HomeMy WebLinkAboutFOSSIL CREEK COMMUNITY PARK - PDP - 44-00 - REPORTS - DRAINAGE REPORTSoils Map
m s
Hormo ylRoad
I v b l Ae
rip I ` I h b v r J b y °��.aoey5
p y. p
°� I z5 out
vI Qo �o by Q
r— J r o �5 rip
p Ae
r I bi 1 \ oE�a e
r J rip I bl `� Werner w OJ.�°A /
hb blem.
t5I oF° c o H
ekeo�E p°rip
I bybylp E
Pro ject i-
Site I by
J
J
" '�I
LL
Ire — J
Trilby Road
-rip
yae
I�ae` °etl0���°\\�
C Gek
F-
A
�o
qO
Q
rip
\ot ,ray e
ci
b
hb I
rip
I
rlp
\
0
by
rip
N
Benson
>
Lake
rip
rlp t
I
LO
,o
rip rip
�5
VICINITY MAP
N.T.S.
Boundary
APPENDIX A
MAPS AND FIGURES
8. REFERENCES
City of Fort Collins, "Storm Drainage Design Criteria and Construction Standards",
(SDDCCS), dated May 1984.
2. Soil Survey of Larimer County Area, Colorado. United States Department of
Agriculture Soil Conservation Service and Forest Service, 1980.
3. Terracon, "Preliminary Geotechnical Engineering Report: Proposed Fossil Creek
Community Park", February 7, 2000.
4. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria
Manual", Volumes 1 and 2, dated March 1969, and Volume 3, dated September 1,
1999.
5. "Final Drainage Report, Fossil Creek Community Park Phase I (Lakes 1, 2 and 3)",
JR Engineering, Ltd., Revised September 13, 1996
6. "Final Drainage Report, Huntington Hills PUD Filing No. 5", JR Engineering, Ltd.,
Revised July 21, 1995
7. "Preliminary Drainage and Erosion Control Report, Huntington Hills PUD, Filing
5", Resource Consultants and Engineers, Revised January 1995
8. "Final Drainage Report for Huntington Hills PUD Filing No. 3", Resource.
Consultants and Engineers, October 1993
9. "Drainage Report for Huntington Hills PUD Filing No. 4", Resource Consultants and
Engineers, June 1994
10. "Addendum to Huntington Hills PUD Filing No. 4 Drainage Report", Resource
Consultants and Engineers, October 1994
11. "Addendum No. 2 - Final Drainage and Erosion Control Report, Huntington Hills
Filing No. 2", Resource Consultants and Engineers, Revised December 1994
Final Drainage and Erosion Control Report Page 9
Fossil Creek Community Park June 20, 2001
7.2 Drainage Concept
Runoff from the major storm will be collected and ultimately conveyed to Fossil Creek. This
will happen via several methods including pipe flow, overland flow and swale flow. The
runoff will be intercepted by inlets and conveyed in pipes to water quality ponds. The minor
storm washes the majority of pollutants from the site. The water quality ponds will allow
the pollutants to settle out of the stormwater runoff before entering the Fossil Creek.
Final Drainage and Erosion Control Report Page 8
Fossil Creek Community Park June 20, 2001
6.3 Tracking Mud on City Streets
It is unlawful to track or cause to be tracked mud or other debris onto city streets or rights -of -
way unless so approved by the Director of Engineering in writing. Wherever construction
vehicles access routes or intersect paved public roads, provisions must be made to minimize
the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface.
Stabilized construction entrances are required with base material consisting of 6" coarse
aggregate. The contractor will be responsible for clearing mud tracked onto city streets on
a daily basis.
6.4 Maintenance
All temporary and permanent erosion and sediment control practices must be maintained and
repaired as needed to assure continued performance of their intended function. Straw bale
dikes or silt fences will require periodic replacement. Sediment traps (behind straw bale
barriers) shall be cleaned when accumulated sediments equal approximately one-half of trap
storage capacity. Maintenance is the responsibility of the developer.
6.5 Permanent Stabilization
A vegetative cover shall be established within one and one-half years on disturbed areas and
soil stockpiles not otherwise permanently stabilized. Vegetation shall not be considered
established until a ground cover is achieved which is demonstrated to be mature enough to
control soil erosion to the satisfaction of the City Inspector and to survive severe weather
conditions.
7. CONCLUSIONS
7.1 Compliance with Standards
The storm drainage improvements designed by this development meet the criteria set forth
in the City of Fort Collins Storm Drainage Criteria manual. Water quality and best
management practices recommended in the "Urban Storm Drainage Criteria Manual —
Volume 3"(1999) have been used.
Final Drainage and Erosion Control Report Page 7
Fossil Creek Community Park June 20, 2001
5.
C
WATER QUALITY CONCEPTS
The water quality provided with this project includes the use of an extended detention basin
and the use of bio-swales and existing wetlands to remove unwanted particulates in the
runoff. The north and eastern portion of this site is treated for water quality in the extended
detention basin located next to Fossil Creek near the Lemay Avenue crossing. The existing
lakes in the park control the water quality for the southern portion of this site. The
northwestern portion of the site that drains to the south releases runoff to the existing
wetlands for water quality treatment.
EROSION CONTROL
6.1 Erosion and Sediment Control Measures
Erosion and sedimentation will be controlled on -site by use of inlet filters, silt fences, straw
bale barriers, gravel construction entrances, and seeding and mulch. The measures are
designed to limit the overall sediment yield increase due to construction as required by the
City of Fort Collins. During overlot and final grading the soil will be roughened and
furrowed perpendicular to the prevailing winds. Straw bale dikes will be placed along
proposed swales. Erosion control effectiveness, rainfall performance calculations and a
construction schedule will be provided with the final report.
6.2 Dust Abatement
During the performance of the work required by these specifications or any operations
appurtenant thereto, whether on right-of-way provided by the City or elsewhere, the
contractor shall famish all labor, equipment, materials, and means required. The Contractor
shall carry out proper efficient measures wherever and as necessary to reduce dust nuisance,
and to prevent dust nuisance that has originated from his operations from damaging crops,
orchards, cultivated fields, and dwellings, or causing nuisance to persons. The Contractor
will be held liable for any damage resulting from dust originating from his operations under
these specifications on right-of-way or elsewhere.
Final Drainage and Erosion Control Report Page 6
Fossil Creek Community Park June 20, 2001
4.2 Sub -Basin Descriptions
Flows enter this site from the existing developments of Huntington Hills PUD Filings 4, 5
and 6. These contributing areas were described in detail in the "Final Drainage Report,
Fossil Creek Community Park Phase I (Lakes 1, 2 and 3)", JR Engineering, Ltd., Revised
September 13, 1996. The original calculations for these areas were developed using the old
rainfall criteria. These calculations have been updated as part of this report. All calculations
are included in Appendix I.
Runoff from Sub -Basin 101 is delivered via overland flow through the existing wetlands into
pond 3. The flows within the parking area within this subbasin are collected in area inlets
after they are conveyed through proposed grass swales within the parking lot islands. Said
inlets outlet though a pipe system adjacent to said existing wetland.
Sub -basins 102 and 103 deliver runoff to Fossil Creek directly via overland flow.
Runoff from Sub -basin 104 is conveyed via overland flow to area inlets located at low
points. This stormwater eventually enters the proposed Water Quality Pond and then flows
into Fossil Creek.
Runoff from Sub -basins 105a, 105b, and 105c are conveyed via overland and gutter flow to
the proposed Water Quality Pond. From there flows enter Fossil Creek.
Runoff from Sub -basin 106 is conveyed via overland and swale flow to Pond 1.
Runoff from Sub -basin 107 is conveyed via overland and swale flow to Pond 2 and Pond 3.
Runoff from Sub -basin 108 is conveyed via overland and gutter flow to the proposed Water
Quality Pond. From there, flows enter Fossil Creek.
Runoff from Sub -basin 109, the west half of the proposed widening of Lemay Avenue, is
routed via sheet and curb flow northerly to the existing inlets at the Fossil Creek box culvert.
Runoff from Sub -basin 110, the east half of the proposed widening of Lemay Avenue, is
routed via sheet and curb flow northerly to the existing inlets at the Fossil Creek box culvert.
Final Drainage and Erosion Control Report Page 5
Fossil Creek Community Park June 20, 2001
control and if the flow is uniform, vaned, or pressurized and applies the appropriate
equations (Manning's, Kutter's, Hazen -Williams, etc). StormCAD also takes into account
tailwater effects and hydraulic losses that are encountered in the storm structures. It
calculates the losses through an inlet or manhole by allowing the user to assign a coefficient
for the equation,
hL= K*(V2/2g)
Where hL = headloss
K = headloss coefficient
V = average velocity (ft/s)
g = gravitational constant (32.2 fds2)
4. DRAINAGE FACILITY DESIGN
4.1 General Concept
The basic concept for this site is to route stormwater to nearby water features. This is done
via overland flow and some inlets and pipes. Underdrains are also being used on the site in
order to remove some of the runoff from around the basketball courts, tennis courts and
buildings. Since the grading of the site is removing the current outlet for the ponds (an open
ditch), the outlets will require improvements. Pipes are being provided that will allow the
ponds to be drained with the option to drain Pond 2 without draining Pond 1. The new
outlets for the ponds are being incorporated into a large storm sewer system that includes the
under drains and the storm pipes from the low points.
The Fossil Creek Master Plan specifies that detention for this site is not required. The site
is located close enough to Fossil Creek that the peak runoff for the site occurs before the
peak for the basin. Water quality is a concern and therefore the runoff from impervious areas
is treated in either the existing wetland adjacent to pond 2 and 3, within the existing ponds,
or the proposed extended detention basins. The sizing of the proposed water quality pond has
been designed to meet guidelines given in the Urban Storm Drainage Criteria Manual
Volume 3 (1999). The water quality pond outlet has been designed with final construction
plans. Water quality calculations are found in Appendix H.
Final Drainage and Erosion Control Report Page 4
Fossil Creek Community Park June 20, 2001
the time of concentration is required. The following equation is used to determine the time
of concentration
t'=tt+tt
(2)
where tc is the time of concentration in minutes, t; is the initial or overland flow time in
minutes, and tt is the conveyance travel time in minutes. The initial or overland flow time
is calculated with the SDDCCS Manual equation:
ti = [1.87(l.1 - CC)LD.S]/(S)0.33
(3)
where L is the length of overland flow in feet (limited to a maximum of 500 feet), S is the
average slope of the basin in percent, and C and C1 are as defined previously.
All hydrologic calculations associated with the sub -basins shown on the attached drainage
plan are included in Appendix B of this report. A summary of these calculations for the
basins is included in Table 3.1 below.
TABLE 3.1- DRAINAGE SUMMARY TABLE
Design
Tributary
Area
C (2)
C (100)
tc (2)
to (100)
O(2)tot
D(1oogot
DRAINAGE
Sub4)asln
STRUCTURE
Point
(aq
(min)
(min)
(cfs)
(cfs)
/REMARKS
1
101
3.42
0.66
0.83
8.7
5.4
5.3
27.0
To Ponds 2 and 3
2
102
6.36
0.24
0.30
13.4
13.4
3.0
13.2
Flow to Fossil Creek
3
103
4.85
0.25
0.31
13.3
13.3
2.4
10.4
Flow to Fossil Creek
4
104
12.72
0.33
1 0.41
13.6
13.6
8.1
1 35.4
To WD Pond 1
5a
105a
4.54
0.39
0.49
15.2
15.2
3.3
14.3
To WD Pond 1
5b
105b
4.97
0.58
0.72 .-
13.6
13.6
5.6
24.4
To WO Pond 1
5c
105c
2.44
0.59
0.74
8.7
6.7
3.4
16.2
To WO Pond 1
6
106
7.24
0.26
0.32
12.3
12.3
3.6
16.4
To Pond 1
7
107
28.49
0.23
0.28
22.8
22.8
9.7
42.3
To Ponds 2 and 3
8
108
1.93
0.32
0.40
13.1
13.1
1.2
5.4
Flow to Fossil Creek
9
109
3.47
0.77
0.96
20.6
18.4
4.2
19.6
Future development
10
110
2.69
0.01
1.00
20.2
18.0
3.5
16.0
Future development
3.3 Hydraulic Criteria
For the storm pipe design, the computer program StormCAD, developed by Haestad
Methods, Inc. was used. StormCAD considers whether a stone pipe is under inlet or outlet
Final Drainage and Erosion Control Report Page 3
Fossil Creek Community Park June 20, 2001
K
characteristics with slight to moderate erosion hazards. Soils 55, 56, and 90 are classified
by severe runoff and severe erosion hazard. The Kim loams are in hydrologic group B and
the rest of the soils are in hydrologic group C. A soils map for the site is located in
Appendix A. A soils report by Terracon reveals that ground water was encountered at fairly
shallow depths in the southeast portion of the site. Portions of this report are located in
Appendix I.
DRAINAGE DESIGN CRITERIA
3.1 Regulations
This report and associated calculations were prepared to meet requirements established in
the "City of Fort Collins Storm Drainage Design Criteria and Construction Standards"
(SDDCCS), dated May 1984 and updated January 1997. The new rainfall criteria, as
amended by Ordinance 42.199, was used for the 2-year and 100-year design storms. Runoff
computations were made using the rational method. Where applicable, the criteria established
in the "Urban Storm Drainage Criteria Manual' (UDFCD), 1984, developed by the Denver
Regional Council of Governments, has been utilized.
3.2 Hydrological Criteria
The Rational Method was used to determine both 2-year and 100-year peak runoff values for
each sub -basin. Runoff coefficients were assigned using Table 3-2 of the SDDCCS Manual.
The Rational Method is given by:
Q = CfCIA
(1)
where Q is the maximum rate of runoff in cfs, A is the total area of the basin in acres, Cf is
the storm frequency adjustment factor, C is the runoff coefficient, and I is the rainfall
intensity in inches per hour for a storm duration equal to the time of concentration. The
frequency adjustment factor, Cf, is 1.0 for the initial 2-year storm and 1.25 for the major 100-
year storm. The runoff coefficient is dependent on land use or surface characteristics.
The rainfall intensity is selected from Rainfall Intensity Duration Curves for the City of Fort
Collins (Figure 3.1 of SDDCCS). In order to utilize the Rainfall Intensity Duration Curves,
Final Drainage and Erosion Control Report Page 2
Fossil Creek Community Park June 20, 2001
1.
2.
GENERAL LOCATION AND DESCRIPTION
1.1 Location
Fossil Creek Community Park is a tract of land located in the Northeast Quarter of Section
12, Township 6 North, Range 69 West of the 6"' Principal Meridian, City of Fort Collins,
Larimer County, Colorado. The project is bounded on the north by Miramont, Fossil Creek
Meadows and unplatted land, on the west and south by Huntington Hills, and on the east by
Lemay Avenue.
1.2 Description of Property
The property is a 94.4 acre parcel of land in southeast Fort Collins. The property is being
proposed as a community park with basketball and tennis courts and soccer and baseball
fields. There are several buildings proposed with this development as well as parking lots.
Fossil Creek flows through the site from west to east and is joined by flows from Mail
Creek. A vicinity map is located in Appendix A.
DRAINAGE BASINS AND SUB -BASINS
2.1 Major Basin Description
According to the City of Fort Collins Master Drainage Plan, this site lies in the Fossil Creek
Master Drainage Basin. The Master Drainageway Planning Study for the Fossil Creek
Drainage Basin prepared by Simons, Li & Associates, Inc. dated August 1982 does not
require on -site storm water detention for this site.
2.2 Existing Sub -basin Description
Historically, the site has a ridge running northwest to southeast that directs runoff to either
Fossil Creek to the north or to the ponds located in the southern portion of the site. Slopes
on the site vary from 0.7 to 30%.
Soils on site include Kim Loams (soil numbers 54-56), Heldt clay loam (#48), Longmont
Clay (#63), and Renohill clay loam (#90). These soils have a wide variety of runoff and
erosion hazard characteristics. Runoff for soils 54, 48, and 63 have slow to moderate runoff
Final Drainage and Erosion Control Report Page 1
Fossil Creek Community Park June 20, 2001
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
APPENDIX F
APPENDIX G
APPENDIX H
APPENDIX I
MAPS AND FIGURES
HYDROLOGIC CALCULATIONS
INLET CALCULATIONS
PIPE CALCULATIONS
RIP RAP CALCULATIONS
STREET CAPACITY CALCULATIONS
WATER QUALITY POND DESIGN
EROSION CONTROL CALCULATIONS
EXCERPTS FROM OTHER REPORTS
Final Drainage and Erosion Control Report Page ii
Fossil Creek Community Park June 20, 2001
TABLE OF CONTENTS
PAGE
TABLEOF CONTENTS.................................................................................................................
i
1. GENERAL LOCATION AND DESCRIPTION....................................................................
1
1.1 Location..............................................................................................................................
1
1.2 Description of Property.......................................................................................................
1
2. DRAINAGE BASINS AND SUB-BASINS..........................................................................
1
2.1 Major Basin Description.....................................................................................................
1
2.2 Existing Sub -basin Description......................................................................................:....
1
3. DRAINAGE DESIGN CRITERIA.........................................................................................
2
3.1 Regulations.........................................................................................................................
2
3.2 " Hydrological Criteria..........................................................................................................
2
3.3 Hydraulic Criteria.....................................:.........................................................................
3
4. DRAINAGE FACILITY DESIGN.........................................................................................
4
4.1 General Concept..................................................................................................................
4
4.2 Sub -Basin Descriptions.......................................................................................................
5
5. WATER QUALITY CONCEPTS..........................................................................................
6
6. EROSION CONTROL...........................................................................................................
6
6.1 Erosion and Sediment Control Measures............................................................................
6
6.2 Dust Abatement..................................................................................................................
6
6.3 Tracking Mud on City Streets.............................................................................................
7
6.4 Maintenance........................................................................................................................
7
6.5 Permanent Stabilization......................................................................................................
7
7. CONCLUSIONS.....................................................................................................................7
7.1 Compliance with Standards................................................................................................
7
7.2 Drainage Concept................................................................................................................
8
8. REFERENCES.......................................................................................................................
9
Final Drainage and Erosion Control Report Page i
Fossil Creek Community Park June 20, 2001
r
June 20, 2001 ft)
J•R ENGINEERING
Basil Hamdan A Subsidiary of Westrian
City of Fort Collins
Stormwater Utility
P.O. Box 580
Fort Collins, CO 80522-0580
Re: Final Drainage and Erosion Control Report for Fossil Creek Community Park
JR Project #: 9262.00
Dear Mr. Hamdan:
We are pleased to submit to you for your review and approval the attached "Final Drainage and
Erosion Control Report for Fossil Creek Community Park". All computations within this report
have been completed in compliance with the City of Fort Collins Storm Drainage Criteria Manual
and address the comments from the April 2001 submittal.
We appreciate your time and consideration in reviewing this submittal. Please call if you have
any questions.
Sincerely,
JR Engineering
Amber Reed, EIT
Design Engineer I
David W. Klockeman, PE
Division Manager
2620 East Prospect Road, Suite 190, Fort Collins, CO 80525
970-491-9888 • Fax 970491-9984 • w Jrengineering.com
FINAL DRAINAGE AND
EROSION CONTROL REPORT
FOSSIL CREEK COMMUNITY PARK
June 20, 2001
Prepared by
JR ENGINEERING
2620 E. Prospect Rd., Suite 190
Fort Collins, Colorado 80525
(970) 491-9888
Prepared for
City of Fort Collins
Cultural, Recreational and Library Services
Park Planning and Development
Fort Collins, CO
Job Number 9262.00