HomeMy WebLinkAboutCENTERPOINT PLAZA (RE-APPLICATION) - PDP - PDP150014 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE AND EROSION CONTROL REPORT
FOR
CENTERPOINT PLAZA
Job Number 1028
July 14, 2015
FINAL DRAINAGE
AND EROSION
CONTROL REPORT
FOR
CENTERPOINT PLAZA
Section 20, Township 7 North, Range 68 West
Sixth Principal Meridian, Fort Collins, Colorado
Design and Analysis Based Upon a Local Vertical Datum
Prepared for:
Mr. Sean Sjodin
NexGen Properties, L.L.C.
One Denver Tech Center
5251 DTC Parkway, Suite 8000
Greenwood Village, CO 80111
(303) 923-2442
Prepared by:
RICK ENGINEERING COMPANY, INC.
4 Inverness Court East, Suite 300
Englewood, CO 80112
(303) 565-8080
JN 1028
July 14, 2015
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
TABLE OF CONTENTS
Subject Page
1.0 INTRODUCTION ................................................................................................................. 1
1.1 Site Location .............................................................................................................. 1
1.2 Site Description ......................................................................................................... 2
1.3 Purpose and Objectives ............................................................................................. 2
1.4 Previous Studies ........................................................................................................ 2
1.5 Methodologies and Procedures ................................................................................. 2
2.0 DRAINAGE BASIN AND SUBBASINS ............................................................................ 4
2.1 Major Basin Description ......................................................................................... 4
2.2 Sub-basin Description ............................................................................................. 4
3.0 DEVELOPED DRAINAGE PATTERNS ............................................................................5
4.0 STORMWATER DETENTION REQUIREMENTS ...........................................................6
5.0 POST-CONSTRUCTION STORMWATER MANAGEMENT .............................................................7
5.1 Water Quality ................................................................................................................... 7
6.0 LONG TERM MAINTENANCE ......................................................................................... 8
7.0 SUMMARY ........................................................................................................................... 9
8.0 ENGINEER’S STATEMENT ............................................................................................. 10
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDICES
APPENDIX A – FIGURES AND EXHIBITS ........................................................................... A-1
APPENDIX B – HYDROLOGIC DATA SHEETS................................................................... B-1
APPENDIX C – HYDRAULIC CALCULATIONS.................................................................. C-1
APPENDIX D – HYDRAULIC MODELS (STORM DRAIN)................................................. D-1
APPENDIX E – BMP CALCULATIONS ..................................................................................E-1
APPENDIX F – REFERENCE DOCUMENTATION................................................................F-1
LIST OF FIGURES
Figure 1 - Location Map .................................................................................................................... 1
Figure 2 – FEMA FIRM ............................................................................................................. A-2
Figure 3 – Proposed Drainage Map ............................................................................................ A-3
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 1
1.0 INTRODUCTION
1.1 Site Location
Centerpoint Plaza (project site) is located in the northwest quarter of Section
20, Township 7 North, Range 68 West of the 6th Principal Meridian in the
City of Fort Collins, Colorado. More specifically, the project site is bounded
by Timberline Road on the west, Midpoint Drive on the north, Railroad
Right of Way on the north and industrial development to the east as shown
on the location map (Figure 1) below.
Figure 1 - Location Map
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 2
1.2 Site Description
The project site is a total of approximately 2.34 acres. Phase 1 development was
completed in May of 2006. The Phase 2 area is approximately 1.57 acres.
Vegetation on Phase 2 consists of native weeds and grasses. Onsite soils are
Hydrologic Group C according to the Natural Resources Conservation Service
(NRCS). The site is zoned E (Employment) and is adjacent to industrial
development. The project site is within Flood Insurance Zone X, the areas
determined to be outside the 500-year flood plain according to the FEMA Flood
Insurance Rate Map, Community-Panel No 08069C-0983G.
1.3 Purpose and Objectives
The purpose and objectives of this Drainage Report are to:
1. Provide supporting information required for the Site Plan drainage scheme,
which meets or exceeds the City of Fort Collins Storm Drainage Design
Criteria and Construction Standards and Erosion Control requirements defined
in the Fort Collins Stormwater Manual, Section 1.3.3, Volume 3, Chapter 7 of
the Fort Collins Amendments.
2. Provide the onsite Federal Emergency Management Agency (FEMA) Special
Flood Hazard Areas (SFHA).
3. Determine the onsite detention requirements for the runoff volume difference
between the 100-year developed inflow rate and the 2-year historic release
rate.
4. Determine the required onsite drainage improvements to convey the runoff
through the project site.
1.4 Previous Studies
1. Anderson Consulting Engineers, Inc, Spring Creek Master Drainage Plan,
Baseline Hydrologic Analysis, Volumes I & II, Fort Collins, Colorado, May 5,
2003.
2. Anderson Consulting Engineers, Inc, Hydrologic modeling and Hydraulic
Analyses for Spring Creek Downstream of Edora Park, Fort Collins,
Colorado, October 21, 2005.
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 3
3. DMW Civil Engineers, Inc, Final Drainage Report for Centerpoint Plaza First
Replat, Fort Collins, Colorado, October 28, 2008.
1.5 Methodologies and Procedures
1. Drainage design criteria is based on the City of Fort Collins Storm Drainage
Design Criteria and Construction Standards and Erosion Control requirements
defined in the Fort Collins Stormwater Manual, Section 1.3.3, Volume 3,
Chapter 7 of the Fort Collins Amendments
2. Hydrologic Criteria
The rational method has been used to estimate peak storm water runoff form
the project site. An initial 10-year and major 100-year design storms have
been used to evaluate the proposed drainage system. Calculations made as
part of the investigation, along with other supporting material, are contained
in Appendix B. Rainfall intensity data for the rational method has been taken
from the intensity data tables contained in the City of Fort Collins Storm
Drainage Design Criteria and Construction Standards manual (see Figure 3-
1a). Composite coefficients were generated using Table 3-3 and 3-4 of the
City of Fort Collins Storm Drainage Design Criteria and Construction
Standards manual.
3. Hydraulic Criteria
Spreadsheets from the Urban Storm Drainage Criteria Manual have been used
to analyze the capacity of proposed pipes and swales for the site. Various
spreadsheets using City of Fort Collins criteria have been used in the design of
the proposed detention ponds.
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 4
2.0 DRAINAGE BASINS AND SUBBASINS
2.1 Major Basin Description
The Centerpoint Plaza site is within the Spring Creek Drainage Basin, as identified
by the City of Fort Collins Master Drainage Plan, but not within any regulatory
floodplains designated by either the City or FEMA. Spring Creek is a major
watercourse that flows from Spring Canyon Dam at Horsetooth Reservoir to its
confluence with the Poudre River. The Spring Creek drainage basin encompasses
nearly nine square miles in central Fort Collins. The basin is dominated by
residential development, but it also includes open space, parks and isolated areas
of commercial and industrial development.
2.2 Sub-Basin Description
Stormwater runoff from the project site drains overland generally from northwest
to southeast at slopes ranging from 1.0% to 2.0%. Stormwater runoff from most
of the site is conveyed to a water quality pond and routed via storm pipes to
Spring Creek, located north of the site. Runoff not captured by the pond currently
is conveyed from the site towards the southeast in a shallow swale adjacent to the
railroad.
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 5
3.0 DEVELOPED DRAINAGE PATTERNS
The developed site has been divided into nine (9) on-site and one (1) off-site drainage basins.
Stormwater runoff will be conveyed overland to an onsite detention and water quality pond and
released into existing stormwater utilities at the northwest corner of the site.
Basins 1 (0.09 acres) and 2 (0.12 acres) are comprised primarily of asphaltic paving.
Runoff from Basins 1 and 2 sheet flows across the paving, parking lot, and along
concrete gutters from northwest to southeast. Stormwater runoff follows existing
flow patterns and is conveyed to the southeast. The peak 10 and 100-year flows
from Basin 1 are 0.3 and 0.9 cfs, respectively. The peak 10 and
1- 100-year flows from Basin 2 are 0.4 and 1.0 cfs, respectively.
Basin 3 (1.30 acres) is comprised mostly of the existing building and parking lot,
and includes existing landscaping, and proposed roof and parking. Runoff from
Basin 3 follows existing flow patterns and flows from west to east. Runoff is
conveyed in concrete trickle pans and gutters to Basin 4, and then to Basin 5.
The peak 10 and 100-yr flows from Basin 3 are 4.1 and 11.5 cfs, respectively.
Basin 4 (1.01·acres) is currently primarily grassed meadow, but was modeled as
developed. Runoff was modeled as flowing east to west, conveyed by pans and
gutters to Basin 5. The peak 10 and 100-yr flows from Basin 4 are 4.2 and 10.1 cfs,
respectively.
Basin 5 (0.09 acres) is composed primarily of a grassed swale. Runoff is conveyed
to the south and into a storm drain pipe discharging in the Pond. Basin also conveys
runoff from Basins 3 and 4 to the storm pipe. The peak 10 and 100-yr flows from
Basin 5 are 0.02 and 0.4 cfs, respectively. The combined peak 10 and 100-yr flows
from Basins 3, 4, and 5 are 7.5 20.7 and cfs, respectively
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 6
Basin 6 (1.18 acres) is a combination of developed and undeveloped areas, but
was modeled as fully developed. Runoff was modeled as flowing east to west,
conveyed by pans, gutters and sheet flow to Basin 7 and then to the Pond. The
peak 10 and 100-yr flows from Basin 6 are 4.9 and 11.7 cfs, respectively
Basin 7 (0.33 acres) is composed primarily of paving and roof. Runoff from
Basins 6 and 7 is conveyed via sheet flow and gutters to an 8-foot wide concrete
sidewalk culvert and into the Pond. The peak 10 and 100-yr flows from Basin 7
are 1.5 and 3.3 cfs, respectively. The combined peak 10 and 100-yr flows from
Basins 6 and 7 are 6.2 and 14.7 cfs, respectively
Basin 8 (0.73 acres) is composed primarily of roof and paving. Runoff is conveyed
by pans, sheet flow, and gutters to a 6-foot wide curb opening into the Pond. The
peak 10 and 100-yr flows from Basin 8 are 2.6 and 6.6 cfs, respectively.
Basin 9 (0.21 acres) is composed primarily of grassed slopes, and the Pond.
Runoff is conveyed by sheet flow and pans to the existing outlet structure, and
then to Spring Creek. The peak 10 and 100-yr flows from Basin 9 are 0.4 and
1.0 cfs, respectively. The combined peak 10 and 100-yr flows from Basins 3
through 9 are 15.3 and 42.0 cfs, respectively
4.0 STORMWATER DETENTION REQUIREMENTS
The drainage report for Phase 1 called for a Detention Pond which lies in Phase 2.
The City of Fort Collins Stormwater department has indicated that detention is not
required for this development providing that proper drainage facilities exist to
convey the un-detained flows to either Spring Creek to the north of Skunk Pond
far to the east. Due to the fact that a majority of the downstream facilities to
Skunk Pond are inadequate and would require upgrading it was found to be more
economical to convey un-detained flows to Spring Creek to the north. An
Amendment to the Phase 1 Drainage plan was approved with this concept in the
DMW Civil Engineers Final Drainage Report 0805.00-CPR, dated October 28,
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 7
2008. This project reconfigures the approved Phase 1 Pond and provides the
same water quality capture volume and complies with the original Phase 1
drainage report.
5.0 POST-CONSTRUCTION STORMWATER MANAGEMENT
In order to provide treatment of stormwater runoff, stormwater quality best management
practices (BMPs) have been incorporated into the proposed site improvements. BMPs
utilized on this site and shown on the Proposed Drainage Map have been designed
utilizing the guidelines provided in the Urban Storm Drainage Criteria Manual, Volume
3 (USDCM Vol. 3), including the “Four Step Process to Minimize Adverse Impacts
of Urbanization” as listed below:
Step 1. Employ runoff reduction practices
Step 2. Implement BMPs that provide a water quality capture volume with slow
release
Step 3. Stabilize drainageways
Step 4. Implement Site Specific and other source control BMPs
The post-construction stormwater quality BMPs proposed for this project include:
5.1 Water Quality
A Structural Best Management Practices (BMPs) are proposed for the project site to
improve runoff as recommended by the Urban Storm Drainage Criteria Manual and as
described in the Fort Collins Stormwater Management Manual, Volume 3-Best
Management Practices (BMPs). The detention pond incorporates an extended detention
basin for water quality purposes.
An extended detention basin (EDB) is a sedimentation basin which uses a much smaller
outlet that extends the emptying time of the more frequent occurring storm runoff events
to facilitate pollutant removal. Soluble pollutant removal can be somewhat enhanced by
providing a small wetland marsh or ponding area in the basin’s bottom to promote
biological uptake. The detention basin planting will meet the City of Fort Collins
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 8
Detention Pond Landscape Guidelines which will help facilitate successful biological
uptake. The basins are considered to be “dry” because they are designed not to have a
significant permanent pool of water remaining between storm runoff events. Extended
Detention Basin’s may develop wetland vegetation and sometimes shallow pools in the
bottom portions of the facilities.
The water quality pond for the project site has been designed to provide 4,704 cubic feet
of water quality capture and with a water surface elevation of 4909.17. Release of the
captured water is controlled by a steel plate with one column of six 5/8” diameter circular
perforations. The outlet structure itself and 36” diameter RCP outlet pipe convey flows
in excess of the water quality capture volume north to Spring Creek. The pond will reach
a maximum water surface elevation of 4910.50 to discharge these flows through the
outlet structure. The parking lot serves as an emergency overflow and any excess runoff
is conveyed off-site to the southeast towards Skunk Pond.
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 9
6.0 LONG TERM MAINTENANCE
The proper functioning of the drainage systems described in this report is
dependent on the owner providing, annual and continuous maintenance to the
drainage improvements. The firm responsible for the ownership, operation,
scheduled and unscheduled maintenance and liability of drainage improvements
and common areas detailed on this report is:
NexGen Properties or an Officially Designated Entity by NexGen;
Mr. Sean Sjodin
NexGen Properties, L.L.C.
One Denver Tech Center
5251 DTC Parkway, Suite 8000
Greenwood Village, CO 80111
(303) 923-2442
Maintenance guidelines and a checklist is provided within Appendix E. Refer to
Chapter 6 of the Urban Storm Drainage Criteria Manual, Volume 3 for
maintenance of the site’s stormwater quality BMPs (grass swales, grass buffers,
bioretention areas, etc.).
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 10
7.0 SUMMARY
The supporting information required for the Site Plan drainage scheme is being
provided within the report.
The onsite Federal Emergency Management Agency (FEMA) Special Flood
Hazard Areas (SFHA) have been shown on the drainage figures of the report.
The offsite and onsite peak discharges for the 100-year storm event have been
calculated. The 2-year and 10-year event was calculated for comparison of pre-
development and post-development discharges.
The required onsite drainage improvements to convey the runoff through the
project site have been calculated and are shown in the figures of the report.
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 11
8.0 ENGINEER’S STATEMENT
The drainage design concept presented in this Drainage Report assures that drainage
affecting the project will be handled in a manner that does not conflict with any federal,
state, and/or county regulations intended to protect adjacent properties and/or the project
itself from adverse impacts during design storm events specified in the current
regulations.
Disclaimer – Any deviations from the drainage scheme and hydraulic design presented
herein, or any variations in climatic or watershed conditions may affect the
functionality and other hydrologic or hydraulic characteristics of this project and
nullify the results presented herein.
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
7/14/2015
Page 12
WORKS CITED
Anderson Consulting Engineers, Inc, Spring Creek Master Drainage Plan, Baseline
Hydrologic Analysis, Volumes I & II, Fort Collins, Colorado, May 5, 2003.
Anderson Consulting Engineers, Inc, Hydrologic modeling and Hydraulic Analyses for
Spring Creek Downstream of Edora Park, Fort Collins, Colorado, October 21, 2005.
DMW Civil Engineers, Inc, Final Drainage Report for Centerpoint Plaza First Replat,
Fort Collins, Colorado, October 28, 2008.
Urban Drainage and Flood Control District, Urban Storm Drainage Criteria Manual,
Volume 1 and 2. June 2001, Revised April 2008.
Urban Drainage and Flood Control District, Urban Storm Drainage Criteria Manual,
Volume 3 – Best Management Practices. November 2010.
Stantec, Topographic Map.
United States Department of Agriculture – Natural Resouce Conservation Service, Web
Soil Survey. <http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm>.
National Oceanic and Atmospheric Administration (NOAA), NOAA Atlas 14 Point
Precipitation Frequency Estimates: CO. <http://hdsc.nws.noaa.gov/hdsc/pfds/
pfds_map_cont.html?bkmrk=co>.
Federal Emergency Management Agency (FEMA), National Flood Insurance Program
(NFIP); Flood Insurance Rate Map (FIRM) 08069C-0983G.
Bentley, StormCAD V8i. November 9, 2009.
Bentley, FlowMaster v. 8.01. November 9, 2006.
L:\1028_CenterpointPlaza_DrainageReport_FtCollins_20150713.DOCX
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDIX A – FIGURES AND EXHIBITS
PageA-1
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDIX B – HYDROLOGIC DATA SHEETS
PageB-1
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 9
Area = 0.21 Acres
Percent Imperviousness = 20.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.55
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.26
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.26 N/A 0.25 33.90
1
2
3
4
5
500 Computed Tc = 33.90
Regional Tc = 12.78
User-Entered Tc = 12.78
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 3.79 inch/hr Peak Flowrate, Qp = 0.44 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.74 cfs
Rainfall Intensity at User-Defined Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.74 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
9
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:44 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 9
Area = 0.21 Acres
Percent Imperviousness = 20.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.34
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.26
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.26 N/A 0.25 33.90
1
2
3
4
5
500 Computed Tc = 33.90
Regional Tc = 12.78
User-Entered Tc = 12.78
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 2.35 inch/hr Peak Flowrate, Qp = 0.17 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.28 cfs
Rainfall Intensity at User-Defined Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.28 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
9
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:43 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 8
Area = 0.73 Acres
Percent Imperviousness = 20.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.55
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.26
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.26 N/A 0.25 33.90
1
2
3
4
5
500 Computed Tc = 33.90
Regional Tc = 12.78
User-Entered Tc = 12.78
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 3.79 inch/hr Peak Flowrate, Qp = 1.53 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 2.56 cfs
Rainfall Intensity at User-Defined Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 2.56 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
8
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:45 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 8
Area = 0.73 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 2.53 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 2.41 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 2.53 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
8
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:42 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 7
Area = 0.33 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 2.14 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 1.87 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 2.14 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
7
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:51 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 7
Area = 0.33 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 1.14 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 1.09 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 1.14 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
7
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:41 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 6
Area = 1.18 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 7.67 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 6.68 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 7.67 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
6
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:51 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 6
Area = 1.18 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.09 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 3.90 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.09 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
6
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:40 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 5
Area = 0.09 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.51 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
5
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:50 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 5
Area = 0.09 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.30 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
5
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:39 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 4
Area = 1.01 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 6.56 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 5.71 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 6.56 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
4
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:50 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 4
Area = 1.01 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 3.50 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 3.34 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 3.50 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
4
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:36 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 3
Area = 1.30 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 8.45 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 7.36 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 8.45 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
3
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:49 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 3
Area = 1.30 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.51 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 4.30 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 4.51 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
3
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:39 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 2
Area = 0.12 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.78 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.68 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.78 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
2
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:52 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 2
Area = 0.12 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.42 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.40 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.42 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
2
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:38 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 1
Area = 0.09 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.84
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0100 500 0.82 N/A 0.73 11.44
1
2
3
4
5
500 Computed Tc = 11.44
Regional Tc = 12.78
User-Entered Tc = 11.44
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.30 cfs
Rainfall Intensity at User-Defined Tc, I = 4.12 inch/hr Peak Flowrate, Qp = 0.31 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
1
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:37 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 1
Area = 0.09 Acres
Percent Imperviousness = 95.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 100 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 2.60 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.89
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.82
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.0200 500 0.82 N/A 0.92 9.10
1
2
3
4
5
500 Computed Tc = 9.10
Regional Tc = 12.78
User-Entered Tc = 9.10
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs
Rainfall Intensity at Regional Tc, I = 6.35 inch/hr Peak Flowrate, Qp = 0.51 cfs
Rainfall Intensity at User-Defined Tc, I = 7.29 inch/hr Peak Flowrate, Qp = 0.58 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
1
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:52 AM
Project Title:
Catchment ID:
I. Catchment Hydrologic Data
Catchment ID = 1
Area = 0.09 Acres
Percent Imperviousness = 100.00 %
NRCS Soil Type = C A, B, C, or D
II. Rainfall Information I (inch/hr) = C1 * P1 /(C2 + Td)^C3
Design Storm Return Period, Tr = 10 years (input return period for design storm)
C1 = 28.50 (input the value of C1)
C2= 10.00 (input the value of C2)
C3= 0.786 (input the value of C3)
P1= 1.61 inches (input one-hr precipitation--see Sheet "Design Info")
III. Analysis of Flow Time (Time of Concentration) for a Catchment
Runoff Coefficient, C = 0.92
Overide Runoff Coefficient, C = (enter an overide C value if desired, or leave blank to accept calculated C.)
5-yr. Runoff Coefficient, C-5 = 0.90
Overide 5-yr. Runoff Coefficient, C = (enter an overide C-5 value if desired, or leave blank to accept calculated C-5.)
Illustration
NRCS Land Heavy Tillage/ Short Nearly Grassed
Type Meadow Field Pasture/ Bare Swales/
Lawns Ground Waterways
Conveyance 2.5 5 7 10 15
Calculations: Reach Slope Length 5-yr NRCS Flow Flow
ID S L Runoff Convey- Velocity Time
Coeff ance V Tf
ft/ft ft C-5 fps minutes
input input output input output output
Overland 0.4000 500 0.90 N/A 3.42 2.44
1
2
3
4
5
500 Computed Tc = 2.44
Regional Tc = 12.78
User-Entered Tc = 5.00
IV. Peak Runoff Prediction
Rainfall Intensity at Computed Tc, I = 6.33 inch/hr Peak Flowrate, Qp = 0.52 cfs
Rainfall Intensity at Regional Tc, I = 3.93 inch/hr Peak Flowrate, Qp = 0.32 cfs
Rainfall Intensity at User-Defined Tc, I = 5.46 inch/hr Peak Flowrate, Qp = 0.45 cfs
(Sheet Flow)
20
Shallow Paved Swales
Sum
CALCULATION OF A PEAK RUNOFF USING RATIONAL METHOD
Centerpoint Plaza
1
Paved Areas &
UD-Rational v1.02a.xls, Tc and PeakQ 7/13/2015, 11:30 AM
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDIX C – HYDRAULIC CALCULATIONS
Page C-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 = 1.6 2.3 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
= 2.00 2.00 feet
Clogging Factor for a Single Curb Opening (typical value 0.10) Cf
(C) = 0.10
Curb Opening Weir Coefficient (typical value 2.3-3.7) Cw
(C) = 3.00 3.00
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) Qa = 0.0 0.0 cfs
Q PEAK REQUIRED = 16.0 31.0 cfs
INLET IN A SUMP OR SAG LOCATION
Enter Your Project Name Here
Enter Your Inlet ID Here
CDOT Type R Curb Opening
H-Vert
H-Curb
W
Lo (C)
Lo (G)
Wo
WP
Override Depths
UD-Inlet_v3.14.xlsm, Inlet In Sump 7/13/2015, 12:06 PM
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDIX D – HYDRAULIC MODELS (STORM DRAIN)
PageD-1
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDIX E – BMP CALCULATIONS
Page E-1
Sheet 1 of 4
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia
Ia = 85.0 %
B) Tributary Area's Imperviousness Ratio (i = Ia / 100 ) i = 0.850
C) Contributing Watershed Area Area = 2.970 ac
D) For Watersheds Outside of the Denver Region, Depth of Average d6 = 1.60 in
Runoff Producing Storm
E) Design Concept
(Select EURV when also designing for flood control)
F) Design Volume (1.2 WQCV) Based on 40-hour Drain Time VDESIGN
= 0.108 ac-ft
(VDESIGN = (1.0 * (0.91 * i
3
- 1.19 * i
2
+ 0.78 * i) / 12 * Area * 1.2)
G) For Watersheds Outside of the Denver Region, VDESIGN OTHER
= 0.400 ac-ft
Water Quality Capture Volume (WQCV) Design Volume
(VWQCV OTHER = (d
6*(VDESIGN
/0.43))
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VDESIGN USER
= ac-ft
(Only if a different WQCV Design Volume is desired)
I) Predominant Watershed NRCS Soil Group
J) Excess Urban Runoff Volume (EURV) Design Volume
For HSG A: EURVA = (0.1878i - 0.0104)*Area EURV = ac-f t
For HSG B: EURVB = (0.1178i - 0.0042)*Area
For HSG C/D: EURVC/D = (0.1043i - 0.0031)*Area
2. Basin Shape: Length to Width Ratio L : W = 3.0 : 1
(A basin length to width ratio of at least 2:1 will improve TSS reduction.)
3. Basin Side Slopes
A) Basin Maximum Side Slopes Z = 4.00 ft / ft
(Horizontal distance per unit vertical, 4:1 or flatter preferred)
4. Inlet
A) Describe means of providing energy dissipation at concentrated
inflow locations:
Design Procedure Form: Extended Detention Basin (EDB)
Centerpoint Plaza
Rick Engineering Company
July 13, 2015
Pond Outlet Structure
RKF
Choose One
Excess Urban Runoff Volume (EURV)
Choose One
A
B
C / D
Water Quality Capture Volume (WQCV)
UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM
Sheet 2 of 4
Designer:
Company:
Date:
Project:
Location:
5. Forebay
A) Minimum Forebay Volume VFMIN
= 0.007 ac-ft
(VFMIN = 2% of the WQCV)
B) Actual Forebay Volume VF
= ac-ft
C) Forebay Depth DF
= in
(DF = 18 inch maximum)
D) Forebay Discharge
i) Undetained 100-year Peak Discharge Q100
= cfs
ii) Forebay Discharge Design Flow QF
= cfs
(QF = 0.02 * Q
100)
E) Forebay Discharge Design
F) Discharge Pipe Size (minimum 8-inches) Calculated DP = in
G) Rectangular Notch Width Calculated WN
= in
6. Trickle Channel
A) Type of Trickle Channel
F) Slope of Trickle Channel S = 0.0100 ft / ft
7. Micropool and Outlet Structure
A) Depth of Micropool (2.5-feet minimum) DM
= ft
B) Surface Area of Micropool (10 ft
2
minimum) A
M = sq ft
C) Outlet Type
D) Depth of Design Volume (EURV or 1.2 WQCV) Based on the Design H = feet
Concept Chosen Under 1.E.
E) Volume to Drain Over Prescribed Time WQCV = 0.333 ac-ft
F) Drain Time TD
= hours
(Min TD for WQCV= 40 hours; Max T
D for EURV= 72 hours)
G) Recommended Maximum Outlet Area per Row, (Ao) A
o = square inches
H) Orifice Dimensions:
i) Circular Orifice Diameter or Dorifice
= inches
ii) Width of 2" High Rectangular Orifice Worifice
= inches
I) Number of Columns nc
= number
J) Actual Design Outlet Area per Row (Ao) A
o = square inches
K) Number of Rows (nr) nr
= number
L) Total Outlet Area (Aot) A
ot = square inches
M) Depth of WQCV (HWQCV) H
Sheet 3 of 4
Designer:
Company:
Date:
Project:
Location:
8. Initial Surcharge Volume
A) Depth of Initial Surcharge Volume DIS
= in
(Minimum recommended depth is 4 inches)
B) Minimum Initial Surcharge Volume VIS = cu ft
(Minimum volume of 0.3% of the WQCV)
C) Initial Surcharge Provided Above Micropool Vs= cu ft
9. Trash Rack
A) Type of Water Quality Orifice Used
B) Water Quality Screen Open Area: At = Aot * 38.5*(e
-0.095D
) At
= square inches
C) For 1-1/4"", or Smaller, Circular Opening (See Fact Sheet T-12):
i) Width of Water Quality Screen and Concrete Opening (Wopening) W
opening = inches
ii) Height of Water Quality Screen (HTR) H
TR = inches
iii) Type of Screen, Describe if "Other"
D) For Circular Opening (greater than 1-1/4" diameter)
OR 2" High Rectangular Opening (See Fact Sheet T-12):
i) Width of Water Quality Screen Opening (Wopening) W
opening = ft
ii) Height of Water Quality Screen (HTR) H
TR = ft
iii) Type of Screen, Describe if "Other"
v) Cross-bar Spacing inches
vi) Minimum Bearing Bar Size
RKF
Design Procedure Form: Extended Detention Basin (EDB)
July 13, 2015
Centerpoint Plaza
Pond Outlet Structure
Rick Engineering Company
Choose One
Circular (up to 1-1/4" diameter)
Circular (greater than 1-1/4" diameter) OR Rectangular (2" high)
Choose One
S.S. Well Screen with 60% Open Area*
Other (Describe):
Choose One
Aluminum Amico-Klemp SR Series (or equal)
Other (Describe):
UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM
Sheet 4 of 4
Designer:
Company:
Date:
Project:
Location:
10. Overflow Embankment
A) Describe embankment protection for 100-year and greater overtopping:
B) Slope of Overflow Embankment ZE
= ft / ft
(Horizontal distance per unit vertical, 4:1 or flatter preferred)
11. Vegetation
12. Access
A) Describe Sediment Removal Procedures
Notes:
Centerpoint Plaza
Pond Outlet Structure
Design Procedure Form: Extended Detention Basin (EDB)
July 13, 2015
Rick Engineering Company
RKF
Choose One
Irrigated
Not Irrigated
UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM
CENTERPOINT PLAZA – CITY OF FORT COLLINS - DRAINAGE & EROSION CONTROL REPORT
APPENDIX F – REFERENCE DOCUMENTATION
Page F-1
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
This unofficial copy was downloaded on Jan-07-2015 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
WQCV = feet
(Estimate using actual stage-area-volume relationship and VWQCV)
N) Ensure Minimum 40 Hour Drain Time for WQCV TD WQCV
= hours
Centerpoint Plaza
July 13, 2015
Rick Engineering Company
Design Procedure Form: Extended Detention Basin (EDB)
(flow too small for berm w/ pipe)
Pond Outlet Structure
RKF
Choose One
Wall with Rect. Notch
Berm With Pipe
Choose One
Orifice Plate
Other (Describe):
Choose One
Concrete
Soft Bottom
Wall with V-Notch Weir
UD-BMP_v3.03.xlsm, EDB 7/13/2015, 12:13 PM