HomeMy WebLinkAboutLot Certifications - 07/11/1995-·----------® V' VV C: .;:» I C: '-
June 28, 1995
Mr. Basil Hamdan
City of Fort Collins
Utility Services Stormwater
235 Mathews
Fort Collins, Colorado 80522
wELsH ENGINEERING SCIENCE & TECHNOLOGY, INC .
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PRJ# 94415.500
RE: THE SEVEN OAKS ACADEMY -DRAINAGE CERTIFICATION SURVEY
Dear Basil:
This letter is being submitted with the drainage certification paperwork for the Seven Oaks
P.U.D. site as clarification of the existing conditions at the time of the certificat i on. The
configuration of Pond A as shown on the Drainage Certification Survey drawing number 1
represents a temporary grading until the future building and parking areas are constructed.
This grading is necessary to provide drainage to the outlet across grass. Ponds A and B
provide the final required pond volume and outlet structures.
If you have any quest i ons please call me.
Si ncerely,
WESTEC
J. Thomas Knostman , P.E.
Project Engineer
JTK/sea
cc: Larry Neal
2629 Redwing Road . Suite 200 . Fort Collins . Colorado 80526 -2879. Ph . 970 226 3535 Fax 970 226 64 75
Reno
Nevada
Tu cson
Ar izona
Elko
Ne v ada
Winnemucca
Nevada
Pleasanton
California
Eng lewood
Colorado
WATER, WASTE & LAND, Inc.
PROJECT:
PRJ.NO.:
POND:
DATE:
INPUT VALUES
ELEV AREA
(Ff) (SF)
80.10 0
80.20 198
80.40 647
80.60 1,518
80.80 2,869
81.00 4,832
81.20 7,416
81.40 10,100
81.60 12,771
81.75 13,480
Seven Oaks Academy P.U.D.
415.500 pond cert
Pond A, Basin A
06/22/95
TRAPEZOIDAL
INCREMENT CUMULATIVE
VOLUME VOLUME
(CF) (CF)
7 7
80 87
210 297
432 729
762 1,490
1,216 2,706
1,745 4,451
2,282 6,733
1,969 8,701
~ <2-~ D
\lbL ~ ,;s I Z..'5
A VERA GE END AREA
INCREMENT CUMULATIVE
VOLUME VOLUME
(CF) (CF)
7 7
85 91
216 308
439 746
770 1,516
1,225 2,741
1,752 4,493
2,287 6,780
1,969 8,749 -=tr~Eu::J.
POND:
DATE:
Pond B, Basin B
06/22/95 K~~E-~~~
~L__ -\2.. '-\ 57 c.Q ' -J
INPUT VALVES TRAPAZOIDAL AVERAGE END AREA
INCREMENT CUMULATIVE INCREMENT CUMULATIVE
ELEV AREA VOLUME VOLUME VOLUME VO LUME
(Ff) (SF) (CF) (CF) (CF) (CF)
76.40 0
77.00 365 73 73 109 109
77.20 745 109 182 111 221
77.40 1,116 185 367 186 407
77.60 1,490 260 626 261 667
77 .80 1,698 319 945 319 986
78.00 1,838 354 1,298 354 1,340
79.00 2,624 2,219 3,518 2,231 3,571
79.40 3,258 1,174 4,692 1,176 4,747
80.00 5,332 2,552 7,243 2,5 77 7,324
80.40 7,365 2,528 9,772 2,539 9,863
80.60 8,256 1,561 11,333 1,562 11,425
80.80 9,136 1,738 13,072 1,739 13,165
81.00 10,013 1,914 14,986 1,915 15,080
81.20 10,944 2,095 17,081 2,096 17,175
DRAINAGE CERTIFICATION FORM
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Please fill out all applicable items in this certification form l.9c~
for single family, multi-family and commercial properties.
Write "OK" for items checked or actual number checked in field.
Use "N/A" for items that are not applicable to the property that
is being certified.
A. Drainage facilities certification
1. Pond Certification
-volume verification
a. topographic records and volume
b. cross-sections and spot elevations
-positive fall to pan
-side slopes
-invert elevation
-spi llway elevation
v -placement and size of riprap
-side slopes
-grading
V -orifice plate installation and size
v -compaction of berm
-structural integrity of pond
2 . Swales L;tJs.$ 4~
-location (are they within easement)
v'-dimensions and cross-section verification
-longitudinal slopes and side slopes
-spot elevations
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OK:_
1)~ ~,57/e''
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v -permanent erosion control measures
(drop structures, riprap, etc .... )
v -tie-in to pipes, pans, curbs, etc ... .
-weir size (elevations, size, opening, etc ... )
-available freeboard
-landscaping infringement on swales
3. Pines
4.
v -size and type
-slopes (as-built and comparison to minimum
0.4% slope)
-pipe capacity calculations if slopes are
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~
significantly altered
-invert elevations "L-.lue:r-~o l'::f <..c. • 1 tA.
Ou,..,~ -~~ie>
-installation and backfill material
-cover
-encasement and clearance from other utility
lines close by
-joints
o..c.
D~
Ccr..c~ete Pan Channels ~ ~D "T~U::-~
/ -size
,_, -slope
-super ele v atior..
/-cross-seccion
/-t hi ckness
-elevatic:::s
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5. Inlets ~~y
-size and type 4· r~e__~~t-£5;-"
-size of opening (or name of standard used) 4 ' LoNts,.. L,.11 Vea
-grate elevation Al"
-invert elevation ~080>
-box size .1__
6. Cross pans
...,.... -size
/l~tZ.,~ ~l\'llE. [J~J.+ Hui.JI) D/2I7Vtj
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7.
8 .
V -type
t, -grade
-elevation
v -cross-sectional depth
..---tie-in to curb and gutter
C'D"-lc...i...Cr,e:.
/,2.._1o
e23±to 8t.?tf <=re,
L -
0 /::::.
Culverts ~~ ~~ ~N uJe TH%~.o
-type
1-iJ_-:VG cJ:>(4'' o~lttC
We
""-size
I 8D, I ro ~?t0' -invert elevation
i/'-headwalls 6~ --
D~~TE.. 4''~ btC..
Underdrains
-size }!__A_
-type /I
I,
-cover
-backfill 'I
/v
-geotextiles
-cleanouts
9. Curb cuts
v' -size
(../ -tie in to swale, pipe, etc ....
B. Certification of Grade Elevations Adjacent to
Drainage Facilities:
-minimum opening elevations
-top of foundation elevations
-comparison to 100 year WSEL's
(Freeboard requirements and floodplain issues)
C. Certification of Erosion Control Measures:
1. Permanent Measures:
-Permanent vegetation (6" bare spots and weeds
under control l
-riprap
-riprap bedding
-drop sections
-sediment basins /water quality ponds
-netting mats/blankets
-mulching
. ~
2. Temporary Measures:
-mulching
-inlet filter installation
-check bale dams
-seeding and temporary vegetation
-silt fence
D. Site Cleanup After Construction
-construction clean up
-smoothing of ruts
-reseeding
E. Statement of Compliance
This certification is signed and stamped and by signing this
form the engineer(s) attests that to the best of his knowledge
the as-built conditions of the drainage facilities are as
described in the above form and in the redlined plans enclosed.
Failure to properly disclose all known information could
result in the rejection of this certification and prevent the
release of any Stormwater Utility holds on Building Permits
and /or Certificates of Occupancy.
F. Signature and Stamp by a Colorado Registered
Engineer.