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HomeMy WebLinkAboutLELAND STANFORD Soils Information on ALL LOTS GEOLOGIC SOIL INVESTIGATION OF Sl/2 SW1/4 NE1/4 SE1/4, Section 15, T12N, R3W, S.M. REFERRED TO AS: LELAND STANFORD SUBDIVISION Prepared by: DOWLING AND ASSOCIATES 804 East 15th Ave. Suite 2 Anchorage, Alaska 99501 August 15, 1980 TABLE OF CONTENTS INTRODUCTION SITE DESCRIPTION SUB-SURFACE SOILS AND CONDITIONS CONCLUSIONS SOILS LOCATION MAP LOGS OF TEST HOLES ADDITIONAL INFORMATION INTRODUCTION 15, T12N, R3W, S.M. Road on Dehart Ave. Road. This report is the result of a field trip investigation conducted by personnel of Dowling & Associates on August 15, 1980 on the proposed subdivision. This area is located within the SE¼ of Section more generally about 700 feet West of Birch (104th Ave) between Abbott Loop Road and O'Malley This subdivision is the breaking down of a~loquit parts lands into the R-6 proper'ties of not less that 1.25 acres including roads. The subdivision is planned exclusive of publi~water and sewer. The Leland Stanford Subdivision is a newly proposed subdivision surrounded basically by subdivided lands to the north, west and south. The parcel to the east is the same' size as this parcel. It is located within a creek bowl and is a very level piece of ground. Development of adequate sanitary facilities will be the responsibility of the new owner, who intends to construct homes for sale on all four lots. The sewage disposal will consist of conventional septic tanks draining into a seepage pit and/or drain field. Drawings from the Department of Health and'Enviornmental Protection, Municipality of Anchorage, have been included as a part of this report of the septic system required. The Water source will be from individually drilled wells. The purpose of this report is to define the soils conditions within the property and to determine the area requirements for proper sewer seepage in that particular soils. SITE DESCRIPTION The Leland Stanford Subdivision is located off 104th Ave. west of Birch Road. It consists of a 5 acre parcel of land to be broken i~to 4 lots. (Already approved by the M of A with conditions). The land is very flat with drainage in a northerly direction toward a small stream. The land is in its natural state with large spruce and birch with some underbrush. The area is excellent for the subdivision proposed. SUB-SURFACE SOILS AND CONDITIONS The surface of the soils found in this area consists of about 3" of moss and root mat covering a layer of dry to moist light colored topsoil that is about 1.5 to 2.0 feet thick. This topsoil overlays a very thick layer of sandy gravel (GM) to gravelly sand (to GP), There is no silt or claswithin the material (NO GM). The four holes reflect the same materials with slightly different depths of topsoil and moss. The percolation is obvious by obsehvation to be maximim and to. test would have been a waste of time. The moisture content was at a minimum in the materials and after all the rain we have been having, this shows the material does not hold water. No bedrock, frost or wate~ ~s enCoUntered in any' of'the 16',Q ft, holes. Water might be the o~ly thi'ng expected h,ere.but ~ repe~t, non was encountered. CONCLUSIONS The four test holes on this property show that there is a consistancy in the materials throughout and that these materials that'will receive the sewage will be all (GW) materials. Bases on the information obtained in these holes, I feel that each lot will support a well and septic system. Percolation tests are NOT necessary in this very poreous soil. The requirement for 4 holes to be placed (one per lot) was very excessive. Two would have showed the same information. August 17, 1980 es K. Dowling P.E-. (,_/~ ~WLING & ASSOCIATES 804 East 15th Ave. Suite 2 Anchorage, Alaska 99501 13NFIO I . 00'~9 1 O0'g9l O0 '9£ I ,M ,£0 o00 N .' 'I. 00.9£I .M ,£OoOON M £0o00 N O0'g91' ,--,." t,_) 0 Z: (]J J--, .--I 0 O' Dale [~e~u~ Rig No / ," LOG Ob' 'I'EGi' idOltlNG "!' '~o/e No. '"~" "' · "".,.' DOWL'ING':ooH~j's " '"" .... '.: sheet ' ./ of- '~. ' Engineers ~ Surveyors . -.:, .,' ' Total D~t~ ./~ ~ Ground Water 'Table'- Depth in Ft. Time D~te ' Weather :Sampling DESCRIPTION £ocahbn Notes £ Diagram.* ' ' ..... Soil type~ colo6 texlure~ .' : ' · '. "~ .. . · ~ ~: , ,,. , . _ ... ~.' .~ ~ ./ . . ~ ~' . / . :- . - .. . ,... - . ., ~ ~'~ ./~ ~ /~ ~ ~. .. ,. ~. ~... · ~ . ~ ' . :. , ,. ..., /6 ~ ~ . ~... ._ ,-~ ~ ~ -. : . .-.. : ,. ~ ' ~0" .. · ,ld P~rty .... '" Geologist ~ther · ' Ground , Wa/er Tub/e Depth I'~ Ft. . ~ . Tt~e . ,." ' Ground '~ Water Table ' Time . . Flald Partx ·. .... '" Geologist ' Field Party ...... , Geologl$! ' ~ Weather Time Do~e ' · · DESCRIPTION Loaat/bn Notes £ Dia#rom; £of- ~ . ~ ' 'N urficipality of Anchorage' MEMORANDUM TO: January 30, 1979 Planning Department FROM: SUBJECT: Health and Environmental Protection Case..Review S5037: Leland-Stanford Subdivision Due to new information submitted by Dowling and Associates, this department can approve the preliminary petition. However, soils and percolation test must /_~~ed prior to final approval by this department John L. Lyn~ Environmental Specialist JLW/1 j w 91-010 DOWLING AND ASSOCIATES 804 East 15th Ave, Suite 2 Anchorage, Alaska 99501 22 January' 1979 ' Job 79-~1~21 Mr. John Lynn Municipality of Anchorage Department of Environmental Quality 825 L Street Anchorage, Alaska 99501 SUBJECT: Leland -,Stanford Subd. ~0-~7 Dear John: I have been notified by the Municipality of Anchorage (Nelda) that your office has given some information to the Platting Dept., stating that there would be no approval without soils on this project. It is my professional opinion that 'the soils in this 5-acre parcel will be suitable for the four lots described in the Leland-Stanford preliminary plat and that no final plat will be submitted before a full soils investigation have been accomplished on this property. If you have any further questions on this please dog,not hesitate to contact my office. Sincerel~ yours, James(K. Dowling, P~E. JKD/cl DEPARTMENT OF HEALTH AND ENVIRONMENTAL PROTECTION PLATTING OR PLANNING AND ZONING CASE REVIEW CASE NUMBE~__~ PETITION FOR REZONING SPECIAL EXCEPTION VACATION RE6~JBDIVISION COMMENT TO PLANNING BYe_~'' ~-- COMMENTS: ENVIRONMENTAL SANITATION: of Cases PUBLIC WATER NOT AVAILABLE PUBLIC SEWER NOT AVAILABLE TO SERVICE PETITION AREA. ENVIRONMENTAL ENGINEERING: ;'1-014 GEOLOGIC SOIL INVESTIGATION OF S1/2 SW1/4 NE1/4 SE1/4, Section 15, T12N, R3W, S.M. ~~?Y REFERRED TO AS: LELAND STANFORD SUBDIVISION MUNICIPALITY OF ANCHORAGE DEPT. OF 14,,~AL'IFt & ENVIRONMENTAL N~©TECTION N 0\/2 0/,c~80 .RECE! ED Prepared by: DOWLING AND ASSOCIATES 804 East 15th Ave. Suite 2 Anchorage, Alaska 99501 August 15, ].980 TABLE OF CONTENTS INTRODUCTION SITE DESCRIPTION SUB-SURFACE SOILS AND CONDITIONS CONCLUSIONS SOILS LOCATION MAP LOGS OF ~EST HOLES ADDITIONAL INFORMATION INTRODUCTION This report is the result of a field trip investigation conducted by personnel of Dowling & Associates on August 15, 1980 on the proposed subdivision. This area is located within the SE¼ of Section 15, T12N, R3W, S.M. more generally about 700 feet West of Birch Road on Dehart Ave. (104th Ave) between Abbott Loop Road and O'Malley Road. This subdivision is the breaking down of at~oquit parts lands into the R-6 properties of not less that 1.25 acres including roads. The subdivision is planned exclusive of publi6 water and sewer. The Leland Stanford Subdivision is a newly proposed subdivision surrounded basically by subdivided lands to the north, west and south. The parcel to the east is the same size as this parcel. It is located within a creek bowl and is a very level piece of ground. Development of adequate sanitary facilities will be the responsibility of the 'new owner, who intends to construct homes for sale on all four lots. The sewage disposal will consist of conventional septic tanks draining into a seepage pit and/or drain field. Drawings from the Department of Health and Enviornmental Protection, Municipality of Anchorage, have been included as a part of this report of the septic system required. The Water source will be from individually drilled wells. The purpose of this report is to define the soils conditions within the property and to determine the area requirements for proper sewer seepage in that particular soils. SITE DESCRIPTION The Leland Stanford Subdivision is located off 104th Ave. west of Birch Road. It consists of a 5 acre parcel of land to be broken into 4 lots. (Already approved by the M of A with conditions). The land is very flat with drainage in a northerly direction toward a small stream. The land is in its natural state with large spruce and birch with some underbrush. The area is excellent for the subdivision proposed. SUB-SURFACE SOILS AND CONDITIONS The surface of the soils found in this area consists of about 3" of moss and root mat covering a layer of dry to moist light colored topsoil that is about 1.5 to 2.0 feet thick. This topsoil overlays a very thick layer of sandy gravel (GM) to gravelly sand (to GP). There is no silt or clay within the m~terial (NO. GM.). The four holes reflect the same materials with slightly different depths of topsoil and moss. The percolation is obvious by obsebvation to be maximim and to test would have been a waste of time. The moisture content was at a minimum in the materials and after all the rain we have been having, this shows the material does not hold water. No bedrock, frost or wate~ N~s] enCoUntered in any of the 16',Q holes. Water might be the only thing expected h.e~e.but Ii repe~t, non was encountered. CONCLUSIONS The four test holes on this property show that there is a consistancy in the materials throughout and that these materials that will receive the sewage will be all (GW) materials. Bases on the information obtained in these holes, I feel that each lot will support a well and.septic system. Percolation tests are NOT necessary in this very poreous soil. The requirement for 4 holes to be placed (one per lot) was very excessive. Two would have showed the same information. August 17, 1980 C~OWLING & ASSOCIATES 804 East 15th Ave. Suite 2 Anchorage, Alaska 99501 o EVERGREEN · , N O0°03'W 330,00 .: 135,00. \ / ,165,00 . X , o o ~ ' ' _ __ .~ ~ ~ 'o ~ - NO0°03'W' NO0°03' W' "' ,~.oo' ,~.oo ~ ~ 0 ~ m ' I _ - NO0°O~'w C H I E IT"E R Ground Wa/er Table Depth in Ft. Time Date · , ~ ~ ~. ~ ~ deplhs cz~culalz~n lest, . .. .. , ..:.'.'" .". ".,. . : .... _. . .. . .; · .... ~ , .~ ~ ./ ,.: ,, ~ . · ,. . _. -~...9 ., . ~.'.-'~' ~ .- r' ..' ....,.......- II- ' · '...'....- 18 .... ~ ' ' 19' ~ ' ' ~Na ' ' / ,,., , .' . . '. Erg/nears -- Surveyors . 'We~t No ,' ' ' , Anchorage~ · Alaska ,. bid Party ' Gaologlsl ~a/hoc ' ' Ground' '; 'Water Table Depth in Ft, ,I Time ' .... Date ' . ..., . ~ ' .' Ground' ~ Waler Table ' laid Putty ' . ' .... ' '~' Geologist 'eather " ' Sompllng ' '""' " "' Soil lype, colo6 texture, · '. ' .... ,:' '.  N ~ ~ b/ts' used, etc, ....,..~ .-, ~,. : :-:~..... -. ,;..:....~: ~.,..r.,:~, ,.~, , .,, ~.,.,..~....-...~, ~,;...,i ., .... ~ " ~. ~. . .. ) ~ "..~.~.' ,.:..-~. /' . .. ~ '' ... ............... ,..... ~ ~ _ . ../ . ~.. ~ ' . , ..;,...~:~., .....: ,: :, '.., ~ 17- .. . .: : . ..... .,...", :.'. . .. ' :"'~ .... . , ~ ~ ~ ',~ .~. , :, . . .. , , , ".. Halo No. Total D~th ~' ' Ground' ': Water Table" Oapth tn Ft, : . · · Time 9ara ' "' :..., 'A&unicipality Anchorage MEMORANDUM DATE:' TO: January 30, 1979 Planning Department FROM: SUBJECT: Health and Environmental Protection Case. Review S5037: at-~hc car-wash. , Leland-Stanford Subdivision Due to new information submitted by Dowling and . Associates, this department can approve the preliminary petition. However, soils and percolation test must /¢~&d;~ prior to final approval by this department John L. Lyn~ . Environmental Specialist JLW/ljw 91,010 (,4,/76} ~OWLING AND ASSOCIATES 804 East 15th Ave, Suite 2 Anchorage, Alaska 99501 22 January 1979 ' Job 79-,1'.21' Mr. John Lynn. Municipality of Anchorage Department of Environmental Quality 825 L Street Anchorage, Alaska 99501 $-~ ~7 SUBJECT: Lelahd ..Stanford Subd. 5~7 Dear John: I have been notified by.the Municipality of Anchorage (Nelda) 'bhat your office has given some information to the Platting Dept., stating that there would be no approval without soils on this project. It is my professional opinion that the soils in this 5-acre parcel will be suitabl~ for the four lots described in the Leland-Stanford preliminary plat and that no final plat will be submitted before a full soils investigation have been accomplished on this property. If you have any further questions on this please do:'mot hesitate to contact my office. Sincerel~ yours, DOWLIN~ND A~SOCIA~ES Jame~.'K. Dowling, P.E. J~D/cl Test Hole Lo~l - Description Guide e soil descripttons shown un the Inss are the best esttmate of thc solPs ~racteris£ics at thc tirnc ut' field examination and as such do nor achieve the cision ufa laboratory testing procedure. It' the log includes soils samples, ,sc samples receive an independent textural classification in the laboratory logs often include the fullowins hems=. Depth Interval - usually shown to 0,! foot, within that zone no ~ gnificant c. hang¢ in soil type was obs¢rvcd through drill action, direct observation ur samplin$, Frost Classification - NFS, Fl, F2, F3, F4, see "Soil Classification Chart" Texture .f Soil - An engineering ~lassification of the soils by particle s~ze and proportion, see "Soil Classification Chart", note the prop-rsions are appro~imatu and nmdification~ to th~ $oLi group du~ so :tratificatinn. inclusions and ¢hangus in properties are included. Moisture Content ~, this ia a qualitative measure: ~r~, .,, ot little apparent ~urface moisture, damp, moisture forms portion of color, le$~ than plastic limit, ~et, no free water, often soft, it' cohesive soil, sa{orated, free water may be squeezed out, ifa free draining soil; ~'Lia~ent at natural moisture content, ils non.plastic slh or fine  ~ nnd, (The moisture content is f~rther del]nedby reference LW, NP, MV or dilatency.J Dens y- refer~to more-or.l~s non-cohesive soils,~uch as sa.dgrayel ~ixt~ea with or without a fine fraction, derived from drilling ~ction and/or ~mple data; u~ually describecl~: very loose, Ioo~¢, medium dense, very dense. General intent i~ to portray characteristics, , ' Stiffness - refers to more-or.tess cohesive soil~ and t~ne grained silts ~]ailt groups. Derived from drill action and/or ~ampl~ data, Very ~ft, ~oft, stiff, very stiff and hard are commonly u~ed terms. ParHde ~ize -- Th~ largest particle recovered by the *pill spoon ~lby tube Y', auger ~ight~ [minute-man) 2", Auger flight~ (1%~0 hollow ~tem) 6".~", Larger p~rticlea ar~ de$crib~d ind~ectly a~tlon of the drOliug und are ~uferrud t0 as cobblu~, Y' to 8", or boulder~ 8"+. Therefore when reviewing the gradation sheets, if any, the description on the hole log must be considered for an"ind[cztion larger ~rticlea. Unified Soil Classification'- This i~ a two letter code. See ~caHon ~heet for f~ther definition. In som~ ca~e~ AASHO and/or FAA ~oil classifications may be ~hown aa well a: th~ unificd, Atterbezg Limit~ - u~ful for fin~ grained and other plastic ~fl$. P~; hat.al moisture content believed to be le$~ than plastic ~mit P~; n~t~al n:oi*~ure content bdieved to b~ between plastic and liquid ~mi:~ ~; hat.al mois:~ cont~n: believed :o b~ are~ler :h~n liquid limit NPl no.plastic, useful ~ ~ moalfyini ~c~cri~tlon or some silty DilatcncE - is Iht abLii{y of water to migrate to Ehe {urface ~atura<cd of nearly saturated soil sample when vibrated or johcd -- used a~ an aid to determine if a finc.graincd soil is ~ fl~ghHy or non.plastic ~0~ or a volcanic ash, Rock flour- finely ground soil that is not plastic but otherwise appears sT'~]~'"T'~ clayey slit. Organic Content - usually described as Peat. PT. sometimes includes discrete particles such as wood coal, crc, as a modifier to ,,n inorgamc soil, Quantity described as: trace, or an estimate of volume, or, in of all organic, - as Peat. This may include tundra, muskeg anu bog material. Muck - a modifier used to describe very soft, semi.organic deposits ~-'~']~y occuring below a peat deposit A. morphus peat - organic particles henri'7 or fully disintegrated. Fibrous Peat ~ organic particles more.or-less intact. Bottom nfTestholc - includes last tample interval, ' ' Frost Line - seasonal frost depth as described by drilling action and/or ~the time of drilling. Frozen Ground - other than Frost line, described by samples, usually ['~'ncludes description of ice content, often will include modified Unified Classification for frozen soils - this is a spec~a~ case related permafrost studies, Free Water Level - The free water }eve] noted during drilling. Thisi~ not neces~rLiy the static water table at the time of drilling or at other . seasons. Static water table determination'in other than very permeable . soils requires observation wells or piczometer installations, used only in special cases, ~w/6" -'Thc number of blows of a 140 we~ht free falling 30" to advance a 2" split spoon 6"I thc number of blows for a 12" advance by definition, thc standard penetration, ,4% ~ natural moisture content of th~ sell sample, usually not ~ormed on clean sand~ or growls below thc water table. S~, refers to 2" split spoon driven into the soil by 140 pound weight, a disturbed sample, ~ thin wall tube, "Shelby" used to obtain undisturbed samples of fine grained soil, ~ "grab" disturbed sample from auger flights or wall of trench, ~, cut sample, undisturbed sample from wall of trench. D~y. StrcnBth - a useful indicator of a soil's clayey fraction, N=Nonc, L=bow, M=Medium, H=High - The samples are placed into apparently simLiar groupshased or and texture and are arbitrarily assigned a gruup letter. Furlber disturbed tests including Atterbert: Limits, grain size, moisture4cnshy relationship, etc, may be ~erformcd on the group and are a~sumed to reflect thc general distrubed characteritrics of the soils assigned In the group, Th~ i~ an important phase of ~ht' soil analysis and is used [o . ,tgndardize [l~e various qualitative dcterminaHons and ~o reduce SOIL CLASSIFICATION CHART CI'AYEY SILTY SAND :LAY CLAYEY CLAYEY CLAYF-Y S I LTY S I LTY SILTY / ' GRAVEL GRAVELLY SAND SANDY GRAVEL \ \ '0 0 10 SAND GRAVELLY SAND DY GRAVEL · GRAVEL 20 .30 40 50 60 70 80 90 GRAVEL (+.~4 SCREEN) % BY WEIGHT NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN :]% FINER THAN 0.02 mm, GROUPS OF FROST-SUSCEPTIBLE SOILS: F1 GRAVELLY SOILS CONTAINING BETWEEN 3 AND 20% FINER THAN 0.02 mm, . F2 SANDY SOILS CONTAINING BETWEEN 3 AND ~5% FINER THAN 0,02 mm F3 a, GRAVELLY SOILS CONTAINING MORE THAN 20% FINER THAN 0,02 mm, AND SANDY SOILS (EXCEPT FIN'E SlLTY,,SANDS) CONTAINING MORE THAN 15% FINER THAN 0.02 mm, b, CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12, EXCEPT VARVED CLAYS, F4 a. ALL SILTS INCLUDING SANDY SILTS, b, FINE SILTY SANDS CONTAINING MORE TH~AN [5% FINER THAN 0,02 mm. ¢. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN ]2, d, VARVED CLAYS, 100 JIIIIIIHII[I~:II ~._~.--~-r ~, Municipality of Anchorage DEPARTMENT OF HEALTH & ENVIRONMENTAL- pROTEC"~ ~ON PREdN$?ECTION CHECK SHEET 264-'4720 CAST IRON' SIPHON 'SEPTIC ./.~.--~ PiPEWITHAIRTIGHT ~ crib.or Lo9 HOUS ~ - . . ~ . 1__4~ UN ols'ru r~ BE D SOl L ' ' ;"'". ~ ~ .'.'.;., ~ MINIMUM [ 14 ' '"' ' -' CAST IRON REQUIRED WHENEVER UNE CROSSES UNDER ORIVEWAY [] MIN MUM WELL DISTANCES:' i~DIVIbUAL TO TANK 100' D TO PiT 100' r~ NO SEWER LiNE 10'[] PUBLIC - Under 25 service or Less Than, 15 Connects TO TANK 100' ( ) TO PIT 150' 75'-100' ONLY CAST IRON SEWER LINE 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'MINIMUM~ FROM TANK AND PIT RIVER, LAKE OR STREAM ( ) - GRAVEL BACKFILL[] CRIB 4' MINIMUM ,ABOVE WATER TABLE [] 6' MINIMUM ABOVE BEDROCK [] ~, ' ',.' Individual 4" SEWER LINE [3 CONS!OER DISTANCE TO AREA WELLS & SEWER SYSTEMS [] ;~IT EXCAVATION ~ASED ON SOIL TEST [] SEPTIC TANK MUNICIPALITY APPRCVED [] HOUSE INLET&OUTLET'rIUST 5' / GRADE: 2"~ER100' OR / Y," pER ':007 EXCEPT ] BE WATERTIGHT_~ SEPTIC , oRECEED,NO TANK AN ~ TANK / .SHOL LD NOT EXCEED ,/ fi" PER 100' ON FL ~/, TERRAINS E} / SEEPAGE PiT 20' MINIMUM TO NEAREST LOT LINE [] SEEPAOE PIT : CRIB ... SCREENED GRAVEL %" 2~" e^!JO ~o0o$ ~ IOoON N33~9~]A~