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TO: Jeanne A. .'.ahusth, Zoning Administrator <br />FROM: Michael P. Gaffron, Septic System In:;;)ectur <br />DATE: January 5, 1902 <br />SUBJECT: Ringer Subdivision, North Willow Drive 4615 <br />Summary: All proposed lots wera found to have high water tables, <br />nvcv _itating the use of mound systeri3. Percolation rates in the <br />up : soil profile generally were suitable for mound systems, <br />witn slower rates found in ureper test holes. Slo;,es on the entire <br />site are fairly level and suited for :round systc -- <br />This report will consist of: a) a short review of teach lot of the <br />proposed division and b) a discu^Aion of mound systems, including <br />how and why they work and their current aTLd future use as i)r-t of <br />Orono's land use management plan. The Ringer subdivision in <br />perhaps the most extensive de•!c l:.t.ment in Orono to date that will <br />require all mound systems. <br />A. Ringer Subdivision <br />A preliminary review o1 the Hennepin County Soil Sarvey indicat^d <br />a:,tcnsive arc,-!3 of Cordova silty clay loar., and Shorewood silty <br />clay loam as voll as Lesour loan would be found at this site. <br />These soils all would be e::pected to have a seasonal water table <br />or saturation zone Latween 1 and 3 feet brow the sn-face. <br />During the course of the soil3 inveotic7ation, I met the site <br />evaluator, Carl Borg, and realtor r�raydon McCulley ne <br />site. We made a boring which definitely indicated .arse high <br />water table soils were prcuQnt. I later confirmed with Dr. Jamc3 <br />L. Anderson of tLe Univer3ity of Minnezota Soils rxtencion <br />Departr„cnt that mound systc,.a ��ould L;.► _ iv.ppropriato for these coil <br />types. These are rauch th3 sa::.L soils are found in the Mcdina- <br />14orning3ide area, which experience conventional trench septic <br />system failures due to the soil conditions. In general, tt.e <br />lea*::y top, -oil characteristics for the Ringer property are euitat.:e <br />for proper functionin3 of standard prenaure-m.-)und septic aystc:n3 <br />as per Orono's Code ar,d Desion Manual. <br />For clarity's sake I have labeled the northern most tier c£ seven <br />lots as Block 1, the western group of six lots as Block 2, End <br />thy+ two lots to.0— ro .,theast as Block 3. <br />IAAt 1, Block •�• ,,•�„ <br />M+...M <br />Pares Pall thru P816. Horings BB11 thru BB13. Average prrc <br />rates for both Frimar; and alternate sitar are acceptable. :jlupc:r <br />are quite level. Saturation it ieationa (mottling) startel at <br />1.7 to 2.5 feet. Actual -tater able at 5-7' dt•pth. A mound <br />system should be used due to the presences of shallow saturation <br />zones. / <br />