HomeMy WebLinkAboutBEEBE CHRISTIAN SCHOOL - PDP - PDP160022 - REPORTS - DRAINAGE REPORTDrainage Report
for
BeBee Christian School/Church
2103 Nancy Gray Avenue
Fort Collins, CO 80525
Prepared by: Mike Beach, P.E.
Project #:16‐026‐001
Dated: December 8, 2016
5255 Ronald Reagan Blvd, Suite 210 Johnstown, CO 80534
(303) 322-6480 EMAIL: mbeach@ridgetopeng.com
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Section Page
1. Project Engineer’s Certification ........................................................................................ 3
2. Project Location & Overview ............................................................................................ 4
3. Drainage Design Criteria ................................................................................................... 5
4. Hydraulic Calculations ....................................................................................................... 6
5. Facility Design .................................................................................................................... 7
6. Conclusion ......................................................................................................................... 8
7. References ......................................................................................................................... 8
Appendix A – Site Vicinity Map
Appendix B – Flood Insurance Rate Map
Appendix C – NRCS Soils Map
Appendix D – Hydrologic Criteria
Fort Collins Rainfall Intensity Curve
Fort Collins Rainfall Intensity Table
Table RO‐3 – Recommended Percentage Imperviousness Values
Appendix E – Hydraulic Calculations
Runoff Coefficients & Imperviousness
Time of Concentration ‐ SF‐2
Rational Method Runoff Flows – SF‐3 (2‐Year Event)
Rational Method Runoff Flows – SF‐3 (10‐Year Event)
Rational Method Runoff Flows – SF‐3 (100‐Year Event)
Detention Volume by Modified FAA Method
Rain Garden Calculations (both Subbasins)
LID Summary
Drain Times
Appendix F – Maps
Drainage Plan/Subbasin Map
Appendix G – References
Table of Contents
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Section 1: PROJECT ENGINEER’S CERTIFICATION
I hereby attest that this Final Drainage Report for the design of stormwater management
facilities for BeBee Christian School on 2103 Nancy Gray Ave. was prepared by me, or under my
direct supervision, in accordance with the provisions of the City of Fort Collins Storm Drainage
Design Criteria and Construction Standards for the responsible parties thereof.
__________________________
Mike Beach, P.E.
Registered Professional Engineer
State of Colorado No. 45088
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Section 2: Project Location & Overview
Location
The sites address is 2103 Nancy Gray Avenue, Fort Collins, CO; which is described as a portion
of Outlot A, Spring Creek Farms North, City of Fort Collins, County of Larimer, State of Colorado.
For Recording purposes: Part of the Southeast Quarter of Section 19, TP 7 N, R 68 W of the 6th
PM.
Located along the north side of Nancy Gray Ave. and east of South Timberline Road, the site is
described as above and contains 3.326 acres of undeveloped vacant land. (See Appendix A –
Site Vicinity Map)
Existing Condition
The existing site is covered by native vegetation and slopes predominately towards South
Timberline Road at approximately 0.5% slope. Stormwater runoff collected into an existing
stormwater detention pond along the eastern side of the site. Currently the detained water is
released at 2.0 cfs via an existing outlet structure and conveyed via piping to “Storm 2” as
delineated in previous storm reports. Storm 2 connects to Sidehill Filing 2 Storm system. The
Sidehill report requires the outlet be contained to a 1.1 cfs release rate and it appears existing
pond has not been updated since its original construction, therefore, as part of this project the
pond is being redesigned to accommodate the slower release rate.
Proposed Condition
The intent of the development is to construct a new building of approximately 26,200 SF,
asphalt concrete parking, curb and gutter, playground area containing grass and gravel
material, and landscaping. It has been determined by the survey that the existing pond does
not have sufficient detention capacity for this project. Existing pond size of 0.866 ac‐ft is will be
slightly regraded along the west side to increase overall pond volume to meet the minimum
required.
Floodplain
FEMA Floodplain mapping in this neighborhood is located on map‐panel 08069C1000F,
Effective December 18, 2006, (Not Printed), however it appears the subject property is located
in Zone X, which is outside the 100‐year floodplain. Flood Insurance Rate Map not available for
printing.
Existing Soils
The Natural Resource Conservation Service mapped the historic soils on the site as part of the
Nunn clay loam. The Hydrologic Class is Type ‘C’ Soils. (Appendix C – NRCS Soils Map)
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Section 3: Drainage Design Criteria
Reference Manuals
Storm drainage design criteria is defined in the City of Fort Collins “Storm Drainage Design
Criteria and Construction Standards Manual (FCSDCM) and Amendments, which references to
the “Urban Drainage and Flood Control District” (UDFCD) and the “Urban Storm Drainage
Criteria Manual” (USDCM), Volumes 1, 2, and 3, dated 2008 with revisions (the Manual), are
used and referenced in this report.
Low Impact Development (LID) Requirements
The proposed development is required to meet the City’s current Land Use Code, which
includes:
‐ 50% of the newly added or modified impervious area must be treated by LID
techniques and 25% of new paved areas must be pervious.
‐ 75% of all newly added or modified impervious area must be treated by LID
techniques.
Four Step Process
The City of Fort Collins has adopted the “Four Step Process” that is recommended in Volume 3
of the USDCM for selecting BMP’s in urban redevelopment areas. The goal of this process is to
minimize adverse impacts on receiving waters. The following describe how each step of the
process are incorporated in the proposed development:
Step 1 – Employ Runoff Reduction Practices
By selecting a site that is undeveloped that currently does not have water quality treatment,
the impacts of the proposed development will be less due to the addition of the water quality
capture volume included. The project proposes to install a rain garden with underdrains to aid
in conveyance and infiltration opportunities which will reduce the effects of the added
impervious area from the development of the site.
Step 2 – Water Quality Capture Volume (WQCV)
In order to reduce the sediment load and other pollutants leaving the site, it is important to
provide WQCV to minimize the downstream impacts. This project proposes to provide rain
garden prior to the stormwater entering the detention pond, both located on the site. These
facilities are sized to release at or below the historic runoff rates.
Step 3 – Stabilize Drainageways
Since this site is in close proximity to Poudre River it is important to take this Step into
consideration. By providing stormwater detention and water quality and lowering the historic
runoff and providing a metered outflow the project impacts to the drainageway are essentially
reduced. The majority of the drainageway leaving the site is already stabilized.
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Step 4 – Implement Site Specific and Other Source Control BMP’s
The proposed project will contain the following BMP’s:
Rain Garden: All runoff from the site will be directed into and through the proposed
BMP facilities prior to leaving the site. Rain gardens utilize native plants that act as
sponges to reduce the amount of stormwater runoff and absorb contaminants.
Maintenance: In order for BMP’s to remain effective proper maintenance needs are
required. Scheduled visual inspections and routine repair after larger storm events are
critical in the maintenance and effectiveness of the installed BMP’s. The sites owner will
be advised of these practices during installation in order to maximize the efficiency of
the installed BMP’s.
Section 4: Hydraulic Calculations
Criteria
Runoff criteria for the proposed sites was analyzed for the 2‐YR, 10‐YR, and 100‐YR storm
events. The Rational Method is being used for the design of the proposed improvements.
Rainfall Intensities used in the proposed design were determined as a function of the Time of
Concertation for each subbasin. The values used were determined by the City of Fort Collins
Rainfall Intensity/Duration/Frequency curve (Figure RA‐16 and Table RA‐7 (see Appendix D).
Imperviousness
Values from Table RO‐11 (Fort Collins Amendment to the USDCM) were used in determining
the sites imperviousness. The overall proposed site improvements and landscaping equate to a
total onsite proposed Imperviousness of 46%, while the total basin reaching the pond is 53%.
Time of Concentration & Runoff Coefficient
The onsite area was separated into three (3) subbasins with slopes varying between 0.5% to
1.5%. The calculated Time of Concentration (TC) for each subbasin are listed in Appendix E. See
Basin Map in Appendix F for more information.
WQCV
The UD‐BMP_v3.03 (UDFCD) spreadsheet was used to calculated the required Rain Garden
water quality capture volume. See Appendix E for design information.
The existing detention pond design also included a volume allotted for the WQCV. Per the
previous report by Stantec, a volume of 0.033 ac‐ft is required for WQCV and will be included in
the total pond volume calculations. The previous pond design did not allow for an extended
WQ drain time, so therefore a new orifice plate is being designed and included with this
project. The revised pond will outlet the WQCV over a 12 hour period as allowed by the
Manual.
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Detention
The existing detention pond is already constructed and was designed by Stantec with an
allowable release rate of 1.1 cfs. The design was also discussed in the “Interim Timberline Road
Widening – Drake to Prospect” and “Spring Creek Farms North Filing No. 2”. See existing report
information in Appendix G.
The detention facility Drain Time Spreadsheet and Stage Storage relationship spreadsheet have
been calculated and is included within Appendix E of this report. The calculated drain time for
99% of the inflow volume of the pond with the proposed project and off‐site area included is
approximately 23 hours for the 100‐year event, which is below the maximum allowed drain
time.
Section 5: Facility Design
The proposed improvements will increase the amount of impervious area; however, measures
have been included in the design to minimize the amount of stormwater released from the site.
Per previous design reports, specifically the Spring Creek Farms North, the outlet structure is
designed to release at 1.1 cfs. The existing water quality plate in the existing pond will need to
be replaced to meet current requirements and drain times. The plate will be designed with a
single 1‐3/16” diameter orifice to release the WQCV at 0.045 cfs, and a single 2‐5/16” diameter
orifice above the WQCV to release the 100‐year event at 1.1 cfs. Per our report, the
predeveloped 2‐year event release rate is 2.44 cfs per for the entire 3.32‐acre site (see
Appendix E for historic calcs). The runoff will sheet flow until a concentrated point and then be
conveyed via trickle channel or gutters and then deposited into the water quality device and/or
detention pond.
The site was broken into three developed subbasins for water quality purposes; Subbasin 1.0
(0.856 acres), Subbasin 2.0 (1.859 acres), and Subbasin Pond (0.608 acres). OS‐7 and PS‐1 (as
described below) was also modeled and included in the detention calculations. See Appendix E
for breakdown of the different area types for each subbasin and Appendix F for the Subbasin
Map.
Subbasin 1.0 contains half of the proposed building and the parking and paved areas south of
the building. The runoff will be conveyed to the east side of the building and outlet into a
proposed rain garden. The rain garden will outlet to the modified detention pond.
Subbasin 2.0 contains half of the building, the parking and paved areas to the west of the
building, and the playground area. All areas drain to the north and east. Water Quality for this
subbasin will be provided via a rain garden. The rain garden will outlet to the modified
detention pond.
Pond Basin is that area within the existing Drainage Easement on the east side of the site. The
existing detention pond was already sized for a release of 1.1 cfs, however current regulations
require slight modifications to the steel orifice plate to meet drain times. Currently it has one
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3.5” diameter orifice plate that will be replaced with a new plate containing a single 1‐3/16”
diameter orifice to release the WQCV at 0.045 cfs, and a single 2‐5/16” diameter orifice above
the WQCV to release the 100‐year event at 1.1 cfs.. The existing pond was modeled with the
proposed project and the 100‐year WSEL’s is indicated on the Drainage Plan in Appendix F.
OS‐7 – This off‐site basin is the area of Nancy Gray and a portion of Timberline that drain to the
existing detention pond. Full design calculations are included in order to determine the
required detention volume is being provided within the existing pond.
PS‐1 – This off‐site basin is the northeast portion of the Police Services site that drains to the
existing type R in Nancy Gray that is conveyed to the existing detention pond on‐site.
Since there is only one detention pond modeled with this report we have provided a summary
of the proposed design below. See supporting calculations within the Appendix of this report.
Area
(ac)
Sub 1.0 0.86 1.33 2.32 6.21 0.013 ‐ ‐ ‐ ‐ ‐
Sub 2.0 1.86 2.19 3.73 10.20 0.028 ‐ ‐ ‐ ‐ ‐
Pond 0.61 0.17 0.29 0.74 ‐ ‐ ‐ ‐ ‐
OS‐7 1.24 1.81 3.85 11.07 ‐ ‐ ‐ ‐ ‐ ‐
PS‐1 0.88 1.19 2.05 5.79 ‐ ‐ ‐ ‐ ‐ ‐
Total Site 3.32 3.28 5.63 14.48 ‐ ‐ ‐ ‐ ‐ ‐
Total Basin 5.44 5.77 10.02 25.62 0.045 0.033 1.168 1.031 1.213 1.1
Release
Rate (cfs)
2‐Year
Flow (cfs)
100‐Year
Flow (cfs)
WQCV
(ac‐ft)
100‐Year
Vol. (ac‐ft)
Detention
Req'd (ac‐ft)
Tot. Volume
Provided (ac‐ft)
10‐Year
Flow (cfs)
WQCV
Req'd
Section 6: Conclusions
All computations that have been reviewed or completed within this report are in compliance
with the City of Fort Collins Storm Drainage Design Criteria and Construction Standards manual
and the Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual
Volumes 1 &2.
The proposed drainage concepts presented in this report and on the construction plans
adequately provide for stormwater detention and water quality treatment of impervious areas
by releasing the 100‐Year storm event at the required allowable release rate of 1.1 cfs, which is
less than the Predeveloped 2‐Year runoff rates. The Water Quality design will benefit the site
by reducing the initial discharge from the site and removal of any sediments or other pollutants
generated by the developed site. As well, with the modified steel outlet plate, water quality is
now being provided for the offsite basins that drain to the existing pond.
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Section 7: References
The Natural Resource Conservation Service Soil Survey for Larimer County and the WSS
website.
FEMA FIRM map‐panel 08069C1000F Effective 12/18/2006. – Not Printed.
“City of Fort Collins Stormwater Criteria Manual” dated December 2011
Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manual
(UDFCD), Volumes 1, 2, and 3, dated 2008 with revisions (the Manual).
Drainage Report: Police Services Building
Drainage Report – Spring Creek Farms North
Drainage Report – Timberline Road Widening
Drainage Report – Sidehill Filing 2 – Stormwater Pipe Reduction
w Appendix A
Site Vicinity Map
Appendix B
Flood Insurance Rate Map
(Not available to Print)
Appendix C
NRCS Soils Map
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/7/2016
Page 1 of 4
4489690 4489710 4489730 4489750 4489770 4489790 4489810
4489690 4489710 4489730 4489750 4489770 4489790 4489810
496470 496490 496510 496530 496550 496570 496590 496610 496630 496650 496670
496470 496490 496510 496530 496550 496570 496590 496610 496630 496650 496670
40° 33' 32'' N
105° 2' 30'' W
40° 33' 32'' N
105° 2' 20'' W
40° 33' 28'' N
105° 2' 30'' W
40° 33' 28'' N
105° 2' 20'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84
0 45 90 180 270
Feet
0 15 30 60 90
Meters
Map Scale: 1:1,020 if printed on A landscape (11" x 8.5") sheet.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: Larimer County Area, Colorado
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
73 Nunn clay loam, 0 to 1
percent slopes
C 4.3 97.1%
74 Nunn clay loam, 1 to 3
percent slopes
C 0.1 2.9%
Totals for Area of Interest 4.4 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/7/2016
Page 3 of 4
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/7/2016
Page 4 of 4
Appendix D
Hydrologic Criteria
RAINFALL INTENSITY-DURATION-FREQUENCY CURVE
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0.00 10.00 20.00 30.00 40.00 50.00 60.00
STORM DURATION (minutes)
RAINFALL INTENSITY (inches/hour)
2-Year Storm 10-Year Storm 100-Year Storm
Figure RA-16 City of Fort Collins Rainfall Intensity-Duration-Frequency Curves
(13) Section 5.0 is deleted in its entirety.
(14) Section 6.0 is deleted in its entirety.
(15) Section 7.0 is deleted in its entirety.
(16) Section 7.1 is deleted in its entirety.
(17) Section 7.2 is deleted in its entirety.
(18) Section 7.3 is deleted in its entirety.
(19) Section 8.0 is deleted in its entirety.
(20) Table RA-1 is deleted in its entirety.
(11) Section 4.0 is amended to read as follows:
4.0 Intensity-Duration-Frequency Curves for Rational Method:
The one-hour rainfall Intensity-Duration-Frequency tables for use the Rational Method
of runoff analysis are provided in Table RA-7 and in Table RA-8.
Table RA-7 -- City of Fort Collins
Rainfall Intensity-Duration-Frequency Table
for Use with the Rational Method
(5 minutes to 30 minutes)
2-Year 10-Year 100-Year
Duration
(min)
Intensity
(in/hr)
Intensity
(in/hr)
Intensity
(in/hr)
5 2.85 4.87 9.95
6 2.67 4.56 9.31
7 2.52 4.31 8.8
8 2.4 4.1 8.38
9 2.3 3.93 8.03
10 2.21 3.78 7.72
11 2.13 3.63 7.42
12 2.05 3.5 7.16
13 1.98 3.39 6.92
14 1.92 3.29 6.71
15 1.87 3.19 6.52
16 1.81 3.08 6.3
17 1.75 2.99 6.1
18 1.7 2.9 5.92
19 1.65 2.82 5.75
20 1.61 2.74 5.6
21 1.56 2.67 5.46
22 1.53 2.61 5.32
23 1.49 2.55 5.2
24 1.46 2.49 5.09
25 1.43 2.44 4.98
26 1.4 2.39 4.87
27 1.37 2.34 4.78
28 1.34 2.29 4.69
29 1.32 2.25 4.6
30 1.3 2.21 4.52
Appendix E
Hydraulic Calculations
Historic Runoff Coefficients & Percent Impervious Calculated By: RSB
Project - BeBee Christian School Checked By: MRB
Job Number: 16-026-001 Date: 10/28/2016
IMP% Soil Types: Nunn Clay Loam
Table RO-11 (COFC) Roof 0.95 90 Hydrologic Soil Group: C
Table RO-3 (UDSDCM Asphalt 0.95 100
Concrete 0.95 96
Landscaping (flat) 0.10 0
Landscaping (steep) 0.20 0
Gravel & Pavers 0.50 40
Multi-family (attached) 0.65 70
Commercial 0.95 95
Undeveloped Historical 0.02 2
Basin Total Area Roof Paved Gravel Sidewalk Landscape Runoff % Comments
Description (ac) Area (sf) Area (sf) Area (sf) Area (sf) Area (sf) Coeff C Imperv
EX-7 1.240 54014 0 32401 0 6280 15333 0.71 71 Off-Site
EX-8 3.320 144619 0 0 0 2660 141959 0.12 2 Site
EX-PS 0.880 38333 0 12268 0 7970 18095 0.55 52 Police Station
Total Basin 5.44 236966 0 44669 0 16910 175387 0.32 26
Equations:
Calculated C coefficeints & Percent Impervious are Weighted
C = Summation (Ci*Ai) / At
Ci = Runoff Coefficient for Specific Area (Ai)
Ai = Area of Surface with Runoff Coefficient of Ci
n - Number of different surfaces to be considered
Runoff
Coeff C
Total Area
(sq. ft.)
STANDARD FORM SF-2
Event: 2-Year Historic TIME OF CONCENTRATION
Cf = 1.00 SUBDIVISION: BeBee
CALCULATED BY: MRB DATE: 10/28/2016 REV:
SUB-BASIN INITIAL/OVERLAND TRAVEL TIME tc CHECK FINAL REMARKS
DATA TIME (ti
) (tt) (URBANIZED BASINS)
tc
DESIG: C AREA LENGTH SLOPE ti LENGTH SLOPE Mannings VEL. t
t COMP. TOT. LENGTH tc=(L/180)+10
Ac Ft % Min Ft % n FPS Min tc Ft Min Min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)
EX-7 0.71 1.24 150 1.0 9.0 400 1 0.016 1.3 5.1 14.1 14.1 Off-Site
EX-8 0.12 3.32 275 1.0 30.5 236 1 0.025 2.1 1.9 32.4 32.4 Site
EX-PS 0.55 0.88 115 2.0 8.8 150 0.5 0.016 1.2 2.1 10.9 10.9 Police Station
Total Basin 0.32 5.44 290 1.0 24.8 500 1 0.025 2.1 4.0 28.8 28.8 Basins EX-7, EX-8 & EX-PS
References/Equations:
Table RO-12 COFC
tc = ti + tt
ti = {1.87(1.1 - C*Cf)*L}/S^0.33
tt = L/Vel
Velocity from Manning's Equation with R=0.1 (per COFC Figure 3-3)
Final tc = Min of ti + tt and/or Urbanized Check
Location: BeBee RATIONAL METHOD PEAK RUNOOF
Calculated By: RSB Event: 2-Year
Date: 10/28/2016 Historic Flow Rate
Cf = 1.00
SUB-BASIN Direct Runoff Comments
DATA
DESIG: C AREA C*Cf tc i Q
Ac min (in/hr) (cfs)
EX-7 0.71 1.24 0.71 14.1 1.95 1.714 Off-Site
EX-8 0.12 3.32 0.12 32.4 1.35 0.518 Site
EX-PS 0.55 0.88 0.55 10.9 2.35 1.135 Police Station
Total Basin 0.32 5.44 0.32 28.8 1.40 2.444 Basins EX-7, EX-8 & EX-PS
Q = Cf*C*i*A
Q = Peak Discharge (cfs)
C = Runoff Coefficient
Cf = Frequency Adjustment Factor
I = Rainfall Intensity (in/hr) from COFC IDF Curve (I = 24.221 / (10+tc)^0.7968
A = Drainage Area (ac)
Runoff Coefficients & Percent Impervious Calculated By: RSB
Project - BeBee Christian School Checked By: MRB
Job Number: 16-026-001 Date: 10/28/2016
IMP% Soil Types: Nunn Clay Loam
Table RO-11 (COFC) Roof 0.95 90 Hydrologic Soil Group: C
Table RO-3 (UDSDCM) Asphalt 0.95 100
Concrete 0.95 96
Landscaping (flat) 0.10 0
Landscaping (Average) 0.15 0
Landscaping (steep) 0.20 0
Gravel & Pavers 0.50 40
Multi-family (attached) 0.65 70
Commercial 0.95 95
Undeveloped Historical 0.02 2
Basin Total Area Roof Paved Gravel Sidewalk Landscape Runoff % Comments
Description (ac) Area (sf) Area (sf) Area (sf) Area (sf) Area (sf) Coeff C Imperv
1.0 0.856 37287 13497 6509 0 2967 14314 0.62 58
2.0 1.859 80978 12622 28242 0 5813 34301 0.59 56
Pond 0.608 26484 0 0 0 0 26484 0.10 0 Pond Basin
OS-7 1.240 54014 0 32401 0 6280 15333 0.71 71 Directly to Pond
PS-1 0.88 38333 0 12268 0 7970 18095 0.55 52 Police Station
Total Site 3.32 144750 26119 34751 0 8780 75099 0.51 46 Basins 1, 2, & Pond
Total Basin 5.44 237097 26119 79420 0 23030 108527 0.56 53 Basins 1, 2, Pond, OS-7, & PS-1
Equations:
Calculated C coefficeints & Percent Impervious are Weighted
C = Summation (Ci*Ai) / At
Ci = Runoff Coefficient for Specific Area (Ai)
Ai = Area of Surface with Runoff Coefficient of Ci
n - Number of different surfaces to be considered
Runoff
Coeff C
Total Area
(sq. ft.)
STANDARD FORM SF-2
Event: 2-Year & 10-Year TIME OF CONCENTRATION
Cf = 1.00 SUBDIVISION: BeBee
CALCULATED BY: MRB DATE: 12/6/2016 REV:
SUB-BASIN INITIAL/OVERLAND TRAVEL TIME tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASINS) tc
DESIG: C AREA LENGTH SLOPE ti LENGTH SLOPE Mannings VEL. tt COMP. TOT. LENGTH tc=(L/180)+10
Ac Ft % Min Ft % n FPS Min tc Ft Min Min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)
1.0 0.62 0.86 55 2.0 5.2 230 0.5 0.015 1.3 2.9 8.2 285 11.6 8.2
2.0 0.59 1.86 135 1.0 11.1 400 0.5 0.015 1.5 4.4 15.5 535 13.0 13.0
Pond 0.10 0.61 5 2.0 3.3 150 0.5 0.016 1.2 2.1 5.4 155 10.9 5.4
OS-7 0.74 1.24 60 2.0 4.2 400 1 0.016 2.0 3.3 7.5 460 12.6 7.5
PS-1 0.53 0.88 70 4.0 5.6 110 2 0.016 2.8 0.7 6.3 180 11.0 6.3
Total Site 0.51 3.32 140 2.0 10.4 510 0.5 0.016 1.4 6.1 16.5 650 13.6 13.6
Total Basin 0.56 5.44 160 2.0 10.2 620 0.5 0.016 1.4 7.4 17.6 780 14.3 14.3
References/Equations:
Table RO-12 COFC
tc = ti + tt
ti = {1.87(1.1 - C*Cf)*L}/S^0.33
tt = L/Vel
Velocity from Manning's Equation with R=0.1 (per COFC Figure 3-3)
Final tc = Min of ti + tt and/or Urbanized Check
STANDARD FORM SF-2
Event: 100-Year TIME OF CONCENTRATION
Cf = 1.25 SUBDIVISION: BeBee
CALCULATED BY: MRB DATE: 12/6/2016 REV:
SUB-BASIN INITIAL/OVERLAND TRAVEL TIME tc CHECK FINAL REMARKS
DATA TIME (ti) (tt) (URBANIZED BASINS) tc
DESIG: C AREA C*Cf LENGTH SLOPE ti LENGTH SLOPE Mannings VEL. tt COMP. TOT. LENGTH tc=(L/180)+10
Ac Ft % Min Ft % n FPS Min tc Ft Min Min
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14)
1.0 0.62 0.86 0.78 55 2.0 3.5 230 0.5 0.015 1.3 2.9 6.5 285 11.6 6.5
2.0 0.59 1.86 0.74 135 1.0 7.9 400 0.5 0.015 1.5 4.4 12.3 535 13.0 12.3
Pond 0.10 0.61 0.12 5 2.0 3.2 150 0.5 0.016 1.2 2.1 5.3 155 10.9 5.3
OS-7 0.74 1.24 0.92 60 2.0 2.1 400 1 0.016 2.0 3.3 5.4 460 12.6 5.4
PS-1 0.53 0.88 0.66 70 4.0 4.3 110 2 0.016 2.8 0.7 5.0 180 11.0 5.0
Total Site 0.51 3.32 0.64 140 2.0 8.1 510 0.5 0.016 1.4 6.1 14.2 650 13.6 13.6
Total Basin 0.56 5.44 0.70 160 2.0 7.6 620 0.5 0.016 1.4 7.4 14.9 780 14.3 14.3
References/Equations:
Table RO-12 COFC
tc = ti + tt
ti = {1.87(1.1 - C*Cf)*L}/S^0.33
tt = L/Vel
Velocity from Manning's Equation with R=0.1 (per COFC Figure 3-3)
Final tc = Min of ti + tt and/or Urbanized Check
Location: BeBee RATIONAL METHOD PEAK RUNOOF
Calculated By: MRB Event: 2-Year
Date: 12/6/2016
Cf = 1.00
SUB-BASIN Direct Runoff Comments
DATA
DESIG: C AREA C*Cf tc i Q
Ac min (in/hr) (cfs)
1.0 0.62 0.86 0.62 8.2 2.50 1.33
2.0 0.59 1.86 0.59 13.0 2.00 2.19
Pond 0.10 0.61 0.10 5.4 2.75 0.17
OS-7 0.74 1.24 0.74 7.5 1.98 1.81
PS-1 0.53 0.88 0.53 6.3 2.55 1.19
Total Site 0.51 3.32 0.51 13.6 1.94 3.28
Total Basin 0.56 5.44 0.56 14.3 1.90 5.77
Q = Cf*C*i*A
Q = Peak Discharge (cfs)
C = Runoff Coefficient
Cf = Frequency Adjustment Factor
I = Rainfall Intensity (in/hr) from COFC IDF Curve (I = 24.221 / (10+tc)^0.7968
A = Drainage Area (ac)
Location: BeBee RATIONAL METHOD PEAK RUNOOF
Calculated By: MRB Event: 10-Year
Date: 12/6/2016
Cf = 1.00
SUB-BASIN Direct Runoff Comments
DATA
DESIG: C AREA C*Cf tc i Q
Ac min (in/hr) (cfs)
1.0 0.62 0.86 0.62 8.2 4.35 2.32
2.0 0.59 1.86 0.59 13.0 3.40 3.73
Pond 0.10 0.61 0.10 5.4 4.75 0.29
OS-7 0.74 1.24 0.74 7.5 4.21 3.85
PS-1 0.53 0.88 0.53 6.3 4.40 2.05
Total Site 0.51 3.32 0.51 13.6 3.33 5.63
Total Basin 0.56 5.44 0.56 14.3 3.30 10.02
Q = Cf*C*i*A
Q = Peak Discharge (cfs)
C = Runoff Coefficient
Cf = Frequency Adjustment Factor
i = Rainfall Intensity (in/hr) from COFC IDF Curve (i = 84.682 / (10+tc)^0.7975
A = Drainage Area (ac)
Location: BeBee RATIONAL METHOD PEAK RUNOOF
Calculated By: MRB Event: 100-Year
Date: 12/6/2016
Cf = 1.25
SUB-BASIN Direct Runoff Comments
DATA
DESIG: C AREA C*Cf tc i Q
Ac min (in/hr) (cfs)
1.0 0.62 0.86 0.78 6.5 9.30 6.21
2.0 0.59 1.86 0.74 12.3 7.44 10.20
Pond 0.10 0.61 0.12 5.3 9.75 0.74
OS-7 0.74 1.24 0.92 5.4 9.69 11.07
PS-1 0.53 0.88 0.66 5.0 9.95 5.79
Total Site 0.51 3.32 0.64 13.6 6.85 14.48
Total Basin 0.56 5.44 0.70 14.3 6.75 25.62
Q = Cf*C*i*A
Q = Peak Discharge (cfs)
C = Runoff Coefficient
Cf = Frequency Adjustment Factor
i = Rainfall Intensity (in/hr) from COFC IDF Curve (i = 84.682 / (10+tc)^0.7975
A = Drainage Area (ac)
DETENTION VOLUME CALCULATIONS
RATIONAL VOLUMETRIC (FAA) METHOD
LOCATION: BeBee Christian School
CALCULATED BY: MRB
PROJECT NUMBER: 16-026-001
DATE: 12/6/2016
BASIN: Total Basin (Basins 1, 2, Pond, OS-7, and PS-1)
Equations: A trib. To pond = 5.440 acre
QD = CiA C100 = 0.70 (C*Cf)
Vi = T*CiA = T*QD Developed C*A = 3.81 acre
Vo =m*QPO*(60*T) QPO = 1.100 cfs
S = Vi - Vo tc = 14.3 min
Rainfall intensity from Larimer County Area 1 IDF Curve
Storm Rainfall QD Vol. In Outflow Vol. Out Storage Storage
Duration, T Intensity, i (cfs) Vi Adjustment Vo SS
(min) (in/hr) (ft3) Factor, m (ft3) (ft3) (ac-ft)
5 9.95 37.9 11367 1.00 330 11037 0.253
10 7.72 29.4 17639 1.00 660 16979 0.390
20 5.60 21.3 25590 0.86 1135 24455 0.561
30 4.52 17.2 30982 0.74 1465 29517 0.678
40 3.74 14.2 34181 0.68 1795 32385 0.743
50 3.23 12.3 36900 0.64 2112 34788 0.799
60 2.86 10.9 39207 0.62 2455 36752 0.844
70 2.62 10.0 41903 0.60 2772 39131 0.898
80 2.38 9.1 43503 0.59 3115 40387 0.927
90 2.22 8.5 45650 0.58 3445 42205 0.969
100 2.05 7.8 46838 0.57 3762 43076 0.989
110 1.93 7.3 48506 0.57 4138 44368 1.019
120 1.80 6.9 49352 0.56 4435 44916 1.031
130 1.60 6.1 47524 0.56 4805 42719 0.981
140 1.40 5.3 44782 0.55 5082 39700 0.911
150 1.20 4.6 41126 0.55 5445 35681 0.819
160 1.15 4.4 42040 0.54 5702 36338 0.834
170 1.10 4.2 42726 0.54 6059 36667 0.842
180 1.05 4.0 43183 0.54 6415 36768 0.844
Required Storage Volume: 44916 ft3
1.031 acre-ft
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 58.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.580
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.18 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 37,287 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 570.8 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 = 381 sq ft
D) Actual Flat Surface Area AActual = 380 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 764 sq ft
F) Rain Garden Total Volume VT= 572 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 = 0.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 406 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 1.38 in
Design Procedure Form: Rain Garden (RG)
MRB
Ridgetop Engineering
October 28, 2016
BeBee Christian School
Basin 1
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.03_Basin 1, RG 10/28/2016, 9:25 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)
MRB
Ridgetop Engineering
October 28, 2016
BeBee Christian School
Basin 1
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_v3.03_Basin 1, RG 10/28/2016, 9:25 AM
Sheet 1 of 2
Designer:
Company:
Date:
Project:
Location:
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area, Ia Ia = 56.0 %
(100% if all paved and roofed areas upstream of rain garden)
B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.560
C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.18 watershed inches
(WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i)
D) Contributing Watershed Area (including rain garden area) Area = 80,978 sq ft
E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = cu ft
Vol = (WQCV / 12) * Area
F) For Watersheds Outside of the Denver Region, Depth of d6 = 0.43 in
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region, VWQCV OTHER = 1,206.2 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 = 804 sq ft
D) Actual Flat Surface Area AActual = 915 sq ft
E) Area at Design Depth (Top Surface Area) ATop = 1510 sq ft
F) Rain Garden Total Volume VT= 1,213 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 = 0.0 ft
Volume to the Center of the Orifice
ii) Volume to Drain in 12 Hours Vol12 = 1,206 cu ft
iii) Orifice Diameter, 3/8" Minimum DO = 2.37 in
Design Procedure Form: Rain Garden (RG)
MRB
Ridgetop Engineering
October 28, 2016
BeBee Christian School
Basin 2
Choose One
Choose One
18" Rain Garden Growing Media
Other (Explain):
YES
NO
UD-BMP_v3.03_Basin 2, RG 10/28/2016, 11:35 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)
MRB
Ridgetop Engineering
October 28, 2016
BeBee Christian School
Basin 2
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_v3.03_Basin 2, RG 10/28/2016, 11:35 AM
Orifice Calculations (Rain Garden Plates)
BeBee School/Church
12/2/2016
d = diameter (inches)
Q = flow (cfs)
h = hydraulic head (ft)
d = sqrt((36.88*Q)/(sqrt(h))
Water Quality Orifice (RG‐1)
Q (cfs) = 0.013
h (ft) = 1
Diameter (sq‐in) Standard Size (diam)
d = sqrt((36.88*0.045)/(sqrt(1.0)) = 0.69 15/16" Orifice
Set invert of orifice at elevation 4944.0
Water Quality Orifice (RG‐2)
Q (cfs) = 0.028
h (ft) = 1 (Total Pond height minus WQ depth)
Diameter (sq‐in) Standard Size (diam)
d = sqrt((36.88*1.100)/(sqrt(1.0)) = 1.02 1‐1/8" Orifice
Set invert of orifice at elevation 4944.0
LID Table
100% On-Site Treatment by LID Requried
New Impervious Area 69,460 sq. ft.
Required Minimum Impervious Area to be Treated 69,460 sq. ft.
Area Treated by Rain Garden (Basin 1) 22,793 sq. ft.
Area Treated by Rain Garden (Basin 2) 46,667 sq. ft.
Run-on Area 0 sq. ft.
Impervious Area by LID Treatment 69,460 sq. ft.
Actual % On-Site Treated by LID 100%
0% Porus Pavement Requried
New Pavement Area 0 sq. ft.
Required Minimum Area of Porus Pavement 0 sq. ft.
Porus Pavement Area 0 sq. ft.
Run-on Area (up to 3:1 allowed) 0 sq. ft.
Total Porus Pavement Area 0 sq. ft.
Actual % of Porus Pavement Provided #DIV/0!
Stormwater Facility Name:
Facility Location & Jurisdiction:
User (Input) Watershed Characteristics User Defined User Defined User Defined User Defined
Watershed Slope = 0.020 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs]
Watershed Length‐to‐Width Ratio = 2.00 L:W 0.00 1 0.00 0.00
Watershed Area = 5.44 acres 0.60 40 0.60 0.05
Watershed Imperviousness = 52.0% percent 1.60 2,990 1.60 0.05
Percentage Hydrologic Soil Group A = 0.0% percent 2.60 6,291 2.60 1.10
Percentage Hydrologic Soil Group B = 0.0% percent 3.60 8,052 3.60 1.10
Percentage Hydrologic Soil Groups C/D = 100.0% percent 4.60 9,922 4.60 1.10
5.60 11,913 5.60 1.10
6.60 14,033 6.60 1.10
7.10 15,142 7.10 1.10
7.60 16,283 7.60 1.10
User Input: Detention Basin Characteristics
WQCV Design Drain Time = 12.00 hours
After completing and printing this worksheet to a pdf, go to:
https://maperture.digitaldataservices.com/gvh/?viewer=cswdif,
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Routed Hydrograph Results
Design Storm Return Period = WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year
Two‐Hour Rainfall Depth = 0.53 0.98 1.36 1.71 2.31 2.91 3.67 in
Calculated Runoff Volume = 0.076 0.219 0.373 0.518 0.791 1.043 1.393 acre‐ft
OPTIONAL Override Runoff Volume = acre‐ft
Inflow Hydrograph Volume = 0.075 0.218 0.372 0.518 0.791 1.043 1.392 acre‐ft
Time to Drain 97% of Inflow Volume = 12 12 13 13 14 14 16 hours
Time to Drain 99% of Inflow Volume = 12 14 15 16 18 20 23 hours
Maximum Ponding Depth = 1.86 2.62 3.40 4.09 5.19 6.05 7.11 ft
Maximum Ponded Area = 0.088 0.145 0.177 0.205 0.254 0.295 0.348 acres
Maximum Volume Stored = 0.055 0.143 0.269 0.401 0.652 0.889 1.228 acre‐ft
Workbook Protected Worksheet Protected
Stormwater Detention and Infiltration Design Data Sheet
Lot 18 ‐ Pond 1
2590 Midpoint Dr, Fort Collins
Copy of Drain times Pond 1 ‐ RSB, Design Data 12/8/2016, 12:03 PM
Doing_Clear_FoYes
CountA= 1
0123
#N/A
#N/A
0123
#N/A
#N/A
Check Data Set 1 Check Data Set 1
Area
Discharge
Stormwater Detention and Infiltration Design Data Sheet
0
5
10
15
20
25
30
35
0.1 1 10
FLOW [cfs]
TIME [hr]
100YR IN
100YR OUT
50YR IN
50YR OUT
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
WQCV IN
WQCV OUT
0
1
2
3
4
5
6
7
8
0.1 1 10 100
PONDING DEPTH [ft]
DRAIN TIME [hr]
100YR
50YR
25YR
10YR
5YR
2YR
WQCV
Copy of Drain times Pond 1 ‐ RSB, Design Data 12/8/2016, 12:03 PM
PROPOSED DETENTION POND - STAGE/STORAGE
Pond: 1.0
Location: Bebee - Proposed WQ & Detention Pond
Calculated By: MRB
Date: 12/8/2016
V = 1/3 d (A + B + sqrt(A*B))
V = Volume between Contours, ft^2
d = Depth between Contours, ft
A = Surface Area of Contour, ft^2
4936.4 0
4937 40 0.000 0.000
4938 2990 0.026 0.026
WQCV = 4938.26 3521 0.019 0.045 0.000
4939 6291 0.082 0.128 0.082
4940 8052 0.164 0.292 0.246
4941 9922 0.206 0.498 0.452
4942 11913 0.250 0.748 0.703
4943 14033 0.297 1.046 1.000
100‐Year WSEL = 4943.5 15142 0.167 1.213 1.168
4944 16283 0.180 1.393 1.348
4944.5 17448 0.194 1.587 1.541
Required Detention Volume = 1.031 See "Detention Volume Calculations" this report
Provided Detention = 1.168
Required WQCV = 0.033 See "WQCV" Page 11 from Stantec Report
Provided WQCV = 0.045
Total Required Volume = 1.064
Total Volume Provided = 1.213
Stage
(ft)
Surface
Area
(ft^2)
Incremental
Storage
(ac‐ft)
Total
Storage
(ac‐ft)
Detention
Storage (ac‐
ft)
Orifice Calculations (Detention/WQ Outlet)
BeBee School/Church
12/2/2016
d = diameter (inches)
Q = flow (cfs)
h = hydraulic head (ft)
d = sqrt((36.88*Q)/(sqrt(h))
Water Quality Orifice
Q (cfs) = 0.045
h (ft) = 1.86
Diameter (sq‐in) Standard Size (diam)
d = sqrt((36.88*0.045)/(sqrt(1.86)) = 1.10 1‐3/16" Orifice
Set invert of orifice at elevation 4936.4
100 ‐ Year Detention Orifice
Q (cfs) = 1.100
h (ft) = 5.24 (Total Pond height minus WQ depth)
Diameter (sq‐in) Standard Size (diam)
d = sqrt((36.88*1.100)/(sqrt(5.24)) = 4.21 2‐5/16" Orifice
Set invert of orifice at elevation 4938.26
15 | Page
Appendix F
Maps
JOSEPH ALLEN DR.
SCHOOL/CHURCH
NANCY GRAY AVE.
S. TIMBERLINE RD.
BASIN 2
1.859 AC
BASIN 1
0.856 AC
BASIN OS7
1.240 AC
POLICE STATION BASIN
0.88 AC
TOTAL BASIN AREA
DRAINING TO POND
5.44 AC
DRAINAGE
PLAN
C-2.1
8 Of
PROJECT TITLE
REVISIONS
SHEET TITLE
SHEET INFORMATION
SEAL
DATE
PREPARED FOR
ENGINEERING R IDGE & CONSULTING T OP
5255 Ronald Reagan Blvd.,
Ste. 210
Johnstown, CO 80534
T (303) 322-6480
W ridgetopeng.com
CITY COMMENTS 11/28/2016
DRAWN BY:
CHECKED BY:
PROJECT NO.:
ROCHE
CONSTRUCTORS
BEEBE CHRISTIAN
SCHOOL AND
SEVENTH DAY
ADVENTIST CHURCH
361 71ST AVE.
GREELEY , CO
2103 NANCY GRAY AVE.
FORT COLLINS, CO
16-026-001
MRB
BSA/RSB
12
SUBMITTAL
PROJECT
DEVELOPMENT PLAN
10/31/2016
LOGO
WATER QUALITY TREATMENT LEGEND
Minimum 8" Thick Layer of
CDOT No. 4 Aggregate
Minimum 4" Perforated
PVC Pipe (Optional
16 | Page
Appendix G
References
This unofficial copy was downloaded on Dec-07-2016 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 Dec-07-2016 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 Dec-07-2016 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 Dec-07-2016 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 Dec-07-2016 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 Dec-07-2016 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 Dec-07-2016 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 Dec-07-2016 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 Nov-30-2016 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 Nov-30-2016 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
Depending on Underlying
Soil Conditions)
12" Ponding Depth
Minimum 12" Thick Layer
of Bioretention Sand Media
(see Bioretention Sand
Media Specification below)
Minimum 6" Thick Layer of
Pea Gravel Diaphragm
Parking/Building
Water Surface
Minimum CDOT
No. 4 Aggregate
Above and Below
PVC Pipe
Undisturbed Soil
CONNECT UNDERDRAIN
TO OUTLET STRUCTURE
POND BASIN
0.608 AC
Survey Area Data: Version 10, Sep 22, 2015
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: Apr 22, 2011—Apr 28,
2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
Hydrologic Soil Group—Larimer County Area, Colorado
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
7/7/2016
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