HomeMy WebLinkAboutDrainage Reports - 07/21/2017Drainage Report
for
BeBee Christian School/Church
2103 Nancy Gray Avenue
Fort Collins, CO 80525
City of Fort Coll' s Approved PINS
Approved by,
Date: 7 2
Prepared by. Mike Beach, P.E.
Project #.16-026-001
Dated: May 4, 2017
RIDGETOP
ENGINEERING & CONSULTING.
5255 Ronald Reagan Blvd, Suite 210 Johnstown, CO 80534
(303) 322-6480 EMAIL: mbeach@ridgetopeng.com
Section
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: -�A
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
2 1 P a g e
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. .
R
45088 =E
'•• .....:
0NA.l
Mike Beach, P.E.
Registered Professional Engineer
State of Colorado No. 45088
3 1 P a g e
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 Timbe'rline,Road ih %ite is
described as above and contains 3.326 acres of undeveloped vacant land `(See Appendix A —
Site Vicinity Map) �� er
1 a:
Existing Condition ..
The existing site is covered by native vegetation and slopes predomiriate,l:towards-South
Timberline Road at approximately 0.5% slope. Stormwater runoff collected into.,aAxisting
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)
4 1 P a g e
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.
5 1 P a g e
Step 4 — Implement Site Specific and Other Source Control EIMP's
The proposed project will contain the following BMP's:
Rain Garden: All runoff from the project 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. Open Grated Nyloplast
structures (or equivalent) tied to the detention pond will be installed one foot above the
bottom of the Rain Gardens that will accept flows above the required WQCV.
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. This report calculates
a required WQCV for a 40 hour release to be 0.046 ac-ft. This volume is accounted for within
the regraded pond and the 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
6 1 P a g e
this project. The revised pond will outlet the WQCV over a 40-hour period as allowed by the
Manual.
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 40 hours for the 100-year event.
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 new plate is designed with
multiple 3/8" diameter orifices to release the WQCV over 40 hours, and a single 4-1/4"
diameter orifice above the WQCV to release the 100-year event at 1.1 cfs. WQCV Orifice design
per Figure EDB-3, Figure 5, and Figure 4 (all from the UDFCD); see Appendix E for Figures. 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 regraded detention pond will have 1.0-ft of freeboard.
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.
7 1 P a g e
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
3.5" diameter orifice plate that will be replaced with a new plate containing a single 4-1/4"
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 and minor grading efforts will be required to obtain the required volume.
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
2-year
Flow (cfs)
10-Year
Flow (cfs)
100-Year
Flow (cfs)
WQCV
(ac-ft)
WQCV
Req'd
100-Year
Vol. (ac-ft)
Detention
Re 'd (ac-ft)
Tot. Volume
Provided (ac-ft)
Release
Rate (cfs)
(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 Untreated
2.73
3.15
5.37
14.58
0.046
0.046
Total Basin
1 5.44
5.77
1 10.02
25.62
1.166
1 1.031
1 1.212
1.1
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.
8 1 P a g e
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
9 1 P a g e
Appendix A
Site Vicinity Map
m
SITE LOCATION
NANCY GRAY AVE.
CHARLES BROCKMAN
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VICINITY MAP
Appendix B
Flood Insurance Rate Map
(Not available to Print)
Appendix C
NRCS Soils Map
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Hydrologic Soil Group—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 day 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
USDA Natural Resources Web Soil Survey 7/7/2016
Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group—Larimer County Area, Colorado
Component Percent Cutoff.- None Specified
Tie -break Rule: Higher
USDA Natural Resources Web Soil Survey 7/7/2016
a" Conservation Service National Cooperative Soil Survey Page 4 of 4
Appendix D
Hydrologic Criteria
10.00
9.00
8.00
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RAINFALL INTENSITY -DURATION -FREQUENCY CURVE
10.00 20.00 30.00 40.00 50.00
STORM DURATION (minutes)
—2-Year Storm - - - 10-Year Storm —100-Near Stonn
Figure RA-16 City of Fort Collins Rainfall Intensity -Duration -Frequency Curves
s
60.00
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)
Duration
(min)
5
2-Year
Intensity
(in/hr)
2.85
10-Year
Intensity
(in/hr)
4.87
100-Year
Intensity
(in/hr)
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
Table RO-11
Rational Method Runoff Coefficients for Composite Analysis
Character of Surface
Runoff Coefficient
Streets, Parking Lots,
Drives:
Asphalt
0.95
Concrete
0.95
Gravel
0.5
Roofs
0.95
Recycled Asphalt
0.8
Lawns, Sandy Soil:
Flat <2%
0.1
Average 2 to 7%
0.15
Steep >7%
0.2
Lawns, Heavy Soil:
Flat <2%
0.2
Average 2 to 7%
0.25
Steep >7%
0.35
Appendix E
Hydraulic Calculations
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Location:
BeBee
Calculated By:
RSB
Date:
10128/2016
Cf =
1.00
RATIONAL METHOD PEAK RUNOOF
Event: 2-Year
Historic Flow Rate
SUB -BASIN
DATA
Direct Runoff
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)A0.7968
A = Drainage Area (ac)
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Location:
BeBee RATIONAL METHOD PEAK RUNOOF
Calculated By:
MRB Event: 2-Year
Date:
3/14/2017
Cf =
1.00
SUB -BASIN
DATA
Direct Runoff
Comments
DESIG:
C
AREA
Ac
C*Cf
tc
min
i
(in/hr)
Q
(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
2.80
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 OnSite
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
and Ext. WQ
0.52
2.73
0.52
9.7
2.24
3.15
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: 3/1412017
Cf = 1.00
SUB -BASIN
DATA
Direct Runoff
Comments
DESIG:
C
AREA
Ac
C'Cf
tc
min
i
(in/hr)
Q
(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 OnSite
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
and Ext. WQ
0.52
2.73
0.52
9.7
3.82
5.37
Q=CfC'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)^0.7976
A = Drainage Area (ac)
Location: BeBee RATIONAL METHOD PEAK RUNOOF
Calculated By: MRB Event: 100-Year
Date: 3/14/2017
Cf = 1.25
SUB -BASIN
DATA
Direct Runoff
Comments
DESIG:
C
AREA
Ac
C*Cf
tc
min
i
(in/hr)
Q
(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 OnSite
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
and Ext. WQ
0.52
2.73
0.64
8.3
8.30
14.58
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)
Equations:
LOCATION:
CALCULATED BY:
PROJECT NUMBER:
DATE:
BASIN:
QD = CiA
V; = T*CiA = T*QD
Vo =m*QPo*(60*T)
S=V; -Va
Rainfall intensity from COFC RA-16 IDF Curve
DETENTION VOLUME CALCULATIONS
RATIONAL VOLUMETRIC (FAA) METHOD
BeBee Christian School
MRB
16-026-001
5/1/2017
Total Basin (Basins 1, 2, Pond, OS-7, and PS-1)
A trib. To pond =
5.440
Cioo =
0.70
Developed C*A =
3.81
QPo =
1.100
tc =
14.3
acre
(C*Cf)
acre
cfs
min
Storm
Duration, T
(min)
Rainfall
Intensity, i
(in/hr)
QD
(cfs)
Vol. In
V;
(ft3)
Outflow
Adjustment
Factor, m
Vol. Out
V.
W)
Storage
S
(ft3)
Storage
S
(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
1 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
1 0.54
6415
36768
0.844
Required Storage Volume: 44916 ft3
1.031 acre-ft
Design Procedure Form: Rain Garden (RG)
Sheet 1 of 2
Designer:
Company:
Date:
Project:
MRB
Location: Basin 1
1. Basin Storage Volume
A) Effective Imperviousness of Tributary Area,1,
1.=
58.0 %
(100% if all paved and roofed areas upstream of rain garden)
B)Tributary Area's. Imperviousness Ratio (1=Id100)
i=
0.580
C) Water Quality Capture Volume(WQCV)fora 12-1hour Drain Time
WQCV=
0.18 watershed inches
(WQCV- 0.8 •10.91- It_ 1.19 • la+ 0.78' II
D) Contributing Watershed Area (including rein garden arse)
Area =
37,297 sq h
E) Water Quality Capture Volume (WQCV) Design Volume
Vwacv=
cu it
Vol = (WQCV / 12) `Area
F) For Watersheds Outside of the Denver Region, Depth of
it, =
0.43 in
Average Runoff Producing Storm
GI For Watersheds Outside of the Denver Region,
Vwocvowee =
57048 on it
Water Quality Capture Volume (WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume
Vwocvusee=
suit
(Only If a different WQCV Design Volume is desired)
2. Basin Geometry
A) WQCV Depth (12-inch mapmum)
Dwacv=
12 In
B) Rain Garden Side Slopes (Z = 4 min., honz. dist per unit vertical)
Z =
4.00 8 / 8
(Use "0' 8 rain garden has vertical wails)
C) Mlmimum Flat Surface Area
Are., -
311 so it
D) Actual Flat Surface Area
A,. Y =
38D soft
E) Area at Design Depth (Top Surface Area)
ATw =
764 so 8
F) Rain Garden Total Volume
Vr=
572 cu it
(VT= ((AT, +A,) / 2) - Depth)
3. Growing Media
Choose One
a 18" Rain Ganlen Growing Media
O Other (Explain):
4. Undemrain System
A) Are underdrains provided?
Choose One
0 TF5
ONO
B) Underdren system office diameter for 12 hour drain time
i) Distance From Lowest Elevation of the Storage
y=
0.0 it
Volume to the Center of me Orifice
il) Volume to Drain in 12 Hours
Vohs=
406 cu it
) Orifice Diameter. 3/8' Minimum
Dn =
1.38 in
UO-BMP v3.03 Basin 1, RG
10/2812016, 9:25 AM
Design Procedure Form: Rain Garden (RG)
Sheet2 oft
Designer: MRS
Company: Rldgetop Engineering
Date: October 28, 2016
Project: Beads Christian School
Location: Basin 1
5, Impermeable Geomembrane Liner and Geotextile Separator Fabric
Choose One
Q YES
A) Is an Impermeable liner provided due to proximity
® NO
of structures or groundwater contamination?
6. Inlet / Outlet Control
Choose one
® Sheet Flow No Energy Dissipation Rer{ulrN
A) Inlet Control
O Concentrated Flow -Energy Disslpntlon provitletl
One
?. Vegetation
O Seed (Plan for frequent weed control)
[Choose
Q Plantings
Q Sand Grown or Other High Infiltration Sod
8. Irrigation
Choose One
Oy5
A) Will the rain garden be irrigated?
Q No
Notes:
U0.BMP_v3.03 Basin 1, RG 10128/2016, 9:25 AM
i Design Procedure Form: Rain Garden )RG) II
Designer:
Company:
Oat.:
Project:
Location:
MRS
R1dg.top Engineering
October 28. 2016
BaBee Christian School
1. Basin Storage Volume
A) EffeclNre Imperviousness of Tributary Area, I,
1„ =
56.0 v
(100% 0 all paved and roofed areas upstream of rain garden)
B) TdbNary Area's Imperviousness Ralio(I=1./100)
-
0.560
C) Water Duality Capture Volume (WQCV) for a 12-how Drain Time
WQCV =
0.18 wafcrshed inrhes
(WQCV= 0.8' (0.91' 1'-1.19 - Is � 0.78' 1)
D) Contributing Watershed Area (including rein garden area)
Area =
80,978 sq h
E) Water Duality Capture Volume (WQCV) Design Volume
Vwocv=
on 0
Vol = WQCV 112) - Area
F) For Watersheds ONSItle of the Denver Region. Depth of
do =
DA3 In
Average Runoff Producing Storm
G) For Watersheds Outside of the Denver Region,
VwacvoTaea =
1.,208.2eu ft
Water Quality Capture Volume WQCV) Design Volume
H) User Input of Water Quality Capture Volume (WQCV) Design Volume
Vwacvusea =
cu it
(Only ge different WQCV Design Volume Is desired)
2. Basin Geometry
A) WQCV Depth (12-inch maximum)
Dwacv =
12 In
B) Rain Garden Side Slopes (Z = 4 min., horiz. that per unit vertical
Z =
4.00 ff / ff
(Use "0' 8 rain garden has vertical wags)
C) Mlmenun Flat Surface Area
A. =
804 >w ff
D) Actual Flat Surface Area
A� =
915 sq ff
E) Area at Design Depth (Top Surface Area)
A, =
1510 so, ff
F) Rain Garden Total Volume
VT=
1.213 ou ff
(VT= ((AT, - A.m.d 12) ' Depth)
3. Graving Media
rnOOH0"!
0 16' pain Garden G oving. Media
Q Otte (Explain):
4. Underdrein System
A) Are underdralns provided?
Ir Cheese One
L C) R0
8) Undardraln system orifice diameter for 12 hour drain time
1) Distance From Lo sest Elevation of the Storage
y=
0.o it
Volume to the Center of the Orifice
Ill Volume to Drain In 12 Hours
Volga=
1,206 on it
ill) Orifice Diameter. 3/8" Minimum
Co =
2.37 in
UD-BMP y3.03 Basin 2, RG 10/28/2016. 11 35 AM
Design Procedure Form: Rain Garden (RG)
Sued 2 of 2
Designer: MRB
Company: Rldgetop Engineering
Date: October 26, 2016
Project: B.S.. Christian School
Location: Basin 2
5. Impermeable Geomembrane Liner and Geotextile Separator Fabric
Choose One
Q YE
A) Is an impermeable liner prodded due to proximity
Q ND
of structures or grounAnter Contamination
6. In at I Outlet Control
r Choose One
I (5 Sheet Flow- No Energy Dissipation acquired
A) Inlet Control
I Q Concentrated Flow -Energy Dlsslpatlon enraged
Choose Once
7. Vegetation
Q sees! (Plan for frequent weed mntml)
Q plantings
Q Santl Grown or Other High Infiltration Sod
B. Irtigation
Choose One
Q YE
Al Will the rain garden be Imlg3ted9
Q NO
Notes:
UD-BMIsv3.03 Basin 2. RG 10/28/2016, 11:35 AM
STRUCTURAL BEST MANAGEMENT PRACTICES DRAINAGE CRITERIA MANUAL (V. 3)
i 0.60
m
, 0.40
E
0
0.2C
r
0
0
O 0.10
I
0.06
0.046 ac-ft
0.04
0.02
0.01
0.02
EXAMPLE: DWO=4.5 it
WOCV = 2.1 acre-feet
SOLUTION: Required Area per
Row = 1.75 in?
EOUATION.
wocv
a K
40
in which,
K40=0.013Dwo +0.22DwO -010
01
s
�
tirl
OeQr
JF
I
I
I
0.04 0.06 0.10 0.20 0.40 0.60 1.0 2.0 4.0 6.0
0.13in^2 Required Area per Row,a (in.2 )
Figure EDB-3-Water Quality Outlet Sizing: Extended Detention Basin (Dry)
With 40-hour Drain Time for Capture Volume
S-62 Rev.612002
Urban Drainage and Flood Control District
DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BMP DETAILS I
3/8" dia. holes at 4"
separation
i
b.•�
lbt
I lt; I
e[I
_
l
r, ra
1/'i
:0 ^
VW.,
f/H
<
Lqp
F.
<'
_
S 1
• 59
II/
c 'I 4
) f
4
4
Figure 5—WOCV Outlets Orifice Perforation Sizing.
Rev. 12/2812004 SD-7
Urban Drainage and Flood Control Distnct
PPOICU: /�PLaGC .j/ckGo//L/i urc�
OESCPIPTION:
Pe. L,46>rc1> ia, 5 -/y. a
5 = /. 33 c rS
(�$ is - ao
(� ,.s- =
x <
65
3.o )- a' x (-).f ,.s _ .2./oZ% cPs
30 = U.�ygcFS
1 oia I "F I a c,) oo-t.r l,J eTr
I a I T (a) D. P4(8
= 3. 317 > l 3 3 UFS c cre r i 5 S u��ie�t �
GATE. �a - �(-�6 PROJECT: ZjPGCK ti
BY: V DESCRIPTION: wee (.-4(3 67 a
C), = a . I a C-�-S
6t /a— a4D
,.s
CPS
E8 0-a
f� = 43 J�acw x Z }}�.s x 4s' O.�yB cps
rtp4al F/oW over
a S cle= i9n,ea
D
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
#DIV10!
Stormwater Detention and Infiltration Design Data Sheet
Lot 18 - Pond 1
Stormwater Facility Name:
Facility location &Jurisdiction: 2590 Midpoint Dr, Fort Collins
User (Input) Watershed Characteristics
Watershed Slope =
0.020
ft/ft
Watershed Length -to -Width Ratio=
2.00
LW
Watershed Area=
5.44
acres
Watershed Imperviousness =
52.0%
percent
Percentage Hydrologic Soil Group A =
0.0%
percent
Percentage Hydrologic Soil Group B =
0.0%
percent
Percentage Hydrologic Soil Groups C/D =
100.0%
percent
User Input: Detention Basin Characteristics
WQCV Design Drain Time = 40.00 hours
After completing and printing this worksheet to a pdf, go to:
hnps;/Zmapenure.digitaidatasemices.com/vh/?viewer=cswdif.
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Design Storm Return Period -
Two -Hour Rainfall Depth -
Calculated Runoff Volume
OPTIONAL Override Runoff Volume
Inflow Hydrograph Volume
Time to Drain 97% of Inflow Volume:
Time to Drain 99%of Inflow Volume
Maximum Podding Depth
Maximum Podded Area
Maximum Volume Stored:
User Defined
Stage lei
User Defined
Area(ft-21
User Defined
Stage lftl
User Defined
Discharge Icfsl
0.00
1
0.00
0.01
0.60
40
0.60
0.01
1.60
2,990
1.60
0.01
2.60
6,291
2.60
1.10
3.60
8,052
3.60
1.10
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
Routed Hvdrneranh Results
WQCV
2Year
5Year
30 Year
25 Year
50 Year
100 Year
0.53
0,98
1.36
1.71
2.31
2.91
3.67
OD95
0.219
0.373
0.518
0.791
1.043
1.393
0.094
0.218
0.372
0.528
0.791
1.043
1.392
38
35
32
29
23
18
17
40
40
40
40
40
40
40
1,99
2.62
3.41
4.09
5.19
6.05
7.11
0.098
0.145
0.177
0.206
0.254
0.295
0.348
0.067
0. 144
1 0.271
0,402
0.654
0,890
1.230
in
acre-ft
acre-ft
acre-ft
hours
hours
ft
acres
acre-ft
Drain times Pond 1, Design Data 5/1/2017, 9:55 AM
LStormwater Detention and Infiltration Design Data Sheet
35
100YR IN
— 100YR OUT
30
25
10
5
0
0.1
8
—100YR
6
�5
z
a
c
zq
C
z
0
a
3
2
1
0
0.1
0
1
TIME [hr)
10
1 30 100
DRAIN TIME [hr]
Drain times Pond 1, Design Data 5/1/2017, 9:55 AM
Location:
Calculated By:
Date:
CLG`8
100-Year WSEL =
PROPOSED DETENTION POND - STAGEISTORAGE
Pond: 1.0
Babes - Proposed WQ 8 Detention Pond
MRB
5/1/2017
V = 1/3 d (A+ B+sgrt(A•B))
V = Volume between Contours, ftA2
d = Depth between Contours, ft
A = Surface Area of Contour, ftA2
Stage
(ft)
Surface
Area
(ftA2)
Incremental
Storage
ac-ft
Total
Storage
ac-ft
Detention
Storage (ac-
ft
4936.4
0
4937
40
0.000
0.000
4938
2990
0.026
0.026
4938.27
3521
0.020
0.046
0.000
4939
6291
0.081
0.127
1 0.081
4940
8052
0.164
0.291
0.245
4941
9922
0.206
0.497
0.451
4942
11913
0.250
0.748
0.702
4943
14033
0.297
1.045
0.999
4943.5
15142
0.267
1.213
1.166
4944
16283
0,180
1.393
1.347
4944.5
17448
0.194
1.586
1.540
Required Detention Volume =
1.031 See "Detention Volume Calculations" this report
Provided Detention =
1.166
Required WQCV =
0.046Per "StantecReport" WQ=0.033,Per calcsthis
Provided WQCV =
0.046 report WQCV = 0.046
Total Required Volume =
1.077
Total Volume Provided =
1.212
Orifice Calculations (Detention)
BeBee School/Church
5/1/2017
A = Area of Orifice (ftA2)
Q = orifice flow rate (cfs)
H = effective head on each orifice opening (ft)
C = Discharge Coefficient (0.60 for square edges)
g = Gravitational acceleration constant (32.2 ft/secA2)
Q = CA(2gH)A0.5
A = Q/(C(2gH)A0.5
100 - Year Detention Orifice
Q (cfs) = 1.100
H (ft) = 5.24
Eq 12-19 UDFCD
(Total Pond height minus WQ depth)
Total Area (sq-in) Diameter (in) Standard Size Dia. (in)
A = 1.1/(0.6((2*32.2*5.24)A0.5)) 14.37 4.28 4-1/4" Orifice
Diam. = 2*(A/3.14)A0.5 Match existing IE
,.
Appendix F
Maps
151Page
T ---- "- I
_J J
DURET 12 X12' OPEN GRATED '
NYLOPLASi AREA DRNN'DR EQUIVALENT) OUffALL - OS' DEEP.
ELEVATED 1 FT ABOVE ROAD BOTTOM ! 5' WIDE 0 1% '
PIPE 07.2R '
/{ �1,dCA,�
I
PERFORATED
PIPE
I�
L{jL�Ni �ILi ]II 'I
ih II -I li ILL i( 10`
II
ADS 261 LF 6•
ill xll 111 II��I JJII :I. PIPE 00.5R
- III Ill III
I l Il.:f lr W.
lt.
�, III
I
II
•.l
'•SCHOOUCHURCH
±26.200 SF RAIN GARDEN 2
NOL. REWIRED: 1,206.2 CP
• I'I'
J
FFE: 49450 VOL. PROVIDED: 1.213.0 OF
BOTTOM
I
EL 4944.0
TOP El: 4945.0
)
I
SEE DEEM MS SHEET
1 PI
ROOF GRAIN SEE BASIN 1 OUTFALL - 0.5• DEEP
III
ARCH PLANS s 2' WIDE 0 IR
(..- FOR DETAILS 0.856 AC '', RAIN GARDEN 1
' III
1 VOL REWIRED: 570.8 OF _ I
267 LF fi• ADS `NL. M04ED: 572.0 OF
PIPE 0 0.5R BOTTOM EL: 4944,0
111/
I
TOP EL: 49450
III
- SEE GETAI MIS SHEET
1
P
- )•II I
..
I_... CLEANO7 .. lI I I
N n I
I
I
4»2-
I
__ _ jJI _ ___ __
.. ......... ..... ....,
F
Y
I
OUTLET - 12'X12-
f PERFORATED OPEN GRATED
PIPE NY.OPLAST AREA
DRINK (OR IP
EQUIVALENT)
ELEVATED'I-FT j
ABOVE POND BOT10M
POLICE STATION BASIN
0.88 AC
PER REPORT RILED 'FINAL DRAINAGE AND EROSION
CONTROL REPORT FOR THE CITY O FORT COLONS NEW
POLICE SERVICES BUILDING DATED FEBRUARY 23, 2006.
BIORETENTION SAND MEDIA SPECIFICATIONOTY OF FORT MONS
PART I - GENERAL
A SIORETENTION SAND MEDIA (BSM) SHALL BE UNIFORMLY MIXED, UNCOMPACTED. FREE ET STONES,
5. TOPSOIL SHALL HAVE A PH RANGE OF 5S TO 7.5 AND MOISTURE CONTENT BETWEEN 25-55R
STUMPS. ROOTS, OR OTHER SIMILAR OBJECTS LARGER MAN TWO INCHES, NO OTHER MATERIALS
6. CONTRACTOR SHALL CERTIFY THAT TOPSOIL MEETS THESE SPECIFICATIONS.
SUBSTANCES SHALL BE MIXED OR DUMPED YARN ME BIMETENTION AREA THAT MAY BE
0. LEAF COMPOST
HARMFUL TO PLANT GROWTH OR PROVE A HINDRANCE 7O THE FACILITYS FUNCTION AND
1. BSM SHALL CONSIST OF 10-20R LEAF COMPOST BY VOLUME.
MAINTENANCE.
2, LEW COMPOST SHALL CONSIST O CLASS 1 ORGANIC LEAF COMPOST COI OF AGED
B. BSM SHALL BE FREE OF PLANT OR SEED MATERIAL O NON-NATIVE, INVASIVE SPECIES, OR
LEAF MULCH RESULTING FROM BIOLOGICAL DEGRADATION AND TRANSFORMATION OF
WEEDS.
PLANT -DERIVED MATERIALS UNDER CONTROLLED CONDIRONS DESIGNED TO PROMOTE AEROBIC
C. FULLY MIXED BSM SHALL BE TESTED PRIOR TO INSTALLATION AND MEET ME FOLLOWING CRITERIA
DECOMPOSRON.
1. P-INDEX OF LESS THAN 70
J. ME MATERIAL SH&L BE WELL CCMPOStED, FREE Of VIABLE WEED SEEDS AND CONTMN
2. PH OF 5.5-6.5. SHOULD PH FALL OUTSIDE OF THE ACCEPTABLE RANGE, IT MAY BE M001RED
MATERIAL OF A GENERALLY HUMUS NATURE CAPABLE OF SUSTAINING GROWTH O VEGETATION,
WITH LIME (TO RAISE) OR IRON SULFATE PLUS SULFUR (TO LOWER) THE LIME OR IRON
WITH NO MATERIALS TOXIC TO PLANT GROWTH.
j SULFATE MUST BE MIXED UNIFORMLY INTO THE BSM PRIOR TO USE IN ME BIORETENTION
4. COMPOST SHALL BE PROVIDED BY A LOCAL US COMPOSTING COUNCIL SEAL OF TESTING
FAOUTY.
ASSURANCE (STA) MEMBER. A COPY OF THE PROVIDER'S MOST RECENT INDEPENDENT SIX TEST
3, CATION EXCHANGE CAPACITY (CEC) GREATER MAN 10
REPORT SHALL BE SUBMITTED 10 AND APPROVED BY RE OMER PRIOR TO DELIVERY O BSM
4. PHOSPHOROUS (PHOSPHATE, P205) NOT TO EXCEED 59 PPM
TO ME PROJECT SITE.
5, BSA THAT FAILS 10 MEET ME MINIMUM REQUIREMENTS SHALL BE REPLACED AT THE
5. COMPOST MATERIAL SHALL ALSO MEET THE FDLOYANG CRITERIA:
a 100 PERCENT O ME MATERIAL SHALL PASS THROUGH A 1/2 INCH SCREEN
CONTRACTOR'S EXPENSE.
bBETWEEN 6.0 A
. PH O THE MATERIAL SHALL BE AND B/
4, BSM SHALL BE DELIVERED FULLY MIXED IN A DRUM MIXER. ONSITE MIXING OF PIES WILL NOT
GE ALLOWED. MIXING OF ME BSM TO A HOMOGENEOUS CONSISTENCY SHALL BE DONE TO THE I
c POSTURE CONTENT SHALL BE EEBETWETWEEN 35 AND 50 PERCENT
SATISFACTION O ME OWNER.
d. MATURITY GREATER MAN 80 PERCENT (MATURITY INDICATOR EXPRESSED AS PERCENTAGE
Of GERMINAFON/VIGOI BM/BOA)
PART 2 - SOIL MATERIALS
e. MATURITY INDICATOR EXPRESSED AS CARBON TO NITROGEN RATION < 12
A. SAND
I. MATURITY INDICATOR EXPRESSED AS AMMONIAN/NIMATEN RATIO <4
I. BSM SHALL CONSIST O 60-70% SAND BY VOLUME MEEIING ASTM C-33,
g. MNII ORGANIC MATTER SHALL BE 40 PERCENT DRY WEIGHT BASIS
B. WEDDED PAPER
R. SOLUBLE SALT CONTENT SHALL BE NO GREATER THAN 55M PARTS PER MIWON OR 0-5
1. 8SM SHALL CONSIST O 5-10% SHREDDED PAPER BY VOLUME.
MMHOS/CM
2. SHREDDED PAPER SHALL BE LOOSELY PACKED, APPROXIMATE BULK DENSITY OF 50-100
I. PHOSPHORUS CONTENT SHALL BE NO GREATER MAN 325 PARTS PER MILLION
LBS/CY.
1 HEAVY METALS (TRACE) SHALL NOT EXCEED 0.5 PARTS PER MILLION
3. SHREDDED PAPER SHALL GANSS7 OF LOOSE LEAF PAPER, NOT SHREDDED PHONE BOOKS,
k. CHEMICAL CONTAMINANTS. MEET OR EXCEED US EPA CLASS A STANDARD, 40 OR 50113,
AND SHALL BE THOROUGHLY AND MECHANICALLY MIXED TO PREVENT CUUMPNG.
TABLES I do 3 LEVELS
C. TOPSOIL
L PATHOGNI MEET OR EXCEED US EPA CLASS A STANDARD, 40 OR 501 LEVELS
1. BSM SHALL CONSIST O 5-10% TOPSOIL BY VLUME,
2. TOPSOIL SHALL BE CLASSIFIED AS SANDY LOAM, LOAMY SAND, OR LOAM PER USDA TEXTURAL
PART 3 - EXECUTION
TRIANGLE RIM LESS THAN SR CLAY MATERIAL.
A. GENERAL
1 ONSTE, NATIVE MATERIAL SHALL NOT BE USED AS TOPSOIL
1. REFER TO PROJECT SPECIFICATIONS FOR EXCAVATION REQUIREMENTS.
4. TEXTURAL ANALYSIS SHALL BE PERFORMED ON TOPSOIL PREFERABLY Al ITS SOURCE, PRIOR
B. PLACEMENT ME MOD
TO INCLUDING TOPMIL IN ME MIX, TOPSOIL SHALL BE FREE O SUBSIL, DEBRIS. WEEDS,
1. BSM MATERIAL SHALL BE SPREAD EVENLY IN HWZO1l LAYERS. '
FOREIGN MATTER, AND ANY OTHER MATERIAL DELETERIOUS TO PLANT HEALTH.
2, THICKNESS OF LOOSE MATERIAL IN EACH LAYER SHALL NOT EXCEED 9-INCHES
'
C. COMPACTOR OF BSM MATERIAI IS NOT REWIRED.
� I
t `I
1
11 .
EXISTING OUTLET TO BE MgXHED
SEE DETAES ON SHEET C-4.2
IE = 4936.40
WO ORIFICE = SEE DETAIL SHEET C-4.2
100-YR ORIFICE = (1) 4-1/4•• (1.1 CFS)
jPOND BASIN
0.608 AC
Ben
BOTTOM ELEVATION0/0
WO VOL,REQUIRED:
.04 0046AC-Fi
WC VOL,PROVIDED. 0.046 AC -FT
10 OUSEL . REQUI
100 YR OROWED L031 AC -FT
IOU YR OCT.NDVOLRED 1166 AC-F1
TOTAL POND OL. FROUIM 1212 AC -FT
Q TOTAL PONARD L; 4 44.50 O: 1.212 AC -FT
FREEBOARD E4 4944.50
LU in
Z
ILL
ILL
M
m
WATER -QUALITY TREATMENT LEGEND
BASIN BOLNOARY
100-YR WSEL,
I
�. fSl�m1I13FCD]i���
Surface
2 12" bonding Depth
F_
N Inlmum 12" Thick Layer
of Bloretentlon Sand Media
CONNECT UNDERIERAIN
(see Sioretentlon Sand
TO OUTLET STRUCTURE
Media Specification below)
1
Inlmum 6" Thick Layer of
Pea Gravel Diaphragm
Minimum COOT
No. 4 Aggregate!/
Above and BelDw \.
inimum 8" Thick Layer of
PVC Pipe \ h
COOT No. 4 Aggregate
T UnOistu betl Soil
Inlmum 4" Perforated
PVC Pipe (Optional
Depending on Underlying '
-
Soil Conditions)
BIORETENTION CROSS
SECTION
MODIFIED FROM FORT COWNS STANDARD DETAIL D-53
100160n511e Treatment by LID Rbu mend
NOW Impervbus Area
69A60 sq. R.
Required Minimum Impetuous Area W be Treated
69,460 sq. ft.
Ma Treated by Ran Garden (Basin 1)
22,793 so. ft.
Area Treated by Ran Garden (Bash 2) .
46,667 MI. h.
Run-on Area
0e4.A
Impervious Ares by LID Treatment
69.460 sq. ft:
Actual%On-bite Treated by LID
100%
01 Parus Pavement Rs uded
'Nov P. on, Ate.
0sq. ft.
Required Minimum Area of Pone Pavement
0 sq. ft.
Pow Pavement Arse
0 sq. ft.
Run-on Area (up to 3:1 allowed)
. 0 u, ft.
Total Paw Pavement Area
0 sq. f.
Actual % of Porus Pavement P.Wim,
eDIVAR
2 man . so IL
CITY OF FORT COLLINS, COLORADO
UTILITY PLAN APPROVAL
APPROVED:__________
CITY ENGINEER DATE
CHECKED BY: ---- _--- _- -------- ----- --
WATER & WASTEWATER UTILITY DATE
CHECKED BY:
STORMWATER UTILITY DATE
CHECKED BY:______
PARKS AND RECREATION DATE
CHECKED
TRAFFIC ENGINEER DATE
Rives G o
ENGINEERING & CONSULTING
62ss Ama2 eeae.,, WAN. 1 I.1.1 .m
W. 210 w ,Eylgae-
2a.me.RLnMsa.
BEEBE CHRISTIAN
SCHOOLAND
SEVENTH.DAY
ADVENTIST CHURCH
2103 NANCY GRAY AVE.
FORT COLLINS, CO ,
ROCHE
CONSTRUCTORS
361 71ST AVE.
GREELEY. CO
DEVELOPMENT PLAN
DRAM BY
B6P/R6B
CNECNEO BY:
MRB
PROJECT NO.:
160264101
CITY COMMENTS
11128/21,I8
LIFT COMMENTS
01 N31M1]
CITY COMMENTS
0YI84017
01 /11 /2017
DRAINAGE
PLAN
5
C-2.1
9 Of 13
I.SwNT W.wele4ou0nlwn,dauw,�l.,•M11Hf�.iolawlwY vul lTW).Pwnllk.. •tsdaWmlMrN
if MwP a.A..lAtslw MWrr W1MNN(.MemAd sl4r.«.wmMaraw.
A fAw aurMnwn. a o.•MT i W 4Mtlm G W Aen r.nwt PTw Imd.ka
41AVA4wvWPmA•• nu.MpT ),I' h6,.6ov W.M.Wrtn w<al.m.ywm.l)4.rnl+0lgkum+hiwrwpmra)
5. Po.bn.uedT•*Inl nu<uwen Mi4do.wr.mrrdaYw.
IERGTHOP PTRO1EC110N
I- �,•�,r,o,[1 wmnlaarorEcrK)N-
I + A Tr7r1 r�,f+ 7T. T ve,ls•. e.wrs
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AMAr...fw,.MwM.
WMAWAY
P-au+Ne w•WmI . r r '^TIFF -�- d 1N= .�.•wn n, a..w�n��.
CULVERT OUTLET PROTECTION -PLAN VIEW
MAIL. I-.Y DROP
rRurF O,R np�i1K
WRIfT AGCIWM.Il1YMIRPROrECImN
fir^ RRAI[yM1CN M[91 ^w� �-
Iu.N•r.noM•r,•,�r
•^-_
SECTION VIEW AA wR
PROFILE VIEW
I. ._ .T. _. .I
--�
g rt ll�
ANCHOR PATTERN
.m V.n>..me.MMw.n.aA.-Iw
ANCHOR ILLUSTRATION
AQAWNAAWWAAPW" WWA,WMWNN
f aRnPwW
IwuNw.•.R•M.n...am.arrW..
VM.. 4.>A-nl. IMw. RY
fw.Y[W.n=WWA_AWYW.
MY.naON YYnbL MA-s.LLo[.
[,aseM•avM fw,n rl Ardu.
W.nNrn!w WA.WWWn MYphr WA_
n, .AECuEO ru .MXL.a4%IIr6z.mD2ieOW9Cxa AA.-scoutop°
T ,W� 1,xm.1M..B.mrlwwcllNem+1»
SCOURSTOP DETAIL
N.T.S.
FORT COLLINS ONLY
L �
SAPP
ec�cccre�"• 42- BICYCLE RACK IN EXISTING BRICK PAVERS
SET IN SAND ON CONCRETE
6+
Ilrogr+ _ '�EG{II
I Ir I
42' BICYCLE RACK IN EXISTING BRICK PAVERS
SEf IIV SAND ON GRADE
BICYCLE RACK DETAILS
LAN34P.R CoIINIY CONSIRIiCTIOv RRT'ov NO: BRAWLNC
Avo4Ros oRAmvo9 OATS: oe/or/oo 1706E
BIKE RACK
N.T.S.
ETcI
4 aiwi'i enu�
E
9 !4
SINGLE POST
NOTES:
I. ALL VMS SNALL COMPLY WITH U.S. DEPARTMENT OF TRANSPORTAnW, FEDERAL HIGHWAY
ADMINOTRATONS 'MANUAL OF UNIFORM TRAFFIC CONTR0. DEMCES". LOCAL CODES AND AS SPECIFIED. -
uOUNT SIGNS TO POST IN ACCORDANCE MTH MANUFACTURER'S INSTRUCTIONS
2 GALVANIZED SWARE NEE riuraa EMT En [a
POST TUBES - 2".MEET 6' t2A O -
POST TUBE OHAL1 ZED AS1M A1011 A653 50
POST TUBE GALv4xIZE0 AS PER AS1M A65] GRADE 90.
fA0.M RM•Q WJT r.lx f]A
ANCHOR NBE - 2-1/4',2-1/4'l,3/I6" 12go
HEAVY DUTY ANCHOR NBE SHILL MEET ASTM A500 GRADE B. [u�g•^' °O
STRUCTURAL NBE WHO STEEL SHALL BE HOT DIP GALVANISED PER ASTM A123. n'•"'"[• • •• �•
SQUARE TUBE BREAK AWAY POST SIGN LOCATIONS - 90' PARKING
THE UPPER SICK POST SHAH TELESCOPE INSIDE THE ANCHOR TUBE 4 MINIMUM OF tr. THE ANCHOR .n
NBE SHALL BE A MINIMUM 27" OUR WITH 3 AN. MAX. EXPOSED ABOVE RNISI MADE.
SIGN MOUNTING AND BASE WITHOUT BOLLARD
- (USE WHERE SIGN IS WITHIN CURBED ISLAND)
3D'
O
STANDARD LSD AND WHITE SGN
R5-1
'00 NOT INTER'
SON
N, T.S
w �'iii'' •i'i . '• v 4i•'•if••"O 111111111
.�i•Jiiii•'
mmogill
'�ii�%•%�ii'%%tOiO��i•�i'JJi%�•J��'��•'•'••%i3i�
10 • •�JA•ii•�F�•�•i i� ♦..��`�•J •• 6,,��••J•.A•ii' Ody •O
)•J •i• •Jd•��•�Q.•iO�a�i�J••i�%i•'Jai J•�• • A�•�•�ii�
di�ilidM����i������O�i�•�•••••� • p•�•'�'yi�• �• •�• Tip i�i
IIIII�I CHAIN LINK
�7 I�
CHAIN LINK FENCE DETAIL
N.T.S.
SIGN MOUNTING AND DETAILS
N.T.S.
BwNig- I
RROIGNAY
74"
Ill SKN IERFRS m COMPLY NM srNOND
.Au N AM "GOAT 90"S (SEWS C =1
YA PMI6110 - ITS
EMERGENCY
VEHICLES
ONLY
IYRc•111�ILY wa6 OlY
� IEE)0 Ox
Wh BAOIQYIM
N.i.S
•AGM ro G1E 84A IMT M:CFSYAY
�6•
4-1/4' PERFORATION E 493&27 S6,
REMOVE EXISTING STEEL PLATE INSTALL
NEW 1/4' STEEL PLATE ENSURE
FIELD
V4mFY
FIELD
TOP OF STRUCTURE REMOVE EXISTING STEEL PLATE INSTAL I' MS
SECURE TO OUTLET STRUCTURE
r—�
�t4g3&g
NEW 1/4' STEEL PLATE INSURE
- PLATE PER COFC D-46
_
PB STRUCTURE
TO OUTLET STNUCNRE
BOTTOM
I
N
WOUQV: DO6.40
WC VOL PROADED 0.046 AC -FT I
I I
Z-
WC VA PROVIDED: 0.046 AC -FT I "
WE WSEL I C'
$
IDO-YR DET.REQUIRED 1.031 AC-Fl
IW-YR DEi. PROMTIED: 1.166 AC-n
TOTAL POND VOL REWIRED: 1.077 AC -FT I
TOTAL POND VIA. PROMDEO 1.212 AC -FT n I 3
3/8' DIA PERFORATOR `POND BOTTOM: 4936.40 4-1/4' DNA. PERFORATION
IL 4936.40 IF 4938.26
REPLACEMENT WQCV FLOW CONTROL PLATE REPLACEME�
NIS
SEE LaC DETAIL D-46 FOR WELL SCREEN AND
ORIFICE PUT: REWIREMENTS
THE EXISTING STRUCTURE MUST BE
RET2OTT/LPGRADfD. A NEW SMUCNRE IS NOT
REWIRED
a Gum MET
TOP 6 DRYING SUMA)M: W)AW
RDA fO1T0.1 aArt
MP' H
D)SD4 N' WTIET M
VEIL ARFN
rys RIFA srMxIESS
I[O-IN MOfT UIRCE
SIFT Q EWA)
o-M
ATE(11fD1116
4F IWTA
9W[D
PB• WTIOL MILO
ON
Y b' WREN L 4M2W
RETROFIT
POND OUTLET STRUCTURE
TOP OF STRUCTURE
l493&B
Mum: 4936.40
Pff. RWm RNA, r f3]T RtHBO
SM.,L) w ,axlN>ma.can
.,WYA W WSH ,
BEEBE CHRISTIAN
SCHOOLAND
SEVENTH DAY
ADVENTIST CHURCH
2103 NANCY GRAY AVE.
FORT COLLINS, CO
ROCHE
361 71 STAVE.
GREELEY, CO
DEVELOPMENT PLAN
DRAM BY:
SSAMSB
CHECKEDBY:
MRB
PROJECTNO.:
16036001
CITY COMMENTS
imsCu16
CITY COMMENTS
OIMM17
CITY COMMENTS
0411 17
CITY OF FORT COLLINS. COLORADO
nATF
UTILITY PLAN APPROVAL
01111 /2017
APPROVED:
CITY ENGINEER
DATE
_5HEELTITLE
CHECKED BY:_
WATER k WASTEWATER UPUTY
____
DATE
DRAINAGE
DETAIL SHEET
CHECKED BY:
STORMWATER UTILITY
DATE
ARMw
CHECKED BY:
C-4,2
PARKS AND RECREATION
DATE
CHECKED BY:_—______--
TRAFFIC ENGINEER
DATE
Appendix G
References
161 Page
' ISPRING CREEK FARMS NORTH
J
11
LJ�
L
P
B. Specific Details
Ponds 5 and 8 will provide a water quality capture volume as follows:
Pond
WQCV (ac-ft)
Water surface elevation
5
.067
4939.70
8
.033
4940.84
Please refer to Appendices calculations.
VI. EROSION CONTROL
A. General Concept
This development lies within the Moderate Rainfall Erodibility Zone and the
Moderate Wind Erodibility Zone per the City of Fort Collins zone maps. There
should be minimal to no erosion problems after completion of the Spring Creek
Farms development. Silt fence will be installed along the north, east and south sides
of the site to prevent sediment from leaving the site. Tracking pads will also be
placed at entrances/exits to the site:
The Erosion Control Plan may be found in Appendix 8.
B. Specific Details
A silt fence shown on the erosion control exhibit will be installed prior to grading.
All disturbed areas -not in a roadway or greenbelt area shall have temporary
vegetation seed applied within 30 days of initial disturbance. After seeding, a hay or
straw mulch shall be applied over the seed at a rate of 1.5 tons/acre minimum, and
the mulch shall be adequately anchored, tacked, or crimped into the soil. Those roads
that are to be paved as part of the Spring Creek Farms project must have a 1-inch
layer of gravel mulch applied at a rate of at least 135 tons/acre immediately after
overlot grading is completed. The pavement structure shall be applied within 30 days
after the utilities have been installed.
If the disturbed areas will not be built on within one growing season, a permanent
seed shall be applied. After seeding, a hay or straw mulch shall be applied over the
seed at a minimum rate of 1.5 tons/acre, and the mulch shall be adequately anchored,
tacked or crimped into the soil. In the event a portion of the roadway pavement
surface and utilities will not be constructed for an extended period of time after
11
unofficial copy was downloaded on Dec-07.2016 from the City of fort Collins Public Records Website: http://citydocs.fcgov.com '
.dditional information or an official copy, please contact City of Fort Collins.Utilities 700 Wood Street Fort Collins, CO 80524 USA -
Spring Creek Farm: Pond 8
Detention Pond Volume Rating Curve
4934
39
0.00
0.000
0.000 _
-
4935
1,708
0.04
0.015
0.015
4936
3,006
0.07
0.053
0.069
4937
4,741
0.11
0.088
0.157
4938
6,617
0.15
0.130
0.286
4939
8,517
0.20
0.000
0.286
4940
10,546
0.24
0.218
0.505
4941
12,722
0.29
0.266'.
0.771
4942
15,005
0.34
0.318
1.089
100.year WQCEL+ WSEL =
; i •
Volume Required = 0.505
acre-R.
1110-year WQCEL =
Water Surface Area = ' 0.242
acre
(
Volume Required = 0.032
acre ft
V = 3 d(A+B+�
water Surface Area = 0.051
acre
where:
V = volume between contour interval
Volume Required tao-r ws¢ = 0.47 acre-ft.
d = elevation - elevation, ,
TOTAL VOLUME (WSEL+WQCEL) 0.60 acre-iL
A = area of elevation t contour
Volume Provided= 1.089 acre-ft.
B = area of elevation,, contour
The Sear -Brown Group
his unofficial copy was downloaded on.Dec-07-2016
or additional information or an,official copy, please a
12:33 PM
6182005
Collins Public Records Wcbsite: kUp:/)city'docs:fcgov.com
Ilins:Utilities 700: WoodStreeffort Collins, CO 80524 USA -
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unofficial copy was downloaded on Dec-07-2016 from the -City of Fort Collins Public Records Website:
dditional information or an official coos. olease contact City of Fort Collins Utilities 700 Wood Street F,
11
P
Design Procedure Form:
Designer:
Company:
Date:
Project:
Location:
Detention Basin (EDB) - Sedimentation Facility
Sheet 1 of 3
Andrea McDaniel
Stantec
December 15, 2004
Spring Creek Farms
Fort Collins, Pond #8 _
1. Basin Storage Volume
I, =
6.30 %
'
A) Tributary Area's Imperviousness Ratio (i = I, / 100)
i =
_ •_Oi06; - {
B) Contributing Watershed Area (Area)
Area =
7.29 acres
'
C) Water Quality Capture Volume (WQCV)
WQCV
0 04 ';watershed inches
(WQCV =1.0 ' (0.91 ' 13 - 1.1912 + 0.78.1))
D) Design Volume: Vol = (WQCV / 12) • Area ' 1.2
Vol =
_
fi. "0.033 r' acre-feet
2. Outlet Works
'
A) Outlet Type (Check One)
X
Orifice Plate
Perforated Riser Pipe
Other.
B) Depth at Outlet Above Lowest Perforation (H)
H =
1.50 feet
'
C) Required Maximum Outlet Area per Row, (A,)
A. =
; 010-, y square inches
D) Perforation Dimensions (enter one only):
Circular Perforation Diameter OR
D =
0.3700 inches, OR
ii) 2" Height Rectangular Perforation Width
W =
inches
E) Number of Columns (nc, See Table 6a-1 For Maximum)
nc =
1'a':'_ j number
'
F) Actual Design Outlet Area per Row (A,)
A. =
square inches
G) Number of Rows (nr)
nr =
t', ,_7—'6: " 4 number .
':,
H) Total OuUetArea (A,J
Aa=
���;A_48_�7._,)square inches
'
3. Trash Rack
A) Needed Open Area: At = 0.5' (Figure 7 Value)' A,,
A, _
'4`18- - square inches
'
B) Type of Outlet Opening (Check One)
X :
< 2" Diameter Round
r_ _2"
High Rectangular
Other.
'
C) For 2", or Smaller, Round Opening (Ref.: Figure 6a):
i) Width of Trash Rack and Concrete Opening (W.)
from Table 6a-1
W _
,; 3 : ' _,inches
'
is unofficial copy was downloaded on Dec-07-2016 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com -
or additional information oran official, copy, please contact:City of Fort Collins Utilities 700 Wood' Street Fort Collins;: CO 80524,USA _.
ii) Height of Trash Rack Screen (HTR)
HTR = y .,,'A2; „inches
Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility
Sheet 2 of
Designer.
Andrea McDaniel
Company:
Stantec
Date:
December 15, 2004
Project
Spring Creek Farms
Location:
Fort Collins, Pond #8
iii) Type of Screen (Based on Depth H), Describe if "Other"
iv) Screen Opening Slot Dimension, Describe if "Other"
v) Spacing of Support Rod (O.C.)
Type and Size of Support Rod (Ref.: Table 6a-2)
vi) Type and Size of Holding Frame (Ref.: Table 6a-2)
D) For 2" High Rectangular Opening (Refer to Figure 6b):
1) Width of Rectangular Opening (W)
ii) Width of Perforated Plate Opening (W. = W + 12")
iii) Width of Trashradc Opening (W,p,-;n8) from Table 6b-1
iv) Height of Trash Rack Screen (HTR)
v) Type of Screen (based on depth H) (Describe if "Other")
vi) Cross -bar Spacing (Based on Table 6b-1, ldemp' KPP
Grating). Describe it "Other"
vii) Minimum Bearing Bar Size (laempTm Series, Table 6b-2)
4. Detention Basin length to width ratio
5 Pre -sedimentation Forebay Basin - Enter design values
A) Volume (5 to 10% of the Design Volume in 1 D)
B) Surface Area
C) Connector Pipe Diameter
(Size to drain this volume in 5-minutes under inlet control)
S.S. #93 VEE Wire (US Filter)
Other:
"10.139" (US Filter)
Other:
finches
W = f - , { inches
- �,—; t.
W,,,,,= t=:^..,.�� .,inches
W, !inches
Hrn ._"inches
10empTA° KPP Series Aluminum
Other.
3inches
Other.
acre-feet
acres
inches
unofficial copy was downloaded on Dec-07-2016 from. the City of Fort Collins Public Records. Website: hup://citydocs.fcgov.com
dditional information or an official copy, please contact City. of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 US.
C
H
l 1
11
P
'
D) Paved/Hard Bottom and Sides
I yes/no
I
Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility
Sheet_ 3 of 3
Designer. Andrea McDaniel
Company. Stantec
Date: December 15, 200.4
Project: Spring Creek Faints
Location: Fort Collins, Pond #8
6. Two -Stage Design
A) Top Stage (Dv4o =-2' Minimum)
D,,vo = feet
Storage= acre-feet
B) Bottom Stage (Des = Dk,,,o+ 1.5' Minimum, Dwo + 3.9 Ma)imum,
Des = feet
Storage = 5% to 15% of Total WQCV)
Storage= acre-feet
Surf. Area LQ 1,, acres
C) Micro Pool (Minimum Depth = the Larger of
Depth= feet
0.5 ' Top Stage Depth or 2.5 Feet)
Storage= acre-feet
Surf. Area=))E- ° ° !Xacres
D) Total Volume: Volt = Storage from 5A + 6A + 66
Must be> Design Volume in I
Vol, acre-feet
7. Basin Side Slopes (Z, horizontal distance per unit vertical) ,
Z = _ _ - _ (horiiontaltvertical)
Minimum Z = 4, Flatter Preferred
8. Dam Embankment Side Slopes (Z, horizontal distance)
Z = (horizontaVvertical)
per unit vertical) Minimum Z = 3, Platter Preferred
9. Vegetation (Check the method or describe "Other")
Native Grass
Irrigated. Turf Grass
Other:
Notes:
LLLJ
unofficial copy was downloaded on Dec-07-2016 from the City of Fort Collins Public Records
additional information or an official coos, please contact City of Fort Collins. Utilities 700 Wooc
5Pht'kict C2F, I - �'--
Staactec
L v
1u=1! m?is _ l�n;-.•t...•r.l<_
N(st�:�1c. Q-rLE-�E La') = la l cfs q = 3Z2
n=TY2 D=zr
l" I cts * = 13.L,4 � Ws
_ ff^,� 2 _ ))P
1D=
Designed by 4 F r i s Checked by
on official copy was downloaded on Dec-07-2016 from the City of Fort Collins Public RecordsWetisite: http://citydocs.fcgov.com
additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA
Project: Spring Creek Farms
Location: Pond 8 Spillway
Broad Crested Weir - Basic Equation:
Q = C*LeHi.s
Calculate Q from Dimensions:
C= 3.00
L= 10 ft
H= 1.00 ft
Q= 30 cfs
Calculate L from Q and H
C= 3.00
Q= 26.34 cfs
H= 1.00 ft
L= 9 ft
Calculate H from Q and L
C= 3.00
Q= 26.34 cfs
L= 10 ft
H= 0.92 ft
STANTEC
Proj. Number: 187000140
By: A.McDaniel
Q= Qloo x 2....... Q= 13.17x.2 = 26.34 cfs.
H= Freeboard - 100-Yr WSEL = 4941.00 4940.00 = 1.06'
Therefore ... L=10'
unofficial copy was downloaded or
.dditional information or an official
of Fort Collins'Poblic Records Website: ht
Fort Collins Utilities 700 Wood Streei Fort
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SHEET 6 OF 25
0.4
TIMBERLINE ROAD WIDENING
provide its own detention (0.36 efs l acre).`•'Storm A begins at the southeast corner of the.'
police station property (at the location ,where -the detention pond will• most• likely be).
Storm A then flows south to an existing area inlet at the northwest corner of Drake and
Timberline.. Spring Creek Farms will be designed to release detained flows into Storm A..' ;
Storm A has been designed to incrementally accept additional- flows with the makimum
flow being 20 cfs. 'The design flow additions are shown in Appendix C. • T'his'storm .
• .. sewer design has'been reviewed bythe Spring Creek Farms Engineer (Staritec). • ,
Basin 5 — includes Timberline Road adjacent to.the future Police Station and the roads on •
the west and south sides of the Police Station. This area will flow into the street on the
'south side of the Station and be detained on the Police Station site.
Basin 6 — includes the Police Station site (less the perimeter streets). This -area will be'
required to detain to 0.36 cfs /. acre and will release into Storm A. The drainage systems
and roads will be constructed at the same time as this project.
Basins 7 throueh 12 (areas west of Timberline drainine throueh SideHill 2):
Basin 7 — includes what is expected to, be the street on the north side of the future Police
Station and a portion of Timberline Road. - Again, Basins .7, 8, and 9. weie originally
designed to flow south to.the North Tributary Storm Sewer.., Because there .will be a
' drainage outfali (sized for existing) 00-yea'r'flowsy, this land now can drain to the north
which will -eliminate the need for a considerable amount of -storm sewer, and should
reduce the detention constraints on the.iest of Spring Creek Farms. This basin will flow
io a sump in the street north of the Police Station and to a pond on the north side of
Spring Creek Farms.
Basin 8 _ includes the north portion of Spring Creek Farms, which can now drain to the
' north. This area will drain, to a pond proposed with Spring Creek Farms: This pond is
presently being designed;by S'tantec and'per a conversation with Jim Allen -Morley, the
' release rate is designed as the 2-year historic rate. This pond will drain to Storm 2. It is '
assumed that the detained release rate -will be approximately 2 cfs. -
The existing Cargill Irrigation Ditch will be rerouted to tun along the south side of Basin
' 9. The rerouting of the ditch will be shown on the plans for Spring Creek Farms, the pipe
crossing under Timberline Road •will be designed and shown on the SideHill Filing 2 '
6
plans.,:...
Basin 9 -includes the portion of Timberline that is adjacent to Basin'8: This area will'
flow north to a roadside ditch and into Storm 2. Because Basins 7, and 8 are being
detained to the 2-year historic, and the receiving pipe on SideHill has been designed for
the 100-year existing flow,'it•has been decided to allow Basin 9 to discharge to the area '
inlet (Design Point 10) undetained.
..
Basin 10 — includes the area north of Spring Creek Farms that will drain to the southerly
of the two storm pipes that will take flows east through SideHill Filing 2 (Storm' 2). '
Timberline will have a rural section in this area and will drain to a 4' diameter area inlet ,
on'Storm 2..Storm 2 is allowed 21.92 cfs (based on the SideHill design). ;
Basin 11•.7 includes the area: that will drain to the northerlypipe that will 'take flows
through SideHill (Storrri3). A 5"diameter area inlet is proposed to accept flows from a
proposed roadside ditch. Storm 3.is allowed 47.36 cis (based on the SideHill design).. It
should be rioted that the receiving pipe on the SideHill Subdivision is a 30",RCP. Storm
3' has been' designed as a 36" RCP because of the 'Very -high HGL at the connecting
manhole..
Basins 22 througb 26 (east half of Timberline south of ride draining into SideHill):
Timberline Road Street Cap acity•Calculations are provided in .the Drainage Report for
SideHill Subdivision.
Basin 22 —'includes the area south of Iowa Drive that will drain into Krisron Road.
Basin 23 — drains from the proposed highpbint into Iowa Drive. ;
Basin 24 — drains from the proposed highpoint north to Nancy'Gray Avenue.
Basin 25 — drains "to Sandbur Drive. ' ,Design point 25 is a sump that aligns with the • .
proposed street."
Basin 26 — includes the area sbuth of the ridge that drains south and into Blackbird Drive.,
Basins 12 13 14 and 27 (area north of ridge and south of railroad):
Basins 12, 13) and 14 — includes the west,half of'Timberline between the ridge and the ,
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DRAINAGE EXHIBIT
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POLICE STATION
3. PROPOSED (POST -DEVELOPMENT) HYDROLOGY & HYDRAULICS
3.1 General Flow Routing
The site hydrology was analyzed in order to size the proposed detention and water quality
ponds and to complete the hydraulic design of the proposed inlets and pipes. The proposed
site generally follows the existing drainage pattern with a portion of the site draining to the
north and the majority of the site draining to the south into the proposed detention and water
quality enhancement pond. The portion of the site draining to the north will be detained and
treated in the proposed pond located just north of Nancy Gray Drive per an agreement
between the City of Fort Collins and the owner of that property. The on -site drainage basins
are described as follows:
Basin 101 includes the northeast comer of the north parking lot and will drain via overland
flow and gutter flow to a 5' type R inlet located at design point 1. This inlet connects to a
proposed storm sewer pipe system that connects to the existing system in Nancy Gray Drive
and discharges to the detention and water quality pond for Spring Creek Farms North.
Runoff from Basin 102 is conveyed via overland and gutter flow to the proposed 18" wide
concrete curb opening and channel located at.design point 2. This.channel discharges into
the back of the modified Type R inlet located in the middle of the north parking lot.
Runoff from Basin 103 is conveyed via overland and gutter flow to the proposed modified 5'
Type R inlet located at design point 3. This inlet is part of the proposed storm sewer system,
labeled Storm 2 in the plans, which discharges into Pond 2 located just north of Charles
Brockman Drive.
Runoff from Basin 104 is conveyed via overland and gutter flow to the proposed 5' Type R
inlet located at design point 4. This inlet is part of the proposed storm sewer system, labeled
Storm 2 in the plans, which discharges into Pond 2 located just north of Charles Brockman
Drive.
Basin 105 includes the roof area on the north portion of the building that is captured in a
series of roof drains which tie underground into the storm pipe adjacent to the north side of
the building, Storm 2. Although stormwater runoff from the roof drains enters the storm pipe
in several locations, for simplicity in the modeling the pipe was analyzed as if they all
entered at design point 5, located on the upper end of the pipe run.
Drainage and Erosion Control Report Page 5
The New Fort Collins Police Services Building February 23, 2006
Basin 106 includes the west parking lot and the portion of the roof that drains to the west.
This portion of the roof will not be intercepted by underground roof drains that connect to the
storm sewer system. The roof area that is part of Basin 106 is discharged to the surface via a
series of downspouts and overflow scuppers. Runoff from Basin 106 is conveyed via
overland and gutter flow to the proposed 5' Type R inlet located at design point 6. This inlet
is part of the proposed storm sewer system, labeled Storm 2 in the plans, which discharges
into Pond 2 located just north of Charles Brockman Drive. There is a 6" storm line from the
Sally Port area of the building which discharges into Storm 2 at the proposed manhole
labeled STMH 5 in the plans. This pipe connects to an internal floor drain within the Sally
Port.
Runoff from Basin 107 is conveyed via overland and gutter flow to the proposed 2' concrete
curb opening and channel located at design point 7. This channel flows to the parking lot to
the south and in Basin 108.
Runoff from Basin 108 is conveyed via overland and gutter flow to the proposed 5' Type R
inlet located at design point 8 and then is discharged directly into Pond 2 located just north of
Charles Brockman Drive. This inlet and pipe is part of the proposed storm sewer labeled
Storm 2 in the plans.
Basin 109 includes the south, middle portion of the site and a part of the roof. Runoff from
Basin 109 is conveyed via overland and gutter flow to the proposed 5' Type R inlet located at
design point 9 on the south side of the parking lot. This inlet is part of the proposed storm
sewer system labeled Storm 6 in the plans, which discharges into Pond 2. The roof area that
is part of Basin 109 is discharged to the surface via scuppers and downspouts.
Basin 110 includes the southeast portion of the building and parking area. Runoff is
conveyed via overland and gutter flow to the proposed 5' Type R inlet located at design point
10 on the south driveway entrance. The pipe that this inlet discharges into connects ponds 1
and 2.
Basin 111 includes the west pond (Pond 2) which drains via the proposed vegetated low -
flow channel to the pipe located at design point 11. This pipe connects Pond 2 with Pond 1.
Drainage and Erosion Control Report Page 6
The New Fort Collins Police Services Building February 23, 2006
Basin 112 includes the small roof on the northeast comer of the building which discharges
into two 4" roof drams that will daylight under the sidewalk adjacent to Timberline Road,
pass through a metal sidewalk culvert and through a 2' concrete channel to the curb and
gutter on the west side of Timberline Road. Runoff will then travel south along Timberline
and to the proposed storm inlet and pipe located on Charles Brockman Drive and into the
proposed detention pond (Pond 1) on the Police Facility site.
Basin 113 is located in the northeast corner of the site. Runoff is conveyed via overland
flow to the gutter of Nancy Gray Avenue and Timberline Road, to the stormwater system in
Nancy Gray Avenue. This system discharges into the water quality and detention pond
located just north of Nancy Gray Avenue. The stormwater system and the pond is being built
with plans for Spring Creek Farms North.
Basin 114 includes Pond 1 and the portions of Joseph Allen Drive, Charles Brockman Drive
and Timberline Road that drain to the storm sewer system on Charles Brockman Drive which
discharges into the proposed detention and water quality pond for the Police Facility site
3.2 Hydrologic Computations
The Rational Method was used to determine the l0-year and 100=year peak runoff values for
each Basin per guidelines in the SDDCCS Manual. Runoff coefficients were assigned using
Table 3-2 "Rational Method Minor Storm Runoff Coefficients for Zoning Classifications" of
the SDDCCS Manual. All hydrologic calculations for the Basins shown on the attached
drainage plan are included in Appendix B of this report.
• 3.3 Hydraulic Computations
• Hydraulic calculations for sizing of the proposed stormwater inlets and pipes were completed
using StormCAD hydraulic modeling software. The pipes were designed to convey the 10-
year peak storm flows. The 100-year storm was analyzed to insure that the hydraulic grade
line did not exceed the elevation of the storm manhole rims. At design point 4, there will be
ponding during the 100-year storm event within the parking lot at a depth less than 1'. The
OF curves for the City of Fort Collins were entered into the database as well as the physical
parameters for standard Type R inlets used in the City of Fort Collins. Standard roughness
coefficients for the pipes and headloss coefficients through the structures were used. The
storm system profiles, inlet report, node report and pipe'reports are included in Appendix C.
Drainage and Erosion Control Report Page 7
The New Fort Collins Police Services Building February 23, 2006
4. STORMWATER DETENTION & WATER QUALITY TREATMENT
4.1 Overview
Basins 101 and 113 will drain to the north and into the stormwater detention and water
quality facility being proposed for Spring Creek Farms North located in the comer of Nancy
Gray Avenue and Timberline Road. The remaining portion of the site and the equivalent of
one-half of the adjacent streets (Basins 102-112 & 114) will drain to the proposed
stormwater detention and water quality ponds located on the south side of the site just north
of Charles Brockman Drive. .
4.2 Detention Pond Design
The stormwater detention system is divided into two ponds, Pond I on the east side of the
entrance drive and Pond 2 located on the west side of the entrance drive. These ponds are
designed to detain the post -development 100-year storm and release at a peak flow rate less
than or equal to the allowable release rate according to the Foothills Master Drainage Plan
and the capacity of downstream conveyance facilities. The allowable release rate in
accordance to the Foothills Master Drainage Plan is limited to 0.36 cfs/acre as stated in the
"Drainage Design Report for Interim Timberline Road Widening — Drake to Prospect"
(2005). The total tributary area to the Police Services Building Pond is 8.60 acres which
results in an allowable release rate of 3.10 cfs. For reference, the historic peak 100-year flow
to the south is 18.6 cfs and the 10-year peak flow is 7.3 cfs (Basin H2). Thus the proposed
release rate of 3.10 cfs is less than both the 100-year and the 10-year historic (undeveloped)
peak flow at this same point. The Rational Volumetric FAA Method was used to calculate
the required detention volume at the given release rate. The pipe connecting the ponds has
• been sized to convey the 100-year peak flow unrestricted. Detention volume calculations are
included in Appendix D.
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4.3 Extended Detention Basin Design
The recommended water quality enhancement measure is the use of an extended detention
basin (EDB) designed using guidelines set forth in the Urban Storm Drainage Criteria
Manual, Volume 3 (2004). The proposed EDB is a sedimentation facility which will capture
stormwater runoff from frequently occurring rainfall events and extend the emptying time
over 40-hours to allow for pollutant removal through gravity settling. The removal of
soluble pollutants will be enhanced by providing a small wetland marsh area in a lower stage
basin and permanent micro -pool below the active water quality capture volume. This
Drainage and Erosion Control Report Page 8
The New Fort Collins Police Services Building February 23, 2006
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7 OF 13
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SIDEHILL FILING 2 - PIPE REDUCTION City of Ft CollinsApp ved Plans
Approved By -�
Date Li - q - o
March 30, 2007
i
Mr. Wes Lamarque
City of Fort Collins Stormwater.Utility
700 Wood Street
Fort Collins, CO 80521
RE: Stormwater Pipe Reduction Due to Decrease in Offsite Flow Release Rate
Dear Wes:
We are pleased to submit for your review and approval this addendum to the Sidehill Filing 2 Final
Drainage and Erosion Control Report (May 27, 2005). This addendum addresses the drainage impacts
from the revised release rates from the offsite properties to the west of Timberline Road and Sidehill
Filing 2.
Two drainage reports; Final Drainage and Erosion Control Report for Timberline Center Subdivision, and
Final Drainage and Erosion Control Study for Spring Creek Farms, were reviewed to determine the
revised 2-year historic release rates into the Sidehill Filing 2 storm system that initially was sized to
receive the 100-year release rates from the offsite properties. Because the offsite release rates have been
significantly reduced from the previously approved design rates, it is feasible and practical to redesign the
effected Sidehill Filing 2 storm system.
The Timberline Center Report .states a release rate of 2.1 cfs and 13.3 cfs to Storm 2 and Storm 3,
respectively.
The Spring Creek Farms Report states a 2-year release rate of 1.1 cfs from Detention Pond 8 into the
Sidehill Filing 2 storm system. Therefore, the total release rate into the Sidehill Filing 2 storm system is
16.5 cfs.
This reduction in offsite flow enabled 10 pipes on storm profile Line H (sheets 90 & 91) to be reduced in
size. The storm pipe from storm manhole 16 to storm manhole 9 are existing pipes and oversized due to
the decrease in offsite flow into this storm system. The reduction in pipe size occurs downstream from
storm manhole 9 to the flared end section outlet. Also 2 pipes were able to be converted from HERCP to
RCP and still maintain adequate cover.
The storm profile Line El (sheet 88) was revised and the 2 pipes were upsized 0.5 feet but still
maintained the approved inverts.
The supporting calculations and drainage reports are included with this addendum.
JR Engineering has reviewed and concluded that the above -mentioned revisions have been designed with
provisions for safe and efficient control of stormwater runoff in a manner that will not adversely affect the
stormwater system.
s unofficial copy was downloaded on Nov-30-2016 from the City of Fort Collins Public Records Website:,http:pcitydocs
additional information or an official copy, please contact City of Fort Collins: Utilities 700Wood street Fort Collins,. CO
9
L
We appreciate your time and consideration in reviewing this submittal. If you have any questions or need
additional information please call (970) 491-9888.
Prepared by:
Mike Malvey
Design Engineer
Reviewed bv:
/ph arone P.E.
ager
X:\3930000.all\3935006\Word\Re orts\Drainage Addendum Storm R,
is unofficial copy was downloaded on Nov-30-2016 from the City of Fort
or additional information or an official coov. please contact Citv of Fort Co
Public Records' Website: http://citydms.fcgov.com
Iities700 Wood Street Fort Collins, CO 80524 USA