HomeMy WebLinkAboutCSU HEALTH CENTER / GF WAIRDS REPLAT & UTILITY PLAN - PDP/FDP - FDP150039 - REPORTS - DRAINAGE REPORTDRAINAGE REPORT
FOR
CSU HEALTH AND MEDICAL CENTER
AT
151 W. LAKE STREET
FORT COLLINS, CO 80524
PREPARED FOR
COLORADO STATE UNIVERSITY
Fort Collins, CO 80523
DECEMBER 11, 2015
Colorado State University Health and Medical Center Preliminary Drainage Report
Page 1 of 13
TABLE OF CONTENTS
SITE LOCATION AND DESCRIPTION ......................................................................................... 4
DRAINAGE BASINS AND HISTORIC RUNOFF ............................................................................. 5
HISTORIC DRAINAGE ......................................................................................................... 5
DRAINAGE DESIGN CRITERIA ................................................................................................ 7
HYDROLOGIC METHOD AND DESIGN STORM FREQUENCIES ................................................... 7
HYDRAULIC CRITERIA ........................................................................................................ 7
VARIANCES FROM THE CRITERIA ............................................................................................ 7
DRAINAGE FACILITY DESIGN ................................................................................................. 7
GENERAL CONCEPT ......................................................................................................... 7
PROPOSED DEVELOPED SUBBASINS .................................................................................... 8
PROPOSED DETENTION POND ......................................................................................... 10
HISTORIC/DEVELOPED BASIN COMPARISON ..................................................................... 11
STORM WATER MODELING ................................................................................................. 12
STORMWATER POLLUTION PREVENTION/EROSION CONTROL .................................................. 12
TEMPORARY EROSION CONTROL ..................................................................................... 12
PERMANENT EROSION CONTROL ..................................................................................... 12
CONCLUSIONS .................................................................................................................. 12
REFERENCES ...................................................................................................................... 13
LIST OF TABLES
TABLE 1. HISTORIC SWMM BASIN PROPERTIES AND FLOWS ......................................................... 5
TABLE 2.DEVELOPED SWMM SUBBASIN PROPERTIES, FLOWS, AND RUNOFF COEFFICIENTS ........... 10
TABLE 3. DEVELOPED OFFSITE FLOWS AND CAPTURED OFFSITE FLOWS ........................................ 11
LIST OF FIGURES
FIGURE 1. HISTORIC DRAINAGE BASINS (AYRES ASSOCIATES SWMM MODEL) ............................. 6
FIGURE 2. DEVELOPED DRAINAGE SUBBASINS (SWMM MODEL) ................................................. 8
Colorado State University Health and Medical Center Preliminary Drainage Report
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APPENDICES
Appendix A – Referenced Information
1. Urban Storm Drainage Criteria Manual Table RO-3
2. CSU Medical Center Project Drainage Memo from Ayres Associates
3. Referenced Pages from the Alternative Analysis for the Design of the
Mason Street Outfall Study from Ayres Associates Dated November 2010
4. Geotechnical Results and Soil Boring Logs
5. FEMA FIRM Map
Appendix B – Hydraulic/Hydrologic Computations
1. SWMM Input Table (Historic – Ayres Associates Model)
2. SWMM Results (Historic – Ayres Associates Model)
3. SWMM Input Table (Developed)
4. SWMM Results (Developed)
5. Inlet Sizing Calculations
6. Restrictor Plate Sizing
Appendix C – Figure
1. Developed Drainage Map
Colorado State University Health and Medical Center Preliminary Drainage Report
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ENGINEER’S STATEMENT:
“I hereby certify that this report (plan) for the Final Drainage Design CSU Health and Medical
Center was prepared by me (or under my direct supervision) in accordance with the provisions of
the City of Fort Collins Standards for the Responsible Parties thereof. I understand that the City
of Fort Collins does not and shall not assume liability for drainage facilities designed by others.”
______________________________
Kevin A. Tone, P.E.
Registered Professional Engineer
State of Colorado No. 28699
Colorado State University Health and Medical Center Preliminary Drainage Report
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SITE LOCATION AND DESCRIPTION
The Colorado State University Health and Medical Center (site) is located in Section 14, Township
7 North, Range 69 West of the 6
th
Principal Meridian, in Larimer County, Fort Collins, Colorado.
Refer to Appendix A for the site vicinity map. Lake Street (Lake) to the north, South College
Avenue (College) to the east, West Prospect Road (Prospect) to the south, and the Mason Street
Corridor Transitway to the west border the property. Colorado State University (CSU) is located
to the north and west of the site. Developed commercial and residential areas are to the east and
south of the site. The site is located in the Mason Street Outfall (MSO) study performed by Ayres
Associates in 2012. The design requirements and constraints are outline in the study and attached
in Appendix A.
The site is approximately 5.7 acres of developed residential properties with an alley bisecting the
lot from north to south. The site currently drains in several directions with most of the flow directed
to the south with slopes from 1.9% to 2.5% and east at a slope of 1.2% to the intersection of
Prospect and College. A smaller portion of the site drains to the north at a 2.0% slope to Lake and
to the west at a slopes ranging from 1.8% to 3.8% to Mason Street. From the geotechnical report
dated August 18, 2015 the soil is mainly sandy clay with areas of gravely sand and existing fill.
Sandstone bedrock was encountered at 18ft to 24ft below the ground surface with ground water
being located at 12ft to 19ft below ground surface.
According to the FEMA Flood Insurance Rate Map Panel Number 08069C0979H dated
05/02/2012, the site is located outside of the 100-year floodplain area. The map panel is attached
in Appendix A.
Runoff from the existing site enters into the existing storm sewer system at inlets on Lake Street,
Mason Street, and on Prospect just west of College. Currently, as stated in the MSO, the pipe
system at Prospect is too small to handle the existing flows and water ponds at the intersection of
College and Prospect. Flows that are not captured on Lake Street are directed onto College Avenue
and eventually to the inlets on West Prospect Road. The MSO collects water on the Mason Street
Corridor.
The site construction includes approximately 41,300sqft building footprint and 27,000sqft parking
lot areas with associated utilities, roads, sidewalks, detention pond, and landscaped and plaza
areas. A portion of the property located in the northeast corner of the site will not be developed at
this time. However, the storm system was designed to accommodate future development of that
area as a parking lot. The site drains to the southwest corner of the property where the detention
pond is located. The detention pond connects to the existing MSO storm system which outlets into
a regional detention pond and eventually to Spring Creek and the Poudre River. Storm inlets and
pipes are located throughout the site to capture and convey runoff to the detention pond.
The main purpose of this study was to analyze the existing and developed drainage patterns in
order to convey stormwater into the MSO as required by the MSO study. The proposed scope of
work will include new stormwater piping and site grading to accommodate onsite detention pond
and conveyance of the stormwater runoff to the existing storm system. An outlet structure
consisting of a wing wall structure and pipe with a restrictor plate which will be installed on the
pipe to control the 100-year storm outflow rate.
Colorado State University Health and Medical Center Preliminary Drainage Report
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DRAINAGE BASINS AND HISTORIC RUNOFF
HISTORIC DRAINAGE
The existing system was modeled in SWMM by Ayres Associates for the CSU Medical Center
Project Drainage Memo dated July 30, 2015. The Ayres SWMM model was used for the existing
system analysis. Attached in Appendix A is Ayres SWMM model plan view, the SWMM results
are attached in Appendix B. The site is within parts of historical basins E1, E2, E3, E4, E5 and E6.
Basin E1 drains to the north into Lake Street and is collected by inlets on Lake Street. Basin E2
drains to the east onto College. The flow then travels south along College until it turn west onto
Prospect which has a set of sump inlet approximately 50ft west of College. Basin E3 and E4 drain
to the west on the MSO where inlets on the MSO collect the flow. Basins E5 and E6 drain south
onto Prospect where there is a set of sump inlets. Currently the pipe system that the Prospect inlets
tie into is undersized and ponding occurs for larger storm events. There is no existing onsite
detention for the site.
Table 1. Historic SWMM Basin Properties and Flows
Drainage
Basin
Design
Point
Area
(acre)
%
Impervious
Width
(ft)
Slope
(%)
Q-100
(cfs)
Runoff
Coefficient
E1 Lake St 0.92 39.0% 200 2.0 6.4 0.76
E2 College 1.13 49.0% 328 1.20 8.8 0.80
E3 Traintracks 0.67 50.0% 450 1.80 6.1 0.81
E4 Traintracks 0.34 0.0% 294 3.80 2.8 0.64
E5 Prospect 1.86 22.0% 809 2.50 13.8 0.71
E6 Prospect 0.89 18.0% 516 1.90 6.7 0.69
Total 5.81 31.3% 44.7 0.74
Colorado State University Health and Medical Center Preliminary Drainage Report
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Figure 1. Historic Drainage Basins (Ayres Associates SWMM Model)
Colorado State University Health and Medical Center Preliminary Drainage Report
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DRAINAGE DESIGN CRITERIA
HYDROLOGIC METHOD AND DESIGN STORM FREQUENCIES
The drainage for the site was designed to meet or exceed the City of Fort Collin’s Standards and
Specifications, including the Stormwater Criterial Manual which incorporates most of the Urban
Drainage and Flood Control District Criteria Manual (USDCM).
The US Environmental Protection Agency’s (EPA) Stormwater Management Model Version 5.1
(SWMM) was used to calculate the existing and proposed runoff rates and coefficients. The basin
percent impervious values were calculated using impervious values from Table RO-3 in the
USDCM. The City of Fort Collins’ Stormwater Criteria Manual recommended values for the
SWMM basin properties and Table RA-9 provides a 100-year event rainfall intensity duration
curve that were used in the SWMM model.
HYDRAULIC CRITERIA
The proposed drainage facility has been designed to comply with the City of Fort Collins
Stormwater Criteria Manual. SWMM was used to design the storm system, outlet structure, and
ponds. UDFCD’s UD-Inlet v3.14 spreadsheet was used to design the inlet structures for the site.
The SWMM results and inlet design calculations are attached in Appendix B. Complete drainage
plans, details, dimensions, etc. are included in the grading and drainage plans are attached in the
construction documents.
VARIANCES FROM THE CRITERIA
As per the meeting on December 2, 2015 and the City’s comments and response dated December,
4, 2015 the site does not need to follow the City’s LID and paver criteria. The MSO system, as
stated in the MSO study, includes 0.25acre-ft of water quality capture volume (WQCV) for this
site in the regional detention pond. This site has a WQCV of 0.129acre-ft. Therefore, no water
quality control is required on site. The minor storm event was also not controlled on site and the
system was designed to capture and convey the 100-year event.
DRAINAGE FACILITY DESIGN
GENERAL CONCEPT
The storm drainage system has been designed to convey the 100-year event through the
combination of inlets, storm sewer pipes, a detention pond and an outlet pipe. A SWMM model
was created to model the proposed subbasins and storm system. The site was graded to capture
runoff into the storm system and into the detention pond located in the southwest corner of the
site. The site was graded to minimize the amount of flow being directed to College and Prospect.
An inlet was added to College to capture flow and reduce the runoff going to the Prospect inlets.
While the College inlet is not collecting runoff from the developed site it is capturing flow that
would eventually reach the Prospect inlets. Most of the runoff that was originally directed into the
Mason Street Corridor is now captured in the sites system. Two inlets were added to Lake to
capture the runoff from the site that could not be graded towards the detention pond. The inlets
will reduce the flow that is directed to the existing undersized inlets on Lake located near College.
Colorado State University Health and Medical Center Preliminary Drainage Report
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PROPOSED DEVELOPED SUBBASINS
The site was delineated into fifteen subbasin, D1-D15, and were dependent on the location of the
inlets throughout the site. The roof drains split the roof into ten subbasins. There are only three
Subbasins D7, D8, and D15 that are not captured and conveyed to the detention pond. Subbasin
D7 drains to the Prospect inlets, D8 drains to College and eventually flows to the Prospect inlets,
and D15 drains to the existing inlets on Lake. There are 10 roof drains that tie into the storm
system. The developed drainage map is provided in Appendix C.
Figure 2. Developed Drainage Subbasins (SWMM Model)
Colorado State University Health and Medical Center Preliminary Drainage Report
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SUBBASIN DESCRIPTIONS:
• Subbasin D1 contains the north half of Lake Street and drains to a 5ft Type R inlet on Lake
Street.
• Subbasin D2 contains the south half of Lake and the sidewalk and landscaped area along
the north edge of the parking lot. Part of the site that will be undeveloped is also in this
subbasin. A 5ft Type R inlet was placed in Lake Street to capture the runoff.
• Subbasin D3 contains the sites main parking lot, access roads, and part of the undeveloped
area. The subbasin drains into a 10ft Type R inlet.
• Subbasin D4 contains a small parking area, landscaping, and sidewalk. The runoff is
directed away from the building into the parking area and a 5ft Type R inlet.
• Subbasin D5 contains a small parking lot area, landscaping and sidewalk. The runoff is
directed away from the building into the parking area and a 5ft Type R inlet.
• Subbasin D6 contains the detention pond, sidewalk and plaza area and landscaping. The
runoff is directed away from the building and into the detention pond.
• Subbasin D7 contains the sidewalk, bus pull out area, landscaping and the widened
Prospect Road area. This flow is not captured, but flows south onto Prospect and is directed
east to the existing inlets on Prospect.
• Subbasin D8 contains the sidewalk and landscaping. This flow is not captured, but flows
east onto College and onto Prospect to the existing inlets on Prospect.
• Subbasin D9 contains a plaza sitting area and landscaping. This flow is captured by a
18”x18” area drain.
• Subbasin D10 contains parking spaces, sidewalk, and service area. This flow is directed
to a 5ft Type R inlet.
• Subbasin D11 contains the east section of the undeveloped area of the site. The runoff
flows to the east onto College and is captured by 5ft Type R inlet on College which is
connected to the sites storm system. The pipe the inlet is connected to can flow full at
3.5cfs. In order for there to be 3.5cfs runoff flow going to the College inlet in the model, a
dummy subbasin was created, called DUMMYBASIN, that outlets to the College inlet.
This allows for an inflow at the College inlet to be 3.5cfs.
• Subbasin D12 contains a landscaped area, sidewalk and depression storage area. The
depression area is designed to reduce the amount of runoff reaching Prospect. A 12”x12”
area drain is located at the bottom of the depression and is piped into the detention pond.
• Subbasin D13 contains part of the plaza located to the southeast of the building. This flow
is captured by a 18”x18” area drain.
• Subbasin D14 contains sidewalk and a depression storage area. The depression area keeps
runoff from flowing west onto the Mason Street Corridor. A 12”x12” area drain is location
at the bottom of the depression area and the drain ties into the storm system.
• Subbasin D15 contains sidewalk and landscaping along the south side of Lake Street. This
basin was included in the runoff calculations because the sidewalk width is being increased
in this area. This flow will drain to the North onto Lake Street and into the existing inlets
on Lake Street.
• Roof Drain Subbasin: SD1, SD2, SD3, SD4, SD5, SD6, SD7, SD9, SD10, SD11. The roof
drain locations, basin areas, and pipe sizes were supplied by the building architect. All the
roof drains were tied into the storm system and drain to the detention pond.
Colorado State University Health and Medical Center Preliminary Drainage Report
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Table 2.Developed SWMM Subbasin Properties, Flows, and Runoff Coefficients
Subbasin
ID
Design
Point
Area
(acre)
%
Impervious
Q-100
(cfs)
Runoff Coeff's
C100
Discharge
Location
D1 1 0.14 100.0 1.32 0.98 Detention Pond
D2 2 0.41 74.6 3.56 0.89 Detention Pond
D3 3 0.96 72.1 8.91 0.88 Detention Pond
D4 4 0.24 78.7 2.36 0.91 Detention Pond
D5 5 0.32 86.7 3.15 0.93 Detention Pond
D6 6 0.60 27.7 4.67 0.72 Detention Pond
D7 7 0.43 69.0 3.62 0.86 Prospect
D8 8 0.33 29.0 1.81 0.70 College
D9 9 0.07 89.4 0.69 0.94 Detention Pond
D10 10 0.35 93.6 3.47 0.96 Detention Pond
D11 11 0.39 49.9 2.66 0.78 Detention Pond
D12 12 0.21 20.6 1.51 0.69 Detention Pond
D13 13 0.08 81.9 0.77 0.92 Detention Pond
D14 14 0.16 50.7 1.28 0.80 Detention Pond
D15 15 0.05 60.2 0.46 0.84 Lake Street
SD1 SD1 0.13 90.0 1.30 0.95 Detention Pond
SD2 SD2 0.13 90.0 1.30 0.95 Detention Pond
SD3 SD3 0.15 90.0 1.50 0.95 Detention Pond
SD4 SD4 0.08 90.0 0.80 0.95 Detention Pond
SD5 SD5 0.03 90.0 0.30 0.95 Detention Pond
SD6 SD6 0.09 90.0 0.90 0.95 Detention Pond
SD7 SD7 0.19 90.0 1.90 0.95 Detention Pond
SD9 SD9 0.04 90.0 0.40 0.95 Detention Pond
SD10 SD10 0.05 90.0 0.50 0.95 Detention Pond
SD11 SD11 0.04 90.0 0.40 0.95 Detention Pond
Total/Weighted Avg 5.69 67.10 49.54 0.86
DUMMYBASIN N/A 0.085 100.0 0.85 0.98 Detention Pond
PROPOSED DETENTION POND
A detention pond has been designed to capture the 100-year stormwater runoff on the site and
discharge into the MSO system. Due to the existing grade of the site the entire site runoff was not
captured and conveyed to the detention pond. According to the MSO the ponds outflow rate cannot
exceed 13cfs. The original MSO manhole was not used because of the PCB field located in the
southeast corner of the site. The closest MSO manhole to the north of the original manhole will be
the sites tie-in manhole. The invert elevation of the detention ponds outlet pipe at the MSO
manhole is 4989.24ft. The bottom of the pond is at elevation 4989.5ft. Access to the bottom of the
pond and outlet can be achieved by entering the pond from the south. There are retaining walls on
the north and east edge of the pond.
The detention pond has a total volume of 0.873acre-ft including approximately 1.0ft of freeboard
and has a top of pond elevation of 4997.0ft. For the 100-year event the pond will have a maximum
Colorado State University Health and Medical Center Preliminary Drainage Report
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water surface elevation of 4996.06ft which is a pond volume of approximately 0.609acre-ft. The
maximum pond outflow rate is 10.89cfs with the outlet pipe having an outlet pipe of 2.0ft with a
restrictor plate reducing the diameter to 1.65ft. There will be no water quality control in the
detention pond because it will be controlled in the MSO’s regional detention pond.
Not all of the site runoff is being captured in the detention pond. However, placing two inlets on
Lake and an inlet on College the overall total runoff reaching the Prospect from the developed site
is negative 0.72cfs. As shown in Table 3, the only flow that is not being captured is the flow from
subbasin D7 which is the subbasin that discharges directly to Prospect. The inlet on College
captures 3.51cfs which is greater than the flow that is being sent by subbasin D8, which discharges
to College and flow to the Prospect inlets. There are two existing inlets on Lake that captured flow
from Lake Street, but are undersized and it is assumed most of the existing flow from Lake Street
by-passed the inlets and continued onto College. Runoff from Lake Street was not included in the
developed offsite flows because the site project does not include the redevelopment of Lake Street.
However, by placing new inlets on Lake and keeping the existing inlets the runoff from subbasins
D1, D2, and D15 are captured before flow reaches College and eventually Prospect.
Table 3. Developed Offsite Flows and Captured Offsite Flows
Location
Developed
Offsite Flows
(cfs)
Captured
Offsite Flows
(cfs)
Basins Used For Calcs
Lake 2.70 5.34 D1, D2, D15
College 1.81 3.51 D8, D11, DUMMYBASIN
Prospect 3.62 0.00 D7
Total 8.13 8.85
At this time the existing three properties on the northeast edge of the site will not be developed.
However, in the future the properties may be purchased by CSU and developed. The current storm
system and detention pond was sized to allow for the addition of this area as a parking lot. It was
assumed that the backyard area of the properties would become impervious. This would increase
the percent imperviousness for subbasin D2 to 79.5% and D3 to 92.7%, all other basin attributes
would not change. The future changes were modeled and showed no flooding of the storm system
and the ponds new water surface elevation will be at 4996.09ft which is a depth of 6.59ft above
the pond bottom. The detention pond for the future development will have a 100-year a peak
volume of 0.617ac-ft at an outflow rate of 11.07cfs.
HISTORIC/DEVELOPED BASIN COMPARISON
The site contains six historical basins which drain flow all directions, but the bulk of the site drains
to College and Prospect where there are existing inlets on Prospect. The developed drainage basins
will not drastically alter the historical drainage paths, but do decrease the peak flow rates. Flow to
the existing Lake Street inlets decrease from 6.44cfs to 0.46cfs with the installation of two inlets
on the north and south sides of Lake Street. Flow to College decreases from 8.82cfs to 1.81cfs
with the addition of area drains in the plaza area and an inlet on College north of Prospect. The
inlet on College will be able to capture 3.51cfs, restricted by the downstream 12inch pipe. Only a
small portion of the site now flows onto Prospect, the flow decreases from 20.48cfs to 5.43cfs.
However as mention previously the flows captured by in proposed inlets negates the flows from
Colorado State University Health and Medical Center Preliminary Drainage Report
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College and Prospect that are not captured on site. The proposed total 100-year peak runoff for the
site is 49.5cfs with only 5.89cfs of that flow not being captured and conveyed to the detention
pond. The detention pond has a release rate of 10.89cfs. The existing site has a peak 100-year
runoff rate of 44.66cfs. In the event that the detention ponds outlet pipe is clogged and the pond
overflows the water will overflow flow the pond in the south east corner and flow onto Prospect
and east towards College and the Prospect inlets.
STORM WATER MODELING
The pipes, perimeter drains, inlets, and detention pond have been designed to convey the 100-year
storm event flows without flooding the systems. The system has been modeled in SWMM to
analyze the conveyance and capacity of the pipe system and detention pond. A copy of the SWMM
model will be provided upon request. The detentions pond outlet was assumed to have constant
water surface elevation of 4995.1ft. This is the elevation of the 100-year hydraulic grade line in
the MSO manhole that the detention pond outlets into. If the outlet pipe becomes clogged the pond
will overflow to the south onto Prospect.
STORMWATER POLLUTION PREVENTION/EROSION CONTROL
TEMPORARY EROSION CONTROL
A temporary erosion control plan is to be implemented for the site during construction. Temporary
erosion control measures include, but not limited to, slope and swale protection provided by the
use of erosion control wattles/sediment control logs, inlet and outlet protection, vehicle tracking
control at access points to the site and silt fence surrounding the disturbed area. All temporary
erosion control measures are to be removed after they are deemed unnecessary. Refer to the
Erosion Control Plan for the CSU Medical Center Building for additional detail information.
PERMANENT EROSION CONTROL
Permanent erosion control measures include, but not limited to, the constructed detention ponds,
riprap pads placed for culvert outlet protection, seeding and mulch placed to enable and established
vegetative growth, etc. Long-term maintenance of these erosion control measures shall be the
responsibility of the owner of the property. A general erosion control plan has been provided in
the construction documents and is attached.
CONCLUSIONS
This Final Drainage Report for the CSU Health and Medical Center has been prepared to comply
with the stormwater criteria set by the USDCM and City of Fort Collins.
The proposed drainage system presented in this report is designed to convey the 100-year peak
stormwater runoff through the site to the proposed detention ponds. Through calculations,
modeling, and review of the proposed storm drain system, there appears to be adequate capacity
to convey the proposed flows. This report also proposes best management practices for erosion
control, permanent landscaping, riprap, and on-site construction facilities.
Colorado State University Health and Medical Center Preliminary Drainage Report
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It can therefore be concluded that development of the detention ponds comply with all of the
stormwater jurisdictional criteria and will not adversely affect the existing streets, storm drain
system and/or detention/water quality facilities.
REFERENCES
1. Urban Storm Drainage Criteria Manual (Volumes 1, 2, and 3), Urban Drainage and Flood
Control District, June 2001, Revised April 2008.
2. City of Fort Collins Stormwater Criteria Manual, City of Fort Collins, December 2011.
3. “Geotechnical Investigation Proposed Medical Center Colorado State University Fort
Collins, Colorado”, CTL Thompson Incorporated, Dated August 18, 2015.
4. “CSU Medical Center Project Drainage Memo”, Ayres Associates, Dated July 30, 2015.
5. “Alternative Analysis for the Design of the Mason Street Outfall Study”, Ayres Associates,
Dated November 2010.
6. Stormwater Management Model User’s Manual Version 5.0, U.S. Environmental
Protection Agency, Revised July 2010.
7. Stormwater Management Model Applications Manual, U.S. Environmental Protection
Agency, July 2009.
APPENDIX A – REFERENCE INFORMATION
1. Urban Storm Drainage Criteria Manual Table RO-3
2. CSU Medical Center Project Drainage Memo from Ayres Associates Dated July 31,
2015
3. Referenced Pages from the Alternative Analysis for the Design of the Mason Street
Outfall Study from Ayres Associates Dated November 2010
4. Geotechnical Soils Results and Soils Boring Logs
5. FEMA FIRM MAP
DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF
Table RO-3—Recommended Percentage Imperviousness Values
Land Use or
Surface Characteristics
Percentage
Imperviousness
Business:
Commercial areas 95
Neighborhood areas 85
Residential:
Single-family *
Multi-unit (detached) 60
Multi-unit (attached) 75
Half-acre lot or larger *
Apartments 80
Industrial:
Light areas 80
Heavy areas 90
Parks, cemeteries 5
Playgrounds 10
Schools 50
Railroad yard areas 15
Undeveloped Areas:
Historic flow analysis 2
Greenbelts, agricultural 2
Off-site flow analysis
(when land use not defined)
45
Streets:
Paved 100
Gravel (packed) 40
Drive and walks 90
Roofs 90
Lawns, sandy soil 0
Lawns, clayey soil 0
* See Figures RO-3 through RO-5 for percentage imperviousness.
C A = K A + ( 1 . 31 i 3 − 1 . 44 i 2 + 1 . 135 i − 0 . 12 ) for CA ≥ 0, otherwise CA = 0 (RO-6)
C CD = K CD + ( 0 . 858 i 3 − 0 . 786 i 2 + 0 . 774 i + 0 . 04 ) (RO-7)
C B = (CA + C CD ) 2
2007-01 RO-9
Urban Drainage and Flood Control District
400 North Link Lane | Fort Collins, Colorado 80524
Telephone: 970-206-9455 Fax: 970-206-9441
GEOTECHNICAL INVESTIGATION
PROPOSED MEDICAL CENTER
COLORADO STATE UNIVERSITY
FORT COLLINS, COLORADO
COLORADO STATE UNIVERSITY
251 Edison, 6030 Campus Delivery
Fort Collins, Colorado 80526-6030
Attention: Mr. Milt Brown
Project Manager
Project No. FC07034-125
August 18, 2015
COLORADO STATE UNIVERSITY
CSU MEDICAL CENTER
CTLT PROJECT NO. FC07034-125
TABLE OF CONTENTS
SCOPE 1
SUMMARY OF CONCLUSIONS 1
SITE CONDITIONS AND PROPOSED CONSTRUCTION 2
INVESTIGATION 3
SUBSURFACE CONDITIONS 3
SITE DEVELOPMENT 4
Fill Placement 4
Excavations 6
FOUNDATIONS 6
Spread Footings with Minimum Deadload 6
Drilled Piers Bottomed in Bedrock 7
Laterally Loaded Piers 8
Closely Spaced Pier Reduction Factors 9
BELOW GRADE AREAS 10
FLOOR SYSTEMS 10
PAVEMENTS 13
Pavement Selection 14
Subgrade and Pavement Materials and Construction 14
Pavement Maintenance 14
WATER-SOLUBLE SULFATES 15
SURFACE DRAINAGE 16
FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS
FIGURES 2 THROUGH 4 – SUMMARY LOGS OF EXPLORATORY BORINGS
APPENDIX A – RESULTS OF LABORATORY TESTING
APPENDIX B – SAMPLE SITE GRADING SPECIFICATIONS
APPENDIX C – PAVEMENT CONSTRUCTION RECOMMENDATIONS
APPENDIX D – PAVEMENT MAINTENANCE PROGRAM
COLORADO STATE UNIVERSITY
CSU MEDICAL CENTER
CTLT PROJECT NO. FC07034-125
1
SCOPE
This report presents the results of our Geotechnical Investigation for the
proposed Colorado State University Medical Center in Fort Collins, Colorado.
The purpose of the investigation was to evaluate the subsurface conditions and
provide foundation recommendations and geotechnical design criteria for the pro-
ject. The scope was described in our Service Agreement (FC-15-0245, dated
July 8, 2015).
The report was prepared from data developed during field exploration, la-
boratory testing, engineering analysis and experience with similar conditions.
The report includes a description of subsurface conditions found in our explora-
tory borings and discussions of site development as influenced by geotechnical
considerations. Our opinions and recommendations regarding design criteria
and construction details for site development, foundations, floor systems, slabs-
on-grade, pavements and drainage are provided. If the proposed construction
changes, we should be requested to review our recommendations. Our conclu-
sions are summarized in the following paragraphs.
SUMMARY OF CONCLUSIONS
1. In general, soils encountered in our borings consisted of sandy
clay. A layer of gravelly sand was encountered in three of our bor-
ings below and/or within the clay layer. Sandstone bedrock was
encountered in eight of our borings at depths of 18 to 24 feet to the
depths explored.
2. Groundwater was encountered in eight borings at depths of 12 to
19 feet during drilling and 11 to 16½ feet when measured several
days later. Existing groundwater levels are not expected to signifi-
cantly affect the proposed construction, but may affect drilled pier
installation.
3. Existing fill was encountered in our borings. Several structures
were still located on the site that will be demolished prior to con-
COLORADO STATE UNIVERSITY
CSU MEDICAL CENTER
CTLT PROJECT NO. FC07034-125
2
struction. All structures should be completely removed below im-
provements. The existing fill should be completely removed and re-
compacted below the proposed building.
4. We believe the proposed structure can be constructed on spread
footing foundations with a minimum dead load placed on natural,
undisturbed soil and/or properly compacted fill or a drilled pier foun-
dation bottomed into bedrock. Foundation design and construction
recommendations are presented in this report.
5. The presence of expansive soils and bedrock constitutes a geologic
hazard. There is risk that slabs-on-grade and foundations will
heave or settle and be damaged. We believe the recommendations
presented in this report will help to control risk of damage; they will
not eliminate that risk. Slabs-on-grade and, in some instances,
foundations may be damaged.
6. We believe a slab-on-grade floor is appropriate for this site. Some
movement of slab-on-grade floors should be anticipated. We ex-
pect movements will be minor, on the order of 1 inch or less. If
movement cannot be tolerated, structural floors should be consid-
ered.
7. Pavement areas including parking and access drives are planned
for this project. Four borings were drilled in the area of the pro-
posed pavements. Pavement section recommendations are in-
cluded in this report.
SITE CONDITIONS AND PROPOSED CONSTRUCTION
The site is located northwest of Prospect Road and College Avenue in
Fort Collins, Colorado (Figure 1). Several vacant residences are located at the
site that are to be demolished. We understand the proposed construction will in-
clude a new Medical Center. The 4-story Medical Center will be approximately
120,000 square feet. Associated pavement areas will included parking and ac-
cess drives.
APPENDIX B – HYDRAULIC/HYDROLOGIC
COMPUTATIONS
1. SWMM Input Table (Historic – Ayres Associates Data)
2. SWMM Results (Historic – Ayres Associates Model)
3. SWMM Input Table (Developed)
4. SWMM Results (Developed)
5. Inlet Sizing Calculations
6. Restrictor Plate Sizing
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 11/10/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Historic SWMM Input Values for Subbasins (Ayres Associates Model)
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
Subbasin Area Width Slope % Impervious
ID (acre) (ft) (%) (%)
E1 LakeSt 0.92 200 2.0 39.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
E2 College 1.13 328 1.2 49.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
E3 Traintracks 0.67 450 1.8 50.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
E4 Traintracks 0.34 294 3.8 0.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
E5 Prospect 1.86 809 2.5 22.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
E6 Prospect 0.89 516 1.9 18.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
Total 5.81 Weighted Avg 31.3
HORTON
Outlet N-Imperv N-Perv
Dstor-
Imperv
Dstor-
Perv
% Zero-
Imperv
Subarea
Routing
Percent Routed
Max
Infiltration
Min
Infiltration
Decay
Constant
Drying Time
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 11/10/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Historic Runoff Coefficient & Time of Concentration SWMM Result Summary
from Ayres Associates SWMM Model
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
Basin
Name
Outlet
Total Area
(acre)
Runoff Coeff's
Flow Rate
(cfs)
E1 LakeSt 0.92 0.76 6.4
E2 College 1.13 0.80 8.8
E3 Traintracks 0.67 0.81 6.1
E4 Traintracks 0.34 0.64 2.8
E5 Prospect 1.86 0.71 13.8
E6 Prospect 0.89 0.69 6.7
TOTAL SITE 5.81 0.74 44.7
Copy of 2487c - Rational Calculations LAT.xlsx Historic -Results Summary Page 1 of 1
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 11/10/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Historic Runoff Coefficient & Time of Concentration SWMM Result Summary
from Ayres Associates SWMM Model
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
Subbasin ID Outlet
Total Area
(acre)
Runoff Coeff's
C100
Flow Rates (cfs)
Q100
NOTES
D1 C1A 0.14 0.98 1.3 To Lake Captured
D2 C2A 0.41 0.89 3.6 To Lake Captured
D3 C3A 0.96 0.88 8.9
D4 C4A 0.24 0.92 2.4
D5 C5A 0.32 0.93 3.2
D6 POND 0.60 0.75 5.1 Detention Pond
D7 Prospect 0.45 0.91 4.1 To Prospect Not Captured
D8 College 0.30 0.74 1.9 To College Not Captured
D9 C3C 0.09 0.85 0.8
D10 C1B 0.35 0.96 3.5
D11 C2B 0.39 0.78 2.7 To College Captured
D12 C1C 0.23 0.75 1.9
D13 C2C 0.07 0.98 0.7
D14 C1D 0.16 0.78 1.3
D15 Lake 0.05 0.86 0.5 To Lake Not Captured
SD1 RD10 0.13 0.95 1.3
SD2 RD9 0.13 0.95 1.3
SD3 RD7 0.15 0.95 1.5
SD4 RD6 0.08 0.95 0.8
SD5 RD5 0.03 0.95 0.3
SD6 RD3 0.09 0.95 0.9
SD7 RD1 0.19 0.95 1.9
SD9 RD8 0.04 0.95 0.4
SD10 RD4 0.05 0.95 0.5
SD11 RD2 0.04 0.95 0.4
5.70 51.0
Weighted Runoff Coefficient 0.87
TOTAL
Subcatchment Runoff Summary
Total Total Total Total Total Total Peak
Precip Runon Evap Infil Runoff Runoff Runoff Runoff
Subcatchment in in in in in 10^6 gal CFS Coeff
E1 3.67 0.00 0.00 0.89 2.77 0.07 6.44 0.756
E2 3.67 0.00 0.00 0.73 2.92 0.09 8.82 0.797
E3 3.67 0.00 0.00 0.68 2.98 0.05 6.14 0.812
E4 3.67 0.00 0.00 1.37 2.34 0.02 2.78 0.637
E5 3.67 0.00 0.00 1.10 2.58 0.13 13.80 0.705
E6 3.67 0.00 0.00 1.15 2.54 0.06 6.68 0.692
SWMM 5.1 Page 1
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Developed SWMM Input Values for Subbasins
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
Subbasin Area Width Slope % Impervious
ID (acre) (ft) (%) (%)
D1 C1A 0.14 20 1.3 100.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D2 C2A 0.41 60 1.3 74.6 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D3 C3A 0.96 220 2.2 72.1 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D4 C4A 0.24 120 2.2 78.7 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D5 C5A 0.32 90 2.5 86.7 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D6 POND 0.60 180 5.4 27.7 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D7 Prospect 0.43 60 1.6 69.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D8 College 0.33 50 2.0 29.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D9 C3C 0.07 50 0.2 89.4 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D10 C1B 0.35 100 2.0 93.6 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D11 C2B 0.39 70 0.8 49.9 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D12 C1C 0.21 70 3.8 20.6 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D13 C2C 0.08 60 0.2 81.9 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D14 C1D 0.16 50 1.1 50.7 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
D15 Lake 0.05 30 1.1 60.2 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD1 RD10 0.13 150 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD2 RD9 0.13 70 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD3 RD7 0.15 150 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD4 RD6 0.08 70 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD5 RD5 0.03 30 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD6 RD3 0.09 50 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD7 RD1 0.19 150 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD9 RD8 0.04 20 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD10 RD4 0.05 40 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
SD11 RD2 0.04 30 3.0 90.0 0.016 0.25 0.1 0.3 25 OUTLET 100 0.51 0.5 6.48 7
Total 5.69 67.1
Outlet N-Imperv
HORTON
Weighted Avg
Subarea
Routing
% Zero-
Imperv
Dstor-Perv
Dstor-
Imperv
N-Perv
Drying
Time
Decay
Constant
Min
Infiltration
Max
Infiltration
Percent
Routed
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Developed Percent Impervious Calculations
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
I (%) = 100% 100% 90% 40% 10% 0%
Basin
Name
Design
Point
Apaved
streets
(sf)
Adrives/c
onc (sf)
Aroof
(sf)
Agravel
(sf)
Aplygnd
(sf)
Alscape
(C/D soil)
(sf)
ATotal
(sf)
ATotal
(ac)
Imp
(%)
D1 1 4,973 1,024 5,997 0.14 100.0%
D2 2 7,223 5,848 304 4,521 17,896 0.41 74.6%
D3 3 23,514 6,340 375 11,661 41,890 0.96 72.1%
D4 4 4,659 3,553 2,221 10,433 0.24 78.7%
D5 5 8,577 3,371 1,832 13,780 0.32 86.7%
D6 6 7,255 18,900 26,155 0.60 27.7%
D7 7 5,128 7,783 5,796 18,707 0.43 69.0%
D8 8 195 3,964 10,171 14,330 0.33 29.0%
D9 9 2,659 315 2,974 0.07 89.4%
D10 10 12,164 2,090 981 15,235 0.35 93.6%
D11 11 4,530 4,470 8,152 17,152 0.39 49.9%
D12 12 1,920 7,391 9,311 0.21 20.6%
D13 13 2,814 620 3,434 0.08 81.9%
D14 14 3,486 3,394 6,880 0.16 50.7%
D15 15 1,428 944 2,372 0.05 60.2%
SD1 SD1 5,880 5,880 0.13 90.0%
SD2 SD2 5,749 5,749 0.13 90.0%
SD3 SD3 6,693 6,693 0.15 90.0%
SD4 SD4 3,516 3,516 0.08 90.0%
SD5 SD5 1,483 1,483 0.03 90.0%
SD6 SD6 3,824 3,824 0.09 90.0%
SD7 SD7 8,297 8,297 0.19 90.0%
SD9 SD8 1,802 1,802 0.04 90.0%
SD10 SD9 2,303 2,303 0.05 90.0%
SD11 SD10 1,728 1,728 0.04 90.0%
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Developed Runoff Coefficient & Time of Concentration SWMM Result Summary
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
Subbasin ID Outlet Design Point
Area
(acre)
Runoff Coeff's
C100
Flow Rates (cfs)
Q100
NOTES
D1 C1A 1 0.14 0.98 1.32 To Lake Captured
D2 C2A 2 0.41 0.89 3.56 To Lake Captured
D3 C3A 3 0.96 0.88 8.91
D4 C4A 4 0.24 0.91 2.36
D5 C5A 5 0.32 0.93 3.15
D6 POND 6 0.60 0.72 4.67 Detention Pond
D7 Prospect 7 0.43 0.86 3.62 To Prospect Not Captured
D8 College 8 0.33 0.70 1.81 To College Not Captured
D9 C3C 9 0.07 0.94 0.69
D10 C1B 10 0.35 0.96 3.47
D11 C2B 11 0.39 0.78 2.66 To College Captured
D12 C1C 12 0.21 0.69 1.51
D13 C2C 13 0.08 0.92 0.77
D14 C1D 14 0.16 0.80 1.28
D15 Lake 15 0.05 0.84 0.46 To Lake Captured by Exist Inlets
SD1 RD10 SD1 0.13 0.95 1.30
SD2 RD9 SD2 0.13 0.95 1.30
SD3 RD7 SD3 0.15 0.95 1.50
SD4 RD6 SD4 0.08 0.95 0.80
SD5 RD5 SD5 0.03 0.95 0.30
SD6 RD3 SD6 0.09 0.95 0.90
SD7 RD1 SD7 0.19 0.95 1.90
SD9 RD8 SD9 0.04 0.95 0.40
SD10 RD4 SD10 0.05 0.95 0.50
SD11 RD2 SD11 0.04 0.95 0.40
DUMMYBASIN C2B N/A 0.085 0.98 0.85
To College Captured (to achieve 3.5cfs
Captured) NOT INCLUDED IN TOTALS
5.69 49.54
Weighted Runoff Coefficient 0.86
Offsite Flows
Location
Developed
Offsite Flows
(cfs)
Captured
Offsite Flows
(cfs)
Basins Used For Calcs
Lake Street 2.70 5.34 D1, D2, D15
College Avenue 1.81 3.51 D8, D11, DUMMYBASIN
Prospect 3.62 0.00 D7
Subcatchment Runoff Summary
Total Total Total Total Total Total Peak
Precip Runon Evap Infil Runoff Runoff Runoff Runoff
Subcatchment in in in in in 10^6 gal CFS Coeff
D1 3.67 0.00 0.00 0.00 3.59 0.01 1.32 0.979
D10 3.67 0.00 0.00 0.09 3.52 0.03 3.47 0.958
D11 3.67 0.00 0.00 0.76 2.87 0.03 2.66 0.782
D12 3.67 0.00 0.00 1.12 2.54 0.01 1.51 0.691
D13 3.67 0.00 0.00 0.25 3.36 0.01 0.77 0.917
D14 3.67 0.00 0.00 0.70 2.93 0.01 1.28 0.798
D15 3.67 0.00 0.00 0.55 3.08 0.00 0.46 0.840
D2 3.67 0.00 0.00 0.36 3.25 0.04 3.56 0.886
D3 3.67 0.00 0.00 0.39 3.23 0.08 8.91 0.881
D4 3.67 0.00 0.00 0.29 3.33 0.02 2.36 0.907
D5 3.67 0.00 0.00 0.18 3.43 0.03 3.15 0.934
D6 3.67 0.00 0.00 1.01 2.64 0.04 4.67 0.720
D7 3.67 0.00 0.00 0.45 3.17 0.04 3.62 0.864
D8 3.67 0.00 0.00 1.09 2.56 0.02 1.81 0.698
D9 3.67 0.00 0.00 0.14 3.46 0.01 0.69 0.943
SD1 3.67 0.00 0.00 0.13 3.47 0.01 1.30 0.947
SWMM 5.1 Page 1
Total Total Total Total Total Total Peak
Precip Runon Evap Infil Runoff Runoff Runoff Runoff
Subcatchment in in in in in 10^6 gal CFS Coeff
SD10 3.67 0.00 0.00 0.13 3.47 0.00 0.50 0.947
SD11 3.67 0.00 0.00 0.13 3.47 0.00 0.40 0.947
SD2 3.67 0.00 0.00 0.13 3.47 0.01 1.30 0.946
SD3 3.67 0.00 0.00 0.13 3.47 0.01 1.50 0.947
SD4 3.67 0.00 0.00 0.13 3.47 0.01 0.80 0.947
SD5 3.67 0.00 0.00 0.13 3.47 0.00 0.30 0.947
SD6 3.67 0.00 0.00 0.13 3.47 0.01 0.90 0.946
SD7 3.67 0.00 0.00 0.13 3.47 0.02 1.90 0.947
SD9 3.67 0.00 0.00 0.13 3.47 0.00 0.40 0.946
DUMMYBASIN 3.67 0.00 0.00 0.00 3.60 0.01 0.85 0.980
SWMM 5.1 Page 2
Node Depth Summary
Average Maximum Maximum Day of Hour of
Depth Depth HGL Maximum Maximum
Node Type Feet Feet Feet Depth Depth
C1A JUNCTION 1.95 3.33 4996.49 0 00:37
C1B JUNCTION 2.31 3.39 4996.16 0 00:38
C1C JUNCTION 4.16 5.35 4996.07 0 00:51
C1D JUNCTION 0.77 4.68 4999.20 0 00:39
C2A JUNCTION 2.21 3.64 4996.52 0 00:37
C2B JUNCTION 1.92 3.69 4996.92 0 00:38
C2C JUNCTION 1.95 3.20 4996.35 0 00:39
C3A JUNCTION 2.84 3.93 4996.10 0 00:49
C3C JUNCTION 1.10 2.45 4996.58 0 00:39
C4A JUNCTION 3.45 4.60 4996.09 0 00:49
C5A JUNCTION 2.03 3.28 4996.37 0 00:39
J10C JUNCTION 1.19 5.16 4999.29 0 00:39
J11C JUNCTION 0.90 4.99 4999.44 0 00:39
J1A JUNCTION 4.06 5.24 4996.08 0 00:50
J1B JUNCTION 3.09 4.21 4996.09 0 00:49
J1C JUNCTION 4.41 5.61 4996.06 0 00:51
SWMM 5.1 Page 1
Average Maximum Maximum Day of Hour of
Depth Depth HGL Maximum Maximum
Node Type Feet Feet Feet Depth Depth
J2C JUNCTION 3.10 4.21 4996.08 0 00:50
J3C JUNCTION 2.40 3.55 4996.22 0 00:39
J4C JUNCTION 2.20 3.44 4996.32 0 00:39
J5C JUNCTION 1.27 2.61 4996.56 0 00:39
J6C JUNCTION 1.20 2.64 4996.68 0 00:39
J7C JUNCTION 0.88 3.63 4998.03 0 00:39
J8C JUNCTION 0.44 5.61 5000.52 0 00:39
J9C JUNCTION 1.62 2.57 4996.11 0 00:50
M1B JUNCTION 2.55 3.61 4996.09 0 00:49
MH1A JUNCTION 3.73 4.90 4996.09 0 00:50
MH2A JUNCTION 4.21 5.40 4996.07 0 00:51
RD1 JUNCTION 0.06 0.65 4996.50 0 00:40
RD10 JUNCTION 0.29 2.55 4997.66 0 00:39
RD2 JUNCTION 0.72 5.06 4999.72 0 00:39
RD3 JUNCTION 0.67 4.94 4999.65 0 00:39
RD4 JUNCTION 1.14 3.35 4997.47 0 00:39
RD5 JUNCTION 0.93 3.93 4998.24 0 00:38
SWMM 5.1 Page 2
Average Maximum Maximum Day of Hour of
Depth Depth HGL Maximum Maximum
Node Type Feet Feet Feet Depth Depth
RD6 JUNCTION 0.26 2.22 4997.34 0 00:39
RD7 JUNCTION 0.51 3.22 4998.07 0 00:39
RD8 JUNCTION 0.19 3.37 4998.58 0 00:39
RD9 JUNCTION 0.07 5.78 5001.50 0 00:39
College OUTFALL 0.00 0.00 0.00 0 00:00
Prospect OUTFALL 0.00 0.00 0.00 0 00:00
EXMH OUTFALL 5.86 5.86 4995.10 0 00:00
Lake OUTFALL 0.00 0.00 0.00 0 00:00
POND STORAGE 5.33 6.56 4996.06 0 00:51
SWMM 5.1 Page 3
Link Flow Summary
Maximum Day of Hour of Maximum Max / Max /
|Flow| Maximum Maximum |Velocity| Full Full
Link Type CFS Flow Flow ft/sec Flow Depth
L6A CONDUIT 30.71 0 00:39 3.19 0.49 1.00
L5A-1 CONDUIT 24.39 0 00:39 3.45 0.57 1.00
L3A CONDUIT 13.77 0 00:40 3.62 0.48 1.00
L2A CONDUIT 4.88 0 00:40 2.78 0.44 1.00
L1A CONDUIT 1.32 0 00:40 2.16 0.52 1.00
L3B-2 CONDUIT 8.32 0 00:38 2.77 0.29 1.00
L2B CONDUIT 6.98 0 00:39 4.05 0.97 1.00
L1B CONDUIT 3.51 0 00:39 4.46 1.40 1.00
L5A-2 CONDUIT 26.27 0 00:39 3.72 0.63 1.00
LRD1 CONDUIT 1.88 0 00:38 7.25 0.67 0.98
LRD11 CONDUIT 1.80 0 00:39 5.10 0.54 1.00
LRD13 CONDUIT 0.40 0 00:39 2.05 0.72 1.00
LRD5 CONDUIT 0.92 0 00:00 10.93 0.75 1.00
LRD12 CONDUIT 1.30 0 00:39 6.62 2.33 1.00
L7C CONDUIT 4.21 0 00:39 4.04 0.40 1.00
L10C CONDUIT 1.97 0 00:39 3.14 0.55 1.00
SWMM 5.1 Page 1
Maximum Day of Hour of Maximum Max / Max /
|Flow| Maximum Maximum |Velocity| Full Full
Link Type CFS Flow Flow ft/sec Flow Depth
L11C CONDUIT 1.47 0 00:39 3.54 0.41 1.00
L3B-1 CONDUIT 7.01 0 00:38 3.00 0.24 1.00
LRD10 CONDUIT 1.30 0 00:38 6.62 1.22 1.00
L2C CONDUIT 7.71 0 00:39 2.45 0.48 1.00
L4A CONDUIT 16.14 0 00:40 3.36 0.56 1.00
LRD8 CONDUIT 0.42 0 00:39 4.90 1.00 1.00
LRD7 CONDUIT 1.51 0 00:39 7.67 1.19 1.00
LRD6 CONDUIT 0.81 0 00:37 5.21 0.85 1.00
L6C CONDUIT 1.10 0 00:37 1.06 0.10 1.00
L8C CONDUIT 1.43 0 00:38 2.24 0.10 1.00
L9C CONDUIT 3.42 0 00:39 5.59 0.98 1.00
LRD9 CONDUIT 1.37 0 00:39 6.99 1.09 1.00
L5C CONDUIT 5.05 0 00:39 3.66 0.50 1.00
L4C CONDUIT 5.88 0 00:39 4.17 0.52 1.00
L3C CONDUIT 6.19 0 00:39 3.62 0.59 1.00
L1C CONDUIT 9.51 0 00:39 3.03 0.59 1.00
LRD2 CONDUIT 0.40 0 00:39 4.71 0.95 1.00
SWMM 5.1 Page 2
Maximum Day of Hour of Maximum Max / Max /
|Flow| Maximum Maximum |Velocity| Full Full
Link Type CFS Flow Flow ft/sec Flow Depth
LRD3 CONDUIT 0.90 0 00:39 4.58 0.70 1.00
LRD4 CONDUIT 0.50 0 00:39 5.84 1.45 1.00
L1D CONDUIT 1.27 0 00:39 2.03 0.36 1.00
L2D CONDUIT 4.43 0 00:39 5.64 1.28 1.00
PONDOUT ORIFICE 10.89 0 00:51
SWMM 5.1 Page 3
Storage Volume Summary
Average Average Evap Infil Maximum Maximum Day of Hour of Maximum
Storage Volume Percent Percent Percent Volume Percent Maximum Maximum Outflow
Unit 1000 ft3 Full Loss Loss 1000 ft3 Full Volume Volume CFS
POND 17.721 46 0 0 26.526 69 0 00:51 10.89
SWMM 5.1 Page 1
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
POND VOLUME CALCULATIONS - STAGE / STORAGE
Pond Volume = Prismoidal Formula
Volume Equation = (A1+A2+SQRT(A1*A2)*D/3
WEIGHTED INCREMENTAL CUMMULATIVE CUMMULATIVE
ELEVATION DEPTH (D) AREA (A1) AVG AREA (A2) VOLUME VOLUME VOLUME Depth
ft ft ft2 ft2 ft3 ft3 ACRE-FT ft
4989.5 0.0 0 0 0 0 0.00 0.00
4990.0 0.5 204 102 34 34 0.00 0.50
4991.0 1.0 1,462 833 737 771 0.02 1.50
4992.0 1.0 2,933 2,198 2,155 2,927 0.07 2.50
4993.0 1.0 3,978 3,456 3,442 6,369 0.15 3.50
4994.0 1.0 5,113 4,546 4,534 10,903 0.25 4.50
4995.0 1.0 6,963 6,038 6,014 16,917 0.39 5.50
4996.0 1.0 10,536 8,749 8,688 25,605 0.59 6.50
4997.0 1.0 14,432 12,484 12,433 38,038 0.87 7.50
Volume (ft
3
) Volume (ac-ft)
Water Surface
Elevation Water Depth
V100 26,528 cf 0.609 ac-ft 4996.06 ft 6.56 ft
Top of Pond 38,038 cf 0.873 ac-ft 4997.00 ft 7.50 ft
Volume Interpolation Calculations
Vol Elev
25604.71 4996.00
26528.00 4996.06
38037.60 4997.00
Stage / Storage Input Table
Volume Summary Table
V100
2487c - Rational Calculations.xlsx Vol Pond Page 1 of 2
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
Top of Pond
38,038 cf
4997.00 ft
V100
26,528 cf
4996.06 ft
4989.0
4990.0
4991.0
4992.0
4993.0
4994.0
4995.0
4996.0
4997.0
4998.0
0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000
WATER SURFACE ELEVATION
(FEET ABOVE MSL)
POND VOLUME (CF)
STAGE VS. STORAGE
Detention Pond
2487c - Rational Calculations.xlsx Vol Pond Page 2 of 2
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
CSU Medical Center
Water Quality Capture Volume (WQCV) Calculations (UDFCD Volume 3 Chapter 3)
Location: Fort_Collins
Major Design Storm: 100
Soil Type: C/D
WQCV=a((0.91I
3
)-(1.19I
2
)+(0.78I))
Where:
WQCV = Water Quality Capture Volume (watershed inches)
a = Drain Time Coefficient (see table below )
I = Imperviousness (%/100)
Drainage Time (hrs) Coefficient, a
12 0.8
24 0.9
40 1.00
WQCV North Basin:
a= 1.00
I= 0.671 %/100
WQCV= 0.260 watershed inches
Vrequired
=(WQCV/12)*A*43560
WQCV= 0.260 watershed inches
A = 5.69 acre
Vrequired
= 5373 cf
0.123 acre-ft
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
FLOW CALCULATIONS - GRATE INLET SUMP CONDITION
(Reference: Urban Drainage and Flood Control District Drainage Criteria Manual, 2001, V.1, Section 3.3.6)
(Note: Spreadsheet assumes orifice condition for fully developed flow.)
INLET TYPE: BASIN:
Orifice Equation: Q = Cd*Ao*(2gH)^0.5 K = Clogging Coefficent value
for multiple inlets
Adjust Ao (open area) due to clogging as follows: N Grate
1 1
Effective Area Opening Ae = (1-C) Ao, where: 2 1.5
C = K * Co / N 3 1.75
N = Number of Inlets 4 1.88
Co = Single Inlet Clogging Factor: 5 1.94
Co(grate) = 0.5 (50% clogging) 6 1.97
7 1.98
8 1.99
Number of inlets: N = 1
Inlet Dimensions and Effective Open Area:
Grate Opening: Ao(g) = 0.61 ft^2
Total Ao(g) = 0.61 ft^2
K = 1.00
C = K*Co/N = 0.50
Ae(g) = (1-C)Ao = 0.31 ft^2
Allowable depth: H = 3.0 in = 0.25 ft
Constants: g = 32.20 ft/s^2
Cd = 0.67
Flow Calculations:
Grate Flow: Q = Cd * Ae(g) * (2g*H)^0.5
Qg= 0.82 CFS
Total Intercepted Flow with 1 inlet(s) and
an allowable depth of 3 inches is 0.82 cfs
Required Flow (Q 0.77 cfs Bypass = 0.0 cfs
Required Flow (Q 0.69 cfs Bypass = 0.0 cfs
18" Area Drain D9 AND D13
C2C) =
C3C) =
2487c - Rational Calculations.xlsx 18" Area Drain(UDFCD) Page 1 of 1
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 inches
Number of Unit Inlets (Grate or Curb Opening) No = 1 1
Water Depth at Flowline (outside of local depression) Ponding Depth = 6.0 6.0 inches
Grate Information MINOR MAJOR
Length of a Unit Grate Lo
(G) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 10.00 10.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 1.50 1.50 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Q
a = 9.2 9.2 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q
PEAK REQUIRED = 8.9 8.9 cfs
INLET IN A SUMP OR SAG LOCATION
CSU MEDICAL CENTER
C3A
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
2487C - UD-Inlet_v3.14- TYPE R 10FT SUMP C3A.xlsm, Inlet In Sump 11/10/2015, 9:18 AM
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 inches
Number of Unit Inlets (Grate or Curb Opening) No = 1 1
Water Depth at Flowline (outside of local depression) Ponding Depth = 5.5 5.5 inches
Grate Information MINOR MAJOR
Length of a Unit Grate Lo
(G) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 5.00 5.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 1.50 1.50 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Q
a = 4.7 4.7 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q
PEAK REQUIRED = 1.3 3.6 cfs
INLET IN A SUMP OR SAG LOCATION
CSU MEDICAL CENTER
C1A, C2A, C4A, C5A, C1B
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
2487C - UD-Inlet_v3.14- TYPE R 5FT SUMP.xlsm, Inlet In Sump 12/9/2015, 5:29 PM
Project =
Inlet ID =
Design Information (Input) MINOR MAJOR
Type of Inlet Inlet Type =
Local Depression (additional to continuous gutter depression 'a' from 'Q-Allow') alocal
= 3.00 3.00 inches
Number of Unit Inlets (Grate or Curb Opening) No = 1 1
Water Depth at Flowline (outside of local depression) Ponding Depth = 5.5 5.5 inches
Grate Information MINOR MAJOR
Length of a Unit Grate Lo
(G) = N/A N/A feet
Width of a Unit Grate Wo
= N/A N/A feet
Area Opening Ratio for a Grate (typical values 0.15-0.90) Aratio
= N/A N/A
Clogging Factor for a Single Grate (typical value 0.50 - 0.70) Cf
(G) = N/A N/A
Grate Weir Coefficient (typical value 2.15 - 3.60) Cw
(G) = N/A N/A
Grate Orifice Coefficient (typical value 0.60 - 0.80) Co
(G) = N/A N/A
Curb Opening Information MINOR MAJOR
Length of a Unit Curb Opening Lo
(C) = 5.00 5.00 feet
Height of Vertical Curb Opening in Inches Hvert
= 6.00 6.00 inches
Height of Curb Orifice Throat in Inches Hthroat
= 6.00 6.00 inches
Angle of Throat (see USDCM Figure ST-5) Theta = 63.40 63.40 degrees
Side Width for Depression Pan (typically the gutter width of 2 feet) Wp
= 1.50 1.50 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw
(C) = 3.60 3.60
Curb Opening Orifice Coefficient (typical value 0.60 - 0.70) Co
(C) = 0.67 0.67
MINOR MAJOR
Total Inlet Interception Capacity (assumes clogged condition) Q
a = 4.7 4.7 cfs
Inlet Capacity IS GOOD for Minor and Major Storms (>Q PEAK) Q
PEAK REQUIRED = 3.5 3.5 cfs
INLET IN A SUMP OR SAG LOCATION
CSU MEDICAL CENTER
C2B
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
2487C - UD-Inlet_v3.14- TYPE R 5FT GRADE C2B.xlsm, Inlet In Sump 12/9/2015, 5:30 PM
Grass Type Limiting Manning's n
A 0.06
B 0.04
C 0.033
D 0.03
E 0.024
Analysis of Trapezoidal Grass-Lined Channel Using SCS Method
NRCS Vegetal Retardance (A, B, C, D, or E) A, B, C, D or E
Manning's n (Leave cell D16 blank to manually enter an n value) n = 0.030
Channel Invert Slope SO = 0.0200 ft/ft
Bottom Width B = 4.00 ft
Warning 01 Left Side Slope Z1 = 0.09 ft/ft
Warning 01 Right Side Slope Z2 = 0.21 ft/ft
Check one of the following soil types:
Soil Type: Max. Velocity (VMAX) Max Froude No. (FMAX)
Sandy 5.0 fps 0.50
Non-Sandy 7.0 fps 0.80
Minor Storm Major Storm
Max. Allowable Top Width of Channel for Minor & Major Storm TMAX = 8.00 8.00 feet
Max. Allowable Water Depth in Channel for Minor & Major Storm dMAX = 0.45 0.44 feet
Allowable Channel Capacity Based On Channel Geometry Minor Storm Major Storm
MINOR STORM Allowable Capacity is based on Depth Criterion Qallow = 6.66 6.43 cfs
MAJOR STORM Allowable Capacity is based on Depth Criterion dallow = 0.45 0.44 ft
Water Depth in Channel Based On Design Peak Flow
Design Peak Flow Qo = 1.51 1.51 cfs
Water Depth d = 0.18 0.18 feet
Inlet Design Information (Input)
Type of Inlet Inlet Type =
Angle of Inclined Grate (must be <= 30 degrees) θ = 0.00 degrees
Width of Grate W = 1.00 feet
Length of Grate L = 1.00 feet
Open Area Ratio ARATIO = 0.70
Height of Inclined Grate HB = 0.00 feet
Clogging Factor Cf = 0.50
Grate Discharge Coefficient Cd = N/A
Orifice Coefficient Co = 0.64
Weir Coefficient Cw = 2.05
MINOR MAJOR
Water Depth at Inlet (for depressed inlets, 1 foot is added for depression) d = 0.18 0.18
Total Inlet Interception Capacity (assumes clogged condition) Qa
= 0.46 0.46 cfs
WARNING: Inlet Capacity less than Q Peak for Minor and Major Storms Bypassed Flow, Qb = 1.05 1.05 cfs
Capture Percentage = Qa/Qo = C% 31 31 %
Warning 01: Sideslope steepness exceeds USDCM Volume I recommendation.
Warning 02: Depth (d) exceeds USDCM Volume I recommendation.
Warning 04: Froude No. exceeds USDCM Volume I recommendation.
User-Defined
AREA INLET IN A TRAPEZOIDAL GRASS-LINED CHANNEL
CSU MEDICAL CENTER
C1C
Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Choose One:
Sandy
Non-Sandy
2487C - UD-Inlet_v3.14- AREA DRAIN C1C.xlsm, Area Inlet 12/9/2015, 5:32 PM
Grass Type Limiting Manning's n
A 0.06
B 0.04
C 0.033
D 0.03
E 0.024
Analysis of Trapezoidal Grass-Lined Channel Using SCS Method
NRCS Vegetal Retardance (A, B, C, D, or E) A, B, C, D or E
Manning's n (Leave cell D16 blank to manually enter an n value) n = 0.030
Channel Invert Slope SO = 0.0200 ft/ft
Bottom Width B = 3.00 ft
Warning 01 Left Side Slope Z1 = 0.15 ft/ft
Warning 01 Right Side Slope Z2 = 0.20 ft/ft
Check one of the following soil types:
Soil Type: Max. Velocity (VMAX) Max Froude No. (FMAX)
Sandy 5.0 fps 0.50
Non-Sandy 7.0 fps 0.80
Minor Storm Major Storm
Max. Allowable Top Width of Channel for Minor & Major Storm TMAX = 7.00 7.00 feet
Max. Allowable Water Depth in Channel for Minor & Major Storm dMAX = 0.50 0.50 feet
Allowable Channel Capacity Based On Channel Geometry Minor Storm Major Storm
MINOR STORM Allowable Capacity is based on Depth Criterion Qallow = 5.73 5.73 cfs
MAJOR STORM Allowable Capacity is based on Depth Criterion dallow = 0.50 0.50 ft
Water Depth in Channel Based On Design Peak Flow
Design Peak Flow Qo = 1.09 1.09 cfs
Water Depth d = 0.18 0.18 feet
Inlet Design Information (Input)
Type of Inlet Inlet Type =
Angle of Inclined Grate (must be <= 30 degrees) θ = 0.00 degrees
Width of Grate W = 1.00 feet
Length of Grate L = 1.00 feet
Open Area Ratio ARATIO = 0.70
Height of Inclined Grate HB = 0.00 feet
Clogging Factor Cf = 0.50
Grate Discharge Coefficient Cd = N/A
Orifice Coefficient Co = 0.64
Weir Coefficient Cw = 2.05
MINOR MAJOR
Water Depth at Inlet (for depressed inlets, 1 foot is added for depression) d = 0.18 0.18
Total Inlet Interception Capacity (assumes clogged condition) Qa
= 0.45 0.45 cfs
WARNING: Inlet Capacity less than Q Peak for Minor and Major Storms Bypassed Flow, Qb = 0.64 0.64 cfs
Capture Percentage = Qa/Qo = C% 41 41 %
Warning 01: Sideslope steepness exceeds USDCM Volume I recommendation.
Warning 02: Depth (d) exceeds USDCM Volume I recommendation.
Warning 04: Froude No. exceeds USDCM Volume I recommendation.
User-Defined
AREA INLET IN A TRAPEZOIDAL GRASS-LINED CHANNEL
CSU MEDICAL CENTER
C1D
Minor storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Major storm max. allowable capacity GOOD - greater than flow given on sheet 'Q-Peak'
Choose One:
Sandy
Non-Sandy
2487C - UD-Inlet_v3.14- AREA DRAIN C1D.xlsm, Area Inlet 12/9/2015, 5:34 PM
JVA Incorporated Job Name: CSU Medical Center
25 Old Town Square Job Number: 2487c
Fort Collins, CO 80524 Date: 12/9/15
Ph: 970.225.9099 By: LAT
Fax: 970.225.6923
ORIFICE PLATE AT OUTLET PIPE WORKSHEET
Orifice Plate
Q=cA(2gH)^.5 C= 0.65 QMAJOR
allowable release rate: 10.89 cfs
From SWMM:
100-yr Water Surface Elev: 6.56 ft
Inv Elev at Outlet Struct: 4989.50 ft
Outlet Pipe at Structure: 24 in
SWMM Outlet Pipe Diameter: 1.65 ft
Needed Area: 2.14 sf
Using Area- determine
Ao 2.14 sf
Apipe 3.14 sf
theta 2.556 rad
Ao-calced 2.14 sf
m 0.29 ft distance above(+) or below(-) center
H 1.29 ft Height above pipe invert
+
−
=
2
* cos
2
sin
2
2 θ θ
π
APPENDIX C – FIGURE
1. Developed Drainage Map
π θ
A o A pipe r r
=
2
cos θ
m r
H = r + m
2487c - Rational Calculations.xlsx Restrictor Plate Page 1 of 1
Total 8.13 8.85
TOTAL
TOTAL SITE 66,433 58,065 46,424 0 0 76,899 247,821 5.69 67.1%
2487c - Rational Calculations.xlsx Developed Imperv Calcs Page 1 of 1