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Attachment C October 16, 2003 Travis Germundson Area Hydrologist Minnesota Department of Natural Resources, Waters 1200 Warner Road Box 37 St. Paul, MN 55106-6793 RE: Karth Lake Pumping Plan, Arden Hills, Minnesota DNR Permit #2003-3078 Dear Mr. Germundson, Please find enclosed a pumping and maintenance plan for Karth Lake. A permanent pumping station is proposed to control the lake elevation. Pumping shall be coordinated with the DNR and will be dependent on the elevation of the lake and the season. The pumping solution includes the construction of a concrete pump manhole on the south end of Karth Lake in Cummings Park and connecting a 6" forcemain from the pump to the storm sewer system on Fernwood Avenue. It is proposed that this will be an electrical sump pump mounted on a floating raft with a built in fish screen, which could be manually operated when necessary. The City of Arden Hills would coordinate with the DNR to determine appropriate minimum and maximum levels for pumping based. on Lake Elevation and time of year. Pumping rates will not exceed 360 gpm (less than 1 cfs.) At 360 gpm it is anticipate that it will take 2-112 to 3 weeks to draw the Karth Lake Down 2 feet (approximately 10 mgal.) The city would base the commencement and conclusion of pumping on the following criteria: 1) Pumping will not commence if the Lake Level is 934 ft or lower 2) April through September pumping would commence when the lake level reaches 936 feet and would be stopped once the Lake reaches an elevation of 934. 3) October and November pumping would commence when the lake level reaches 935 or higher and would stop once the elevation reaches 934. 4) No pumping is anticipated during the months of December through March Thresher Square 700 Third Street South Minneapolis, MN 55415 Phone: (612) 370-0700 Fax: (612) 370-1378