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Home My WebLink AboutPTARMIGAN ROOST S-2280 GREATER ANCHORAGE AREA BOROUGH FROM: DEPARTMENT: .... INITIATED BY: R(~].~ g.~..StrJ.ck~la~d,....R,S.,..,...Ass~,...D.~ .... DATE OF MEMO: DATE ANSWER TO: DEPARTMENT: ...... P..la~nj~ REQUESTED: RECEIVER: ..... O~ck.,Glas~ee~ REQUESTED ACTION SCHEDULE FOR INF~ATION ONLY ~'~' PREPARE BACK-UP INFORMATION ~ CALL ME BEFORE YOU ANSWER FOR IMMEDIATE ACTION ~ NEED YOUR RECOMMENDATION FOR YOUR CONSIDERATION OTHER .... Depa~,~ment~. wi ~h suff.i ¢i e~t ..i nfo~t on..~ega~ding..~soJ~l s...t~pes., aad wate~ ..av.a(l.ab] ]t. ty ...fo~...us ..~o .... ~ow...approve. ~a~i ga~ ~Roos t...Subdi vi s ] o~.. as. uas ..subm].~ted ....... We....have.~de ~.~o .cha~ges .. ~ .a]~at)~ns :In. lo:L .s~zes o~ .. shapes ...... ~e ..~o~..~ec~,~end.. approval..as..subm .t~e SIGNATURE GREATER ANCItORAGE AREA BOROUGH 104 West Northern Lights Boulevard Anchorage, Alaska 99505 S-2280 Plat Status: Final Date: May 18, 1971 BOROUGH: Engineer Health Department Sand Lake Fire Department School District Street Names Tax Assessor Alaska Department of Highways Alaska Railroad fmchorage Natural Gas Corp. Central Alaska Utilities Chugach Hlectric Association Re: Subdivision CITY OF ANCHORAGE: Fire Marshal ~unicipal Light ~ Pm~er Department Property Management Officer Public Works Department Telephone Utility Traffic Engineer I%'ater Utility GAB Telecommunications, Inc. Matanuska ~lectric Association Matanuska 2%lephone Association Assistant Superintendent of ~!alls Description of Property: Ptarmigan Roost Sub. Panl Boniface Gentlemen: ~ner: Petition.~nas been received by the Greater Anchorage Area Borough Planning and Zoning Comanission for the proposed Subdivision of subject property. Atta~51ed is a Copy of the proposed plat. Will you please submit your comments in writing, specifying any easements or other requirements that your depart- ment or agency may need. If we de not hear from you by June 4, 1971 do not wish to submit any commlents. , we will assume that you If you have no further use for the attac~ed print, please return it with your comments. Eric losure Planning Department GEOLOGIC SOILS INVESTIGATION OF PTARMIGAN ROOST SUBDIVISION Legal Description: NW 1/4, Sec. 2, T Il N, R 3 W S.M, Report to: Paul R. Boniface II Prepared by: HEWITT V. LOUNSBURY & ASSOCIATES 723 West 6th Avenue Anchorage, Alaska June - 1971 INTRODUCTION This report sets forth'the final results of our geologic and soils investigation on Ptarmigan Roost Subdivision which contains a~proximately 39.795 acres. This subdivision is located in the upper Rabbit Creek area, north of Rabbit Creek Road, and has the following legal description: NW 1/4, Sec. 2, TllN, R3W, S.M. The Ptarmigan Roost Subdivision.is being planned without the benefits of public sewer and water utilities. It is therefore required that each lot owner provide for on-site sewage disposal facilities as well as a potable water supply. Sewage disposal facilities~will consist of conventional septic tanks draining into either seepage pits or drain fields. The water source will be from individQally drilled and cased wells. The purpose of our investigation was to define in detail the soils conditions in the immediate vicinity of the above mentioned subdivision to help in determining the area required for seepaoe pits or drain fields in the particular soil encountered, also to determine where the sewer disposal units should be located with respect to the water wells and adjacent nroperty. FIELD INVESTIGATION The field investigation consisted of a review of all available geologic data pertaining to this area, followed by a series of five borings drilled on June 72, 1971. The drilling was done by Northwest Exploration using a B-40 drill rig with a 6 inch solid flight auger. All five bori~ngs were to a depth of 19.5 feet. There were an additional six attempts, three in the vicinity of TH-2 and three in the vicinity of TH-5. -1- All were terminated at very shallow depths due to large boulders encountered by the auger. One sample was recovered from each test hole at a depth of from 13 feet to 16 feet. All test holes were located in the area cleared for roadway, with the exception of TH-3 which was located in Lot 6, Block 2. Additional information was obtained from the investigation of the ditch which runs adjacent to the west property line. SUBSURFACE MATERIALS AND CONDITIONS The specific types and depths of subsurface materials encountered at each test sight are shown on the enclosed boring logs. The soils were found to be an unsorted mixture of silt, sand, gravel, cobbles and boulders; interbedded with layers and lenses of sandy gravel containing little or no silt. This type of material is typical of lateral moraine deposits known as "till". Very wet soil was encountered at 3.5 feet in TH-l, and at 3 feet in TH-2. TH-3, TH-4, and TH-5 revealed only slightly damp soils. No frost conditions were encountered in any of the test holes. .CONCLUSIONS AND RECOMMENDATIONS On the basis of information obtained from our geologic investigation, we conclude that the soil conditions in the area of the proposed Ptarmigan Roost Subdivision are s~c~ that a septic tank, with a seepage pit or drain field, and a water well could be safely located on each lot. For the most part, the percolation and filtering qualities of the soil~ are well suited to on-site sewage disposal. Seepage area requibements for individual systems based upon a 12~ deep pit with 2' of cover will average 190 square feet per bedroom, with the ex- ception of lots l, 2, 3, 4, Block 1; and lots 1, 3, 5, 7, Block 2. -2- Because of the excess amount of moisture encountered in TH-1 and TH-2, it is recommended that the seepage area for these particular lots be held to a minimum of 250 square feet per bedroom. This will insure an adequate margin of safety. If normal precautions are taken in installing both the well and sewage .disposal system, and sufficient spacing is utilized, there should be no con- tamination of the water wells on the property or adjoining properties due to the sewage. We conclude that the lot sizes proposed in the Ptarmigan Roost Subdivision are more than ample for this type of development. Respectfully submitted, HE~iTT V. LOUNSBURY & ASSOCIATES Paul L.'Ja~n, Geologist k~°'u ~S b~ rY, ~' -3- Date Completed / ~rojec! Na Project IVame . ~'~,~.,~ .Veother LOG OF TEST L~OHING He~:~ V. £ounsbury ~ ssoc~.~s Engineers -- Surveyors Anchoroge, . Alosl~a . Sheet Vegetation: ID ~roun d apt: in Ft Dote i W~ter Table 7~~~~ .~>['z~,9~' - 7,?/ , ~ ',./~£ OG OF T~$T ~OHhVG Hew/t/ V. I ounsbury ~ ~ssociat~s Erie/nears -- Surveyors AnchoragG . Alaska Sheet /3round V/a/er Table [D~oth /~ Geologist D£$Ct~ IP TI ON Soil type~ color~ texture~ est/mo/ed part/cie size~ sampler driving notes, depths circulal,~n /ost, notes on drilling ease~ bH$ u$ed~ etc. Vegetation: --4 Ground Ylater Table Depth in FL T~ne DE$CFt l P T I O N L.0caM~n Motes £ ~ ~I ~ ~ ~ ~ ~ notes on drilling ,~ ~ ~ . ~ ~ ~ ~ ~ bM~ u~ed~ etc. '- ~ '~~· :~ ~/' -~ .... ( __ .o-. ~. 'i~ "'"- - ~ ' L I.l~ ~lr II~;J I MU~YIN~.~ J' D~te Completed ~,,.x/' ~ . 'gl He~,, V Lounsbury ~ Associ~ ~ -~/q No ,~' ~'?:A ~.x~ nT - 1~ ~/0 Engineers -- Surveyors ~ °roject No Anchorage, . ~lgsko . ~ Pro]ecl N~me /~ ? ~) ~ .'~ ~.7 ~, n ~' ~ Field P~rty ': "' ' · · ' "" Geologist .: '~ " ''-.'" Sampling ~,neet . / __ of / Total Depth . /-'~. ~ ~ Ground V/o t er Tab le Depth in FL T/me D~te DEScRiPTiON Local/on. Notes £ DlDgram:1 Sol/ type, co/or, texture, ~/o~'/C J /. ~s!imoted particle size, sampler driving notes, ~'/l~ depths ci~cu/ohbn /os/~ ~ nolss on drilling ~ose~ bits used, etc. ~'~ Vggetotio n : Unless oli~rw/'sa not~d all sd'mD/eS ora to,,on v//~L4 iD ~londord Pond/to!lan .5'nmnlnr #riw?n v,/~/4~? Ih hnmmer .~:?= ~.'>.~ L¢.~ ~r ~ig N0. ~o~ ~.~, ~<~- ~ ~0 Eng/'n~ers -- Surveyors °roi~ct No ~nchoroge~ . ~loska . Pro]ecl Name .~ ~ethod Used ~Veother DESCH IP TI ON Soil /ype ~ color! texture~ est,~nated parfio'e size~ sampler driving noles~ de?t.hs ClYculat/on. /osl~ notes on drilling ease~ b#s used, etc. Vegetation; ..... h'e No. _ 7/// ,,nee/ _ / of / Total Depth . /~._~ ~ -- ~V~ter ToMe Un/ass olherY~'isa noted GREATER ANCHOiIAGE AREA BOROUGH 104 West Northern Lights Boulevard Anchorage, Alaska 99503 Plat Status: Preliminary Date; S- 2280 3/9/71 BOROUGtl: Engineer ~alth Department Public Works Department ' Sand Lake Fire Department School District Street Names Tax Assessor Alaska Department of Highways Alaska Railroad Anchorage Natural Gas Corp. Central Alaska Utilities ,Chugach Electric Association CITY OF A~.~OI~GE: Fire ~Imrshal HunicipaI Light & Power Department Property Management Officer Public Works Department Telephone Utility Traffic Engineer Water Utility GAB Telecommunications~ Inco Matanuska Electric Association ~atanuska Telephone Associagion Assistant Superintendent of Mails Description of Property: Ptarmigan Roost Owner: Paul Boniface Gentlemen: Subdivision Petition has been received by the Greater Anchorage Area Borough Planning and Zoning Commission for the proposed Subdivision of shbject property. AttaChed is a copy of ~e proposed plat. Uill you please sv~mit your comments iD writing, specifying any easements or other requirements that your department, or agency may need. If we do not hear from you b~ 3/26/71 __, we will assume that you do not wish to submit any comments° If you have no further use for the attached print, please return it with your comments° :: Enclosure Planning Department ST ¥~T 4, H08~C[ SUBDIVISION