HomeMy WebLinkAbout2000-07-11 BRAA Ltr to OPH Re USPS Drainage AnalysisBonestroo
Rosene
Anderlilc &
Associates
En & Architects
July I 1 2000
Bonestroo, Rosene, Anderlik and Associate in Affirmative Action/E Opportunit
Emplo and Emplo Owned
Principals: Otto G. Sonestroo, P.E. - Marvin L. Sorvala, RE. - Glenn R. Cook, RE. -
Robert G Schunicht, RE. - Jerr A. Bourdon, RE.
Senior Consultants. Robert W. Rosene, PE. Joseph C. Anderlik, RE. ® Richard E. Turner, PE.
Susan M. Eberlin, CYA.
Associate Principals: Howard A. Sanford, RE. w Keith A. Gordon, PE. - Robert R. Pfefferle, RE.
Richard W. Foster, RE. ■ David O. Loskota, RE. ■ Robert C. Russek, A.I.A. it Mark A. Flanson, RE.
Michael T Rautmann, P.E. - Ted K.Field, PE. ■ Kenneth R Anderson, FE. - Mark R. Rolfs, PE, -
David A. Bonestroo, M.B.A. - Sidne P Williamson, PE., L.S. - A M. Rin M.B.A. - Allan Rick Schmidt, PE.
Offices: St. Paul, St. Cloud, Rochester and Willmar, MN - Milwaukee, W1
Website: www.bonestroo.com
Ms. Kris Danielson, Communi-tv Develop-t ent Directof
Cit of Oak Park Hei
'4168 Oak Park Boulevard, P.O. Box 2007
O ak Park Hei MN 55082-2007
Re: USPS Draina Anal
Kern Center 2nd Addition
Our File No. 55-00-000
Dear Kris:
We have anal the impacts of the proposed. United States Post-al Service — Carrier Annex
development within the Kern Center and its effects on the existin Kem Center Pond. Attached
please find a men-iorandum summarizin the existin Kej Center P ond's 100-vear hi water
7 T
le,vel and peak- dischar rate assumin this development in place. In short, the existin Kern
enter pond with its restricted outlet control (12" orifice in the 42" pipe) can. handle storm w"U.1
runoff from the proposed Post Office development without impactin ac Gi U-cent structures.
If 4
y ou have an rluestions or re additional information, please contact me at ( 651 ) 604-4815.
V
Ver trul y ours,
BONESTROO, ROSENE, ANDERLIK & ASSOCIAT. 1!1�C.
T
1 M,. Po,,-;t-h--I-r, P.1"I
Enclosure
cc: ' porn Melena, Administrato., r
Ja Johnson, Public Works Director
Anthcn Pini - Van Sickle, Allen & Assoc.
Michael Scheck - US PS
John Hanson - Barr En Co.
DNIP, File- f
Dra.na Anal 3-7-1 I -00.doc
2335 West Hi 36 ■ St. Paul, MN 55113 a 651-636-4600 w Fax: 651-636-1311
Sonestroo
Memo Rosene
Anderlik &
Associates
Engineers & Architects
Project Name: Kern center Pond
To: Dennis Postler
From: Jason Swenson
Client: city of oak Park Heights
File No: 55 -98 -802
Date: 7111100
Re. Hydologic review of impacts of the Post office carrier Annex Plans issued 6/27/2000
Remarks: The Post office carrier Annex in the Kern center was reviewed for its impact on the high
water levels in Kern Pond. Kern Pond was constructed to provide rate control for this area located in the
Valley Branch Watershed District.
Kern Pond is equipped with a 12" orifice to provide rate control for this area. Kern Pond drains to the west
to a large wetland. current plans tali for the large wetland to ultimately provide rate control with a peak
discharge of 10 cfs as called for in the AUAR completed by the city of Stillwater in 1997. After the
installation of the rate control outlet for the wetland, the 12 orifice in the Kern Pond may be removed.
Three scenarios were analyzed, including the existing condition, proposed condition after the construction
of the Post Office, and the ultimate condition after the installation of rate control in the wetland.
Existing conditions: Existing conditions for this area includes all existing development, including the
WATB Enterprises project reviewed 512412000.
0 Kern Pond Peak Discharge: 8.9 cfs
0 Wetland HWL 929.7 feet
0 Wetland Peak Discharge: 34.1 cfs
Proposed conditions: This scenario includes all existing conditions as well as the construction of the Post
Office. The plans indicate the possibility of future building and parking expansions. Both scenarios were
reviewed with negligible differences.
0 Kern Pond HWL: 934.9 feet
0 Kern Pond Peak Discharge: 9.2 cfs
i Wetland HWL: 929.7 feet
® Wetland Peak Discharge: 34.3 cfs
The critical overflow elevation from Kern Pond is 936.0 feet. Adjacent structures will not be affected until
elevation 836.0 feet.
Bonestroo, Rosene, Anderlllc and Associates
2335 West Highway 36 + St. Paul, MN 55113 + Phone: 651-636-4600 + Fax: 651 - 636 -1311
Bonestroo
Rosene
Memo Anderlik &
Associates
Engineers & Architects
Ultimate conditions: Under ultimate conditions, the entire watershed has been developed and the 12"
restriction in the Kern center Pond Removed.
0 Kern Pond HWL: 934.2 feet
0 Kern Pond Peak Discharge: 42.6 cfs
0 Wetland HWL: 931 .1 feet
0 wetland Peak Discharge: 8.4 cfs
Assuming ultimate development of the drainage area for Kern Pond consists of primarily of commercial
and Industrial development, Kern Pond should provide 12.9 acre -feet of water quality storage, assuming an
average depth of 3.5 feet and an existing surface area of 3.5 acres. The Post office project accounts for
6% of this required volume. This will lower the phosphorous concentration in the storm water leaving the
pond to less than 200 pans per billion, as called for in the oak Park Heights 1995 surface water
Management Plan. This assumes another water quality pond will be constructed to handle future
development located to the south of the intersection of county Road 15 and Highway 5.
Bonestroo, Rosene, Anderlik and Associates
2335 West Highway 36 + St. Paul, MIN 55113 + Phone: 651 - 636 -4600 + Fax: 651 - 636 -1311