HomeMy WebLinkAboutLot Certifications - 04/20/2001 (3)1 R�
North Star
design, inc.
April 17, 2001
0
Jay Barber
City of Fort Collins Storm Water
700 Wood Street
Fort Collins, CO 80522
E
Re: New Belgium Brewery Office Pond volume certification
Jay; 60 ��0/j 3 .
This letter is to indicate the volume of the Detention Pond A as was constructed with the
Office Addition to the New Belgium Brewery. The survey of the pond was conducted by
JR Engineering and the as -constructed volume calculations for the Detention Pond A are
attached.
The required detention for Detention Pond A with the Office Addition was calculated to
be 0.125 acre-feet. A variance was granted to the 1' freeboard requirement for this pond
because of the proximity of the irrigation ditch and the small required size of the pond.
As you can see from the calculations, the pond provides approximately 0.114 acre-feet of
detention as surveyed. This is approximately 92% of the required volume (about 480
cubic feet less than the required volume). The restrictions placed on this area by the
existing building, the proposed building and the existing irrigation ditch have made it
difficult to achieve the design volume in the pond. It is the desire of the owner to request
that you to accept the volume provided in this pond as adequate and, if required, provide
excess volume in the existing pond east of this pond. This could be accomplished by
slightly increasing the allowable release from Pond A and slightly decreasing the reiease
rate for the pond to the east. Please advise if this is acceptable.
I appreciate your time in reviewing this submittal.
r� __�l
PPQ0 REC,�sl
�J
Patricia Kro t
President
700
Automation
Drive, Unit
I Windsor,
Colorado
80550
970-686-6939
Phone
9 970-686-1188
Fax
LOCATION:
PROJECT NO:
COMPUTATIONS BY
SUBMITTED BY:
DATE:
NEW BELGUIM BREWERY
Detention Pond A = Stage/Storage
New Belguim Brewery Office Pond
110-03
ppk
NORTH STAR DESIGN
4/ 18/01
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
DESIGN POND VOLUME
100-yr WSEL-
Overflow elev
Stage
(ft)
Surface
Area
W)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
49.62
0
50
498
0.00
0.00
51
2926
0.04
0.04
52.0
3948
0.08
0.115
52.1
3956
0.01
0.125
52.2
4194
0.10
0.134
Total required detention =
ASBUILT POND VOLUME
Overflow elev
0.125 Ac. Ft.
Stage
(ft)
Surface
Area
li
(ft`)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
49.62
0
50
166
0.00
0.00
51
2371
0.02
0.02
52.0
3918
0.07
0.096
52.1
3926
0.01
0.105
52.2
4220
0.09
0.114
detention.xls
North Star
Antos design, inc.
April 17, 2001
Jay Barber
City of FortCoWns Storm Water
700 Wood Street
Fort Collins, CO 80322
Ito. New Belgium Brewery Office Ppad volume certification
Jay;
�anlil�3 .
0
This letter is to indicate the volume of the Detention Pond A as was constructed with the
Office Addition to the New Belgium Brewery. The mrvey of the pond was conducted by
JR Engineering and the as -constructed volume calculations for the Detention Pond A are
attached:
The required detention for Detention Pond A with the Office Addition was calculated to
be 0.125 acre-feet. A variance was granted to the l' freeboard requirement for this pond
because of the proximity of the irrigation ditch and the small required si2a of the pond.
As you can see liom the calculations, the pond provides approximately 0.114 acre-feet of
detention as surveyed. This is approxunatelY 921/9 of the required volume (about 480
cubic feet less than the required volume). Thu restrictions placed on this area by the
existing building, the proposed building and the a-wting irrigation ditch have merle it
difficult to achieve the design volume in the pond. it is the desire of the owner to request
that YOU to accept the volume provided in this pond as adequate and, if required, provide
excess volume in the existing pond east of this pond. This could be accomplished by
slightlY increasing the allowable release from Pond A and slightly decrwmg the release
rate for the pond to the east. Please advise if this is acceptable.
I appreciate Your time in reviewing this submittal.
700 Automation Drive, Unit I Wlndeon, Colorado 80550
070.686.6638 phone a 870-6'46.1999 Fax
;i
detentbnxls
NEW BELGUIM BREWERY
Det®ntlon Pond A - Stage/Storage
LOCATMN: NewBdv=BwwwyOfoePond
PROJECT NO: 110-03
COMITITATIONSBY: pp]:
SUBMIT 16 BY:. NORTH STAR DESIGN
DATE: 4118/01
V =1/3 d (A+ B + egrgA`8))
where V = volume between oontoure, ft
d = tlaplh between contoure. R
A = surfaoe area of contour
DESIGN POND VOLUME
700•yr WSEL-
OveMow elev
Surface
!�
incremental
Storage
Total
She
498
0.00
0,00
MSF2
2926
004
0.04
3948
0:08
0.1 5
39M
Ot
0.125
. 94 -
0.10
0.1
Tote) required deten*m a
ASSUILT POND VOLUME
Overflow owv
0.125 Ac. Ft.
Stage
fl
Su ca ""
Area
te)
increments
storage
ac fl
Total
-%rage
aafl
49.82
0 - --
50
156
0.00"
0.00
5T
23T1
0.02
0.02
52.0
3918
OAT _
_ .0.096
521
3928
0.01
106
4220
O:Q9
0.11