2003-P06845 - new septic system - Laserfiche WebLink

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� � 333 East Main SVeet � P.O.Box 388 Elk River,MN 55330 I� + (763)441-7509 (800)554-7509 Fax:(763)441-9176 Eco svsTEMs Er,ciNEEaiNc,iNc. e-mail:h2olabOlkdliink.net July 9, 2003 Chris Bollis m�S��E�MfD FOR y Of BEOROOMS�INVAUD ,N�R��N�� 220 Stubbs Ba Road AT�j��s�� Long Lake,MN 55356 �1• Subject: Onsite Wastewater System(OWS)Design 1. Le Description -470 Big Island,City of Orono,Hennepin County,Minnesota 2. Site Conditions-The 1 acre lot is located on an island of Lake Minnetonka with a cabin,private well and proposed OWS as depicted on Figure 1. The proposal is to replace the existing OWS serving the two bedroom, single family residence with an OWS located on Figure 2. The proposed drain field site is locaxed on a convex shoulder slope of 5-8%. 3. Soil Conditions—The Hennepin County soil survey, completed in the early 1970's, mapped the soil within the area of this property as a Hayden Series. A copy of the Hayden Series description from the soil survey is included in Appendix A. The soil survey described the Hayden Series as a deep, well- drained; loamy soil formed in glacial till with the depth to water table greater than 5 feet in all sea.sons. A discussion with the Natural Resource Conservation Service (NRCS) soil scientist who recently completed the Hennepin County soil survey update (not available for distribution) indicated the Lester Series has generally replaced the Hayden Series in the updated soil surveys. The Lester Series is the Minnesota state soil and is very common in Des Moines Lobe glacial till deposits of central Minnesota, specifically Wright and Hennepin Counties. A copy of the description for the Lester Series, completed for the Wright County soil survey update, is included in Appendix A. The soil survey indicates the soils in the Lester Series are very deep, well drained loamy soils formed in glacial till with relict redoximorphic features. The percolaiion rdte of the soil ranges from 10 minutes per inch to 40 minutes per inch. Our own soil borings closely matched the soil survey description (see Appendix A).Boring #1, #2 and #3 indicate the site is underlain by high chroma loam and clay loam soils to approximately 6 feet The parent material for the area, high chroma loam soils with many threads of calcium carbonates(often misidentified as low chroma iron reductions), was found to the depth of the borings. Many fine gray shale fragments were observed in the profile along with gray calcium carbonates and reddish iron concretions. These soil features are a result of the soil parent material not a fluctuating seasonal water table. 1