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Home My WebLink AboutAUDUBON HILLS #1 Block 1 Lots 9A & 10 A S-11423Audubon Hills #1 Block 1 Lots 9A & 10A 511423 DHI CONSULTING ENGINEERS Civil Engineering · Surveying · Planning December7,2005 W.O.: 05685 Onsite Septic System Report Lots 9A and 10A, Block 1 Audubon Hills Subdivision, Addition #1 Project: Proposed Re-Plat Date: August 30, 2005 I. Existing Subdivision: The subject prope¢o/~ oftwo Lots (9and 10, Block I Audubon Hills Subdivision, Addition ~1 ). The exJ,slJng bls are zoned R6 and lolal 2.37 acres. The lots have a sbpe from soulJ-~*~ 10 northwest with an average slope of 9.5%. II. Proposed Subdivision: Rgure I shows 1he pmpc,~d subclMsion. The common lot line is being ~ 10 provide for a bet~r hc, ~.~_- site on each lot. III. Investigation: In June of 2005, (Garness Engineering Gro,,up LTD.) dug two test holes on the subject Lot 9A (T.H. #1) This1~stpitwasdug10adeplhof 15fast Wa1~rvvasencount~ at 13f~-:~ Af~ 10days, lhewat~rose lo 11 fast betowlheground surface. The w~t~le~l was ~ in OclDberar~ found 10 be 7.2 feet below the ground surface. The percolation rate 5.2 minutes per inch Late in the summer, w~ noted 1hat 1he q~per two feet of organic rna~l had beo3rne satui~d and ~illed the monitoring tubeand last pitwith wam~. Wa'asr in lhisorganiclay~r for Lot 9Awill need 10 be controlled with a curtain drain as part of any septic system design. Lot 1OA (T.H. #2) vval~tablevvas 12 f~¢ belowl~eground surface. In Oc10ber, thewatsr tablewas 10.8feet belowthe ground surfac~ A percolation l~st vvas conducted by DHI ~ Engineer~ The ~ ra~e was 9.6 minutes per inch. A curtain.drain will be require 10 control the surfacevvat~ and will need 10 be included as part of any septic design. Dimond Center Tower, 5th Floor · 800 East Dimond Blvd. Suite 3-545 · Anchorage, Ak. 99515 Ph (907) 344-1385 · Fax (907) 344-1383 · Email: dhiconsulting~nsn, com SERVING ALASKA SINCE 1985 Lot 10A (T.H. #3) A second test hole was dug on lot 10A to a depth of 16 feet. No water was encountered. After a 10 day monitoring period, the water rose 8.5' below the ground surface. In October, the water table was still 8.5 feet below the ground surface. The soils percolation rate was 40 minutes per inch. IV. Recommendations: Based on the above soil investigation, both lots will support a standard on-site septic system. We recommended the use of a standard "wide trench" or a standard "bed 'absorpt'on system for these lots. A curtain drain should be an integral part of any septic system design on these lots. It should be installed up hill from any absorption field in accordance with MOA guidelines. The curtain drain should reach a minimum of 12 feet below the ground surface and extend at least 25 feet each side ofthe absorption system in a north south direction. There is a drainage easement located along the entire length of the west property line on each lot. Discharge from the curtain drain can be directed towards this channel. The construction of septic systems and associated curtain drains is governed by AMC Title 15.65 (Waste Water Disposal). Figure 1 show the 12,000 S.F. septic reserve areas for each lot, the proposed well locations and possible house locations. See Appendix A for the Soil Log Information. Prepared By: Mr. Dee High,~. ,~ Date 685ossr(soils)8dec05 ~ "' 280' 100' PROTECITIVE WELL RADIUS-TYPICAL AREA LOT 9A = 53603 S.F LOT 10A AREA = 49591 S,F, PROPOSED WELL / TEST PiT LOCATION & NUMBER PROPOSED PROPERTY LINE DOWNEY FIN~4H LANE \ \ \ (~ Di:n' CONSti'LTING CIVIL · ~f'EYING · PLANNING 05685 ioo,~,, r,.~. ISO^~'=5o' IDATE 7-,31-05 POSSIBLE HOUSE \ LOCATION \ I I 55' I~IGUP,,~ 1 Proposed Subdivision Site Plan On- Site Septic Report ISOIL LO0 - PERCOLATION TESTI ~GAL DESCRIPTION: AUDUBON HI~S SUBD~ISION; LO~ 9 ~ 10, BLOCK 1, SOIL O~SSIFIOATIONS GM~~ CL-- - L 0 E - = GC OL ' ~N) APPROXIMATE L u~s~ w/ sw HH SOME CL ~ ' ' ~' ' ,, SP CH SM OH SC DEPTH TO GROUNDWATER DATE 13.0' 6/22/2005 11.0' 7/1/2005 SU/~L W/ SOME GM 11 DATE READING CLOCK NET TIHE WATER LEVEL NET DROP TIHE (MINUTES) READING (INCHES) 12 6/27/2005 1 4:13 - 6- _ 2 4:43 30 1/2" 5 1/2" 4 5:13 50 1/4" 5 3/4" 14 5 5:13 - 6- _ 6 5:43 30 1/4" 5 3/4" 16 17 18 19 PERCOLATION RATE 5.45 (HIN./INCH) PERC. HOLE DIA. 6 (INCHES) TEST RUN BETWEEN 6 FT. AND 7 FT. 20 A POUR HOUR PRESOA~ WAS PERFORHED: ~ YES ~ NO SOILS LOGGED BY:. JODY MAUS PERCOLATION TEST PERFORHED BY: JOE ~ECH~ COHHENTS: DUE TO VISUAL APP~CE OF SOILS, RECOMMEND USING A 0.6 APPLICATION ~TE PERFORMED BY GEG, Ltd, I, JEFFR~ A. GAENESS, CERTI~ THAT THIS WAS~E~FOEMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN E~CT ON THIS DATE: DHI CONSULTING ENGINEERS PERFORMED FOR: WILLIAM WORALL DA~ PERFORMED: o/za/uD ~GAL DESCR~P~ON: LOT ~OA, ELK ~, AUDOBON HILLS NO. 1 (PRELIMINARY PLAT)~rofe~,~ FILL & OROANIC~ SLOPE GM/SM ~TH WAS GROUND WATER SOME CL ENCOUNTERED ? YES If YES, AT WHAT DEPTH ? 13' DEPTH OF WATER AFTER MONITORING ?. 12' TEST HOLE LOGGED BY GARESS. PERCOLATION DATA CONDUCTED BY DHI CONSULTING ENGINEERS B,O.T, SITE PLAN DATE: 8-8-05 PERCOLATION RATE: 9.8 (MINUTES/INCH,) PERC. HOLE DIAMETER: 6" TEST RUN BETWEEN: 4'-0" FT. AND 4'-6" FT. COMMENTS: SEEPS NOTED AT 4' 8~ 15'. SOILS WERE PRE-SOAKED PRIOR TO RUNNING TEST, RECOMMEND 12' DEEP CURTAIN DRAIN UP HILL OF LEACH REI~D. PERFORMED BY: DEE HIGH CERllFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE, DATE: 8/29/0~ 685TEC2D W.O.# 05685 DHI CONSULTING ENGINEERS ~_~, OF,~. NOLO: 800 E. Dlmond BI~,, Sutte 3-5~ A~ROVA~ ~ u~ ~ ~,s ,.~,~=~ SOILS LOG-PERCOLA~ON TEST . " · PERFORMED FOR' ~LLIAM WORALL - · DA~ PERFUMED: 8/11/05 A ~GAL DESCRIP~ON' LOT 9A BLOCK 1~ UDOBON HILLS NO 1 {PRELIMINARY ORGANIC TOP SOIL SANDY GRAVEL SOME VERY CLEAN SAND LAYERS DRY-NO WATER SLOPE SLIGHTLY SILTY SANDY WAS GROUND WATER S GRAVEL-BROWN ENCOUNTERED 9 NO ROCK TO 2 1/2"-DRY · L 0 AFTER 12' SOILS GET MORE IF YES. AT WHAT p SANDY LESS ROCK ,~' SILT, DEPTH ? MORE LAYERS OF CLEAN SAND DEPTH OF WATER E DRY NO WATER AFTER MONITORING ?8.8' PUT IN 16' Of PERF. PIPE BELOW GROUND 3.0, T. SiTE PLAN DATE: 8/29/05 PERCOLATION RATE: 4.0 (MINUTES/INCH.) PERC. HOLE DIAMETER: TEST RUN BETWEEN: 5'-0" FT. AND 5'--6" FT. COMMENTS:PIPE CRUSH AT 9'-5". SOILS PERSOKED FOR 12 HOURS PRIOR TO RUNNING TEST. ID 12' DEEP CURTAIN DRAIN UP HILL FROM SEPTIC FIELD. PERFORMED BY: DEE HIGH CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE: 8/29/05 685TEC1D D H I CONSULTING ENGINEERS Civil Engineering ® Surveying · Planning December 7, 2005 W.O.: 05685 Water Report for Lots 9A & 10A Block 1 Audubon Hills Subdivision, Addition 1 This report has been prepared in support of the proposed re-subdividing Lots 9 & 10, Block 1, Audubon Hills Subdivision, Addition # 1. The proposed subdivision does not create any additional lots than what already exists. Wells in the immediate area range in depth from 40' to 200' with most being under 100' Bedrock has been encounter as shallow as 81 feet. Review of well logs indicate that well are producing betweer{ 3 and 15 gallons per minute with the average being above well above 8 gpm. There should be adequate ground water to support an additional well for each of the proposed lots; and we expect the wells to produce 5 gpm or better. Copies of well logs for the surround lots are attac[~~~..i~? 368waterreport Dimond Center Tower, 5th Floor · 800 East Dimond Blvd. Suite 3-545 · Anchorage, Ak. 99515 Ph (907) 344-1385 · Fax (907) 344-1383 · Email: dhiconsulting~msn, com SERVING ALASKA SINCE 1985