02-02-1981 Planning Packet - Laserfiche WebLink

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F TO: FROM: DATE: SUBJECT: Jeanne A. Mabusth, Zoning Administrator Michael P. Gaffron, On-Site Systems Manager January 21, 1981 Preliminary review, Judd Ringer Proposal, Wayzata Blvd. I have reviewed the soil survey maps and topographic site plan property. Generally, the existing and proposed Duildxngs lie on or near the best soils of the property for drainfield use. These soils according to the Hennepin County Soil Sur^ey are Hayden clay loam, with an expected percolation 30-100 minutes per inch and a water table usually deeper than 5, These soils might be expected to accept a standard trench system. The approximately 10 acre, relatively flat area north of the buildings consists of Shorewood silb/clay loam which has a shallow water table (3') and would probably be suited to use of a mound system. The proposed facility capacity of 24 residents plus staff could be expected to use approximately 75 ^’•llons per resident per day with la^dry, dishwasher, etc., plus approximately 15 gallons person per 8 hour shift. Assuming 4 staff per shift is about 4 staff X 3 shifts X 15 gallons = 180 gallons or 180 + (24 X 75) = 3000 gallons per day water usage for the entire facility. Then if testing indicated a standard trench system would work, using a 60 minutes per inch perc rate, would need 3,000 X 2.2 square feet/gallons per day = 6,600 square feet of standard drainfield which would require about 15-20,000 square feet of ground area or about 100X200 feet for primary and 100X200 for secondary or alternate site. A mound system would be designed based on 0.83 square foot rock area per gallon per day or .83X3000 » 2490 square foot rock area. This translates (with sand bed underlying it) to about 7500 square feet and with an alternate site would need 15-20,000 square feet or area cr approximately H an acre. In either case, the parcel appears to contain soil types and enough land area so that it is likely that suitable sites can be found for some type of drainfield to serve the proposed facility. Soil testing for this project should first identify the depth to seasonal water table with soil borings and include percolation tests approximately every 50 feet over a >s to 1 acre area. Ihe applicant should be advised to have his site evaluator contact staff prior to doing any borings.