HomeMy WebLinkAboutFORT COLLINS BREWERY - FDP - 32-08/A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFinal Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
IX. APENDICES
Appendix I
Hydrology
Detention
Hydraulics
Appendix II
Drainage and Erosion Control Plan (24"x36" - 20 scale)
Offsite Drainage Exhibit (I I "x 17" — 300 scale)
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
2. Permanent sediment\erosion control measures will include riprap forebays at
all storm sewer outfalls.
a. A 40-hour extended detention basin has been designed inside of the
regional detention pond.
b. All disturbed areas will be paved, landscaped or revegetated to prevent
soil erosion and sedimentation.
3. Maintenance of all sediment\erosion control devices will remain the
responsibility of the contractor until the project is completed.
VII. CONCLUSIONS
A. Compliance with standards
I. All drainage design will conform to the criteria and requirements of City of
Fort Collins Storm Drainage and Design Criteria and Construction Standards.
2. Proposed drainage improvements will conform to the concepts and
recommendations of the Dry Creek Basin master plan.
3. Proposed sediment/erosion control measures will conform to the
recommendations of City of Fort Collins Storm Drainage and Design Criteria
and Construction Standards and generally accepted erosion control
procedures.
B. Drainage Concept
I. The proposed drainage plan concept for Fort Collins Brewery will be effective
for the control of stormwater runoff and water quality for the proposed site
and conforms to Larimer County engineering staff recommendations for the
Dry Creek Basin master plan.
VIII. REFERENCES
• City of Fort Collins Storm Drainage and Design Criteria and Construction Standards
• The Dry Creek Basin Master Plan
• Urban Storm Drainage Criteria Manual Volume I; Urban Drainage and Flood Control
District, Denver, Colorado, March, 1969.
• Urban Storm Drainage Criteria Manual Volume 2; Urban Drainage and Flood Control
District, Denver, Colorado, March, 1969.
• Urban Storm Drainage Criteria Manual Volume 3. Best Management Practices; Urban
Drainage and Flood Control District, Denver, Colorado, September, 1999.
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
b. Construction BMP's will consist of gravel filters at inlets, surface
roughening and revegetation, vehicle tracking at Lemay and Lincoln access
points, and silt fence around downstream construction limits.
D. Specific Details — Swales
I. There are no Swales requiring analysis within the project site.
E. Specific Details — Inlets and Storm Sewer
I. The project site generally drains to the center line of the drive aisles, which are
designed with an inverted crown. Inlets in this location collect storm
discharges for conveyance to the detention pond through an 18" RCP. It
should be noted that the inlets are not proposed for capacity reasons, but
only to enable parking lot detention. Site flows could adequately be
conveyed via curb/gutter or the inverted crown.
2. Two (2) new inlets are proposed to convey street flows from Lincoln and
Lemay to the proposed detention pond. Both of these inlets are 5' type R
inlets. They are placed in the locations of the ultimate curb/gutter for the
adjacent streets. In the interim condition, the top portions of the inlets will
not be constructed, allowing these inlets to function as field inlets during the
interim condition. In the future, the top portions of the inlets can be
constructed along with the anticipated street improvements.
F. Specific Details — Culverts
3. Off -site discharges from basins E-I, E-2 and E03 are conveyed through two 30"
RCP culverts through the site.
VI. SEDIMENT/EROSION CONTROL
A. General Concept
I. Temporary erosion control measures will be installed with this project.
These measures will include:
a. Silt fence along the property lines.
b. Inlet filters at all inlets.
c. Water trucks and soil terracing to address construction dust abatement.
d. Vehicle tracking pad at the construction entrance.
e. The detention pond will act as a sediment basin during construction.
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
3. The tributary area of the proposed site has been delineated as Basin P-1. This
basin is used to calculate detention pond storage volumes, water quality volumes
and emergency spillway sizing. All off -site flows are routed around the project
site and conveyed to their original discharge points downstream of the project
site.
B. Specific Details —Detention
This site will require 0.99 acre feet of storage to attenuate the 100 year
developed condition runoff for the site to the maximum allowable release rate
of 0.20 cfs per acre. For the site's 2.70 acres of proposed development this is
equal to 2.70 acres * 0.20 cfs/acre = 0.54 cfs.
2. The required water quality volume is 0.092 acre feet of storage for the 40
hour extended detention treatment. This volume is attained at a water surface
elevation of 4936.19.
3. The total required storage of the site detention facility is 0.99 (100yr storage)
+ 0.092 (WQCV) = 1.08 acre feet. This volume is attained at 100 year water
surface elevation of 4940.54 feet.
4. Parking lot detention provides 0.17 acre-feet of the required storage. The
inundation area of the parking lot areas at the 100 year water surface elevation
level of 4940.70 feet has been hatched in the Drainage and Erosion Control
drawing.
5. The emergency spillway for the pond is located on the access drive off Lemay,
and is adequate to convey the 100-year of 26.86 cfs from Basin P- I.
6. The outlet structure will be a 100 year single stage box control structure with
an orifice control plate at the back of the box over the entrance of the 18"
RCP outlet pipe. Please see the outlet control structure calculations in the
Detention section of Appendix I.
C. Specific Details — Stormwater Quality
1. Water Quality will be provided in accordance with Best Management Practices
as presented in the Urban Storm Drainage Criteria Manual Volume 3. Best
Management Practices; Urban Drainage and Flood Control District, Denver,
Colorado, September, 1999.
a. Permanent structural BMP's will consist of riprap pads at each culvert, grass
scrubbing across the bottom of the detention pond during first flush
conditions, and a 40-hour extended detention basin facility incorporated
into the detention pond.
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
IV. DRAINAGE DESIGN CRITERIA
A. Development Regulations
Design criteria from the City of Fort Collins Storm Drainage and Design
Criteria and Construction Standards were followed for this drainage report.
B. Development Criteria Reference and Constraints
I. The Larimer County engineering staff was consulted with to obtain their
position on conformance to the Dry Creek Basin master plan detention pond
release rates. The County requested that this site release at no more than 0.20
cfs per acre into the existing drainage system, which is in accordance with the
Master Plan.
C. Hydrological Criteria
I. Peak flow rates for the 10-year and 100-year storms have been calculated in
accordance with the City of Fort Collins Storm Drainage and Design Criteria
and Construction Standards. Please see these calculations in the Hydrology
- section of Appendix I.
D. Hydraulic Criteria
I. The City of Fort Collins Storm Drainage and Design Criteria and Construction
Standards are used to determine the adequacy of the culverts, storm sewers,
inlets and street capacities throughout the project.
2. Analyses are performed using methodologies presented in Urban Storm
Drainage Criteria Manual Volumes I and 2; Urban Drainage and Flood Control
District, Denver, Colorado, September, 1999. Please see the various
computation spreadsheets in the Hydraulics section of Appendix I.
V. DRAINAGE FACILITY DESIGN
A. General Concept
I. An inverted crown parking surface with concrete pan will be utilized to convey
surface and roof runoff to area inlets that will collect the flow into a piped storm
sewer system that will carry all of the site runoff to the detention pond.
2. Runoff from offsite basins E-I, E-2 and E-3 will be piped around the site to their
original historic discharge point at the entrance to the two existing 15" CMP
culverts located at the southeast corner of the site. These flows by-pass the site.
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
Ill. DRAINAGE BASINS AND SUB -BASINS
A. Major Basin Description
I. Fort Collins Brewery project lie within the City of Fort Collins Dry Creek
Basin.
a. Through discussion with City of Fort Collins and Larimer County
engineering staff it was determined that the site will be required to detain
the site's 100-year developed condition runoff event with an ultimate
maximum site release rate of 0.20 cfs per acre to be in conformance with
the Dry Creek Basin drainage master plan.
2. Portions of the project site lie within the FEMA 500 year floodplain of the
Cache La Poudre River, as shown on FIRM panel #08069C0983G, dated June
17, 2008. There are no new critical facilities or expansion of existing critical
facilities proposed with this project. The site is protected from the 100 year
event flow from the Cache La Poudre River by the Oxbow Levee.
B. Existing Conditions
I. The site consists of native weeds and grasses. The site is fairly flat with the
terrain sloping gently to the southeast at approximately 0.33%. Runoff from
the site is intercepted by the two existing roadside ditches on Lemay and
Lincoln that carry the flow to two (2) existing 15" CMP culverts that take the
flow east under Lemay.
2. Four (4) offsite tributary areas that flow to the project site have been labeled
as Basins E-I through E-4. Please see the 10 year and 100 year runoff
calculations for these basins in the Hydrology section of Appendix I and their
delineations in the Offsite Drainage Exhibit in Appendix II.
C. Developed Conditions
The proposed uses consist of one industrial/commercial building to house the
Fort Collins Brewery and one multi -use building. The parking areas will be
paved with asphalt and internal concrete walks and plaza areas will serve
pedestrians. A landscaped detention area will be provided. A deck platform
will be placed over the west end of the detention pond with the low -chord of
the structure to be placed above the 100 year water surface elevation.
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
INTRODUCTION
This report presents the pertinent data, methods, assumptions, and references used in
analyzing and preparing the final drainage, erosion control and water quality design for
the Fort Collins Brewery project.
II. GENERAL LOCATION AND DESCRIPTION
A. Property Location
I. The Fort Collins Brewery project is located on Lots 2 and 3 of the North
Lemay Subdivision, Second Filing, and consists of 2.58 acres.
2. The project site is located on the northwest corner of Lincoln Avenue and
Lemay Avenue in Fort Collins, Colorado, as shown below:
Vicinity Map, NTS
B. Description of Property
I. The project site is currently undeveloped. The proposed uses consist of one
industrial/commercial building to house the Fort Collins Brewery and one
multi -use building. The project includes associated street, water, sewer and
private infrastructure improvements.
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
TABLE OF CONTENTS
Title Page
Engineer's Certification
Table of Contents
1.
INTRODUCTION3
............................................................................................
11.
GENERAL LOCATION AND DESCRIPTION ............................................. 3
A.
Property Location......................................................................................................................3
B.
Description of Property ............................................................................................................3
I11.
DRAINAGE BASINS AND SUB-BASINS......................................................4
A.
Major Basin Description...........................................................................................................4
B.
Existing Conditions....................................................................................................................4
C.
Developed Conditions..............................................................................................................4
IV.
DRAINAGE DESIGN CRITERIA....................................................................5
A.
Development Regulations........................................................................................................5
B.
Development Criteria Reference and Constraints.............................................................5
C.
Hydrological Criteria................................................................................................................5
D.
Hydraulic Criteria......................................................................................................................5
V.
DRAINAGE FACILITY DESIGN.................................................................... 5
A.
General Concept.......................................................................................................................5
B.
Specific Details — Detention....................................................................................................6
C.
Specific Details — Stormwater Quality ..................................................................................6
D.
Specific Details — Swales..........................................................................................................7
E.
Specific Details — Inlets and Storm Sewer.............................................................................7
F.
Specific Details — Culverts........................................................................................................7
VI.
SEDIMENT/EROSION CONTROL................................................................7
A.
General Concept.......................................................................................................................7
VI1.
CONCLUSIONS...............................................................................................8
A.
Compliance with standards.....................................................................................................8
B.
Drainage Concept......................................................................................................................8
VIII.REFERENCES
8
...................................................................................................
IX. APENDICES....................................................................................................... 9
Final Drainage, Erosion Control and Water Quality Report
Fort Collins Brewery
ENGINEER'S CERTIFICATION
hereby state that this Preliminary Report for the drainage, erosion control and water
quality design of the Fort Collins Brewery project was prepared by me or under my direct
supervision for the owners thereof and meets or exceeds the criteria in the City of Fort
Collins Storm Drainage Design Criteria and Construction Standards.
Stacy J. Gowing
Registered Professional Engineer
State of Colorado No: 34290
Final Drainage, Erosion Control and Water Quality Report
For
Fort Collins Brewe
Fort Collins, Colorado
Prepared for:
OUTWEST PROPERTIES, LLC
C/O TOM PETERS
1900 EAST LINCOLN AVE, #13
FORT COLLINS, CO 80524
Prepared by:
ENGINEERING
171 NORTH COLLEGE AVENUE
FORT COLLINS, CO 80524
970-219-2834
JANUARY 30, 2009