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HomeMy WebLinkAboutSPENARD HEIGHTS ADDITION LT 6,nard H ights Addn Lot 6 #012-052-36 G 3LitA woo/ p Inc 0010{6. tide, w • vn9n1 1'1 inlet • Ju)4.4e9i119 05\j 111O$11 August 30, 2017 Onsite Reviewer Municipality of Anchorage On-site Water & Wastewater Program 4700 Elmore Road Anchorage, Alaska 99519-6650 Re: Lot 6 Spenard Heights Subd; Parcel #01205236000 3729 W 61St Ave, Anchorage, AK 99502 Separation distance Waiver request Background: The owner of the subject property (single family home) is requesting a waiver for a separation distance from a private water well established in November of 2016. Well was shifted per Owner request to allow well drilling rig improved access to the site area. The presence of a 2nd cleanout was not detected during installation in early winter conditions. The existing sewer service for Lot 3 was field located during the sewer pipe condition check and our LCG Lantech survey crew surveyed the field locates on 8/23/17. The sewer extends around the carport to the west side of the house and connects into W. 61st Avenue as shown per the attached site plan map. A 25' setback buffer radius is shown around the existing well in the site plan. Subject property existing well to: a. Existing sewer cleanout/private sewer line: 11'-4" (11.3 feet) Justification: 1. The well casing was seal grouted by well driller from the surface down to 20' bgs with bentonite. Casing protrudes approximately 30" above ground surface and has a sanitary seal. 2. All existing cast iron pipe within the 25' well setback buffer will be replaced with 4" DR18 PVC C900 pipe with restrained joint integral bell (RJIB) gasketed joints conforming to AWWA C900. The existing cleanout riser pipe located within the setback buffer shall be field-verified for pipe material type and if cast iron pipe shall be replaced with restrained Certa-Lok C900 RJ pvc pipe if riser is not already RJ pvc pipe. Contractor shall verify where existing sewer service on Lot 6 changes to pvc plastic pipe. Depending on where the existing plastic pipe begins, the cleanout shall be shifted, to the extent possible, to increase setback distance from the well. Joint connections of the existing pvc pipe within, or in close proximity to, the setback buffer shall be checked for leaks and joint integrity. If necessary, encase existing pvc pipe joints with bentonite to fully seal joint connection. 250 H Street,Anchorage,Alaska 99501 I Main Line: (907) 243-8985 I Fax: (907) 243-5629 I www.lcgak.com Onsite Reviewer, MOA Water & Wastewater Program August 30, 2017 Lot 6 Spenard Heights Addition Page 2 of 2 3. The water service from the new well will be routed around to the east side of the house with 12 to 15' separation and will not cross the existing sewer. Contractor shall re-seal the well casing after the pitless and house service tie-in is installed. 4. Surface pollution. Site slopes away from the house to the north and to the west. Beyond the edge of the grassed area, is undeveloped terrrain (wooded) that slopes to the northwest. Well location is north of the cleanout per site plan. Overflow around the cleanout would drain primarily to the west and be visible to be addressed before it could accumulate enough to move toward the well. The well casing was seal grouted from the surface to 20' bgs with bentonite. 5. Subsurface pollution: Well depth is 280 feet with a static water level of 85 feet, which equates to a pressure of 84 psi [(280 ft - 85 ft) x 0.43 psi/ft = 83.9 psi]. The relative pressure at this location indicates the aquifer is well-confined and unlikely to be influenced from the subject property above. 6. See attached site analysis calculation (14.0 points) using ADEC waiver criteria. Per ADEC waiver guidelines for values between 12 and 16, no bacteriological pollution is possible, however chemical pollution from household chemicals is considered possible but unlikely. 7. Other: The population density is relatively low in this subdivision (-5000-7500 SF per bedroom). No other wells in the area would be affected by the location of this waiver request. The well driller submitted a well water sample for testing and is awaiting the results. The testing results of this sample will be submitted along with this request for waiver. If you have any questions please call me at (907) 245-8884. Thank you. cerely, D vid Coolidge, PE Senior Civil Engineer, LCG Lantech LLC Enc. Well log, waiver site plan and site analysis reference data 4114"' OF 40 % :r, •....... . `' ••. 0 1' •9�t : t Ili .%. IA- D.YID R. COOLIDGE. Ncr.‘.el.,C0.8st:10;..3E.580.:::.‘11;;:k.;.\;14...treco-toio• ------- --- -- ----- --- ------------- 100' 100' SEWER /SETBACK LOT 3 .77 ,-100'PROPOSED IFS % WELL BUFFER LOT 4 N89° 59' 27"E 116.25 / 1 / 75 SEWER MAIN,, \ SETBACK LOT 5 / LOT 6 / 25'SEWER g SETBACK 8 Lo I o g1 ' EXISTING e7.996 1 -EXISTING WELL WELL SEWER SERVICE wj - 5.7% •co � 1 V 1J' I , 75 SEWER MAIN p ../ co j SETBACK 'ter//////// O EXISTING o z HOUSE "'I 1 A 1 25 SEWER SETBACK I - SEWER 100'SEWER ` SERVICE i �;, 100' SEWER / SETBACK SETBACK / 'S89' 59' 27"W 116.25; W. 61ST AVE N. W. 61ST AVE (m—i-) -LEGEND: ~ —.- 1 O -WELL e -SEWER MANHOLE euA.w.r.bear. ocn •CLEANOUT LOT 11 ----PROPOSED WELL BUFFER ———-LOT EASEMENT LINE GAS AND OTHER UTILITY LOCATIONS ARE APPROXIMATE. SEWER LINE SETBACK CALL 811 FOR LOCATES PRIOR TO DRILLING. I -SEWER LINE SEPERATION DISTANCES AND SETBACKS PER -UNDERGROUND GAS LINE AMC 15.55.060 TO BE VERIFIED BY DRILLER '' L( 'G: SPENARD HEIGHTS SUBDIVISION DRAWN BY: PS CHECKED BY: SC �r�f-Jr�rtr Inc LOT 6 DATE: 08/24/2017 auititectwte•enyoiee161•ou:weytit¢ JOB NO: 15064 •--•--• WELL SITE PLAN I SHFFTNC) P`907243-8983 PARCEL# 01205236000 SCALE: 002 Fw )243-5629 ww., 1"..40' cyak.com General Lot 6 Spenard Hts; Parcel #01205236000; Well permit OSP161216; Owner: Margaret Johnson ADEC site evaluation criteria for waiver request: Water Table Point Value Cased depth to water bearing layer 278 Depth of existing sewer service pipe 5 7.53 Soil Sorption soil descriptions per attached well log from Hefty Drilling DEC points Depth fron Depth To Thickness Calc'd points Casing stick up n/a 0 2 n/a Organic top soil 0 2 4 2 0 Silt and Gravel 3 4 35 31 0.33 Clay 6 35 140 105 2.25 Sandy Clay 4.5 140 230 90 1.45 moist gravel w/clay 2 230 269 39 0.28 coarse gravel w/water 0 269 280 11 0 278 4.31 l 4.311 Permeability soil descriptions per attached well log from Hefty Drilling DEC points Depth fron Depth To Thickness Calc'd points Casing stick up n/a 0 2 n/a Organic top soil 0 2 4 2 0 Silt and Gravel 1.5 4 35 31 0.17 Clay w/some silt 0.8 35 140 105 0.3 Sandy Clay 2 140 230 90 0.64 moist gravel w/clay 1.7 230 269 39 0.24 coarse gravel w/water 0 269 280 11 0 278 1.35 I 1.351 Water Table Gradient assume gradient slopes toward the water source assume -25% slope (conservative estimate) 0.5 Horizontal Separation 11-5" (11.42') 0.32 Total Points 14.01 Per ADEC waiver guidelines, the sum of the area conditions reviewed equate to a point value of 14.0. For values between 12 and 16, no bacterological pollution possible. Chemical pollution from household chemicals may be possible, but unlikely. On-Site Water System Permit MUNICIPALITY OF ANCHORAGE Development Services Department On-Site Water & Wastewater Program 4700 EImore Road, PO Box 196650 Anchorage, AK 99519-6650 Telephone: (907) 343-7904 Permit Number: OSP161216 Tax Code Number: 01205236000 Work Type: Well Initial Permit Effective Dates: August 27, 2016 Design Engineer: to August27,2017 Subdivision: SPENARD HEIGHTS ADDTION Site Legal Address: SPENARD HEIGHTSADDTION LT 6 G:2026 Owner/Address: JOHNSON MARGARET L TRUST JOHNSON MARGARET LORRAINE/TTE 3729 W 61ST AVE ANCHORAGE AK 995022002 Site Mailing Address: 3729 W 61ST AVE, Anchorage Lot Size in Sq Ft: 17438 Total Bedrooms: 4 }artment This permit is for the construction of: N Disposal Field N SepticTank N Holding Tank N Privy Y Private Well N Water Storage All construction must be in accordance with: 1. The attached approved design. 2. All requirements specified in Anchorage Municipal code Chapters 15.55 and 15.65 and the State of Alaska Wastewater Disposal Regulations (18AAC72) and Drinking Water Regulations (18AAC80). 3. The wastewater code requires inspections during the installation. The engineer must notify the Development Services Department at least 2 hours prior to each inspection. Provide notification by calling (907) 343-7904 (24 hours). 4. From October 15 to April 15, a subsurface soil absorption system under construction during freezing weather must either: A. Open and Close on the same day. B. Covered, sealed, and heated to prevent freezing. MUNICIPALITY OF ANCHORAGE Community Development Department ~.~ Phone: 907-343-7904 Deveropment Services Division ~ Fax: 907-343-7997 On-Site Water & Wastewater Program ON-SITE SEWER/WELL PERMIT APPLICATION Propertyowner(s) ~'~::A'(~-__~ t~'¥_..~ j_. '~'l ~ Mailing address ~ ~ ~[ ~' ~ ~~ Site address ~ ~ ~ [ ~[~ ~'~ Legal descnphon (Sub d., Block & Lot) ~ ~th~ ~ ~[~ ~ Legal description (Township, Range & Section) Lot Size Sq. Ft, Number of Bedrooms APPLICATION IS FOR: APPLICATION IS AN: TYPE OF DWELLING: ([] all that apply) Absorption Field [] Initial [] Single Family (SF) (w/we ADU) Septic Tank [] Upgrade [] Duplex (D) Holding Tank [] Renewal [] Multiple Dwellings Privy [] (SF and/or D) Private Well ~ Water Storage [] ~214. ~r~or THIS APPLICATION INCLUDES A VARIANCE I WAIVER REQUEST FOR: Distance: I certify that the above information is correct. I further certify that this is in accordance with applicable Municipal Codes. (Sign~..~o'~)roperty o~'or huthorized agent) Permit/Rush Fees: ~'~(J~, ~ Waiver Fees: Date of Payment: oC'~/'-'/~ Date of Payment: Receipt Number: Receipt Number: Permit No.05'i i4/g/ Waiver No. 7 ' //~~ LOT 3 -- t /~' __ ./ / ///~ x - , LOT 4 / / %. / ~00'PROPOSED ~ / WELL BUFFER ] / //./ / N89059'27"E 116.25 ~. / / / / SETBACK t. ~ ~ ~~-/.~1~ , LOT 5 /g' / ...... ~.... .~~ LOT 6 /% I ~/ / / / SETBACK / ~ / / 0 SITE LOCATION 0 / / / / / 0 / / / / ~ ~ / ~ ~//////~ HOUSE ' 7 , , ~ S89° 59' 27"W 116.25 / ~EGEND: ~ 'X .~ ~ - PROPOSED WELL ~ ~- SEWER MANHOLE ~ ~ _ ~OSS,B~ w~:: :OC*~,ON LOT 11 ~ .... PROPOSED WELL BUFFER ~ ~ .... LOT EASEMENT LINE G~ ~ND OTHER UTILI~ LO~TIONS ARE APPROXIMATE. SS - SEWER LINE S~BACK CALL 811 FOR LOCATES PRIOR TO DRILLING. - S --SEWER UNE ~ SEPE~TION DI~ANCESAND SETBACKS PER ~ SS .... 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