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Home My WebLink About1992-09-30 Septic System Design Report' S-iP TESTZN 9 ZNQ Steven B. Schirmero — MPCA Cert. No. 627 951 Katydid Lane NE • St. Michael, MN 55376 • (612) 497-3566 September 30, 1991 Paul Boyke Lotl, Block 1 Lauranne Woods, 10 .1/2 Orono, Henn. Co., MN This On -Site Sewage Treatment System is Designed for a Type 1, four bed-nom home in accordance with the Minnesota Pollution Control Agenc./ Chapter 7080 and local ordinances. The soils on this site are SCS soils mapped - HbC - Hayden loam. A seasonally high water table was located at 26" to 38", (mottled soil). Due to the seasonally high water table, a Pressurized Mound System will need •.-) be installed. The bottom of the rock bed must be located at leas. 3' above the seasonally high water table. The soils at a depth of. '2" have a percolation rate averaginq 6.2 min/inch. A pumping chamber will need to be installed to lift the effluent to the treatment area. The manifold and supply line pipe must have back drainage to the pumping chamber. The distribution pipes shall have their ends capped. Be sure the rock and sand fill material are clean. The sod layer below the entire mounded area must be turned over, just break up the sod, be sure not to over work. The power supply and H:.tches must be located outside the manhole and pumping chamber in a weather proof enclosure. A warning device.raust be installed with a light and sound device, this is in case of -a pump failure. Mercury floats are a good method. All neighboring wells are located greater than 100' away from the proposed treatment area. CONT'D Paul Boyke Lotl,Blk.1 Lauranne Woods, W.1/2 Orono (2) Keep all heavy equipment off of the proposed treatment area before and after construction. The treatment area should be marked off before construction►. This Design is not valid & the System will need to be relocatfd if failure to protect the areas proposed for On -Site Sewage Treatment occurs. With proper installation and maintenance, this system should have no problem in treating septic effluent effectively. Nothing other than gray water, (laundry,showers,etc.; human waste & toilet tissue should be disposed of into the septic tanks. Garbage disposals are not recommended. Additives must not be used, they may cause harmful damage to your septic system. Recommend to pump your tank every year if you have 1 tank & every 2 years if you have 2 tanks. 13 ' -`� � • �z� Steven B. Schirmersrt SBS/ds fl o Ali jr 4r :lg CIO# 61 s t� v�/ 2 w p rl Olop P r. n fn rn ` LO 1 h S I = = 2 m in m m In z s y� C 1 ' 10 N \ 1 1 MOUND DESIGN WORKSHEET (For Flows up to 12M gpd) A. FLOW Estimated 175L;' go (see pages D-7 or 1-3,4, 5) or measured — gpd x 1.5 = B. SEPTIC TANK LIQUID VOLUMES - !d -. . , -f- gallons (see pages C-3 or C-5) C. SOILS (refer to site evaluation) 1. Depth to restricting layer I -ro 7, v inches 2. Depth of percolation Bests = IQ-" inches 3. Percolation rate mpi 4. Land slope S % D. ROCK LAYER DIMENSIONS I. Multiply flow rate by 0.83 to obtain required area of rock layer: Daily Flow x 0.83 = '? sU gpd x 0.83 sq. ft./gpd : fa sq. 2. Select width of rock layer (10 feet or less) _ ft. 3. Length of rock layer - Area + Width - �, y �) sq. ft. + 1, ft. _ � ft. E. ROCK VOLUME I. Multiply rock area by rock depth to get cubic feet of rock; 9% ft. x ft. _ ?1'l cu. ft. 2. Divide cu. ft. by V cu. ft./cu. yd. to get cubic yards; I - cu. ft. + 27 = - -, cu. yd. 3. Multiply cubic yards by 1.4 to get weight of rock in tons; cu. yd. x 1.4 ton/cu. yd. _ 7 � tons. F. ADSORPTION VVID'ITI ! ri 1. Percolation rate in top 12 inches of soil is mpi 2. Select allowable soil loading rate from table on page E gpd/ft2 3. Calculate adsorption width ratio by dividing rock layer loading rate of 1.20 gpd/fO by allowable soil loading rate; 1.20gpd/ft3+ ,y.; gpd/ft'- a•+.�1 Check this value on Page E-16. 4. Multiply adsorption width ratio by rock layer width to get required adsorption width; x ft = ft EMWrr/ftwWw MOefoerf 2 30 us IN 3 1X 30e 210 eae sn us lob an "a • use srs � ..:. a�leeO��i�u e>� =1 f �W Rock BW SOIL Asw.p" wilt SWIS 7Mte MNeweeow ►�er eeNAe� fee after :�1+. we�...•i awes,,. e10 i" w u US •R"eerr . in .6 m �, — -- G: DOWNSLOPE DIKE WIDTH I. If 'landslope is 3% or more, subtract rock layer width from adsorption width to obtain minimum downslope dike toe for absorption: ft - ft = 1 I? feet Calculate minimum mound sire based on geometery: a. Determine depth of clean sand fill at upslope edge of rock layer. Sepamion /, v feet b. Multiply rock layer width by landslope to determine drop In elevation; Stop Di/jrerence 1.. v x S- 96 + im c. Add depth of clean sand depth of clean sand for `" :• _ �:,�:• separation at upslope edge (2a) to depth of rock layer to `_: rock depth and the depth of raver to find the total mound height at upslope edge of rock layer; • 0 ft + 1 ft + 1 ft = ? feet d. Enter table on page bottom with landslope and upslope dike ratio. Select dike multiplier of 3 . . e. Multiply dike multiplier by upslope mound height to get upslope dike width: . x _ _feet f. Add the depth of slope difference (2b) to the upslope height to get the downslope height S. LD + _ feet g. Enter table on page bottom with landslope and downslope dike ratio. Select dike multiplier of 5. U h. Multiply dike multiplier by downslope mound height to get downslope dike width: x -. = 1 r' feet I. Compare the values of step G.1 and Step G.2.h. Select the greater of the two values as the downslope dike width; 1 �4 feet k. Total mound width is the sum of upslope dike width plus rock layer width plus downslope dike width; l 0_ ft + ft + ? f ft = -2 4' feet L Total mound length is the sum of upslope dike width plus rock layer length plus upslope dike width; ft + r c ft + i ft = feet h TOW LOW& kt t1 1M111 S1 k1 7:1 11 11 7.00" &I !t 0A 0 11 a0 1.0 40 70 3.0 l0 f0 as 7J Y 1 10N 417 M a70 777 t" Ill 476 111 GA 1A I I.0 1.11 9A a 114 to ).70 am LU 414 a01 I Is a!1 I.� 77? all 171 IN a71 1w L1• &At / It l71 aJl 711 9.77 J11 � 4.17 1M &0 aw 1 1A ' I01 am a37 1077 261 C Ll/ 4 / a &SO SA/ 111 &Z 7.14 •!1 1 J 07 J i/ I.1) I r /./t to $Al 7 1w 1!0 7M tell/ 17.77 2/1 LIJ 7.10 /.2 4.10 1.11 1 Lw iw w us/ 17.•1 to I.01 I.f/ /.r ar 40 • /.11 LS 901 110/ 1192 2.16 !M IA1 LM as /r le /20 am W 150 13s1 231 is 7.71 I.7! u: 4&M 11 U9 1.14 11.11 1716 MA1 131 2.70 1.71 IAI to US 13 40 7.M It" 21A7 an tt1 L70 W to is aw A. Determine pump capadtlr. Gravity DisWbutlon I. Minimum suSpoed is 600 gallons per hour (10 gyre) to may ahead of water use rate. 2. Maximum suggested for delivery to a drop box of a home system is 2,7M gallons per hour (45 gpm) to prevent build-up of pressure in drop box. Press re Dbefttlaa 3. a. Select number of perforated laterals b. Select perforation spacing • ft. c. Subtract 2 ft. from the rock layer length. - 2 ft. d. Determine the number of spades between perforations. Length pert. spacing =1c!` ft. e. -J., spades * 1= .%- perforations/lateral f. Multiply perforation per lateral by number of laterals to Set total number of perforations. x_ perforations. g• = x , •s: z gpm SELECTED PUMP CAPACITY 3 "")_ ape+ D. Determine head requirements: 1. Elevation difference between pump and point of discharge. _' feet 2. If pumping to a pressure distribution ,ystem, add five feet for pressure required at manifold r feet 3. Friction loss a. Enter friction loss table with gym and pipe diameter. Read friction loss in feet per 100 feet from table. F.L. = . ;,; ft./100 ft of pipe b. Determine total pipe length from pump to discharge point. Add 25 percent to pipe kngth for fitting loss, or use a fitting loss chart. Equivalent pipe lenl,th - I M times pipe length = _-/ s x 1.25 = /,`_ feet c. Calculate total friction loss by multiplying hkoon lag in ft/10D ft by equivalent pipe length. Total frklbn loss = rr x .100 = feet 4. Total head required is the sum of elevation difference, v special head requirements, and total friction Im. (il (2) (30 TOTAL HEAD r feet C F"Mp selection 1. A pump must be selected to deliver at least gpm (Step A) with at least ' .r' feet of total head (Step 8). NO res�oMI M OF is POWO s t arwa WM s.r uw �romp Mw R TANIJIMPOWOM atOMCKA119t•M4M OmwANOW rora�M 1/4 FSOM are tars 1a 1.17 IM 110 M IM us .t1r.1 �s b�sl anew tar wdinw w� awls bat d W Ise i sMiM hirteat 401sias elasttaa DM111aaas Iva 1) 5' F-Ifr 13 lash 2A Imh 3A hub On FAWW a OM Maisrs 4110 12 0 996 0�2f 1i 1M SA *As 30 M? all 23 3.73 1.11 0.16 30 S.23 135 t1.23 40 N is 147fI.73 3M o so 3.99 ass 35 4.76 a70 so s.sf aft 0 L-13 CERTIFICATION 1 00627 Logo of Soil Borinya Location or Project Paul Boyke, Lotl,B1k.1,Lauranne Woods, W .1/2,Orono Borings made by S-P TTestinl Inc. Steve Schirmers Date 9-23-92 Classifiction System: AASHO s USDA-SCS X s Unified t Other Auger used (check two): Hand X , or Power , Flight , or Bucket X Depth, Boring number I Depth, Boring number 2 in in feet Surface elevation 1 - feet Surface elevation `! w0.f, 0 - 0 - Topsoil dark brown loam Topsoil dark brown loam 0 - 8" 0 - 6" Brown clay loam 1 I - Gray brown loam •~ - 10" 2 - 8" - 212"-MOTTLED 212" 2 - Brown clay loam Rusty olive brown 100 - 21100-MOTTLE 2' 3 - clay loam 3 - Rusty olive brown --lay loam 21100 - 3-1/2' 6 - 2'2" - 3110" � - Rusty olive brown Rusty olive brown loam loam S _ 3010" - 5' 5 _ 3-1/2' - 5' 6 - 6 - 7 - 7 - 6 End of boring at 5' feet. Standing water table: present at feet of depth, hours after boring. Not present in hole x Mottled soil: Observed at 2'?" feet of depth. Not present in hole Comments: End of boring at 5' feet. Standing water table: present at feet of depth, hours after boring. Not present hole x Mottled soil: Observed at 2'10" feet of depth. Not present in hole Comments: CERTIFICATION # 00627 Logs of Soil Borings L-13 Location or Project Paul Bovke,Lot1,Blk.l,Lauranne Woods v.1.1/2,Orono Borings made by S-P TestIng, Inc. Steve Schirmers Date 9-23-92 Classifiction System: AASHO t USDA--SCS X Unified s Other Auger used (check two): Hand X , or Power , Flight , or Bucket X Depth, Boring Limber 3 Depth, Boring number 4 in in feet Surface elevation feet Surface elevation sy Z s" 0 - 0 - T opsoll dark brown oam 0 - 6" Topsoil dark brown 0 - 10" loam Gray 6„ _ 1, brown loam 1 - 1 - Brown clay loam Brown clay loam 2 - 1' - 2'2"-MOTTLED 2'2 2 - Rusty olive brown i0" - 2-1/2 3 _ clay loam Brown loam 2'2" - 314" 3 - 2-1/2' - 3120-MOTTLED 4 _ Rusty olive brown 4 _ Olive brown loam loam 3'4" - 5' 5 3'2" - 5' - 6 - 7 - 0- End of boring at 5' feet. Standing water table: present at! feet of depth, hours after boring. Not present in hole X Mottled soil: Observed at 2'2" feet of depth. Not present in hole Comments: 6 - 7 - 8 - End of boring at 5' feet. Standing water table: present at feet of depth, hours after boring. Not present in hole X Mottled soil: Observed at 3'2" feet of depth. Not present in hole Comments: L-13 CERTIFICATION i 00627 Logs of Soil Borings Location or Project Paul Boyke,Lotl,Blk.l,Lauranne Woods U1.1/2,0rono Borings made by S-P Testing, Inc. Steve Schirmers Date 9-23-92 Classifiction System: AASHO USDA-SCS X ; Unified Other Auger used (check two): Hand X , or Power , Flight , or Bucket X Depth, Boring number 5 Depth, Boring number 6 in in feet Surface elevation 177S feet Surface elevation yJ41, r 0 Topsoil p 0 - 6" af6amrown (Iray 6" - 10" broein loam 1 - Browb clay loam 2 - 10" - 212"-MOTTLED Rusty olive brown 2'2" clay loam 2'2" - 2010" 3 - Rusty olive brown loam strong 4 _ 2'10" - 4' Rusty olive brown loam 5 _ 4' - 5' 6 - 7 - 8 End of boring at 5' feet. Standing water table: present at feet of depth, hours after boring. 'Tot present in hole___ X Mottled soil: Observed at 212" feet of depth. Not present J.n hole Comments: 0 - Topsoil dark brown 0 - 10" loam 1 - Brown 10" - 1'2" loam Brown clay loam 2 - 1 1'2" - 2'4"-MOTTLED 2' Rusty olive brown 3 - 2'4" - V 2" clay loam Rus*•.• olive brown loam _ 3'10" 4 - Rusty gray loam ,in" - S1 5 - 6 - 7 - I'm End of boring at 5' feet. Standing water table: present at feet of depth, hours after boring. Not present in hole X Mottled soil: Observed at 2'4" feet of depth. Not present in hole Comments: GERT.#00627 PERCOLATION TEST DATA SHEET Percolation test readings made by S - P Testing I ne . on— 9 - 2 4 - 9 2 startingat : 0 7 p.m. Test hole locatiM+Lot1,B1k.1,Lauranne Wood ''1tW� 1 9-23-92 . �6R ndrtlHe� ,Date hole was prepared Depth of hole bottom 12 finches, Diameter of hole 6 inches Soil data from test hole: Depth, inches 0 - 8" 8" - 12" Method of scratching sidewall Knife Soil texture Topsoil dark brown loan Brown clay loam Depth of gravel in bottom of hole inches Date and hour of initial water filling 9 - 2 3 - 9 2 • Depih0t�tnitial water filling 12 —inches above hole bottom Method used to maintain at least 12 inches of water depth in hole for at least 4 hours Automatic siphon 6 Maximum water depth above hole bottom during test griches Time Time interval, minutes Measurement. inches Drop in water level, inches Percolation rate, minutes per inch Remarks 2:51 prefi11 6 3:07 3:22 4-1/8 3.6 15 min 3:33 3:48 3-7/8 3.9 " 3:49 4:04 3-13/16 3.9 " Percolation rate = 3 ' 8 minutes per inch. CERT.N00627 PERCOLATION TEST DATA SHEET Percolation test readings made by S — P Testing, Inc. m - 9 — 2 9 2 starting at 3 : 08 `A. e+' TeathoklocatiM+Lotl,B1k.1,Lauranne Woods,.? . /2 2 9-23-92 Hole num r . Date hole was prepared Depth of hole bottom 12 inches. Diameter of hole 6 inches Soil data from test hole: Depth, inches Soil texture 0 — 6" Topsoil dark brown loam 6" — 10" Gray brown loam 10" — 12" Brown clay loam Method of scratching sidewall K n i f e Depth of gravel in bottom of hole 2 inches 9-23-92 ,De 30ppm. , 12 Date and hour of initial water filling pth of initial water filling inches above hole bottom Method used to maintain at least 12 inches of water depth in hole for at least 4 hours_ A» t-.,matiC aiphoD Maximum water depth above hole bottom during test 6 inches Time Time interval, minutes Measurement, inches Drop in water level, inches Percolation rate, minutes per inch Remarks 2 : 5 3 pre f111 6 3:08 3:23 3-15/16 3.8 15 min 3:32 3:47 3-3/4 4.0 " 3:50 4:05 " 3-5/8 4.1 Percolation rate : a - n minutes per inch. CERT.000627 PERCOLATION TEST DATA SHEET a.m. Percolation test readings made by S- P TP c t i n T n c_ or 9- 2 d- 9? starting at A Q .,4.N Test holeIOCari(ln Lot1,B1k.1,Lauranne woofter��J2 3 Date hole was prepared 9-23-92 Depth of hole bottom 12 inches, Diameter of hole 6 inches Soil data from test hole: Depth, inches 6" - 12" Method of scratching sidewall Kn i f e Gray brown loam Depth of gravel in bottom of hole - imbes Soil texture Date and hour of initial water filling 99� 2 3 - 9 2 l'epf RRnitial water filling 12 - inches above We bottom Method used to maintain at [east 12 inches of water depth in hole For at least 4 hours Automatic siphon , Maximum water depth above hole bottom during test 6 inches Time Time interval, minutes Measurement. inches Drop in water level, inches Percolation rate, minutes per inch Remarks 2:53 prefill 6 3:09 3:24 It 2-3/16 6.9 15 min 3:31 3:46 412-1/16 7.3 « " 3 : 5 1 4:06 2 7.5 » » Pacolation rate - 7 • 2 --minutes per inch. CERT.N00627 PERCOLATION TEST DATA SHEET Percolation test readings made by S — P Testing, Inc. on 9 — 2 4 — 9 2 starting at 3 : 10 'moa (n Test hole location_Lot 1, B 1 k .1, Lauranne Wootkkyt;,bW2 4 Date hole was prepared 9-23-92 Depth of hole botto12 inches, Diameter of hole 6 inches Soil data from test hole: Depth, inches 0 — 10" 10" — 12" Method of scratching sidewall Soil texture Topsoil dark brown loam Brown clay loam Depth of gravel in bottom of hole 2 inches 9-23-92 2:30pm 12 Date and hour of initial water filling , Depth of initial water filling inches above hole bottom Method used to maintain at Ieast 12 inches of water depth in hole for at least 4 hours Automatic siphon 6 Maximum water depth above hole bottom during test inches Time Time interval, minutes Measurement, inches Drop in water level, inches Percolation rate, minutes per inch Remarks It 2 7.5 15 min 11 N N N N tl 11 N N N Percolation rate = 7 - 9 minutes per inch. CERT.#00627 PERCOLATION TEST DATA SHEET LAL Percolation test readings made by c- p To c h i n q, T N r_ 9m 9- 2 4- 9 2 starting at p.m. 4J.W1 Test holelocatiort.Lot 1, B 1 k .1, Lauranne woocl�bl ItllorhlaCr2 5 Date hole was pn;+a 9-23-9 2 Depth of hole bottom 12 inches. Diameter of We 6 inches Soil data from test hole: Depth, inches 0 - 6" 6" - 10" 10"- 12" Method of scratching sidewali Knife Soil texture Topsoil dark brown loam Gray brown loam Brown clay loam Depth of gravel in bottom of hole - inches 9-23-92 2:30pm 12 Date and hour of initial water filling , Depth of initial water filling inches above hole bottom Method used to maintain at least 12 inches of water depth in hole for at least 4 hours Automatic siphon , Maximum water depth above hole bottom during test 6 inches Time Time interval, minutes Measurement. inches Drop in water level, inches Percolation rate, minutes per inch Remarks : 5 3 prefill 6 �:11 3:26 to 1-11/16 8.9 15 min �:29 3:44 1-5/8 9.2 " I:53 4:08 " 1-5/8 9.2 w w Percolation rate - 9 - 1 minutes per inch. CERT.#00627 PERCOLATION TEST DATA SHEET S—P Testing, Inc. 9-24-92 3:12 a.m. Percolation test readings made by on starting a m. Lot1,B1k.1,Lauranne woods L—.112 6 9-23— Test hole locati, Hole number Date We was prepared Depth of hole bottom t 2 inches, Diameter of hole 6 _inches Soil data from test hole: Depth, inches 0 — 10" 10" — 12" Method of scratching sidewal Soil texture Topsoil dark brown loam Brown loam Depth of gravel in bottom of hole 2 inches 9-23-92 2:30pm 12 Date and hour of initial water filling , Depth of initial water filling__ inches above hole bottom Method used to maintain at least 12 inches of water depth in hole For at least 4 hours Automatic siphon 6 Maximum water depth above hole bottom during test inches Time Time interval, minutes Measurement, inches [)top in water level, inches Percolation rate, minutes per inch Remarks of 2-7'8 5.2 15 min It _ 4 5. " to 7 _ " w Percolation rate - S - 4 minutes per inch. PERFORATED ram_ LATERALS SANDY LOAM SOIL LAYER OF GEOTEXTILE NA�CpyOR 4 INCHES OF BUILOING ; PER --1 IV OR 2' PIPE FROM PUMP-- 3/ -2/• CIt0AN DOCK — y V TOPSOIL i `;aN L6EASLO F ll / DIVERSION FOR SURFACE WATER rg e LAY q RpkEN vER BA IERRAL4vER LAYOUT OF PERFORATED PIPE LATERALS FOR PRESSURE DISTRIBUTION IN MOUND PERFORATED PLASTIC PIPE PERFORarIoNs SPACED ]B' ON CENTER PERFORATION END VIEW on - W1v BE�: h" PERFORATIONS ON BOTIOM or PLASTIC PIPE ENO CAP b. �y K�Arlo TM o` m IOFTfICAT PPC F." P !w Y rIPE FROM PUMP04 CHAMBER LAVER OFGETExTILE GRASS COVER .EAN SAND FILL---- kx 4 SLOPE It LOAAIV SAND CAP r PERFORATED LATERAL % TO►SOILS TOPSOIL L PLOWED OR oiSsKEOSKEo SURFACE UBSOIL CROSS SECTION A - A -- Pipe FROM PUMPING CHAMBER _ W PERFORATED I - LATERALS BED AREA 1 ._. -._. 20 egg - IN HE II N - - I I DIKE — OMFE T�+-DIKE X. TOTAL WIDTH - z! END PERFORATHM OF A PERFORATED LATERAL Gr. Cau r�rrr of onallm FrrY qr ur- ww" So" LAW • MMi 4 40 IIke N r" Sam" ffam Fam No or wrwnrr � M Los" ur 08 bM /rlrawr =d M c"m !W LMr wK+ M Lawn WATER TIGHT 0 LOCKABLE ELECTRIC BOX— � PLUGS OR ELECTRIC CONNECTIONS - �---� 2" PVC CONDUIT SCHEDULE BO 6�SPAC MANHOLE COVER CHAINED a LOCKEOT � �-- SEALED MANHOLE RINGS .. , , SEALED TANK COVER --I PLASTIC ROPE OR CHAIN WITH ANCHOR ---�` ALARM FLOAT ON SEPARATE ELECTRICAL CIRCUIT-- S►1UT-OFF_LFVEI,--Q _ } PUMP CON I140L FLOAT METAL COVER CONCRETE - MANHOLE RING TRREATED�POST ( x min)__ IA16DkLECTRIC CONNECTIONS MADE Box LOOP OF POWER CORD FOR SETTLEMENT I AT LEAST 12- BELOW GRADE } WIRE FROM POWER SUPPLY �-SLOPE FROM pPIP�EpISgTU�ITI� � O UNIFORM TREATMENT AREA FOR PRDPER ORAINBACK (-IF PIPE AT TANK MUST BE LOWER THAN UNION TO GET ELEVATION FOR DRAINBACK A 1/4 INCH WEEP HOLE MUST BE USED — WEEP HOLE NOTES ELECTRICAL WIRE FROM POWER SUPPLY MUST NOT RUN OVER ANY TANKS BUT STSTDI ITS AND M BE PLACED INCONDUU ALONG POST ELECTRICAL CORDS FROM PUMP AND FLOATS MUST BE RUN THROUGH CONDUIT WIRES CANNOT HAVE GROUND CONIACT Figure F-11 METHODS OF SECURING MANHOLE COVER TO PREVENT UNAUTHORIZED ENTRY Figure C• 14 VERTICAL SIDEWALL SEPTIC TANK FINISHED GRADE AT LEAST 6' TO 12" SOIL AT LEAST 4" DIA. —� I COVER 4" DIA. AT LEAST I" AT LEAST I" T � 1 A 1 A UIME.N51()1`45 FOR TANKS WITH VERTICAL _510ES WIU7H`W _ 24� MINIMUM^ --- - -- LENGTH, L 2 70 3 TIMES T_HE_ IN M s-- 8 E)IAMETER GO' MINIMU •- ULI,THLD _ 30' MINIMUM; TB_MAXIMUM — C AT LEAST 9 g" MINIMUMI 6.2 D MAXIMUM s' l— AT LEAST 4 FEET N/11 S I SN.IIAIIV las Ai I rAS1 alNllli W[ 11A►i 1f(1 I AWAftf ttivEIB SIWIRIOCAI[D1M111M 17 tIG4] 11[(1I I.IINI Ill �Nr CYllrlll 4NtUlCS PrUAS1 If log M KAIE MIItM btt4f[� II( SkAAM qft I"kW IISt7N AMIl (W.A I I I I M 1 N.tl11I(if Al11A/A1 ` f11 t Aryllt}aM11 A10ElK rvM It IZI Er"AM: WN111 7 AM uvYCIlClw rrrM +l llAYl. w(.IN7MAMrin Nr A11j�r/Vt1111/OMrIf tl Ml►mM171CslUWIt tIGrt on A WVt1(1l[ SIv111 M lQCA1E0(IVEfI["M Off ME1 Q1 W)I"I! I1NM I RICO rt91 Ivt1(1U11E 1lllvt'CS hrt CUIIEIIINC CY 11f tI:1'lC1t]I t rMIQt1UMINCvltK1rcm fArM; D(I�IK.IIMAHf1S0 1.1ySlIWllM. 11(SAIl AS 111111 "It It WEn I-* A1/r1 d.rt N11CWCIiDtI(/ IIYI it WI NWC-tNI GAIMI AI II I L I S A 11 wvl NY1(7 I.0.1 YI.1 Ilr 1CJC A 111, It IV" I w f11F 0411 AN,t.�111 I Pod 11 rs INLET r CLEAN OUT TAME WHEN: "T W IS Y OR LESS OR '6' IS 12' OR LESS 1111� Iw MEASURE SCUM AND SLUDGE ACCUMULATIONS I N THE SEPTIC TANK It.. tJ 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 This lot has an existing residence with an on -site sewage treatment •stem. The system is a conforming system according to MPCA RulE 'hapter 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 for a 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 412", 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. P. Subdivision #1762, Septic Review October 15, 1992 Page 2 LOT 1, BLOCK 1 - WEST ONE-HALF Soil testing and septic system design has been provided for a 5-bedroom home including primary and alternate drainfield sites. Both sites meet MPCA Rules Chapter 7080, however a 25' section of the alternate drainfield site encroaches within the 20' setback required for driveways. The proximity of the driveway to the alternate site cannot be avoided due to site limitations. Driveway specifications should be provided to show that drainage will not adversely effect this site. Due to the proximity of the access road to the septic sites, snow fencing will be required around both drainfield sites prior to the issuance of final plat approval. Specific septic system details are included below: - Depth of seasonal saturation (mottling) is 1' 2" to 3' 6", requiring a mound. - Slope at the primary and alternate drainfield sites is up to 5%. - Percolation rates average 6.2 minutes per inch at 12". - A 10' driveway setback variance will be required for the alternate site. SUMMARY The site inspection revealed several concerns regarding drainage around the drainfield sites due to the existing driveway for the east lot as well as the proposed driveway for the west lot. Additional information will be required regarding the proposed driveway to assure that a 10' setback from both the existing system for the east lot and the proposed alternate system for the west lot is feasible as well as to assure that it is possible to drain the driveway away from both of these septic sites. The alternate drainfield site for the existing residence will also be required to assure that drainp--e can be directed around this site from the existing driveway. Provided that acceptable information can be provided regarding these drainage questions, staff is comfortable with the septic plans provided. One condition of the subdivision must be that both the existing and proposed drainfield sites must be staked using snow fencing to prohibit any traffic from compacting these sites. The fencing must be installed prior to the granting of a final plat approval and any motorized travel across these areas. lsv