HomeMy WebLinkAboutHEARTHFIRE PUD - RESUBMITTED PRELIMINARY (REMAND FROM CITY COUNCIL) - 31-95C - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTHearthfire at Richard's Lake Preliminary Drainage Report
A. INTRODUCTION
This report analyzes the drainage impacts of the proposed "Hearthfire at
Richard's Lake" development. The design considerations for this project are to
provide a drainage system capable of handling runoff generated on the proposed
site as well as convey the existing runoff from off -site tributary areas. In order to
accomplish this, the off -site and on -site drainage areas are studied as they are
impacted by the proposed project. This report was prepared following guidelines
and criteria presented in the "Fort Collins Storm Drainage Design Criteria and
Construction Standards", 1984 and the "Urban Storm Drainage Criteria Manual"
(USDCM), 1992.
1. Location
The project is located in the West half of Section 30, Township 8 North, Range
68 West, of the Sixth Principal Meridian, City of Fort Collins, Larimer County,
State of Colorado. (see Figure 1, page 2 - Vicinity Map) The project site is
bordered on the north by Douglas Road and single family homes located on
lands in unincorporated Larimer County and on the southwest by Richard's Lake.
County Road 13 borders the site on the northwest. Developed single family
home sites of the Serramonte Highlands subdivision, unincorporated Larimer
county border the northeast property line, the undeveloped Richard's Lake
Master Plan area lies adjacent the site to the southeast.
2. Property Description
The project site contains 107 gross acres of which approximately 20 acres are to be
I, drainage tracts and open space and approximately, 87 acres will be developed as
streets, and as single and multi -family residences. The site has previously been farmed
and used as grazing pasture. It contains 2 producing oil wells of the Ft. Collins Field
I which produces from the Cretaceous Muddy sandstone. The existing vegetation
consists of mainly native grasses and weeds. The soils on -site are silty to sandy loam
I type. The north part of the site has moderate wind and rain erodability, the portion of
the site adjacent to the lake has low erodibility for wind and rainfall. The site slopes to
the southwest at an average of 4% with slopes ranging for 0.5% to 12% on the site.
The south edge of the site presently drains to Richard's Lake, the northern portion of
"Hearthfire at Richard's Lake" site drains to an existing on -site closed topographic low
spot which retains water and supports a wetland.
The on -site wetlands will be set aside as a water quality open space. The permanent
wetland presently covers approximately 12.6 acres within a proposed tract.
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WINDSOR�
KILOMETERS 1 0 1 2 3 4 5 6 7 8 9 1•
MILES 1 0 1 2 3 4 5 6 '
The Pond at Hearthfire Subdivision Preliminary Drainage Report
F. REFERENCES
1. City of Fort Collins, Colorado - Storm Drainage Design Criteria and Construction
Standards, 1984 EDITION.
2. Urban Drainage and Flood Control District - Urban Storm Drainage Criteria
Manual, 1990 Revisions.'
3. Dry Creek Drainageway Planning, prepared by Gingery Associates, Inc.
January, 1980.
4. Larimer County Storm -water Management Manual, prepared by Resource
Consultants, Inc., May, 1979
5. Master Drainage Plan and Study, Richard's Lake Property, by Downing Leach,
October, 1986
6. Wellington Quadrangle, Colorado, U.S.G.S. 7.5 Minute Series (Topographic),
1965, Photorevised 1980.
7. Report of a Preliminary Geotechnical Investigation for Richard's Lake P.U.D.
Larimer County, Colorado prepared by. Empire Laboratories, Inc.
November, 1986.
8. Reviewer Comments, City of Fort Collins, Colorado - Stormwater Utility
June, 1995
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Hearthfire at Richard's Lake Preliminary Drainage Report
A Drainage Plan has been prepared and is included in the back of this report.
Included in the Appendices are calculations to support the swale, detention
pond, street and inlet capacities, and stormdrain pipe designs.
3. Summary of Erosion Control Concept
A majority of the site drains to the on -site wetland/detention pond. Sediment
control barriers will protect the wetlands from siltation. Disturbance of the
wetlands will be minimal. Silt fences will protect the on -site existing wetland and
will help prevent wind erosion. Overlot grading will be followed by temporary
seeding, utility installation and paving. Gravel filters and hay bales will protect
street inlets and swales respectively. The proposed development erosion plan
will provide protection in excess of the required effectiveness and with
downstream impacts consistent with historic patterns. The erosion control plan
meets the requirements of City of Fort Collins criteria.
Respectfully submitted,
MERRICK & COMPANY
Mark F. Ericson, PE
Project Engineer
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Hearthfire at Richard's Lake Preliminary Drainage Report
"Hearthfire at Richard's Lake" lies within Moderate to Low Rainfall and
Wind Erodibility Zones as shown by City of Fort Collins' maps. Soils on
the site include the Fort Collins Loam, Kim loam, and the Nunn Clay as
detailed in the 1986 Geotechnical Investigation for the Richard's Lake
P.U.D. by Empire Laboratories, Inc. Erosion is a potential problem during
construction and after until exposed soils are revegetated. Erosion control
performance standards were calculated according to criteria presented in
the City of Fort Collins Erosion Control Reference Manual for Construction
Sites. Temporary seeding with mulch will be used for areas that are
overlot graded. Permanent seeding with mulch will be used for areas that
are final graded. Permanent seeding with mulch will follow installation of
storm sewers and any swales. Gravel filters will be placed at all curb
inlets immediately after installation. Straw bales will be placed in all
erosion -prone swales. Outfall velocities will be at velocities low
enough to prevent erosion, rip -rap or other protection will be provided to
prevent scour and bank erosion.
Wind erosion will be minimized by phased grading and construction, and
placement of wind barriers and silt fences when cleared areas exceed the
maximum 200 foot criteria as presented in the City of Fort Collins Erosion
Control Reference Manual for Construction Sites.
F. CONCLUSIONS
1. Compliance with City Requirements
I The designs and calculations included in this report comply with the 1984 City of
Fort Collins Storm Drainage Design Criteria. Hydrologic and hydraulic
calculations were based on accepted practices for the Rational Method as
I contained in the City of Fort Collins Storm Drainage Design Criteria and in the
Urban Drainage and Flood Control District Criteria Manual. Calculations of the
i runoff rates and storm system for this project are included in Appendices 1 .and 2
of this report.
1. Summary of Drainage Concept
The existing site currently drains to the southwest to on -site existing low/wetland
i areas or to Richard's Lake. The proposed development drainage plan will
continue that pattern, with downstream impacts consistent with the historic flow
rates and volumes and meet the requirements of City of Fort Collins criteria.
I
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the water levels exceeded 5088.6 feet. The outfall will be designed to discharge
at non -erosive flow velocities acceptable to Water Supply and Storage Company
and compatible with the historic flow path. (Refer to Appendix 2 for outlet
design).
Wetland Management
Off -site wetland/pond B to the north will experience minimal disruption from the
development of the proposed "Hearthfire at Richard's Lake" The wetland will
continue to retain runoff generated in historic basin OH2, the existing topography
surrounding Pond B provides 23.4 acre feet of storage capacity above the
average water level of 5108 feet. The proposed "Hearthfire at Richard's Lake"
will not reduce that off -site capacity. The proposed emergency outlet
improvements for Pond B will allow the wetlands' water level to fluctuate as it has
historically. The emergency outlet structure is designed to release to the
southern, on -site Pond A only in the event Pond B water levels exceed 5110
feet.
On -site wetland/pond A will be minimally disturbed by the proposed "Hearthfire at
Richard's Lake" development. A detention outlet structure with emergency
spillway will be constructed outside of the existing wetland on the southeast side
of the topographic depression. Water quality and vegetation in the wetland will
be protected by a proposed sediment trapping gravel berms located downstream
of each stormwater pipe inlet to the wetland. These berms will slow inflowing
storm runoff allowing sediments and adsorbed pollutants to settle out in sediment
basins upstream of the wetland. Periodic maintenance of these sediment traps
by the homeowners association will insure continued water quality in the
wetland. Detention releases from the detention pond will utilize a water quality
outlet structure that protects the Richard's Lake receiving waters from sediments
and pollutants. (See detention release structure design detail sheet).
E. EROSION CONTROL
1. General Concept
i A majority of the site drains to the on -site wetland/detention pond. Silt fences will
be placed to protect the on -site existing wetland and to prevent wind erosion.
Overlot grading will be followed by temporary seeding, utility installation curb and
i gutter placement, and street, paving. Gravel filters and hay bales will protect
street inlets and swales respectively. The proposed development erosion plan
will provide protection in excess of the required effectiveness. Downstream
Iimpacts of runoff will be consistent with historic patterns.
2. Specific Details
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feature. Disturbance of this off -site wetland will be minimal since improvements
will be at elevations above the established wetland.
2. Specific Details
The site has been divided into 8 primary on -site basins and 2 off -site basins.
(See included Preliminary Drainage Plan). An effort was made to grade the site
in a manner that would cause the greatest amount of area to drain into pond A.
Five of the eight on -site basins drain into the existing wetlands pond A. The only
basin which drains directly toward Richard's Lake without detention is the 7.60
acre basin A6.
Street and Inlet Capacities
Appendix 2 contains spreadsheets showing the allowable 2 and 100 year street
flows for a variety of street slopes. Detailed inlet sizing will be presented with the
final drainage report. All inlets will be sized to maintain street capacities within
City criteria for the 2 and 100 year storms.
Stormwater Detention
"Hearthfire at Richard's Lake" site historically drained to either a privately owned
lake or to an on -site wetland. The City of Fort Collins requires detention of the
Maffior (100 year) Storm Provision to accept off -site flows discharging through
the property is also necessary. Using the Rational Method as outlined in
UD&FCD's Drainage Criteria Manual Volume 2 "Storage", a required detention
volume of cubic feet was calculated for the "Hearthfire at Richard's Lake"
assuming a release rate from the detention/wetland of 0.0 cfs. This assumes that
the undetained releases to Richard's Lake from developed Basin Al, A7 and
A8 are approved. The net increase in flows (presuming allowable historic
release rates from wetland pond A in the historic scenario, and no release from
wetland pond A (complete retention) in the developed condition) is:
Historical Developed
2 year 16.6 cfs 28.64 cfs (from basins Al, A7 and A8)
100 year 97.0 cfs 119.50 cfs (from basins Al, A7 and A8)
Easement to discharge these undetained flows and the detention pond releases
will be obtained from the privately owned Richard's Lake. Off -site flows from off -
site basin OH2 and any discharges from wetland/Pond B are not included in the
detention sizing of Pond A; it is assumed that any future development of
Basin OH2 will be detained on that site. Proposed Pond A is designed with 1 foot
of freeboard and an emergency release structure which would only discharge if
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volume requirement was determined to be not applicable since the
existing pond A retains all runoff for the 100-year storm. The
detention volume provided was determined by planimeter of the
proposed detention pond area in Tract A. The available volume
was calculated as that above the elevation of the existing wetland
average water level. Spreadsheets for both calculations are
included in the Appendix.
d. The Initial (Minor) storm was calculated using the 2-year recurrence
interval for Residential Land Use as required by the City of Fort
Collins' Design Criteria. The Major storm was calculated using the
100-year recurrence interval.
3. Hydraulic Criteria
a. The storm sewer pipe hydraulic capacities used for the system
design are as outlined in UD&FCD's Drainage Criteria Manual
Volume 2. Swale capacities and design depths were calculated
using Manning's equation and follow procedures referred to in
UD&FCD's Drainage Criteria Manual. Inlet capacities will be
calculated following the City of Fort Collins Storm Drainage Design
Criteria and follow procedures referred to in UD&FCD's Drainage
Criteria Manual.
D. DRAINAGE PLAN
1. General Concept
This drainage design is based on the 2-year recurrence interval storm for the
initial storm, and the 100-year recurrence interval storm for the major storm.
Proposed site improvements will direct the off -site flows through the site by
means of curb and gutter, storm sewers, and graded swales. The developed on -
site flows will be directed away from the houses and into the streets or swales
where they will flow to the proposed wetland/detention pond located in the center
of the site or to Richard's Lake. Disturbance and grading around Richard's Lake
and its existing wetlands will be avoided. Disturbance and grading of the on -site
wetlands (Pond A) will be the minimum necessary to provide the needed
detention outlet structure and emergency spillway proposed for "Hearthfire at
Richard's Lake" detention pond. Detention releases will meet the restrictive
criteria of the owners of Richard's Lake, and will include a water quality outlet.
Provision for pass through of any discharges from off -site wetland B in the
unlikely event it overflows will be made. Improvement to the existing off -site
Pond B/wetland outlet will be made in cooperation with the owners of this off -site
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Hearthfire at Richard's Lake Preliminary Drainage Report
IUnder normal conditions, this wetland drains by evaporation and percolation to
the groundwater table and no flows enter the "Hearthfire at Richard's Lake"
C. DESIGN CRITERIA
1. References and Regulations
a. "Richard's Lake Subdivision, First Filing Preliminary Drainage
Plan", by Downing -Leach 10%86, was reviewed and utilized to
assess off -site contributions to the proposed "Hearthfire at
Richard's Lake" site. No previous drainage studies for the project
site have been prepared per available information. No drainage
study for the adjacent property to the north, was available at the
time this preliminary report was prepared.
b. This report and the analysis and design of the storm drainage
facilities for the "Hearthfire at Richard's Lake" site are based upon
regulations outlined in the City of Fort Collins Storm Drainage
Design Criteria and Construction Standards Manual" May, 1984
and Urban Drainage and Flood Control District's "Urban Storm
Drainage Criteria Manual", 1989.
C. The Dry Creek Master Plan by Gingery Associates, Inc., 1/80 was
reviewed for this preliminary report.
Hvdroloaic Criteria
�. a. The design rainfalls were determined using the "Rainfall - Intensity
- Frequency for City of Fort Collins, Colorado" (Graph included in
Appendix 1) from the City's Storm Drainage Design Criteria
Manual.
b. The Rational Method was used for calculation of storm runoff
associated with this development. Overland flow time of
concentrations were calculated based on the "Overland Time Of
Flow Curves" (included in Appendix 1) from UD&FCD's Drainage
Criteria Manual. Travel times for channelized flow were calculated
using the "Estimate Of Average Flow Velocity" (included in
Appendix A) also from the UD&FCD's Criteria Manual.
C. The City of Fort Collins Criteria specifies detention of the 100 year
(major) storm and release at the 2 year historic rate. The detention
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Hearthfire at Richard's Lake Preliminary Drainage Report
drainage divide between the area draining northwestward toward wetland pond
A and a gentle eastward sloping pasture area off -site towards the Master
Planned Richard's Lake P.U.D. property to the southeast. Off -site flows enter
Historic Basin H4 along the east property line as sheet flow from the
Serramonte Highland Subdivision. A portion of these off -site flows are directed
to the southeast across the Richard's Lake P.U.D. property, and a portion are
directed by existing slopes to the wetland pond A. Basin H4 generates a 2 year
storm flow of 2 cfs and a 100 year storm flow of 11.9 cfs and. passes through
respectively 0.2 cfs and 0.5 cfs of off -site flows.
Historic basin OH2
Off -site historic basin OH2 is defined by the drainage divide caused by Douglas
road on the north and County Road 13 on the west and includes the residences,
farmland and oil field area to the north of the proposed development. Basin OH2
is somewhat developed with approximately 10 homes, barns and oil field sheds,
tanks, and graded dirt roads. Basin OH2 covers 50.2 acres. Runoff generated
in basin OH2 drains internally by sheet flow to an existing wetland/pond (Pond
B). Under normal conditions, the wetland/pond drains by percolation to the
water table and evapo-transpiration and does not discharge any flows off -site.
During extremely high water events, a poorly graded channel on the southwest
side of wetland/pond. B would allow it to discharge to "Hearthfire at Richard's
Lake" on -site wetland, Pond A. These high water releases could only occur
when water levels in Pond B exceed 5110 feet elevation. The existing available
storage volume in the Basin OH2 wetland/retention pond is 23.4 acre-feet at the
5110 foot contour, which is 7 times greater than the 100 year historic runoff of
3.2 acre feet.
Historic basin OS1
Off -site historic basin OS1 is defined by a drainage divide in the landscaped
yards of the Serramonte Highlands subdivision. Basin OS1 is developed with
i approximately 3 homes with landscaped yards. Runoff generated in basin OS1
drains by sheet flow to the southwest. This off -site runoff enters the "Hearthfire
at Richard's Lake" site along the northeast property line and eventually flows to
ithe existing on-site/wetland/pond (Pond A).
3. Outfalis Downstream From Proper y
' The southern edge of the existing site drains by overland flow and swale to the
south into Richard's Lake. The northern majority of the existing site drains to the
' existing on -site wetland -pond area which will only releases flows to Richard's
Lake during extremely high water events whose magnitude is in excess of the
100-year storm. Off -site flows in basin OH2 presently flow to wetland/pond B.
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Hearthfire at Richard's Lake Preliminary Drainage Report
western boundary of Historic basin H1. County Road 13 is superelevated at a
point about 1200 feet south of Douglas Road. This superelevation causes a
drainage divide at the west turn in the road, and prevents the crossing of flows
generated west and north of the road. An existing roadside swale collects flow
from the east 1/2 of County Road 13. This swale discharges into a pasture
located on the west side of the site. The County Road 13 swale collects the
gravel road runoff from an area of approximately 0.33 acres. Basin H1 is defined
on the south west by the water level of Richard's Lake. The northeast flank of
the basin boundary is created by an existing topographic divide which separates
Richard's Lake from the on -site low, wetlands/pond area to the north (Pond A).
Total flows generated by Historic Basin H1 are 10.2 cfs and 60 cfs for the 2 year
and 100 year storms respectively.
Historic basin H2
Historic basin H2 comprises the majority of the site and includes the central,
closed basin area which drains internally to the existing wetland/pond (Pond A).
Basin H2 covers 59.4 acres. This sub -basin presently sheet flows to the
wetland. Under normal conditions, the wetland/pond drains by percolation to the
water table and evapo-transpiration. During high water events, a graded
channel on the south side of the wetland allows it to discharge to the southwest
to Richard's Lake. These. high water releases occur when water levels in Pond
A exceed 5089.5 feet elevation (for events in excess of the 100-year storm). In
like manner, Pond B located off -site to the north, overflows through a graded
channel into Pond A during high water events when water levels exceed 5110
feet in the off -site pond B (for events in excess of the 100-year storm).
Historic Basin H2 generates 16.6 cfs in the 2 year event, and 97 cfs during the
major storm event.
Historic basin H3
Historic basin H3 is a small (2.9 acre) area along the southeast property line of
the site where existing natural slopes direct flows towards the Master Planned
Richard's Lake P.U.D. property to the southeast. These flows are directed to the
southwest on that property and eventually reach Richard's Lake. The basin
generates a 100 year storm flow of 3.9 cfs.
Historic basin H4
Historic basin H4 is a small (5.6 acre) on -site area along the east property line of
the site where the topographic high caused by the oil service road defines a
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Hearthfire at Richard's Lake Preliminary Drainage Report
The proposed project will be impacted by two off -site sub -basins
a. Off -site basin OS1, located immediately to the east of the central part of
the proposed "Hearthfire at Richard's Lake" site is presently developed as
single family houses and landscaping at a density of 0.5 units per acre.
OS1 is 1.6 acres of the Serramonte Highlands Subdivision. OS1 is
calculated to have a developed 2 year runoff coefficient of 0.25, and a 100
year runoff coefficient of 0.45. The existing 100 year peak flow to
"Hearthfire at Richard's Lake" site from Basin OS1 is calculated to be 4.9
cfs. This runoff flows to the southwest across an existing dirt track and
enters the site along the east. An existing poorly defined swale conveys
these flows to the southwest to the wetlands (Pond A).
b. Off -site Historical OH2 contains 50.2 acres of farmland, residences, farm
buildings, and oil field buildings located to the northeast of the proposed
"Hearthfire at Richard's Lake" site. Under normal conditions this basin
does not discharae runoff to the south onto the proposed site Basin OH2
has an existing wetland/pond with an average water level of 5108 feet
elevation. At 5108 feet, the north, off -site wetland covers 6.7 acres. The
highest closing contour for the 15.67 acre closed area containing this
wetland/pond is 5111 feet.
C. There are no major drainage ways on the proposed development site.
2. Drainage Patterns Through Property
The site can be divided into four historic sub -basins and 2 off -site historic basins.
On -site Historic basins are designated with an H, the off -site historic basins are
labeled with OH. (See Figure 1, Appendix 1- Historic Basin Map).
Historic Basin H1
Historic Basin H1 contains 40.6 acres of pasture sloping to the south and
southwest. The basin presently drains to Richard's Lake. The basin is defined
on the north by a natural high point located about 250 feet south of the
intersection of County Road 13 and Douglas Road. County Road 13 defines the
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Hearthfire at Richard's Lake Preliminary Drainage Report
A
I B. HISTORIC DRAINAGE
1. Overall Drainage Basin Description
The site is located in the major historic Dry Creek Drainage Basin.
The portion of the major drainage basin in which this project is located is
presently partially developed. Major basin drainage is generally from northeast to
southwest and then southeast with major defined man-made channels fed by
sheet runoff and local irrigation and roadside ditches. The slopes vary across
the site from 12.6% to as low as 0.5%, with an average of approximately 4
percent. Present zoning for the site calls for residential development.
Jurisdictions in the drainage basin include unincorporated Larimer County, and
the City of Fort Collins. The site lies entirely within the City of Fort Collins.
The existing tributary sub -basin in which the site lies is defined by County Road
11 to the east, Richard's Lake on the south, County Road 13 on the west, and
Douglas Road (County Road 54) on the north. Runoff from landscaped rear
yards of the Serramonte Highlands Subdivision to the east enter the site as
sheet flow along a portion of the eastern border of the property. Douglas Road
on the north forms a man-made drainage divide preventing southward flows from
the farmland north of the road. On the west side of the property, the eastern half
of County Road 13 is superelevated where it turns west; this superelevation
prevents flows from crossing from the north and west. A ditch along the east
side of County Road 13 drains into the site at the location of the west bend in the
road. No flows enter the site from the south.
The site slopes to the southwest at an average of 4%. An oil field service road
located at the southeast corner of the site acts as a drainage divide diverting
runoff from a small area off -site to the southeast and directing the majority of the
flows generated in the southeast corner of the site to the on -site wetland (Refer
to Historic basin map, Basin 112). The existing drainage pattern of the majority of
the site is surface flow draining to the existing on -site wetland area. The historic
on -site 100 year storm flow to this wetland is calculated to be 97 cfs (2.4 cfs/ac).
The edge of the property on the south side of the site drains south into Richard's
Lake (Refer to Historic Drainage Basin Map, Basin 111). The historic on -site 100
year storm flow to Richard's Lake is calculated to be 68.4 cfs (1.7 cfs/ac) See
Appendix 1 - Historic Runoff calculation).
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The Pond at Hearthfire Subdivision Preliminary Drainage Report
' Scale: V=1/2 Mile
' Vicinity Map
Figure 1
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Hearthfire at Richard's Lake - Preliminary Drainage Report
TABLE OF CONTENTS
PAGE
INTRODUCTION.......................................................................................................................... 1
GENERAL LOCATION AND DESCRIPTION.............................................................................. 1
Location........................................................................................................................................ 1
PropertyDescription..................................................................................................................... 1
VicinityMap..................................................................:............................................................. 2
B.
HISTORIC DRAINAGE....................................................................................................
3
OverallBasin Descriptions................................................................................................
3
Drainage Patterns Through the Property ..........................................................................
4
Outfalls Downstream from the Property............................................................................
6
C.
DESIGN CRITERIA...........................................................................................................
7
Referencesand Regulations.............................................................................................
7
HydrologicCriteria.............................................................................................................
7
IHydraulic
Criteria...............................................................................................................
8
D.
DRAINAGE PLAN.............................................................................................................
8
General Concept...............................................................................................................
8
I
SpecificDetails.................................................................................................................
9
E.
EROSION CONTROL PLAN..........................................................................................
10
GeneralConcept.............................................................................................................
10
SpecificDetail..................................................................................................................
10
F.
CONCLUSIONS...............................................................................................................11
Compliance with Standards............................................................................................
11
I
Summaryof Drainage Concept.......................................................................................
11
Summary of Erosion Control Concept............................................................................
12
G. REFERENCES................................................................................................................13
H. APPENDICES
Appendix 1- Hydrologic Calculations...................................................................................
Appendix 2 - Hydraulic Calculations....................................................................................
I
Merrick & Company Page 2
I: AC015011782%PRELIM11HFMNDRNG.N15
IHearthfire at Richard's Lake Preliminary Drainage Report
Prepared for:
Hearthfire at Richard's Lake
Richard's Lake Development
1412 Richard's Lake Road
Fort Collins, Colorado 80524
Contact: Mr. Bill Yunker or Mr. Craig Hash
(303) 484-1921
Prepared by:
MERRICK & COMPANY
2450 S. Peoria Street
Aurora, Colorado 80014
Contact: Mr. Mark Ericson, PE
Telephone: (303)-751-0741
Merrick & Company Job Number: 15011782
' Merrick & Company Page i
I: ACL%15011702%PRELIM1IHFMNDRNG.N15
HEARTHFIRE AT RICHARD'S LAKE
PRELIMINARY DRAINAGE
AND EROSION CONTROL REPORT
August 3, 1995
Revised November 14, 1995
Revised February 19, 1996
Revised April 19, 1996
Revised July 10, 1996
Presented to
The City of Fort Collins
Prepared by
Merrick & Company