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Home My WebLink About1982-09-13 Septic System Design ReportSEPTIC SYSTEM INFORMATION STREET ADDRESS 2 1�4 76-- Pu,ov my, /D er vig LOT 8L04.x SUBDIVISION-,alol,71"—%)QAw_/)lAAJo - SNE MOIIRii AND YEAR TESTING DONE _.�.. /98I ITEMS ALREADY COMPLETED 6 Pec yrs S MEED TO COMPLETE BEFORE ISSUING BUILDING PERMIT; OWRINGS 0 FERC TESTS 0 SYSTEM DESIGN 1-W o L,_„ 0 SITIF PLAN O OTHER :'N SUBDIVISION FILE NO. DATE THIS SHEET FILED _ 9-/3 - X32 BY l ' JO 4 MV �:: Vit., . • i �� . r r � .. � . . -si �... •�i, ...� ;,e 1,7 inw IlkIp • � of i �'iT i � � 1 S � 4' J i s• s s j a .• ,r y rQ♦ e� • o a k .+ C P .. • •Ip 1 y �� r 1 ' w ��taNMrMrI�tA�rtNwiw�;�r�•1 jSt?^:v 1 r �,,.. 4 .. :•;1 S ki-4C _ ••,. 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(`�{ra r a•.,� `sM•L 41 /La -4r. )r S �•+� . �iYT'�Lfa �wfiR :� S.S• 1rM • k • VIL aawy Cj A v • r �,,.. 4 .. :•;1 ki-4C _ ••,. h• �.�� •.f ��p� RA 6 1,S li !� ;,h 1 . �•.}►�• �Jr''•i�1) ��R-.t '� 3 5• Ste~ s�••» GJ►Y L 1;sLaxil' V ct% r �,,.. 4 .. :•;1 JJuun • 1. 1981 soxe Ways HN 95391 r, Mr. Richard r3nry ' 21350 Excleslor Boulevard Excelsior, Minnesota 55331 Dear Hr. Conry: We have completed a site evaluation for on-site sewage treatment facilities on 6 lots located west of Willow Road in Orono. Minnesota. A location map has been enclosed showing the location of the percolation tests, percolation data, location of soil borings and relative elevations of the surface at the location of the percolation tests. (For detailed contours please see topography prepared by Cary Gabriel). A log of the soil borings is also enclosed. The soil borings reflect a uniformly high water table throughout the area tested. This condition prohibits the installation of conventional soil absorption j systems and shallow trench systems. The percolation rates encountered and the gentle slopes on this site would indicate that sound systema should be satisfactory on each of these lots. We recormend that the future homes be provided with ssoued systems of soil absorption. Please call if you have any questions. Thank you. Yours very truly � QG . % C Carl W. Borg. P.E. EXHUT TO: Jeanne A. Mabusth, Zoning Administrator FROM: Michael P. Gaffron, Septic System Inspector DATE: November 6, 1981 SUBJECT: #654 Dicon, Willow Drive South - Subdivision I have reviewed the submitted report for the above referenced proposed subdivision, and wish to make the following comments: The report by Borg indicates high -water -table soils throughout the 6 lots tested. Lot 1 - Slopes of 88, 101. Percolation rates at a depth of 25" - 31" averaged 10 mpi in the primary site and 23 mpi for the alternate site. Both sites are acceptable for standard _mound systems. Lot 2 - Slopes of 4-6% in areas tested. Percolation rates averaged 25 mpi in the primary site and 13 mpi in the alternate site. Both sites are acceptable for standard mound systems. Lot 3 - Slopes of 51 - 61 in areas tested. Average percolation . rates averaged 27 mpi for the primary site, and 34 mpi in the alternate site. Both sites are acceptable for standard mound systems. Lot 4 - Slopes of 3-41 in areas tested. Percolation rates averaged 41 mpi in primary site and 20 mpi in the alternate site. Both sites are acceptable for standard mound systems. Lot 11 - Slopes of 8-101 in areas tested percolation rates averaged 40 mpi in the primary site and 31 wpi at the alternate site. NOTE: CARE MUST BE TAKEN TO PLACE THE MOUND ON A SLOPE OF 61 OR LESS ON THIS LOT. Lot 10 - Slopes average 68. Percolation rates averaged 48 mpi on the primary site and 87 mpi on the alternate site. General Comments: Percolation testing was done at a range of depths from 13" to 31". No real correlation appears to exist between depth of testing and percolation rates. The soil borings reflect a seasonably saturated zone beginning at a a range of depths from 1.2 ft to 2.5 ft. Actual current perched water tables were found on some sites at a depth of 3.5 ft. or greater. Based on the above data, the site evaluations recommendation for all mound systems is appropriate. I confirmed the soil boring report with a boring of my own. CITY OF ORONO GENERAL CONSTRUCTION REQUIREMENTS MOUND DRAINFIELD SYSTEM TO BE USED WHERE: Seasonal perched water table is between 2 feet and 4 feet below surface. Percolation rate in top 12" of soil is faster than 60 MPI. Percolation rate in subsoil but above water table is faster than 120 MPI. Where percolation rate is 60-120 MPI, depth to groundwater shall be at least 31 and slope must be no more than 34. Where percolation rate is 30-60 MPI, depth to groundwater shall be at least 2# and slope must not exceed 64. If percolation rate is faster than 30 MPI, depth toggroundwater shall be at least 31 and slope must not exceed 6-124. CONNECTION TO HOUSE House to tanks may be PVC (ASTM D-3034 or better), cast iron or clay tile. PVC should be sand -bedded in flat runs over long distances. No outside air test required but joints must be tight. TANKS Two (2) precast concrete tanks are required. Min. size 1000 gal. and'750 gal.; we recommend 2 1000's..Tanks must have 20" manhole riser to within 12" of final Erade, and at least one 4"-6" inspection stack to surface. Baffles must be acid resistant and may be plastic, fiberglass, or precast with tank. DRAINFIELD Mound consisting of 12-24" layer of sand on plowed, chopped, or otherwise scarified natural surface soil. 12" rock bad on top of sand layer, 10' maximum width X length dependent on water use. Distribution pipe is laid in top 3" of rock. Cover rock bed with straw or hay AND building paper. A layer of sandy loam 6-12" thick should be placed over the covered rock bed and a 6" layer of topsoil then placed over the entire mound. Finished sidealopes to be 3:1 or flatter. Grass cover should be established as soon as possible over the mound area to reduce erosion and aid in evaporation. THE MOST IMPORTANT STEP IN CONSTRUCTING A MOUND IS PREPARING THE NATURAL SOIL SURFACE BY DISC -PLOWING OR CHOPPING WITH A BACKHOE TO A DEPTH OF ABOUT 12". When sand is pushed or dropped onto this loosened raw top- soil (DON'T drive on it), an interface is formed which will allow percolation to occur from the sand into the topsoil. SEE SKETCH ON BACK OF THIS SHEET. DISTRIBUTION The mound must use pressure distribution and requires a pump from the sotic tanks. Distribution must be 1V PVC or plastic with K" holes (turned down) every 36". Pumping from a 2" manifold, distribution system should be 3 lengths of pipe spaced 40" on center capped at the ends, running the length of the rock bed (see sketch). No drop boxes or distribution boxna are used. 4" PIPE WITH GRAVITY DISTRIB- UTION IS NOT ACCEPTABLE IN A MOUND SYSTEM. PUMPING : Pump should go in a 3rd tank or in a oaffled chamber of 2nd tank. The idea is to retain the 2nd tank's capacity for solids retention. An alarm device and reserve capacity equal to one days sewage flow (300 gal. recommended min.) are required. rM2CAL-MOUM1,- R 2MO TNUT%m Sy&= &^VotI? 4 INCHES STRAw OR MARSH SANDY LOAM SOIL 6-12• deep - MAY AND LAYER OF RED ROSIN PAPER PERFORATED LATERAL GRASS COVER 6 INCHES 12-24" SAND FILL TOPSOIL MAXIMUM SLOPE 7 TO 1 CL EAN ROCK 90 lQ.DM DISK oESURFFACE yIyi. 2. 0110! CROS5 SECTION A -1i its _2. PIPE FROM PIMPING CHAMBER x•111 �C � A f ' ROCK RIED - ll 3 911 Rowe - 10's 01 4 OR Hone - 1011 50, 5 8R How - 10'a 65- 1. 1411 ry, I -r SAXD FILL MRODLD PERFORATED EAT: -3D 101 07T YRON LATERALS ( J ROC[ RID 011 ALL >Y" Holes SIDES. every 36" �- eED ARE A r1+ v 3S2,11 TO 2 . I rINC I - CLEANHES ROCK A 120 DEV ' N N 1 20 1: IN IL s s 20 '- INCHES _ LAMP 1 10 irEET_,L*_SAIID MAN 101win ROCKdIV - OVIR SAND PLAN VIEW QUESTIONS 7 CALL THE SEPTIC SYSTEM INSPECTOR AT 473-7357. TO: Jeanne A. Mabusth, Zoning Administrator FROM: Michael P. Gaffron, Septic System Inspector DATE: June 14, 1982 SUBJECT: #654 Dicon, 155 Willow Drive South - Additional On -Site Testing I have reviewed the submitted soil and site evaluation for the two lots on the north side of the road in Phase 1. Testing indicates average perc rates varying from 1 to 48 mpi, with high water tables (saturated zones) in all but the most northeasterly site. Mound systems are applicable for all these sites, although the northern site for Lot 1, Block 1, could support a shallow trench system. I note that Lots 2, 3 and 4 in Block 2, have been realigned. By superimposing the previous testing over the new lot lines, it is apparent that 2 of the 6 perc tests originally done on Lot 4 are now on Lot 3. Technically, additional testing should be done within the boundaries of the revised Lot 4. However, since the soils appear to be fairly consistent throughout the division, and since mounds will be used on all the lots, this minor additional testing is not critical and may be waived until a house is proposed for the site. I will reiterate that mounds should be placed on the most level sites within the tested areas; and that prior to road construction, all drainfield sites should be staked off to eliminate traffic or disturbance. Two additional comments are necessary: 1 - Enough sand should be placed above the surface soil to maintain a 3• separation between the shallowest mottled zone and the bottom of the rock bed in the wound. On some sites this will mean 2' of sand should be placed. 2 - In all cases, mound placement should be at the most level spot available in the natural topography in the area tested. I recommend approval of the subdivision, with the further stipulation that during road construction the drainfield sites remain totally undisturbed. P.O. Box 209 Wayzata, MN 55391 March 15, 1982 Mr. Curtis Anderson 6016 Beachwood Road Mound, MN 55364 Dear Mr. Anderson: We have enclosed a Plan and detail drawing for the construction of a "mound' type sewage treatment system for Lot 2, Block 2, Countryside Manor in Orono, Minnesota. The details of construction are specified by the City of Orono and are shown in the current 'Orono Mound Package" and the "On-site Sewage Treatment System Design Manual" adopted 4-13-78 by the City of Orono. If you have any questions, please call me. Yours very LruI a,,.A1kN Carl W. Borg, P.E. Minnesota Reg. No. CWB:pb cc: Michael Gaffron City of Orono