HomeMy WebLinkAboutPOTTS PUD FINAL - 6 92A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTNt�l Only
For RVI and COMITIent
"FINAUipq
DRAINAGE INVESTIOX-h
END
POWs' - P. U. D.
A PROPOSED 26 UNIT MULTI -FAMILY
RESIDENTIAL. COMPLEX
FORT COLLINS, C01A)RAD0
Prepared for
ARCHOVEMURE ONE
150 East 29th Street
Suite 200
Loveland, Color -ado 80538
May 4. 1992
Project No. PILA-971-92
IUM1604401111:
MOOMM Engineering Associates
ISO East 291h Street, Suite 225
Loveland, Colorado 80538
Telephone: (303) 663-2221
Civil and Environmental Engineering Consultants
Engineering Associates
May 4, 1992
Project No. PLA-071-92
I
Mr. John Freeman, Architect
ARCHITECTURE ONE
150 East 29th Street
Suite 200
Loveland, Colorado 80538
Dear Mr. Freeman,
i The enclosed report represents the results of the Final Drainage Investigation for
POTTS' - P. U. D., a proposed multi -family residential complex to be located on a 1.7 ±
acre parcel at the Southwest corner of the Matador Apartments - Phase IV in the City of
i Fort Collins, Larimer County, Colorado.
This investigation was based upon the proposed site development plan; proposed site
grading plan; on -site observations; and available topographic information. The
i investigation was performed in accordance with the criteria established in the City of
Fort Collins "Storm Drainage Design Criteria and Construction Specification Standards"
manual.
i
Thank you for the opportunity to be of service to you. If you should have any questions,
please feel free to contact this office.
Respectfully Submitted,
Dennis R. Messner, P.E.
MESSNER Engineering Associates
DRM/mkm
Enclosures
Civil and Environmental Engineering Consultants
150 E. 29th Street, Suite 225 Loveland, Colorado 80538 Telephone: (303) 663-2221
TABLE OF CONTENTS
IZ
Letter of Transmittal
Table of Contents
Scope
Site Description
Existing Conditions
Proposed Development
Erosion Control Measures
Conclusions and Recommendations
ii
2
2
3
EXHIBITS
Vicinity Map
Existing Conditions Exhibit
Grading & Drainage Exhibit
Landscape Plan/Erosion Control Exhibit
Calculations
Matador Phase IV Drainage Report & Plan
ii
SCOPE
The following report represents the results of a final drainage investigation for a
proposed 26 unit multi -family residential complex to be located on a 1.67± acre parcel of
land situated in the Southeast Quarter of Section 15, Township 7 North, Range 69 West of
the 6th P.M., Larimer County, Colorado. The site is located at the Southwest corner of the
"Matador Apartments - Phase IV" in the City of Fort Collins.The investigation was
performed for ARCHITECTURE ONE. The purpose of this investigation is to determine
the effects of the proposed development on the area's existing drainage conditions and to
determine the improvements, if any, and the appropriate sizing for proposed
improvements so that it may be incorporated with the construction of the project. The
conclusions and recommendations presented in this report are based upon the proposed
site development plan; proposed site development construction plans; on -site
observations; and the available topographic information. The analysis was performed in
accordance with the City of Fort Collins "Storm Drainage Design Criteria and
Construction Standards" manual.
SITE DESCRIPITION
The site is irregular in shape and contains approximately 1.699 acres. The site's
East-West dimension varies but is considered to average approximately 175 feet. Its
North -South dimension is approximately 450 feet. The site abuts the easterly right-of-way
of the Larimer County Canal #2. The site is located approximately 350 feet south of West
Elizabeth Street and 700 feet west of City Park Avenue. The site is located In the SPRING
CREEK DRAINAGE BASIN.
EXISTING CONDITIONS
The site is presently vacant and undeveloped. The ground cover consists of native pasture
grasses and a few volunteer trees. The ground slopes toward the northeast and is
relatively flat with grades ranging from 0.75% to 1.5%. The "Soil Survey For The Larimer
County Area" prepared by the U.S.D.A., Soil Conservation Service, indicates that the
upper layer soils are a sandy clay loam. "The Survey" indicates that the soils have a slow
to moderate runoff potential and have slight to moderate wind and water erosion
potential.
The area surrounding the site is virtually fully developed. As previously stated, the
Larimer County Canal #2 forms the western boundary of the site. The area to the west of
the canal is a single-family residential subdivision known as Fairview. To the north of
the site are a Taco Bell restaurant and a Diamond Shamrock convienence store. The
areas immediately adjacent to the site on the north consist of parking lots for the Taco
Bell and a C.B. & Potts restaurants. The area adjacent to the site on the east consists of
the Matador Apartment complex.
The site does not receive runoff from the surrounding properties. The runoff from the
area to the west is intercepeted by the Larimer County Canal #2. Runoff from the area to
the north flows to the north and east away from the site. Runoff from the area to the east
flows to the north and east away from the site. Runoff from the site flows overland to the
C.B. & Potts' parking lot. The flow is detained within this parking lot and discharged
through a controlled release into the Diamond Shamrock drainage system. This
eventually discharges into a 15" dia. storm drain that flows east in West Elizabeth Street.
1
PROPOSED P
The proposed development of the site is to consist of constructing 24 multi -family
residential units along with the associated access drives and parking. The runoff
generated on the major portion of the site is to be routed overland to the access drive. The
drive has been preliminarily designed to be graded to a low point situated near the
southeast corner of the site. A storm drain inlet is to be constructed at this point in order
to intercept and collect the runoff. An orifice plate is to be placed over the inlet end of the
pipe outfalling from the storm drain inlet. The orifice plate will act as a control device to
limit the rate of flow discharging from the site. The runoff will be detained and will pond
in the access drive and parking areas due to the restricted release rate. A 15" dia. storm
drain pipe is to be installed to route the flow to the north and east through the C. B. &
Potts' parking lot to an existing 15" dia. Storm Drain located along the easterly boundary
of the C.B. & Potts' parking lot: The minor area in the northeast corner of the site that is
not routed to the access drive detention area will be detained in a small detention area to
be located in the landscaped border at the northeast corner of the site. The existing inlet
located in the C. B. & Potts' parking lot is to be rerouted to discharge into the proposed 15"
dia. Storm Drain. This routing will retain the intent of the original drainage design
pattern.
EROSION CONTROL MEASURES
Erosion control considerations have been made based upon the short term, i.e., during
construction activities and the long term, through the life of the facility. The long term
measures that are to be incorporated into the project in order to reduce erosion are the
proposed methods and materials to be used to provide a surface covering for the parking
areas, walkways, driveways and the landscaped open areas. The structures and hard
surfaced areas will provide a covering to deter erosion. The landscaping to be established
will be a combination of plantings and ground covers to deter erosion. (Please refer to the
proposed "Landscaping Plan")
The short term erosion control method to be incorporated into the construction
requirements for the project is the placing of "Curb Inlet Filter Gravel" at the proposed
storm drain inlet to be constructed onsite. It is not considered as necessary to provide any
wind erosion measures due to the protected nature of the site.
The schedule for construction activities is anticipated to be: April 15 - June 30, perform
earthwork grading operations, install utilities and construct access drive; May 1 -
August 15 construct initial 6 unit structure; July 1- April 1, 1993 construct remaining
structures; July 15 - April 15, 1993 instal landscaping in conjuntion with completion of
each structure. This schedule is proposed as the conservative time line with the
anticipation that actual construction will proceed on a faster schedule. In any case the
site will be "open" and subject to water caused erosion for an extremely short period of
time.
VO
CONCLUSIONS AND RLIOMMENDATIONS
1. 'The proposed development will retain the existing drainage patterns.
2. The site is located in the SPRING CREEK DRAINAGE BASIN. The site is not
located within the floodway or flood plain.
3. All development is to be performed in accordance with City of Fort Collins
Standards and Specifications.
4. Onsite detention of stormwater is to be provided. The runoff volume difference
between the existing and proposed conditions is estimated to be 2,656 cu. ft. when
based upon the difference between the runoff from a 2 Year Storm with the site
considered at the existing condition and the runoff from a 100 Year Storm with the
site considered at the proposed conditions. Therefore, a detention volume of
approximately 9,350 cu. ft. has been designed to be provided onsite and the flow is to
be released at a rate of 0.55 c.f.s.
5. The City of Fort Collins Standards for temporary erosion control measures are to be
incorporated with the construction activities.
3
VICINITY MAP
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u
Vicinty Map for
POTTS' - P. U. D.
located in
SE 1/4 Section 15, Township 7 North, Range 69 West of the 6th P3L
Fort Collins, Colorado