1981-04-14 Septic System Design Report

Home Browse Search

HAKANSON NAERSA'V ASSOCIATES, Inc* A 0. Box 665 222 Monroe Street Mr. John Laurent 70 Rockwell - 3660 Independence St. Louis Park, Minnesota 55426 Re: Percolation Testing Dear John: professional engineers and surveyors Anoka, Minnesota 55303 April 14, 1981 6121427-5860 At your request percolation testing was performed on the two lots of the proposed Laurent Addition located in part of Government Lot 3 Section 36 Township 118 Range 23, Hennepin County, Minnesota. Standard methods of percolation testing were employed. Elevations are relative to an assumed elevation of 100.0 based at a single spike placed in the east face of the power pole located on the south line of Lot 1 (see enclosed sketch). This report includes: 1. Soil boring logs 2. Percolation test results 3. Testhole location sketch 4. Septic system configuration sketch 5. Discussion and recommendations. The soil boring logs show that, in general, silt loam to silty clay loam surface horizons overlie clay subsurface horizons at the site. Below 1.5 to 2.0 feet depth, mottled and gleyed horizons occur. Soil mottles (spots of contrasting soil color) are accepted indicators of periodic saturation in soils. G1,kyiug (dull gray soil color) forms in soils which are saturated and in a chemi�:a.11y reduced condition for long periods of time. Because the City of Orono requires at least three (3.0) feet elevation difference between the bottom of standard sewage treatment trenches and the water table and/or soil m.,ttling and gleying, the soils at this site are unsuitable for standard methods of on -site waste disposal. It is recommended that an alternate method of sewage disposal, such as the mound (also called the berm) system be utilized at this site. Percolation test results show that measured percolation rates are faster thin the 120 minute per inch minimum rate for mound systems (see below). civil 8 municipal 0 planning 0 soils 0 land surveving