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HomeMy WebLinkAboutINDIAN VALLEY ALASKA S-5301Indian alley a 5 KcL 5/D CQ -5e No 5 - X301 L-" MUNICIPALITY OF ANCHORAGE ~- -~ DEPARTMENT OF HEALTH & ENVIRONMENTAL PROTECTION ENVIRONMENTAL HEALTH CASE REVIEW WORK SHEET [] PLATTING BOARD ~ PLANNING & ZONING ;ASE NUMBER NAME S-5301 Lots 1, 2, 3, Tract B-1 1st Addition DATE RECEIVED November 28, 1979 COMMENT TO PLANNING BY FOR MEETING OF Indian Valley Alaska ~Subdivision CASE OF [~PUBLIC WATER NOT'AVAILABLE TO PETITION AREA [2~BLIC SEWER NOT AVAILABLE TO PETITION AREA REVIEWER'S COMMENTS: ! 71-014 (Rev. 2/78) GEOLOGIC SOIL INVESTIGATION of Tracts B and C, First Addition Indian Valley, Alaska Subdivision Sections 31 and 32 T11N, R1W, S.M. Referred to as Lots 1,2,3 and Tract B-1 Indian Valley, Alaska Subdivision Prepared By: DOWLINGANDASSOCIATES 804 East 15th Ave Suite 2 Anchorage, Alaska 99501 November 23, 1979 TABLE OF CONTENTS INTRODUCTION SITE DESCRIPTION SUB-SURFACE SOILS AND CONDITIONS CONCLUSIONS SOILS LOCATION ~IAP LOGS OF TEST BORINGS ADDITIONAL INFORMATION INTRODUCTION This report is the result of a field trip investigation conducted November 21 , 1979 on the proposed subdivision. This area is located within protracted Sections 31 and 32, Tl~N, R1E, S.M. (within the general area of Indian). This subdivision is a resubdivision of tracts B and C of the 1st Addition Indian Valley, Alaska Subdivision into three lots and one large tract residual. The proposed area is planned exclusive of public water and sewer utilities for the present. Development of adequate sanitary facilities will be the responsibility of the individual property owners. The sewerage disposal will consist of conventional septic tanks draining into a seepage pit and/or drain field. Drawings extracted from the Department of Health and Environ- mental Protection, Municipality of Anchorage, have been included as a part of this report for pictorial purposes of the septic system required. Water source will be from individually drilled wells. ~e purpose of this report is to define the soils conditions within the property and determine the area requirements for proper sewerage seepage, in that particular soil. SITE DESCRIPTION This subdivision is located approximately 0.5 miles northerly of the eating establishment now called the Bore Tide on the Seward Highway. The land is within the general bowl of the Indian Creek basin. It is sufficiently high enough within the bowl as not to have any adverse effects on the creek itself. The land is gently slopeing from west to southeast and is very well wooded with spruce and birch. Tree size is from 2" to about 10" but predominately in the 4" bracket. There is little to no underbrush over the entire area. Open roadway cuts show an abundance of gravels in the entire area. Most of the area has been logged over in "the old days" and most of the growth is good looking new (within 30 years) trees. Drainage would be no problem over the entire terraced but sloping area. SUB-SURFACE SOILS AND CONDITIONS The surface soils found in this area are good to rich topsoil to three feet in thickness. There is about 6" of black to dark brown hunms covering a layer of lighter brown topsoil loam. The root mat only extends into the black hunms leaving the ren~ining topsoils relatively free of roots. This topsoil covering yeilds to sandy gravel mixed with bolders to an unknown depth. The gravels and sands are interspersed with a lot of rocks and bolders. These are probably no greater than 1.5 feet in diameter. The whole area is in a layered strata consisting of the creek deposits of greater and smaller sized materials, all of which is well washed of most of the fines. The area is within the drainage runoff of the mountain to the northwest, with small tumbling streams of clear water. The water table although encountered only once near test pit 3, could be encountered at different depths throughout the entire area. There would be a shallow water in areas of streams and of an unknown depth on the benches, kb frost was encountered no would there be any likelyhood of frost being encountered. CONCLUSIONS These medium to coarse gravelly and rocky materials have excellent percolation abilities and assured to be fairly consistant throughout the entire property. They may be classified by the Unified Classification System as G.W. to G.P. The Soils encountered in each excavation are shown in the Test Hole Log drawings A-1 through A-4. These logs display specific conditions encountered at the test locations, how- ever sub-surface conditions change slightly throughout the project, because of the indescriminate stream bed deposit of a maturity young stream, Bedrock was not encountered in any of the four holes but does not preclude the fact that bedrock might conceivably be within a short distance of the bottom of these holes because of the close proximity of the rock of the mountain to the northwest. At the time the holes were sampled, there was no frost, no permafrost was encountered. Based on the information obtained in these test pits and holes, it is felt that this subdivision is very suitable for single family units as well as any other type of construction that nmy be desired in the future. It is felt that the soils conditions encountered do not preclude the utilization of septic tanks and soils absorption systems for residential sererage disposal. It must be pointed out at this time that further approval may be required for septic tank locations by the Department of Enviornmental Concervation (State) on eac~_~L~lOt~ specific location and percolation. fl°''~ .............. ~ .... ~'""~'~ Jam~s K. Dowling, ~.E. ' ~,/~.: J~mes K~ri Do~lil~g · cQ~ ~ 804 East 15th Ave. Suite 2 ~ ~3~'~'..% o...'~ Anchorage, Alaska 99501 .~1~'6.,1~- 3,,ZI,OIoOON /~ ~eCu,' 21 November-1979 , Nd "":., N/A ~/.~ct No. 79-~14 DOWLING & ASSOCIATES En.qineer$ -- Survd~ors ,~nchorzg~, . /~lzs2~ . i~ct Nome 'Lee Miller Subd 1st Addn. Indian Valley, Ak Subd. ct/o~ .... In~an: Alaska (M of Al 'hod U~ed Hand Auqer and open pit visual ,,'her Snow and about 31 o F '~ /~o;e ;/o Test Hole 1 Sh,.~t 1 ot 4 Totol D_~p~h 15.0 Ground ;'/gl.-r Toble ~ sampler dFl'~'/ny note~-, '~1 · ~, ~ -~ ~ ~ ~, ,. -~ ..- 6 ~ depths.ct'rfg/ohb~.lost, ~ ~ ~ ~ N ~ ~ ~ b,'/s v~:~d, sic. ~ ~:,~-- ~ ~.~ ~.~. . . ___ L -..,? · .... ~- . . , ~o ., ...:,~ -- -- -~ _.."0 _ _ ~ .~-~ , /~ ~c! Na 'hod Used ,21 ,.Nov~r-1979 k~=~_, DOWLING & ASSOCIATES Com.~/eted 21 ~r ]979: . N/A En~in~er~ -- 79-814 ~nchoragG · ~ ~ller Ind~an~ ~aska ~d ~qer ~d o~n~it vis~l Dowlin9 and Se2nn Snow and about 31 o F gmph'ng Vegelot~on: / -' -- DOWLING & ASSOCIATES raider, late# 21 k~u~_m'e,~r 1979 ~. No '" ... N/~ ~n~ineers -- Surveyors ~]vct A'ame ~ ~ller ~ 1st ~. Indi~ Valle~t ~ S~. ~/~ Ind~an~ ~aska (M of A) ,'hod U$ed ~d Auqer ~d o~n pit vis~l Party ~wling ~d ~ ~,,~ Snow ~d ~ut 31° F I~ J 21 ~ovt L, ~mph'n] Soil lype, cslimoted Derriere s,z~, deplh$, circul,gh~n. Io51~ nol~s cn drilhS~g eus~, bils u3,~d, e/c. Begun 21 November - 1979 . £omp/eted 21 ~V~m~r ] 979 ;Jo' ,: N/A ~/~¢! ;/~ . 79-814 DOWLING & ASSOCIATES l~nchoroge, . x~los2o ff_-o! ^'~e Lee Miller Subd 1st A~dn. Indian Valley, Ak Subd. .-cHon Indian: Alaska (M of A/ 'hod Used Hand Auqer and open pit visual Id Port/ Dowling and Senn ~.'her Snow and about 31° F ~mph'n~ ~'-~ff Hol~ ;1o Test Hole 4 To/o; Depth 15.0 J D~-- Ground ,'n £,'. : N/A U£$CI~IP £ I .go// //p~, co/or, D/limo/ed por,'."cle size, S~mp/,e~ ~/r/v,'ny nO/DY, d~p/hS. C/r~u/ollbn- los/, n~les On drilling bHs used, e!c. Vegelolion: · 'j (k(~I' '1') 'Fli?_~ '~i'l'Ji Toble ............. , ~, ,*c~L~ N:I'~vlr~uINIVlr-INIALPHOTECTIO~, ;64-4720 PR E-I']tTSP ECTION CHECK SHEET ~ TYPICAL TRENCH ON LEVEL TOPO~GRAPHY MINIMUM'WELL DISTANCES: INDIVIDUAL TO TANK 100' TO TRENCH 100' Minimum 5' cast into undisturbed 4" CAST IRON CLEANOUT WiTH ~II~TIGHT CAP ~ CLEANOUT WITH AIRTIGHT CAP ALL CLEANOUTS MUST COME AT LEAST TO GROUND LEVEL[] PERFORATED PiPE INSTALLE'O LEVEL [] SEEPAGE TRENCH INSTALLED ACCOROING TO SOIL TEST ED SEPTIC TANK MUNICIPALITY APPROVED INLET AND OUTLET OF SEPTIC TANK WATERTIGHT[] TRSNCH INSTALLED ACROSS SLOPE PERFORATED PIPE LEVEL LINE BETWEEN TANK ;ND HOUSE 2% to 6% SLOPE NOTE: 100'MINIMUM FROM TANK AND TRENCH TO RIVER, LAKE OR STREAM [] CLASS A,' B PUBLIC - Over 25 Service or More Than 15 Connects TO TANK 200' TO TRENCH 200' Public wells ~nust CLA$~ C PUBLIC i- Under 25 Service~or Less Than 15iConnects TO TANKi150' TO TRENCH 150' have dedicated protective radius recorded=on the S/D plat. Adequate engineering plans iron are required soil (4" Pipe) Plastic Pipe ASTM D3034 may be used in place of the cast iron. ~_ L__r_eplacemen t site MINIMUM j 2x gravel depth Perforated Pipe (Perforations ,...~.: .. ,..., j. · ~.... .. olid Pipe "" ' "-' with cap ...... ~'.' .'.'~ '..~' .[:.~;.:i~..'J., , ,. ..:.....2.2....-.~...., . ........ Perforated Pipe Bottom of seepage trench 4' Minimum above water table And 6' minimum above bedrock Excavation to lot line 10' ( ) RAKE SIOEWALLS BEFORE INSTALLING GRAVEL [2] ,.. ,.,....,.... · ..... .. ;..,,.:... . ~. ,,';.>.'.~.~,2,~ ~.-~..'.,. · ' DEPARTMENT OF IIEALTII& ENVIRONMENTAl. PROTECTION 264-4'72.07~~. :' · PRE.INSPECTION CHECK$ItEhT 4" CASI' IRON SIPHON HOUSE SEPTIC ~f-~" PIPE WITtt AIRTIGiiT MINIMUfl LEVEL 0 0 0 ""° O O O ',..' O O O '"", CAST IRON REQUIRED WHENEVER LINE CROSSESUNOERORIVEWAYE] GRAVEL BACKFILL[] CRIB 4' MINIMUM ABOVE WATER TABLE E G' MINIMUkl ABOVE BEDROCK ~ MINIMUM WELL DISTANCES: INDIVIDUAL TO TANK 100' [3 TO PIT 100' ~3 NOSEWER LINE 10'63_ PUBLIC - Under 25 Service or Less Than 15 Connects TO TANK 100' ( ) TO PIT 150' 75'-100' ONLY CAST IRON SEWER LIRE PUBLIC - 'Over 25 Service or More Than 15 Connects TO TANK 200' ( ) TO PIT 200' ( ) 100'-200' ONLY CAST IRON SEWER LINE 100~ NO SOURCE OF CONTAMINATION NOTE: 100't. IlNIFIU:q FROM TANK AXD PIT RIVER, LAKE OR STnE,V4 ( ) 4"SEWER LINE [] IndividL CONSIDE[{ [JISTANCE TO AREA WELLS & SEWER SYSTEMS PITEXCAV^TION BASED ON SOIL TESTCJ SEP~[IC TA,WK MUNICIPALI1'Y APPROVED HOUSE INLET& OUTLE[MUSI' fiEWA'fERllt;Hi '~ GRADE: 2' PER lO0'  SEPTIC '/," PER FOOT EXCEl: TANI( PflECEEDINGTANK \ SttOULONOTEXCE[ 6'PER 100' 0N TERRAINS [3 SEE A(,E PI ']' /¢ SEEPA6E PIT 20' t,IINIt,IUM TO I,IEAREST LOT LINE CRIB SCREENED GRAVEL %"- 2%"