HomeMy WebLinkAboutFORT COLLINS INTEGRATED RECYCLE CENTER - PDP - PDP130020 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT
Integrated Recycling Center
Prepared for:
City of Fort Collins
Operation Services
300 LaPorte Ave., Building B
Fort Collins, CO 80521
(970) 221-6610
Prepared by:
Interwest Consulting Group
1218 West Ash, Suite C
Windsor, Colorado 80550
(970) 674-3300
June 12, 2013
Job Number 1165-012-12
iii
TABLE OF CONTENTS
TABLE OF CONTENTS ............................................................................................................ iii
1. GENERAL LOCATION AND DESCRIPTION ................................................................ 1
1.1 Location ........................................................................................................................... 1
1.2 Description of Property ................................................................................................. 1
2. DRAINAGE BASINS AND SUB-BASINS .......................................................................... 2
2.1 Major Basin Description ................................................................................................ 2
2.2 Sub-Basin Description ................................................................................................... 2
3. DRAINAGE DESIGN CRITERIA ...................................................................................... 2
3.1 Regulations ...................................................................................................................... 2
3.2 Directly Connected Impervious Area (DCIA) Discussion .......................................... 2
3.3 Development Criteria Reference and Constraints ...................................................... 4
3.4 Hydrological Criteria ..................................................................................................... 4
3.5 Hydraulic Criteria .......................................................................................................... 5
3.6 Floodplain Regulations Compliance ............................................................................. 5
4. DRAINAGE FACILITY DESIGN ....................................................................................... 5
4.1 General Concept ............................................................................................................. 5
4.2 Specific Flow Routing .................................................................................................... 5
4.3 Drainage Summary ........................................................................................................ 6
5. CONCLUSIONS .................................................................................................................... 6
5.1 Compliance with Standards .......................................................................................... 6
5.2 Drainage Concept ........................................................................................................... 6
6. EROSION CONTROL ......................................................................................................... 7
7. REFERENCES ...................................................................................................................... 8
APPENDIX A VICINITY MAP, DRAINAGE AND EROSION CONTROL PLAN
APPENDIX B HYDROLOGIC COMPUTATIONS
APPENDIX C HYDRAULIC COMPUTATIONS (SUBMITTED DURING FINAL)
APPENDIX D WATER QUALITY AND DETENTION POND INFORMATION,
LID CALCULATIONS
APPENDIX E SOILS INFORMATION, FIGURES, TABLES AND EXCERPTS
FROM REPORTS
1
1. GENERAL LOCATION AND DESCRIPTION
1.1 Location
The Integrated Recycling Center development is located in east Fort Collins. It is located
in the Northeast Quarter of Section 19, Township 7 North, Range 68 West of the Sixth
Principal Meridian, in the City of Fort Collins, Larimer County, Colorado. Please refer to
the location map in Appendix A.
The project is located west of Timberline Road and south of the Timberline Substation.
The Power Trail and Union Pacific Railroad is located to the west of the project and the
unplatted Timberline Star property is located to the south.
1.2 Description of Property
The property consists of 3.72 acres and is owned by the City of Fort Collins. The project
is an open air facility and will not have any buildings (except for a service shed). It will
consist of a variety of hard surfaced areas for unloading and materials storage as well as
circulation drives.
The land currently slopes to the north at about 8%. The land is currently vacant. The
majority of the ground cover is dry land vegetation. There is no offsite flow onto the
property. Flow from the Timberline Star property to the south enters a drainage ditch at
the southeast corner of the property and then north in a ditch adjacent to Timberline.
The majority of existing soil type on-site consists of Larimer-Stoneham complex which is
classified as Type B by the Natural Resources Conservation Service. Soil information is
located in Appendix E.
2
2. DRAINAGE BASINS AND SUB-BASINS
2.1 Major Basin Description
The proposed development lies within the Spring Creek Master Drainage Basin. It is also
a portion of Basin 13 of the Timberline Road Widening Drake to Prospect Drainage
Report, by North Star Design, Inc. dated April 6, 2005.
Excerpts from the City approved “100% Design Drainage Report for Interim Timberline
Road Widening Drake to Prospect” can be found in Appendix E of this report. The
Developed Drainage Plan for the Timberline Road Widening is also located in Appendix
E.
2.2 Sub-basin Description
The existing site drains to the north where it is intercepted by an existing 24” storm
system in the RR right-of-way that discharges into Spring Creek.
3. DRAINAGE DESIGN CRITERIA
3.1 Regulations
This report was prepared to meet or exceed the “City of Fort Collins Storm Drainage
Design Criteria Manual” specifications. Where applicable, the criteria established in the
“Urban Storm Drainage Criteria Manual” (UDFCD), developed by the Denver Regional
Council of Governments, has been used.
3.2 Directly Connected Impervious Area (DCIA) Discussion
Urban Drainage and Flood Control District (UDFCD) recommends a Four Step Process
for receiving water protection that focuses on reducing runoff volumes, treating the water
quality capture volume (WQCV), stabilizing drainageways and implementing long-term
source controls. The Four Step Process applies to the management of smaller, frequently
occurring events.
3
Step 1: Employ Runoff Reduction Practices
To reduce runoff peaks, volumes, and pollutant loads from urbanizing areas, implement
Low Impact Development (LID) strategies, including Minimizing Directly Connected
Impervious Areas (MDCIA).
Runoff for the site will be routed through vegetated areas, gravel paved areas and rain
gardens thereby reducing runoff from impervious surfaces over permeable areas to slow
runoff and increase the time of concentration and promote infiltration. Runoff will also
flow through a grassy bioswale which will also slow runoff and promote infiltration.
Step 2: Implement BMPs that Provide a Water Quality Capture Volume with Slow
Release
Once runoff has been minimized, the remaining runoff shall be treated through the water
quality pond located north of the project.
Step 3: Stabilize Drainageways
Natural Drainageways are subject to bed and bank erosion due to increases in frequency,
duration, rate and volume of runoff during and following development. Because the site
will drain to a proposed detention and water quality pond, bank stabilization is
unnecessary with this project.
Step 4: Implement Site Specific and Other Source Control BMPs
Proactively controlling pollutants at their source by preventing pollution rather than
removing contaminants once they have entered the stormwater system or receiving waters
is important when protecting storm systems and receiving waters. This can be
accomplished through site specific needs such as construction site runoff control, post-
construction runoff control and pollution prevention / good housekeeping. It will be the
responsibility of the contractor to develop a procedural best management practice for the
site.
4
3.3 Development Criteria Reference and Constraints
The runoff from this site has been routed to conform to the requirements of the City
Stormwater Department. Water quality facilities are required for the new construction
proposed on the site. Water quality will be met through the use of a water quality pond.
Onsite detention is required for the runoff volume difference between the 100 year
developed inflow rate and the 2 year historic release rate and will be provided in the
proposed water quality and detention pond.
Runoff reduction practices (LID techniques) are also required. No less than fifty percent
of any newly added impervious area must be treated using one or a combination of LID
techniques. This project will incorporate tree LID techniques: a bioswale, two rain
gardens and permeable pavement technology. The project added 76,850 sf of new
impervious area. Using the three LID techniques, 54,555 sf of new impervious area
(71%) will be treated which exceeds the 50% requirement.
No less than twenty five percent of any newly added pavement areas must be treated
using a permeable pavement technology. The project added 79,945 sf of new pavement
area. This project will incorporate porous gravel and will treat 25% or 20,104 sf of the
required pavement area.
Please refer to Appendix D for LID calculations and exhibit.
3.4 Hydrologic Criteria
Runoff computations were prepared for the 2-year and 10-year minor and 100-year major
storm frequency utilizing the rational method.
All hydrologic calculations associated with the basins are included in Appendix B of this
report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub-
basins. Standard Form 9 (SF-9) provides a summary of the design flows for all Sub-
basins and Design Points associated with this site.
Water quality volume and detention were calculated using the method recommended in
the “Urban Storm Drainage Criteria Manual”. All calculations are located in Appendix
D.
5
3.5 Hydraulic Criteria
All hydraulic calculations will be presented in the final drainage report and prepared in
accordance with the City of Fort Collins Drainage Criteria. All calculations will be
included in Appendix C of this report and will be presented in the final drainage report.
3.6 Floodplain Regulations Compliance
The site is not within a City of Fort Collins floodway or FEMA special flood hazard area
(Panel 08069C1000F). Therefore, a completed “City of Fort Collins Floodplain Review
Checklist for 50% Submittals” has not been included with this report.
4. DRAINAGE FACILITY DESIGN
4.1 General Concept
The majority of the proposed development will be collected and conveyed to the
proposed water quality and detention pond on the northern most portion of the site where
it will be treated before being released. The pond outfall will discharge to an existing 18-
inch storm pipe and swale that discharges north to an existing 24-inch storm system in the
Railroad right-of-way. This system discharges into Spring Creek. An emergency
overflow spillway will be constructed and will be designed to pass the 100-year flow.
4.2 Specific Flow Routing
A summary of the drainage patterns within each basin is provided in the following
paragraphs.
Basin A is 1.35 acres and includes the southwestern portion of the site. Runoff from this
basin will sheet to a grassy swale and then a culvert located at design point a. The swale
and culvert will convey flow to the water quality and detention pond located to the north.
Basin B and C are 0.38 and 0.42 acres, respectively. These basins include the drive aisle.
Both basins drain to rain gardens and area inlets that direct the flow to the proposed pond
to the north
6
Basin D is 1.01 acres and includes the northern portion of the site. This basin includes
the container storage area, drive aisle and the water quality and detention pond. Runoff
from this basin will sheet north to the pond. The service area in this basin is proposed to
be gravel pavement.
Basin E is 1.45 acres and includes a small portion of the drive aisle and the bermed area
located to the east of the project. This basin will drain untreated to the pond outfall area
and existing 18-inch storm pipe.
Water will be detained and treated for water quality in the water quality and detention
pond located north of the site. Water will be released to the north to an existing storm
system and eventually to Spring Creek.
4.3 Drainage Summary
Drainage facilities located outside of the right of way (including, water quality and
detention pond, proposed storm drain system and the pond outlet) will be maintained by
the owners and operational staff of the facility.
5. CONCLUSIONS
5.1 Compliance with Standards
All computations that have been completed within this report are in compliance with the
City of Fort Collins Erosion Control Reference Manual for Construction Sites and the
Storm Drainage Design Criteria Manual.
5.2 Drainage Concept
The proposed drainage concepts presented in this report and on the construction plans
adequately provide for stormwater quantity and quality treatment of proposed impervious
areas. Conveyance elements will be designed during the final report to pass required
flows and to minimize future maintenance.
7
If, at the time of construction, groundwater is encountered, a Colorado Department of
Health Construction Dewatering Permit will be required.
6. EROSION CONTROL
Erosion and sedimentation will be controlled on-site by use of culvert inlet protection,
sediment control logs in swales, seeding and mulch. The measures are designed to limit
the overall sediment yield increase due to construction as required by the City of Fort
Collins. During over-lot and final grading the soil will be roughened and furrowed
perpendicular to the prevailing winds.
During the performance of the work required by these specifications or any operations
appurtenant thereto, whether on right-of-way provided by the City or elsewhere, the
contractor shall furnish all labor, equipment, materials, and means required. The
Contractor shall carry out proper efficient measures wherever and as necessary to reduce
dust nuisance, and to prevent dust nuisance that has originated from his operations from
damaging crops, orchards, cultivated fields, and dwellings, or causing naissance to
persons. The Contractor will be held liable for any damage resulting from dust
originating from his operations under these specifications on right-of-way or elsewhere.
Wherever construction vehicles access routes or intersect paved public roads, previsions
must be made to minimize the transport of sediment by runoff or vehicles tracking onto
the paved surface. The contractor will be responsible for clearing mud tracked onto city
streets on a daily basis.
All temporary and permanent erosion and sediment control practices must be maintained
and repaired as needed to assure continued performance of their intended function.
The disturbed area is greater than 1 acre and will require a State of Colorado Discharge
Permit.
8
7. REFERENCES
1. City of Fort Collins, “Storm Drainage Criteria Manual”, (SDCM), dated March,
1986.
2. Urban Drainage and Flood Control District, “Urban Storm Drainage Criteria
Manual”, Volumes 1 and 2, dated June 2001, and Volume 3 dated September
1999.
3. North Star Design, “100% Design Drainage Report for Interim Timberline Road
Widening Drake to Prospect”, dated April 6, 2005.
A
APPENDIX A
VICINITY MAP AND DRAINAGE AND EROSION CONTROL PLAN
B
APPENDIX B
HYDROLOGIC COMPUTATIONS
SUMMARY
DRAINAGE SUMMARY TABLE
Design Tributary Area C (10) C (100) tc (10) tc (100) Q(10)tot Q(100)tot
Sub-basin REMARKS
Point (ac) (min) (min) (cfs) (cfs)
a A 1.35 0.64 0.80 11.7 9.3 3.1 8.7 Proposed Swale
b B 0.38 0.64 0.80 5.0 5.0 1.2 3.0 Proposed Area Inlet and Rain Garden
c C 0.42 0.54 0.68 5.1 5.0 1.1 2.8 Proposed Area Inlet and Rain Garden
d D 1.01 0.51 0.63 8.6 7.6 2.1 5.5 Pond
e E 1.45 0.18 0.22 12.2 12.2 0.9 2.3
Page 7
Interwest Consulting Group
RUNOFF COEFFICIENTS & % IMPERVIOUS
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/30/2013
Recommended Runoff Coefficients from Table 3-3 of City of Fort Collins Design Criteria
Recommended % Impervious from Urban Storm Drainage Criteria Manual
Type B Soils Runoff %
coefficient Impervious
C
Streets, parking lots (asphalt): 0.95 100
Sidewalks (concrete): 0.95 96
Roofs: 0.95 90
Gravel: 0.50 40
Landscape Areas (Flat, Sandy) : 0.10 0
Landscape Areas (Steep, Sandy) : 0.20 0
SUBBASIN TOTAL TOTAL PAVED GRAVEL SIDEWALK LANDSCAPE RUNOFF %
DESIGNATION AREA AREA AREA AREA AREA AREA COEFF. Impervious REMARKS
(ac.) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (sq.ft) (C)
Existing 3.16 137,681 0 0 0 137,681 0.20 0 Existing
Proposed 3.16 137,681 59,574 15,240 11,677 51,190 0.58 56 Proposed
A 1.35 58,997 30,974 5,935 3,713 18,376 0.64 63 Proposed Swale
B 0.38 16,509 10,521 0 0 5,988 0.64 64 Proposed Area Inlet and Rain Garden
C 0.42 18,254 9,496 0 0 8,758 0.54 52 Proposed Area Inlet and Rain Garden
D 1.01 43,922 8,584 9,305 7,964 18,068 0.51 45 Pond
A-D 3.16 137,681 59,574 15,240 11,677 51,190 0.58 56
E 1.45 63,208 5,779 0 0 57,430 0.18 9
Equations
- Calculated C coefficients & % Impervious are area weighted
C = Σ (Ci Ai) / At
Ci = runoff coefficient for specific area, Ai
Ai = areas of surface with runoff coefficient of Ci
n = number of different surfaces to consider
At = total area over which C is applicable; the sum of all Ai's
05-23-13 Flow.xls
Interwest Consulting Group
STANDARD FORM SF-2
TIME OF CONCENTRATION - 2 and 10 YR
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/30/2013
2 and 10-yr storm Cf = 1.00
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
Existing 3.16 0.20 300 6.0 16.1 0 1.0 0.016 2.0 0.0 16.1 300 11.7 11.7
Proposed 3.16 0.58 187 4.5 8.0 464 0.8 0.030 0.9 8.3 16.3 651 13.6 13.6
a A 1.35 0.64 187 4.5 7.1 210 0.5 0.030 0.8 4.6 11.7 397 12.2 11.7
b B 0.38 0.64 40 4.0 3.4 208 3.3 0.016 3.6 1.0 4.4 248 11.4 5.0
c C 0.42 0.54 40 4.0 4.2 213 3.6 0.016 3.8 0.9 5.1 253 11.4 5.1
d D 1.01 0.51 68 7.8 4.6 254 1.0 0.030 1.1 3.9 8.6 322 11.8 8.6
e E 1.45 0.18 95 2.9 11.8 304 6.7 0.030 2.8 1.8 13.6 399 12.2 12.2
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
05-23-13 Flow.xls
Interwest Consulting Group
STANDARD FORM SF-2
TIME OF CONCENTRATION - 100 YR
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/30/2013
100-yr storm Cf = 1.25
SUB-BASIN INITIAL /OVERLAND TRAVEL TIME / GUTTER OR CHANNEL FLOW tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASIN) tc
DESIGN SUBBASIN(s) Area C C*Cf Length Slope ti Length Slope n Vel. tt tc = Total L tc=(l/180)+10
PONIT (ac) (ft) (%) (min) (ft) (%) Manning (ft/s) (min) ti + tt (ft) (min) (min)
(1) (2) (3) (4) (5) (6) (7) (8) rough. (9) (10) (11) (12) (13) (14)
Existing 3.16 0.20 0.25 300 6.0 15.2 0 1.0 0.016 2.0 0.0 15.2 300 11.7 11.7
Proposed 3.16 0.58 0.73 187 4.5 5.7 464 0.8 0.030 0.9 8.3 14.1 651 13.6 13.6
a A 1.35 0.64 0.80 187 4.5 4.6 210 0.5 0.030 0.8 4.6 9.3 397 12.2 9.3
b B 0.38 0.64 0.80 40 4.0 2.2 208 3.3 0.016 3.6 1.0 3.2 248 11.4 5.0
c C 0.42 0.54 0.68 40 4.0 3.2 213 3.6 0.016 3.8 0.9 4.1 253 11.4 5.0
d D 1.01 0.51 0.63 68 7.8 3.6 254 1.0 0.030 1.1 3.9 7.6 322 11.8 7.6
e E 1.45 0.18 0.22 95 2.9 11.2 304 6.7 0.030 2.8 1.8 13.1 399 12.2 12.2
EQUATIONS:
tc = ti + tt
ti = [1.87 (1.1 - CCf ) L0.5 ] / S 1/3
tt = L/Vel.
Velocity from Manning's Equation with R=0.1 (corresponds to Figure 3-3 of City of Fort Collins Design Manual)
final tc = minimum of ti + tt and urbanized basin check
min. tc = 5 min. due to limits of IDF curves
05-23-13 Flow.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 2-Yr Storm)
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/30/2013
2 yr storm, Cf = 1.00
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C Cf tc i Q (2) from Q (2) Q(2)tot
Sub-basin Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
Existing 3.16 0.20 11.7 2.09 1.3 1.3
Proposed 3.16 0.58 13.6 1.95 3.6 3.6
a A 1.35 0.64 11.7 2.08 1.8 1.8
b B 0.38 0.64 5.0 2.85 0.7 0.7
c C 0.42 0.54 5.1 2.78 0.6 0.6
d D 1.01 0.51 8.6 2.36 1.2 1.2
e E 1.45 0.18 12.2 2.05 0.5 0.5
Q = Cf C iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 24.221 / (10+ tc)
0.7968
05-23-13 Flow.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 10-Yr Storm)
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/30/2013
10 yr storm, Cf = 1.00
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Design Tributary A C Cf tc i Q (10) from Q (10) Q(10)tot
Sub-basin Design
Point (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
Existing 3.16 0.20 11.7 3.57 2.3 2.3
Proposed 3.16 0.58 13.6 3.33 6.1 6.1
a A 1.35 0.64 11.7 3.56 3.1 3.1
b B 0.38 0.64 5.0 4.87 1.2 1.2
c C 0.42 0.54 5.1 4.76 1.1 1.1
d D 1.01 0.51 8.6 4.03 2.1 2.1
e E 1.45 0.18 12.2 3.50 0.9 0.9
Q = Cf C iA
Q = peak discharge (cfs)
C = runoff coefficient
Cf = frequency adjustment factor
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 41.44 / (10+ tc)
0.7974
05-23-13 Flow.xls
Interwest Consulting Group
RATIONAL METHOD PEAK RUNOFF
(City of Fort Collins, 100-Yr Storm)
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/30/2013
100 yr storm, Cf = 1.25
DIRECT RUNOFF CARRY OVER TOTAL REMARKS
Des. Area A C Cf tc i Q (100) from Q (100) Q(100)tot
Design
Point Design. (ac) (min) (in/hr) (cfs) Point (cfs) (cfs)
Existing 3.16 0.25 11.7 7.29 5.8 5.8
Proposed 3.16 0.73 13.6 6.80 15.7 15.7
a A 1.35 0.80 9.3 8.00 8.7 8.7
b B 0.38 0.80 5.0 9.95 3.0 3.0
c C 0.42 0.68 5.0 9.95 2.8 2.8
d D 1.01 0.63 7.6 8.60 5.5 5.5
e E 1.45 0.22 12.2 7.14 2.3 2.3
Q = C iA
Q = peak discharge (cfs)
C = runoff coefficient
i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99)
A = drainage area (acres) i = 84.682 / (10+ tc)
0.7975
05-23-13 Flow.xls
C
APPENDIX C
HYDRAULIC CALCULATIONS
(Submitted during Final)
D
APPENDIX D
WATER QUALITY AND DETENTION POND SIZING, LID CALCULATIONS
Sheet 1 of 4
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia
Ia
= 41.2 %
B) Tributary Area's Imperviousness Ratio (i = Ia
/ 100 ) i = 0.412
C) Contributing Watershed Area Area = 4.610 ac
D) For Watersheds Outside of the Denver Region, Depth of Average d6
= 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
= 0.084 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
= ac-ft
Water Quality Capture Volume (WQCV) Design Volume
(VWQCV OTHER
= (d6
*(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 = 2.0 : 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)
Integrated Recycling Center
Interwest Consulting
June 10, 2013
Fort Collins
ES
Riprap
Choose One
Excess Urban Runoff Volume (EURV)
DETENTION VOLUME CALCULATIONS
Rational Volumetric (FAA) Method
100-Year Event
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/23/2013
Equations: Area trib. to pond = 3.16 acre
Developed flow = QD = CIA C (100) = 0.73
Vol. In = Vi = T C I A = T QD Developed C A = 2.3 acre
Vol. Out = Vo =K QPO T Release rate, QPO = 1.3 cfs
storage = S = Vi - Vo K = 1.0 (from fig 2.1)
Rainfall intensity from City of Fort Collins IDF Curve with (3.67") rainfall
Storm Rainfall QD Vol. In Vol. Out Storage Storage
Duration, T Intensity, I (cfs) Vi Vo S S
(min) (in/hr) (ft3) (ft3) (ft3) (ac-ft)
5 9.95 23.0 6886 380 6506 0.15
10 7.72 17.8 10685 761 9925 0.23
20 5.60 12.9 15502 1521 13981 0.32
30 4.52 10.4 18768 2282 16487 0.38
40 3.74 8.6 20706 3042 17664 0.41
50 3.23 7.5 22353 3803 18550 0.43
60 2.86 6.6 23751 4563 19188 0.44
70 2.60 6.0 25190 5324 19867 0.46
80 2.34 5.4 25910 6084 19826 0.46
90 2.17 5.0 27031 6845 20187 0.46
100 1.99 4.6 27543 7605 19938 0.46
110 1.87 4.3 28471 8366 20105 0.46
120 1.75 4.0 29066 9126 19940 0.46
130 1.66 3.8 29868 9887 19982 0.46
140 1.57 3.6 30422 10647 19775 0.45
150 1.48 3.4 30727 11408 19319 0.44
160 1.42 3.3 31446 12168 19278 0.44
170 1.36 3.1 32000 12929 19071 0.44
180 1.29 3.0 32138 13689 18449 0.42
Required Storage Volume: 20187 ft3
0.46 acre-ft
05-23-13 Pond 1.xls,FAA-100yr
DETENTION VOLUME CALCULATIONS
Rational Volumetric (FAA) Method
100-Year Event
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/23/2013
0
5000
10000
15000
20000
25000
30000
35000
0 50 100 150 200
Volume (ft3
)
Storm Duration (min)
Inflow Volume Outflow Volume
05-23-13 Pond 1.xls,FAA-100yr
DETENTION VOLUME CALCULATIONS
Rational Volumetric (FAA) Method
100-Year Event
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/23/2013
0
5000
10000
15000
20000
25000
0 50 100 150 200
Volume (ft3
)
Storm Duration (min)
Storage Volume
05-23-13 Pond 1.xls,FAA-100yr
Detention Pond 315 - Stage/Storage
LOCATION: Intergrated Recycling Center
PROJECT NO: 1165-012-12
COMPUTATIONS BY: es
DATE: 5/23/2013
V = 1/3 d ( A + B + sqrt(A*B))
where V = volume between contours, ft3
d = depth between contours, ft
A = surface area of contour
Surface Incremental Detention Total
Stage Area Storage Storage Storage
(Elev) (Ft^2) (Ac-ft) (Ac-ft) (Ac-ft)
4928.7 0
4929.0 0 0.00 0.00 0.00
4930.0 2801 0.02 0.00 0.02
WQCV- 4930.2 3827 0.02 0.00 0.04
4931.0 7933 0.11 0.11 0.14
4932.0 12168 0.23 0.33 0.37
100-YR WSEL- 4932.5 14167 0.15 0.49 0.52
TOP OF BERM- 4933.0 16165 0.17 0.66 0.70
REQUIRED WQCV= 0.04 AC-FT
PROVIDED WQCV= 0.04 AC-FT
REQUIRED DET VOL= 0.46 AC-FT
PROVIDED DET VOL= 0.49 AC-FT
05-23-13 Pond 1.xls
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Type of Permeable Pavement Section
A) What type of section of permeable pavement is used?
(Based on the land use and activities, proximity to adjacent
structures and soil characteristics.)
B) What type of wearing course?
2. Required Storage Volume
A) Effective Imperviousness of Area Tributary to Permeable Pavement, Ia Ia = 40.0 %
B) Tributary Area's Imperviousness Ratio (I = Ia / 100) i = 0.400
C) Tributary Watershed Area ATotal = 20,652 sq ft
(including area of permeable pavement system)
D) Area of Permeable Pavement System APPS = 11,692 sq ft
(Minimum recommended permeable pavement area = 3442 sq ft)
E) Impervious Tributary Ratio RT = 0.3
(Contributing Imperviuos Area / Permeable Pavement Ratio)
F) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 248 cu ft
(WQCV = (0.8 * (0.91 * i3 - 1.19 * i2 + 0.78 * i) / 12) * Area)
G) Is flood control volume being added?
H) Total Volume Needed VTotal = cu ft
3. Depth of Reservoir
A) Minimum Depth of Reservoir Dmin = 12.0 inches
(Minimum recommended depth is 6 inches)
B) Is the slope of the reservoir/subgrade interface equal to 0%?
C) Porosity (Porous Gravel Pavement < 0.3, Others < 0.40) P = 0.30
D) Slope of the Base Course/Subgrade Interface S = 0.024 ft / ft
E) Length Between Lateral Flow Barriers (max = 5.88 ft.) L = 5.9 ft
F) Volume Provided Based on Depth of Base Course V = 2,968 cu ft
Flat or Stepped: V = P * ((Dmin-1)/12) * Area
Sloped: V = P * [(Dmin - (Dmin - 6*SL-1)) / 12] * Area Volume assumes uniform slope & lateral flow barrier spacing.
Calculate the volume of each cell individually when this varies.
4. Lateral Flow Barriers
A) Type of Lateral Flow Barriers
B) Number of Permeable Pavement Cells Cells =
5. Perimeter Barrier
A) Is a perimeter barrier provided on all sides of the
pavement system?
(Recommeded for PICP, concrete grid pavement, or for any
no-infiltration section.)
Intergrated Recycling Center
Design Procedure Form: Permeable Pavement Systems (PPS)
ES
Interwest Consulting Group
June 11, 2013
Choose One
No Infiltration
Partial Infiltration Section
Full Infiltration Section
Choose One
YES
NO
Choose One
YES- Flat or Stepped Installation
NO- Sloped Installation
Choose One
Concrete Walls
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
6. Filter Material and Underdrain System
A) Is the underdrain placed below a 6-inch thick layer of
CDOT Class C filter material?
B) Diameter of Slotted Pipe (slot dimensions per Table PPs-2)
C) Distance from the Lowest Elevation of the Storage Volume y = ft
(i.e. the bottom of the base course to the center of the orifice)
7. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is there a minimum 30 mil thick impermeable PVC geomembrane
liner on the bottom and sides of the basin, extending up to the top
of the base course?
B) CDOT Class B Separator Fabric
8. Outlet
(Assumes each cell has similar area, subgrade slope, and length
between lateral barriers (unless subgrade is flat). Calculate cells
individually where this varies.)
A) Depth of WQCV in the Reservoir DWQCV = inches
(Elevation of the Flood Control Outlet)
B) Diameter of Orifice for 12-hour Drain Time DOrifice = inches
(Use a minimum orifice diameter of 3/8-inches)
Notes:
Intergrated Recycling Center
Design Procedure Form: Permeable Pavement Systems (PPS)
ES
Interwest Consulting Group
June 11, 2013
Choose One
YES
NO
Choose One
4-inch
6-inch
Choose One
Choose One
YES
NO
Placed above the liner
Placed above and below the liner
N/A
UD-BMP_v3_01Pervious Pavement 06-11-13.xls, PPS 6/11/2013, 12:31 PM
Sheet 1 of 1
Designer:
Company:
Date:
Project:
Location:
1. Design Discharge for 2-Year Return Period Q2
= 1.80 cfs
2. Hydraulic Residence Time
A) : Length of Grass Swale LS
= 350.0 ft
B) Calculated Residence Time (based on design velocity below) THR
= 6.7 minutes
3. Longitudinal Slope (vertical distance per unit horizontal)
A) Available Slope (based on site constraints) Savail
= 0.015 ft / ft
B) Design Slope SD
= 0.015 ft / ft
4. Swale Geometry
A) Channel Side Slopes (Z = 4 min., horiz. distance per unit vertical) Z = 4.00 ft / ft
B) Bottom Width of Swale (enter 0 for triangular section) WB
= 0.00 ft
5. Vegetation
A) Type of Planting (seed vs. sod, affects vegetal retardance factor)
6. Design Velocity (1 ft / s maximum) V2
= 0.87 ft / s
7. Design Flow Depth (1 foot maximum) D2
= 0.72 ft
A) Flow Area A2
= 2.1 sq ft
B) Top Width of Swale WT
= 5.8 ft
C) Froude Number (0.50 maximum) F = 0.25
D) Hydraulic Radius RH
= 0.35
E) Velocity-Hydraulic Radius Product for Vegetal Retardance VR = 0.30
F) Manning's n (based on SCS vegetal retardance curve D for sodded grass) n = 0.107
G) Cumulative Height of Grade Control Structures Required HD
= 0.00 ft
AN UNDERDRAIN IS
8. Underdrain REQUIRED IF THE
(Is an underdrain necessary?) DESIGN SLOPE < 2.0%
9. Soil Preparation
(Describe soil amendment)
10. Irrigation
Notes:
Design Procedure Form: Grass Swale (GS)
ES
Interwest Consulting Group
June 11, 2013
Integrated Recycling Center
Basin A
Choose One
Temporary Permanent
Choose One
Grass From Seed Grass From Sod
Choose One
YES NO
UD-BMP_v3_01Grass Swale Basin A 06-11-13.xls, GS 6/11/2013, 7:49 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 64.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.640
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.20 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 16,509 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 276 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQCV = 12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin = 184 sq ft
D) Actual Flat Surface Area AActual = 198 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 544 sq ft
F) Rain Garden Total Volume VT= 371 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 30.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 276 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 0.22 in MINIMUM DIAMETER = 3/8"
Integrated Recycling Center
Basin B
Design Procedure Form: Rain Garden (RG)
ES
Interwest Consulting Group
June 11, 2013
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3_01Rain Garden Basin B 06-11-13.xls, RG 6/11/2013, 7:39 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
ES
Interwest Consulting Group
June 11, 2013
Integrated Recycling Center
Basin B
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3_01Rain Garden Basin B 06-11-13.xls, RG 6/11/2013, 7:39 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 52.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.520
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.17 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 18,254 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 258 cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = cu ft
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER = cu ft
(Only if a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum) DWQCV = 12 in
B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft
(Use "0" if rain garden has vertical walls)
C) Mimimum Flat Surface Area AMin = 172 sq ft
D) Actual Flat Surface Area AActual = 291 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 544 sq ft
F) Rain Garden Total Volume VT= 418 cu ft
(VT= ((ATop + AActual) / 2) * Depth)
3. Growing Media
4. Underdrain System
A) Are underdrains provided?
B) Underdrain system orifice diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage y = 30.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 258 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 0.21 in MINIMUM DIAMETER = 3/8"
Integrated Recycling Center
Basin C
Design Procedure Form: Rain Garden (RG)
ES
Interwest Consulting Group
June 11, 2013
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3_01Rain Garden Basin C 06-11-13.xls, RG 6/11/2013, 7:41 AM
Sheet 2 of 2
Designer:
Company:
Date:
Project:
Location:
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
A) Is an impermeable liner provided due to proximity
of structures or groundwater contamination?
6. Inlet / Outlet Control
A) Inlet Control
7. Vegetation
8. Irrigation
A) Will the rain garden be irrigated?
Notes:
Design Procedure Form: Rain Garden (RG)
ES
Interwest Consulting Group
June 11, 2013
Integrated Recycling Center
Basin C
Choose One
Choose One
Choose One
Sheet Flow- No Energy Dissipation Required
Concentrated Flow- Energy Dissipation Provided
Plantings
Seed (Plan for frequent weed control)
Sand Grown or Other High Infiltration Sod
Choose One
YES
NO
YES
NO
UD-BMP_v3_01Rain Garden Basin C 06-11-13.xls, RG 6/11/2013, 7:41 AM
E
APPENDIX E
SOILS INFORMATION, FIGURES, TABLES AND EXCERPTS FROM REPORTS
Timberline Rd
Solstice Ln
62
73
64
74
22
22
496360
496360
496400
496400
496440
496440
496480
496480
496520
496520
496560
496560
496600
496600
496640
496640
496680
496680
4490160
4490160
4490200
4490200
4490240
4490240
4490280
4490280
4490320
4490320
4490360
4490360
0 50 100 200 300 Feet
0 20 40 80 120 Meters
40° 33' 50''
105° 2' 20''
40° 33' 42''
105° 2' 20''
40° 33' 42''
40° 33' 50''
105° 2' 36'' 105° 2' 36''
Map Scale: 1:1,780 if printed on A size (8.5" x 11") sheet.
Hydrologic Soil (Intergrated Group—Larimer Recycling County Center) Area, Colorado
Natural Conservation Resources Service
National Web Cooperative Soil Survey Soil Survey
Page 4/30/1 2013 of 4
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Political Features
Cities
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1:1,780 if printed on A size (8.5" × 11") sheet.
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 13N NAD83
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
Survey Area Data: Version 7, May 1, 2009
Date(s) aerial images were photographed: 8/6/2005
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Hydrologic Soil Group–Larimer County Area, Colorado
(Intergrated Recycling Center)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/30/2013
Page 2 of 4
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
22 Caruso clay loam, 0 to 1 percent
slope
C 0.6 5.4%
62 Larimer-Stoneham complex, 3
to 10 percent slopes
B 6.7 64.9%
64 Loveland clay loam, 0 to 1
percent slopes
C 1.0 9.6%
73 Nunn clay loam, 0 to 1 percent
slope
C 1.3 12.6%
74 Nunn clay loam, 1 to 3 percent
slopes
C 0.8 7.5%
Totals for Area of Interest 10.3 100.0%
Hydrologic Soil Group–Larimer County Area, Colorado Intergrated Recycling Center
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/30/2013
Page 3 of 4
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group–Larimer County Area, Colorado Intergrated Recycling Center
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
4/30/2013
Page 4 of 4
PVC geomembrane installed normal to flow
N/A- Flat installation
Other (Describe):
Choose One
YES
NO
Choose One
PICP
Concrete Grid Pavement
Pervious Concrete
Porous Gravel
UD-BMP_v3_01Pervious Pavement 06-11-13.xls, PPS 6/11/2013, 12:31 PM
Choose One
A
B
C / D
Water Quality Capture Volume (WQCV)
UD-BMP_v3_01 Water Quality 05-23-13.xls, EDB 6/10/2013, 2:53 PM