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HomeMy WebLinkAboutSILVERWOOD HILL ESTATE #2 S-11770Silverwood Hill Estates 511770 -'~4~1~2 CONSULTING, lNG ~ 20441 Ptarmigan B vd, Eagle River AK Office (907) 696-6111, Fax (907) 868-3793 November 23, 2009 Municipality of Anchorage Development Services Department On-Site Water & Wastewater Program P.O. Box 196650 Anchorage, AK 99519-6650 RE: Silverwood Hill Estates - S- 11770-1 Summary of Action Comments #5 Dear Debbie, Attached are the available well logs from properties in the immediate vicinity as you requested. While ground elevations do not typically affect bedrock wells we have reviewed downslope lots south and west of this property as reconm~ended and still feel there is adequate water available for tttis subdivision. DSD well data shows the average yield for the surrounding area to be approximately 2.0 GPM, with a range from 0.3 GPM to 5 GPM. The owner has agreed to place an advisory note on the plat as you requested. It will read "Some area wells have iow water production, so water storage may be needed in addition to a well." I have attached an original topo drawing with the test hole m~d utility easement locations from the surveyor which has been drawn to scale. As shown, the septic reserve areas do not encroach on the utility easement. Though it does not appear water monitoring was done in October, the original monitoring was in September, and we verified that the northern test hole is dry this past weekend. We respectfully request approval and plat signoff of the above referenced plat. If you have any questions, please contact me at 696-6111/FAX 696-8111. Respectfully submitted, ArcTerra Consulting, Inc. Attachments: Cc: Nell Nichols file As noted 20441 Ptarnngan Blvd, Eagle R~ver AK Office (907) 696-6111, Fax (907) 868-3793 November 18, 2009 Municipality of Anchorage Development Services Department On-Site Water & Wastewater Program P.O. Box 196650 Anchorage, AK 99519-6650 RE: Silverwood Hill Estates - S- 11770-1 Summary of Action Comments #5 Dear Debbie, We are submitting the requested information for the above referenced property for your review and approval. Attached is the topographic information, proposed septic reserve areas with corresponding soils logs and water availability data of properties in the immediate vicinity. DSD well data shows the average yield for the surrounding area to. be approximately 2.0 GPM, with a range from 0.5 GPM to 4 GPM. Two recent well logs, Lot 4 drilled in 9/05, and Lot lA drilled in 9/06 show yields of 1.5 gpm and 2 g-pm respectively. The property generally slopes towards the west at approximate grades of 10 to 30%. The available data of the referenced and adjacent properties show that the proposed lots have adequate soils, water production, topography and other characteristics to support on-site water and wastewater systems that meet the criteria specified in AMC 15.55, AMC 15.65 and AMC 21.15. We respectfully request approval and plat signoff of the above referenced plat. If you have any questions, please contact me at 696-6111/FAX 696-8111. Respectfully submitted, ArcTerra Consulting, Inc. Attachments: As noted Cc: Nell Nichols file UPPER SKYLINE DR EAGLE RIYER/CHUGIAK AREA REFERENCE MAP ~ ~C NW 254 SW 114 SEC. 6, TI4N · 8lA · ~'~ 18945 Timberline Drive V,~dl Depth: 400 feet Flow rate: 4.0 gpm Hydrofmclion done when ~ drilled 1097 188~5 Timberline Drive Well Depth: 400 feet F~ow rote: 0.5 gpm No Hydrofre~ton per- fon~ed. Ullllze ,500 gaL holdin~ lank for high Page 2 of 2 19336 Tlmberll. e Ddve Flow rote: 1.3 gpm ComparatiVe Well Data ~ Affix i'~orlhem edge of pag~ two to southern edge of page one ~oalec: 1 Inch = 200 feet (, 8 9- 10- 11- 12- 13- 14- 15- 16- t7- 18- 19- 20- ,~r formed For: Legal Descripiion: Deplh 3- 4- Municipality of AnchOrage Development Services Depadment Building Solely Division On-Site Water and Was[ewaler Program 4700 South Bragaw SI. P.O. Box 196650 Anchorage, AK §g51g-6550 www.munl.org/onsite (gO7) 343-7904 ~1 Soil,s Log - Percolation Test '~ Slope Sile Plan // WAS GROUND WATER ENCOUNTERED? IF YES, AT WHAT DEPTH? L Depth to Waler After ~ Dp Reading Dale Gross Time Nel Time J Depth to Waler N~.t Drop PERCOLATION RATE ~ (minule~inch) PERC HOLE DIAMETER ~ TEST RUN BETW1EEN ~ FT ..~'~ ' FT F~FbRMEDBY: ~. 5' Z~¢/d~¢/J~ I~/ ~~ CERTIFYT~TTHISTESq~AS PERFORMED IN ACCORDANCE W,~ ALL STATE AN~UNI~/AFG~¢ES IN EFFECT ON THIS DATE. DATE: J.t'Na'fl ~ ENGINEERING 20441 PTARMIGAN BLVD. EAGLE ~R, ~ 99577-8736 SOILS PERCOLA~ON ~ST Performed for: Neil Nichols Date Project: Silverwood Hills "Lot 7' TEST HOLE # 2005-6 Depth (Feet) 1- 2- 3- 5- 6-1 7- 8- 9- 10- 11- 12- 13- 14- 15- 16- 17- 18- 19- 20- Org]OL GM SLOPE 20-25% HOLE PRESOAKED PRIOR TO TEST SEE ATTACHED SITE PLAN FOR HOLE LOCATION I Was Ground water encountered? YES What depth? 6' [ Depth to water after monitoring? 5.5' Date? I0/05/05 Reading Date Gross Net Depth to Net Time Time Water Drop 1 9/29/05 1:00 6" 2 1:30 30 min 4 14/16" 1 2/16" 3 * 1:31 6~ 4 2:01 30 rain 5" 1" 5 * 2:02 6" 6 2:32 30 rain 5" I" · Water Added IPercolation Rate 30 (rain/in) Perc Hole Diameter 6" Test Run Between 3 feet and 4 feet I, Kenneth M. Duffus, certify that this test was performed in accordance with all State and Municipal guidelines in effect on this date.