1992-10-15 Septic System Review - Laserfiche WebLink

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it s 79 3 /'`1, ��ewb4t-o To: Michael P. Gaffron, Asst Planning & Zoning Administrator From: Stephen Weckman, On -Site Systems Manager Date: October 15, 1992 Subject: Subdivision #1762, Paul Boyke - Septic Review I have reviewed the proposed septic system testing and design for this property and would make the following comments. LOT 1, BLOCK 1 - EAST ONE-HALF 71 3 N - .-OWc- C, fir. This lot has an existing residence with an on -site sewage treatment system. The system is a conforming system according to MPCA Rules Chapter 7080 and City of Orono Code. The system includes two 1,000 gallon pre -cast concrete septic tanks and approximately 1,000 s.f. of shallow drainfield trenches. The septic system was installed in 1987 at which time soil testing indicated a three foot separation between the trench bottom and the seasonally high water table as indicated by mottling and is presumed to be installed as designed. The existing drainfield is approximately ten feet from the proposed driveway for the west lot. Due to the elevation of the existing driveway, the proposed driveway for the west lot would likely require fill to be constructed which would impede the natural drainage and could adversely effect the function of the drainfield. Driveway specifications should be provided including a topographic map detail so the impact of any) may be noted. Soil testing has been provided indicating an alternate drainfield site fora 4-bedroom home to the east and north of the existing drainfield. This area would also be suitable for a shallow trench system. Drainage from the existing driveway would flow directly across the alternate drainfield site, therefore a drain tile or other method for redirecting the drainage must be incorporated at the time the future site is to be used. Specific alternate site details are included below: - Depth of seasonal saturation (mottling) is 4' to 4'2", requiring shallow trenches. - Slope is 4%. - The percolation rate averages 7.9 minutes per inch at 12 inches. - Drainage must be directed away from drainfield site.