INDUSTRIAL PARK
LOT 22
PROSPECT
INDUSTRIAL PARK
LOT 7
PROSPECT
INDUSTRIAL PARK