HomeMy WebLinkAboutSite Certifications - 10/22/2001i
North Star
�*ftm, design, inc.
October 22, 2001
Basil Hamdan
City of Fort Collins
700 Wood Street
Fort Collins, CO 80522
a
Dear Basil,ZZ%���
This letter is in reference to the Water Quality Pond Certification for Loll of -the
Timberline ac Terres on ih SubdivisiFort Collins. Attached is a grading plan showing the
as constructed elevations in and around the water quality pond in Lot 1 which provides
water quality for all of the Timberline Terraces Subdivision. Also attached is a
calculation sheet showing the volume in the pond. The designed water elevation was
4939.20. The actual water elevation based on the as constructed grades is 4939.31.
A site inspection was completed on October 19, 2001. The drainage facilities have been
installed per the plan including the curb openings, the outlet structure, the outlet pipe and
orifice plates. Measurements of the outlet structure confirmed that the size and openings
conform to the design detail. Riprap at the north end of the outlet pipe has not been
buried but contractor was notified and committed to resolve this discrepancy. Three
columns of openings were drilled in the orifice plate rather than one as shown on the plan
detail. Again, the contractor was notified of the discrepancy and committed to resolve
this discrepancy by covering two of the columns of openings. Sod has been installed in
the water quality pond. Refer to -the attached grading plan for as constructed elevations
of the drainage facilities.
.An underground drainage pipe was added to the west side of the building to collect flows
from 2 roof drains and pipe that flow to the water quality pond. This drain is shown on
the attached plan.
mments.
700 Automation Drive, Unit I Windsor, Colorado 80550
970-686-6939 Phone 9 970-686-1188 Fax
North Star Design, Inc.
Windsor
W. Ash Stre�ro Suite
Water Quality Pond Volume
Windsor, CO 805 P Y
LOCATION:
PROJECT NO:
COMPUTATIONS BY
SUBMITTED BY:
DATE:
bottom inv.-
spill elev -
Home State Bank
138-01
ppk
North Star Design, Inc.
10/22/01
V = 1 /3 d (A + B + sgrt(A'B))
where V = volume between contours, ft3
d = depth between contours, ft
A = surface area of contour
Stage
(ft)
Surface
Area
(ft`)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
4937
0
4938
685
0.01
0.01
4939
1585
0.03
0.03
4939.2
6031
0.02
0.05
4940
23814
0.24
0.27
WQCV required =
WQCV provided at elevation =
DwQ =
ASBUILT POND
bottom inv.-
0.05 ac-ft
4939.2 ft
2.20 ft
Stage
(ft)
Surface
Area
(ft)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
4936.95
0
4937.5
258
0.00
0.00
4938
598
0.00
0.01
4938.5
1013
0.01
0.02
4939
1532
0.01
0.03
4939.2
2526
0.01
0.039
4939.31
5453
0.01
0.049
4940
23814
0.24
0.27
Page 1
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CALL UTILITY NOTIFICATION
COLOR
CENTER OF COLORA00
1=800RA922.1987
W534.6700
]2LL 2-Wi1NESS GAYS IN ADVANCE
BEFORE YW BIG i GRAN, W EXCAVATE
FOR THE MARKING OF UNDERGROUND
LEND MERGER UTILMIS
HP
HIGH POINT
RF
FINISHED FLOOR ELEVATION
TOW
TOP OF WALK ELEVATION
----- -- -- - -
- - EXISTING CONTOURS
EXISTING INDEX CONTOURS
— PROPOSED CONTORS
4905—
PROPOSED INDEX ONTOURS
— PROPOSED INFLOW CURB
— PROPOSED DUVALL CURB
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