HomeMy WebLinkAboutSPRINGBROOK PUD FINAL - 7 90A - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT0
STORM DRAINAGE REPORT
SPRINGBROOK P.U.D.
PREPARED FOR
MR. GARY MACKEY
MARCH 5, 1990
PREPARED BY
STEWART & ASSOCIATES, INC.
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SITE LOCATION:
The site is located in the Northwest I of the Northwest } of Section
27, Township 7 North, Range 69 West of the Sixth P.M., Fort Collins,
Larimer County, Colorado. The site is bounded on the north by West Drake
Road, on the east by the constructed Georgetown Project, and undeveloped
on the west and south sides of the site. Spring Creek is adjacent to
the south side of the project.
SITE DESCRIPTION:
The site contains 6.28 gross acres. There is an existing house and shed
located in the Northwest part of the project. The majority of the site
is covered with grass type vegitation. There is a 21.5 foot driveway
access to a house south of the project located along the east property
line of the site. The North 52 feet of Drake Road is constructed. The
south portion of the site is in the floodway of Spring Creek as shown
in the Spring Creek major Drainageway Plan completed for the City of
Fort Collins by Gingery Associates, Inc., dated August, 1980. From the
City topography maps the site runoff is from the northwest to southeast.
The runoff in the southwest portion of the site in more to the south.
The slope of the site varies from 0.9% over the East 'I to 8.52 in the
Southwest a. There is currently no offsite runoff across the site.
All runoff from the site is to Spring Creek. The existing runoff from
the site is Q2 = 2.55 c.f.s.; Q10 = 4.54 c.f.s.; Q100 = 9.69 c.f.s, more
or less.
PROPOSED DESIGN:
The site will be subdivided into 24 dots, a street along the east side
of the site and a cul-de-sac running west to east in the middle of the
site. Drake Road will be constructed to arterial standards and the other
two to residential standards. The. North 14 lots will be duplex lots
and the remaining 10 lots are single family lots. The existing house
is to remain.
There will be no home construction or fence construction allowed in the
floodway. All houses in the 100 year flood plain will be required to
have finished floor 11 feet above the developed 100 year flood plain
elevation. The Spring Creek major drainageway will be used to determine
this elevation. Due to the close location of the site to Spring Creek
we propose to not have any detention.
The site has been divided into three sub -basins. Basin 1 which is the
South 2.1 acres of the site will drain overlot to Spring Creek. The
developed runoff from this basin is Qpp = 1.01 c.f.s.; Q10 = 1.83 c.f.s.;
and Q1p = 3.62 c.f.s. Basin 2 is 1.T acres South of Springbrook Court.
Runoff �rom this basin is to Springbrook Court, to Springbrook Lane to
Spring Creek. The developed runoff from this basin is Q2 = 0.89 c.f.s.;
Q10 = 1.58 c.f.s.; and Q1 0 - 3.16 c.f.s. Basin 3 is North of Springbrook
Court. Runoff from this basin is to Springbrook Court to Springbrook
Lane, then to Spring Creek. The developed runoff
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Springbrook P.U.D.
January 1990
Page 2
for this basin is Q = 1.48
c.f.s. The combine runoff
is Q = 2.70 c.f.s.; Q10 =
runoff from Basins 1,2 and
Q100 = 12.85 c.f.s.
c.f.s.; Ql = 2.57 c.f.s.; and Q100 = 5.20
of Basins 4 and 3 at the S.outh property line
4.71 c.f.s.; and Q 00 = 9.23 c.f.s. The total
3 is Q2= 3.71 c.f.s.; Q10 = 6.54 c.f.s.; and
Runoff from the South 2 of Drake Road will be to east to the existing
curb opening about 500 feet more or less east of our site. All of the
South 2 of Drake Road from Taft Hill Road will flow east. The developed
runoff from Taft Hill at our east property line is Q2 = 2.31 c.f.s.;
Q10 — 4.02 c.f.s.; and Q100 = 6.75 c.f.s. There wi12 not be any inlets
required -along Drake Road.
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AV OCOMPUTATIONS
James H. Stewart & Associates, Inc. 214 N.,Howas St. Ft. Collins, CO 80521 (303) 492-9131
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®COMPUTATIONS
James H. Stewart & Associates, Inc. 2,1,44 N..Howes St. Ft. Colliris, CO 805.21 (303)482-9331
By: —%41"14 Date-W0 Client: 4 �y Sheet No.of 7
Chkd By: Datatee Project:) Job No.
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AMPUTATIONS ® .
James H. Stewart & Associates, Inc. 214 N..Howes St. Ft, Collins, CO 80521 (303) 48Z9331
By: .-AG Date 3 S 90 Client: --gga/�y /�A�.le Sheet No. 5� of
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