1983-06-30 Septic System Design Report

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TOM SMITH ASSOCIATES Inc Consulting Engineers June 30, 1983 YArvin H. Anderson Construction Co 8903. I,yndale Ave South Minneapolis, IN 55420 ATTV's Fred Haas SuoJECT: Site evaluation report for on site sewage treatment system, 4300 9ayside, Orono, Minnesota Job N 1962 Per your recent request, we have conducted a site evaluation for the above subject site. This report presents our findings, recommendations, and designs for the sewage treatment system for thii site. MCMWIDATIONS: The depth to seasonal ground water at the referenced site is 0o shallow to allow installation of a standard on -site sewage treatment system* Conditions are appropriate to allow the installation of a mound system which should adequately treat and discharge to the environment, the sewage anticipated for the two bedroom rambler which you. plan to build. EVALUATION: The site in question is heavily wooded with mature hardwood trees, and slopes pre dominatel,y to drain to the north, with some quite steep sloping conditions throughout. Property dimensions are approximately 6621 by 665E plus access off county road 81;. Soil borings indicate that the soils comprise a very organic forrest mat of silty clay to a depth of arproxima-�ely 2 feet below grade, and then grade into an increasingly stiffer silty clay and medium fat to fat clay soil in the area of the primary treatrent area selected. In the secondary area evaluated, the Forrest mat is slightly thinner, and the underlying silt; clay retains the grey color suggestive of leachin., of organic natter to the depth of the boring at 61. In both areas, soil mottling, evidence of seasonal3,- high ground water level, was approximately 2 to 21 feet below grade. Details are contained on the attached logs of borings. The first set of percolation tests, conducted on June 15, showed very high rates, generally 60 minutes per inch or higher. A second set of percolation tests was run on June 22, at quite shallow depths of about 15", and showed percolation rates generally loser than 30 minutes per inch. This infonration serves to evaluate the upper 210" of soil and forms the basis upon which a mound system can bs recormiended. The details of the soil borings and percolation tests are given on the attached copies of the field logs and data sheets. :hc borings were done .-:ith a hand Elite auger, and elassificati +n of the soils is by the Unified soil classification system. The percolation tests were conducted acc�,rdinc to procee!°ures outlined in the 11PCA Orsitc .:eu•:age Treatnert ::arual and City of Orono Onsitc Seu:a,-e Treatment. '_`.antral. The Fcrcalation tests m-ere nin ir. 6" diar^eter roles with 2" of rea gravel or coarse sand in the bottom, allowod to soak for at least 1: hours with at least 12" of water above the bottom of t;_e hole, and then left overnifht. The tests were run by filli.nf to 8" above the bottom of the hole and mcasur'_ng the drop over 30 r..inute periods. After reading the drop, the level of crater was 5109 Kimberly Road, Minnetonka, Minnesota 55343 16121 934-8031