1993 - Req. for rev. of septic sys. nonconformity

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u s, te 1: r • T..phone 4ramat • 4 44 CITY of ORONO• Post UfRee Box 66•Crystal Ray,Minnesota b8, 9xMueicipal Officio On the North Shore of Lake Minnetonka ,s, ?7RONO. December 28, 1979 { Mr. Jason C. Becker 9200 Wayzata Boulevard Minneapolis, Minnesota 55426 Re: Your letter of December 20, 1979 Dear Jay: You do have two 1 ,000 gallon septic tanks. Each one should have an inspection/cleanout pipe at the inlet end of the first tank and the outlet end of the second tank. These pipes may have been covered up when the lot was finish graded and may have been broken off or pushed aside at that time. The tanks are fairly shallow and using the dimensions on your drawing you should be able to find the holes in the tanks by digging down a foot or two. The 50' water table you referred to is the static water level in your well. Without getting into it too technically, this level is due to the water pressure in the sand aquifer in which your well terminates. The attached drawing should help explain it. The water "table" that may have some effect on your drainfield is a seasonally perched water table due to surface runoff water from high ground settling into lower flat areas and soaking in. The rate and amount of water flowing down into these lower flat areas is greater than the rate the water can move downward through the clay layers of soil below the topsoil. This causes a buildup or saturation of the upper soil layers until the water gets a chance to move downward. If the saturation level of the soil increases to where no more water can be absorbed, it is feasible that further loading of the system (flushing toilets, etc. ) would cause sewage to overflow the tanks at the inspection pipe or back up into the house. Not likely, but possible. Whenever possible we try to get the contractor to keep drainfields in the more desirable soils. Your existing drainfield was installed so as to eliminate the use of a pump which is a mechanical device and therefore prone to failure. If at some future time your present system drainfield ceases to function properly, you could always pump up to a new drainfield on higher ground to the southwest of the existing system. Hopefully this should not be necessary for 20 to 30 years or more. If you have further questions, please do not hesitate to call or write. Sincerely, Michael . Gaffron Septic System Inst- =c:tor • MPG:kh . :x