HomeMy WebLinkAboutRAINTREE ANIMAL HOSPITAL - PDP/FDP - 22-98A - REPORTS - DRAINAGE REPORT(3)
EROSION CONTROL:
The site is in the moderate wind erodibility zone and in the high rainfall erodibility zone. A
' silt fence will be constructed along the North, East and West property lines.- Straw bales will be
placed at the area inlet after the discharge pipe is constructed for the time interval until the water
quality outlet tower and riser pipe are constructed and the gravel filter is placed. The entire site will
Ibe disturbed with the grading. The basement foundation will be constructed as soon as the site is
graded. A water quality outlet for a dry extended detention basin will be constructed.
The storm water runoff calculations, the erosion control calculations, the extended erosion
control calculations and the Grading, Drainage and Erosion Control plan are enclosed as a part of this
report.
This drainage report and the design of the drainage system are in compliance with the City
of Fort Collins Storm Drainage Specifications and Criteria.
If you have any questions regarding this report, please call.
Sincerely,
Richard A. Rutherford, P.E. & L.
I RAR/meh
STEWART&ASSOCIATES
Consulting Engineers and Surveyors
IJanuary 26, 2000
Mr. Basil Harridan
Fort Collins Utilities
City of Fort Collins
P.O. Box 580
Fort Collins, CO 80522-0580
IDear Basil,
The following is the final storm drainage report for the Raintree Village Animal Hospital
P.D.P. situate in the Southeast 1/4 of Section 22, Township 7 North, Range 69 West of the 6th P.M.,
Fort Collins, Colorado. The site is bounded on the North by Evenstar Court, on the East by South
' Shields Street, on the South by a metes and bounds parcel with a single family residence and on the
West by the Fort Collins Senior Center P.U.D. The site is in the Spring Creek Drainage Basin. The
site contains 0.36 acres more or less. It slopes from South to North at an approximate slope of 4.3%.
I The ground cover is existing dryland grass and weeds. The historical drainage condition is to runoff
into the South gutter of Evenstar Court and then East to existing curb inlet on the South side of
Evenstar Court, 70 feet West of Shields Street. The inlet discharges North and Northwesterly to
Spring Creek.
The proposed site plan will have the Raintree Village Animal Hospital and its parking lot. The
' parking lot will have an access from Evenstar Court and an access through the Fort Collins Senior
Center P.U.D. to Raintree Drive.
' It is proposed to provide onsite detention in the parking lot and in a grass area at the
Southwest corner of the site. The extended detention for water quality will be in the grass area.
I There will be an area inlet box, with water quality orifice plate, in the extended detention area with
an overflow grate at elevation 5051.54, which is the highwater line of the extended detention. The
area inlet will have a vertical restriction plate in the bottom of the inlet over the 12 inch R.C.P. storm
I drain which will discharge into the Fort Collins Senior Center existing stormdrain at a new manhole.
The existing Senior Center drainage system discharges to Spring Creek, West of the Senior Center.
The release rate from the detention area is at the two year historic runoff rate from the site, which
was calculated by the Rational Method. The detention volume was calculated as the difference
between the two year historic runoff rate and the 100 year developed runoff rate, using a mass
diagram. The release rate is 0.17 cubic feet per second and the required volume of detention for the
I site is 2,838 cubic feet. The amount of detention provided is 3171 cubic feet to a high water line of
5052.75.
James H. Stewart
I and Associates, Inc.
103 S. Meldrum Street
P.O. Box 429
Ft. Collins, CO 80522
I 970/482-9331
Fax 970/482-9382
TABLE OF CONTENTS
1-2
Text of Report
3
Vicinity Map
479
Storm Water Runoff and Detention Calculations
10-11
Senior Center Drainage Table
12-15
Erosion Control Calculations
16-19
Extended Detention Calculations
Pocket
Grading, Drainage & Erosion Control Plan
FINAL DRAINAGE REPORT FOR
RAINTREE VILLAGE ANIMAL HOSPITAL P.D.P.
SPRING CREEK DRAINAGE BASIN
PREPARED FOR
RAINTREE VILLAGE ANIMAL HOSPITAL
JANUARY 26, 2000
PREPARED BY
STEWART & ASSOCIATES
103 SOUTH MELDRUM STREET
P.O. BOX 429
FORT COLLINS, CO 80522
TEL. 970-482-9331
FAX. 970-482-9382