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HomeMy WebLinkAbout1982-05-25 Septic System Site ReportfH€ - IBS' s, ^>eou>/0 ^ f=wt.ru»^ la.^€ - « *. ^ SITE EVALUATION REPORT FOR CHARLES KROGKESS OROKO, MINNESOTA <-:i...I W 2 61982 '^! r — 5-25-62 iillLOl- ORONn 'ij- ■On May 7-8» 1962 six percolation holes were tested and three I soil borings taken on the above property to determine both a pri­ mary and alternate drairfield site for a proposed new lot. On May IH-lb* 1962 two additional holes and one soil boring were tested for an alternate site for the existing house« and two percolation holes and one soil boring were taken on the original site since it appears that the new house would extend into the original pri­ mary site and thus a new alternate site would be needed. All of the percolation holes were dug 3-3*5 feet deep and 6 inches in diameter while the soil borings were dug 6 inches in diameter to the k foot depth and 3 Inches in diameter to the re­ maining depth. The ■ sfSfl wore dug with both power and hand augers while the soil borings were dug with bucket type hand aug­ ers. Since the house might extend into the original primary site the new primary site will comprise of holes end 6 with the alternate site being holes 7 and 8. Both had very fast percoLa-'.r tlon rates which would enable standard or shallow trench systems to be constructed. Because of the sandier layers a lot of water seeps throxigh the ground causing a high seasonal water table that follows the contours of the hill down to the pond. Thus, it will be necessary to construct some type of diversion for this water when the drainfleld is put in. This will be covered in more de­ tail in a system design once the house size and location is * known. The alternate site for the existing house also had a fast percolation rate enabling a standard system to be used if the . need ever arises. If any other information is needed, please contact me. Sincerely, PERCOR, INC. At— r CHARLES KROGNESS PROPERTY ORONO, MINNESOTA LOT 2 Percolation Results Hole No.Material P-1 P-2 Percolation Rate Red Brn. Clayey Sand 7.1 Min./Inch Dk. Brn. Clayey Sand 5*7 ” The average percolation rate is 6.U minutes per Inch. Soil Borinff S.B. # 1 DepthCft.) 0.0-3.0 3.0- 4.0 4.0- 6.0 6.0-7.0 Material Black Sandy Loam Dk. Brn. Clayey Sard Dk. Brn. Clay Loam Brovm Clay Loam Mottled soil at $.0 ft. and water table at 5*6 ft. after 24 hrs. . - i < <4.-*:-r '' '* ‘v‘ - ^ -mill IQ / ( I>ji’ i . »- • !A 1 * 4 -4 I >« .11 f • • •• ft' •♦-■C^A/nes /^AO(^ess PMA^Arr h ^ kU r .. T Jl rf*A.n kHIfl Mt.Jr • / 4 * MilCk-^ . . . EXHIBIT L TO:Jeanne A. Mabusth, Zoning Administrator FROM:Michael P. Gaffron, Septic System Inspector DATE:June Ir 1982 SUBJECT: #685 Charles Krogness - Subdivision - Septic System Review I have reviewed the proposed subdivision and wish to make the following comments: Lot 1 (new lot) - Primary and alternate sites were tested, with percolation rates averaging 7.4 and 5.7 ropi respectively. Water table depth ranged from 3.7 ft to 5.8 ft or deeper, hence shallow trenches would be recommended, as well as runoff and groundwater diversions uphill from the system, assuming house location does not change. Lot 2 - Existing house with existing system. Existing system was inspected in 1981 and appeared to be in operable condition. An alternate site has been tested and is suitable for a standard drainfield. One problem does present itself, however. At least one drainfield line protrudes approximately 15-20' into the proposed new lot at a point where the new house would presumably be located. Orono code requires a 20* setback for drainfield from property lines, although only 10* is normally enforced where reasonable to do so. For this subdivision, since the existing drainfield would be very close to the proposed new house, two options present themselves: 1 - Rearrange lot lines to give the 10* setback. - This would severely limit the area where the proposed house could be located. 2 -Cut off the existing drainfield to a point at least 10* back from the proposed lot line, then add an equivalent amount of drainfield downhill on Lot 2. While it may seem unreasonable to remove an existing functional drainfield becuase it is over the lot line, it is equally unreasonable to expect a future owner of Lot 1 to allow treatment of his neighbors sewage on his lot. Futhermore, the expected runoff from a house on Lot 1, as well as construction fill and disturbance, might possibly disrupt the proper functioning of that portion of drainfield anyway. One problem that may crop up is that by cutting off the end of the drainfield, the* soil disturbance may create a seepage point if the line fills up. My recommendation is that the entire line (or lines) be abandoned and the equivalent or more of new drainfiel.d be constructed further south, -where the effect of added runoff will be lessened. (While allowing the lines to be merely shortened would be acceptable if we knew Mr. Krogness would continue to own the existing house, we should not take the chance that drainfield changes made necessary by the subdivision cause a future problem for a new owner of the existing house).