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Home My WebLink AboutMOUNTAIN TERRACE ESTATES #2 Plat# 80-106 S-5415 MUNICIPALITY OF ANCHORAGE DEPARTMENT OF HEALTH & ENVIRONMENTAL PROTECTION / 0 ENVIRONMENTAL HEALTH CASE REVIEW WORK SHEET '~r~u [] PLATTING BOARD [~ PLANNING & ZONING CASE NUMBER NAME S-5415 Mountain Terrace Estates Unti No. 2 DATE RECEIVED July 1, 1980 COMMENT TO PLANNING BY July 25, 1980 FOR MEETING OF CASE OF E~ PUBLIC WATER NOT AVAILABLE TO PETITION AREA [] ~AILAB E TO PETITION AREA _ REVIEWER'S C~-IV]ENTS: ~ /~ ~ 71-014 (Rev. 2/78) CONSTRUCTION TEST I AB PERFORMED FOR: LEGAL DESCRIPTION: THIS FORM REPORTS: 78~0 W. 48TH AVE. STE. 'C' ANCHORAGE, ALASKA 99503 248-1533 H.V. Lounsbury & Associates Lot 2 Block ~/isual Soils Examination DATE PERFORMED: 6/25/80 Subdivision Mountain Terrace ~2 D Percolation Test DEPTH SOIL FEET DESCRIPTION TOPSOIL SILTY COBBLES TAN SANDY GRAVEL, MOIST, GP, 125 SF/BEDROOM TAN SILTY SANDY GRAVEL, MOIST BOTTOM OF FIOLE WAS GROUND WATER ENCOUNTERED NO iF 'VES, WHAT DEPTH LEGEND ~ -- Parc zone :oS- Sample ~aken ;~ -- Frozen zone '2 -- Wafer table :~ EADING I. DATE GROSS TIME NOTES NET TIME :)ERCOLATION RATE: :'ROPOSED INSTALLATION: '3OMMENTS: '.m:,-;-¥-i . , . i , J.: ~-,.:-~-- ! :~ ~ : . : i ....... GENERAL SITE SLOPE DEPTH' TO H20 NET DRAINAGE DRAINAGE REQUIREMENTS'-*/125 ~F/BEDROOM SEEPAGE PIT XI~ DRAIN FIELD ~ . TEST PERFORMED BY: Robert Peters DATA CERTIFIED BY: DATE: 6/30/80 DATE: TO: FROM: SUBJECT: unicipality of Anchorage MEMORANDUM July 2, 1980 Jerry Weaver, Planning Department Sewer and'Water Program, Department of Health and Environmental Protection S-4999, Mountain Terrace Estates ~2 department has reviewed the additional soil tests submitted and has no objection to final recording. ager Sewer and Rolf Strickland, Manager Environmental Health 91-010 (4/76) PERFORMED FOR: LEGAL DESCRIPTION: THIS FORM REPORTS: CONSTRUCTION TEST LAB H.V. Lounsbury & Associates Lo~ 5 Block D Visual Soils Examination 1800 W. 48TH AVE. STE. 'C' ANCHORAGE, ALASKA 99503 248-1:533 DATE PERFORMED: 6/26-6/27/80 Subdivision Mountain Terrace Estates #2 Percolation Test DEPTH SOl L FEET DESCRIPTION NOTES 4" TOPSOIL BROWN SILTY GRAVELLY SAND SP-SM MOIST SEEPAGE ON UPHILL SIDE NOTED @ APPROXIMATELY' 10' SEASONAL FROST MELT. BOTTOM OF HOLE WAS GROUND WATER ~N~.~, '~' NAi~,~ DEPTH 13 · 5 ~r YES, ' YES LEGEND ~ -- Perc zone ~S - Sample taken F.J -- Frozen zone ~7' -- Water labia READING DATE GROSS TIME jNET: TIME o.~ r::t:5 j t --¥-~'? .....,-' '~- ...... l-=--7 '----i GENERAL SITE SLOPE DEPTH TO H20 NET DRAINAGE 6/26/80 SATURATION PERIOD 6~27/80 8: 05 0 6; 25 0 9:00 0:55 Z. 5 1 . 2~'_' '~ 1~:00 1:55 8,0 , . , 5_0" -- /iX 7-3-6 - - - I 2: 2m_ ~_~o_ k,_o~o" ---- ~2:00 J 3:55 ~.75 .75" PERCOLATION RATE// 40~in/inch DRAINAGE REQUIREMENTS: 275 SF/BCdroQm COMMENTS: FRO~'~ IN HOLE - NOT sUSPECTED TO ~%~-FROST AS SiTE AND OTHER TESTS DO NOT EXHIBIT CHARACTERISTICS TO INDICATE SAME. 6/30/80 L~¢- ~ TEST PERFORMED BY: Liza DATA CERTIFIED BY: DATE: PERFORMED FOR: LEGAL DESCRIPTION: THIS FORM REPORTS: CONSTRUCTION TEST I AB H.V. Lounsbury & Associates LoI 6 Blocl~ EIVisuol Soils Examination 18OO W. 48TH AVE. STE. 'C' ANCHORAGE, ALASKA 99503 248-15S3 DATE PERFORMED:6/26-6/27/80 Subdivision Mountain Terrace Estates Y~Percolation Test DEPTH SOIL FEET DESCRIPTION NOTES TOPSOIL BROWN SILTY GRAVELLY SAND SP BOTTOM OF HOLE WAS GROUND WATER ENCOUNTERED. NO !F v~ ~ ...... m LEGEND ® -- Perc zone .1~S- Sample taken ['t -- Frozen zone '~' -- Water ~able READING DATE _ ,6/26/80 L6~/27/8o J~:00 9:00 ~0:00 ~1:30 NET TIME PER OD 0 1:00 2:00 3:30 GENERAL SITE SLOPE DEPTH TO H20 NET DRAINAG~ 7 ]_ _'L/8 8 7/8 ! 1/8 10 7/8 4:00 . ¢./~-]~ .7/8 DRAINAGE REOUIREMENT~.D.~_sf/bedr°~m YDfDRAIN FIELD U OTHER PERCOLATION ~RATE: zn/~nch n'ROPOSED INS ,ALLATI~kN :/D SEEPAGE PIT COMMENTS: ~ James R. Ri~g4~¢d~ TEST PERFORMED BY: Liza DATA CERTIFIED BY: DATE: PoE. CONSTRUCTION TEST I,..AB PERFORMED FOR: LEGAL DESCRIPTION: THIS FORM REPORTS: H.V. Lounsbury & Associates 18OO W. 48TH AVE. STE. 'C' ANCHORAGE, ALASKA 99503 248-1333 DATE PERFORMED6/26-6/27/80 Lot 8 Block D Visual Soils Examination Subdivision Mount~ace Estates: 32 ~{ Percolation Test DEPTH SOIL FEET DESCRIPTION NOTES 4" TOPSOIL TAN SILTY SANDY GRAVEL MOIST, GP, GM SEEPAGE ON UPHILL SIDE FROM 9' TO BOTTOM, SEASONAL FROST MELT !5' i BOTTOM OF HOLE WAS GROUND WATER ENCOUNTERED yes iF YES, WHAT DEPTH 13' LEGEND ¢ -- Perc zone ~) S - Sample token !] -- Frozen zone V -- Water table ~9 GENERAL SITE SLOPE 6/2-67%~ ISATURATION PER~OD 16/27/80 8:20 I 0 9:20 I 1:00 11:50 3:30 DEPTH TO H20 6 t/2 10 1/2 z2 ~/2 1~ z/2 12:20 [ 4:00 PERCOLATION RATE: 15 min/inch DRAINAGE. REQUIREMENTS~ 190 SF/bedroom PROPOSED INSTALLATION: [] SEEPAGE PiT ~ DRAIN FIELD ~ OTHER COMMENTS: SUSPECT SEASONAL FROSTi @ 9', MELTS FAST,__G2L(iU~ND ~E,Z3~ERATf[RE NET DRAINAGE 0 ~" 2" 2" 32°F~:.. TEST PERFORMED BY:Liza/B'P' DATA CERTIFIED BY: James R. DATE: 6/30/80 INDEX INTRODUCTION INVESTIGATION SUBSUJ~FACE SOILS AND CONDITIONS r CONCLUSIONS AND RECOMMENDATIONS 'TEST HOLE LOCATION MAP BORING i LOGS 1980 Page 1 Page 2 Pages 3 - 4 Pages 5 - 6 Page ? Pages 8 - 12 INTRODUCTION This report is the resul~ of our field geologic and soil investigation con- ducted on September 26, 1972, on the Thomas Culhane property in the Little Rabbit Creek area. Legal descriptionI a portion of Section Lot 4, Section 6, Township ll North, Range 2 West, Seward Meridian, Alaska. The purpose of the investigation was to define in detail the soils condit- ians within the property to determine area requirements for proper sewer seepage as well as the overall feasibility for development from a soils standpoint. Development of adequate sanitary facilities will be the respons~bil-ity of the individual property owners. Since this area will not be served by public utilities in the immediate future, sewage disposal would consist of conventional septic tanks draining into 'a feepage pit 'a~d/or drain field. The water source would be from individually drilled and cased wells. PaGe 1 ~. INVESTIGATION Our investigation consisted of (1) a geologic review of the general area, {2) field reconnaissance of slope and contour, and {3} exploratory test borings at selected representative sites° Test borings were performed using a Mobile B-50 drill employing a 6" solid flight auger to the depths shown on the Boring Logs. Grab samples were taken and the material was visually classified in the field° Specific types and depths of soils are shown on the accompanying Boring Logs. Page 2 SUBSURFACE SOILS AND CONDITIONS Two different areas were defined during the course of the investigation. The steeply sloped area $~hich encompasses most of the lot, and the area below, along th~ southern boundary which has a lesser slope. The steep area, with a slope approaching 20% to 25%, is underlain irmedi- ately below, the root mat with a slightly silty sand and gravel. This soil, hereinafter referred to as Group I soils,'was found to be fairly consistent between the three test holes dug in this area and is believed to be the pri- mary soil type, above bedrock, for the entire area° The amount of silt varied from a few percent to approximately 10%-12%. The soil varied from slightly .moist to dry. The area along the south boundary consists of gray silts and sandy silts covered with 1 foot of peat. These Soils overlay the Group I soils and were found to be in excess of l0 feet deep over most of the area. This area is hereinafter referred to as Group II. The slope in this area varies from 21% at the top to 12% along the lower edge. The area has much standing, water and small streams and the underlying silt is highly saturated. C No true water table was discovered in any of the test holes. Water en- countered in Group II soils formed a somewhat perched water table. This fact is born out by the occurrence of only moist soils below the Group II formation. page 3 Vegetation over the Group I soils consisted of medium size birch and a few clumps of alder. The Group II soils are vegetated by low bushes and small black spruce trees. CONCLUSIONS AND RECOMMENDATIONS From the information gathered during our investigation, we conclude that the majority of the soils over the area are suitable for rural residential development. The Group I soils are quite competent as foundation soils in their present compact condition. These soils are also well suited to the development of 'septic tank seepage pit sewer systems. For seePAge pit design, consider the Group I soils to be an average between well graded sand and gravel (factor 125) and si"~ty, sandy gravel (factor 225) resulting in an average design factor of 175 square feet per bedroom. The Group II soils along the southern end of the property are of a nature such that they are not as readily developable as the Group I soils. Their high moisture_' co'tent makes them poor foun~atioh 'soils.· i~'this' hil'lsiae situation, and combined with the above reason, their impermeability makes them unsuitable for·the development of seepage pit sewer systems. Along the fringes of this area it is possible that shallow areas exist to the extent that houses with basements extending down to the Group I soils could be~constructe, d. Indi'~dual Sewer~.disposal systems are also possible within this area provided the seepage pit and/or drain field is placed in the Group I soils below. '- We recommend that development be concentrated in the area outlined on the accompanying Test Hole Location Map as Group I soils. Development of shallow Group II soils can be carried out as previously outlined. Deep Group II soils which are expected to exist extensively along the south boundary are not suited to individual sewer systems, mainly because of the depth that would be required to reach Group I soils. As mentioned before., these soils are poorly suited for placing foundations on; however, at such time as when pub!ic sewer disposal becomes available, it may be profitable to explore other alternatives for development in this type of soil situation. Such data as: (1) Design requirements for septic tanks, (2) Subsurface disposal fields and seepage pits, and (3) Locations for disposal systems may be found:in Ordinance No. 28-68; Section l, Chapter 9, Article VI, Sewage Disposal Practice, Greater Anchorage Area Borough, Alaska. Respectfully submitted, HEWITT Vo LOUNSBURY &'ASSOCIATES Charles W. Wainwright, Technician Charles S. Mortimer, P.E. Fa.ge 6 () Dote Completed LOG OF TEST BORING Hole N~ Hew/It V. Lounsbury ~ Associates Sheet [ of Engineers -- Sumeyors . Tol~l Depth :C ;t Na , Anchorage, Alaska { Ve a the t $ampling Grcund DESCRIPTION SuM type, color, te~tu,e, estimated pa, Mole ~zet sampler driving note~ ; d~oths circulation lost, notes on drilling ease, bits used, etc. Loceh~n Hates £ O~agrarm Vegelalio n: W~ter Tobla / / / Ds,s Completed Hewitt ~ Lo~'nsbury ~..Associates Skeet Pig ~a Engineers ~ Surveyors To~ol Depth .:~ st No ~nchorage~ · Alaska . Ground Water Table Time Dote .'/ethod Used ,'*//oz~/ L ~-' ~-~ . ~ " .Yo r/ p F~eld Party ~&~-/..~,~)'~-,I ~r~f~-~),~.~* ~ . .. Geoloqi$! ~. ~' ~'~' Y/ealhe~ Locat,"o~ tlote$ £ Diogran~'. .DESCRIPTION Sampling Soll type, co/of, texture, ~ ~ c ~ ~ ~ depths circulation b ' J '¢~ fi...,1 I I __ ~ . F _ I ,, 1_ _ 9 _ "~'~'~lsN. ,,,~~.. '~',~ ~o~ ~ ii · " t I~ ~ ,, J Sampling OE$CRIPTIOH Soil type~ color, texture, estimated particle sampler driving nota~ depths circulation nate~ on dr//hng ease, bit$ used, etc. No. ~ S.*.e~t ~ of Ground Water Table Time J Dui~_ Location Hates ~ Diagrarm 0- I~ i - i ~ C~e~eu Hewitt V t ° unsbury' ~ Associates.. S~e~ Rig N~ "Engineers -- Su~eyors ~'~ N~ Anchoroge~ · ~laska . Ground Ware, Table Time Field Party ~-~ ~-~ l_ ~,) ~-L t,l~r~ Geologist Y/e~the¢. "' Location Motes £ Dia]farr~' i $omplin9 ' DESCftlPTIOIV i ~ Soil type, colo~ tenure, ~ ~ ~timoted porticl~ ~ze~ j z ,t,./i ~.~ -- ~. . . .. .,.... : ~. .~-- ~ 5'~..~ -'~ .. j G x I~ O,s 0 ~ ' ' ' -i-~ " ',~ ~/~ " /~ Completed Hewitt V. Lounsbury' ~ Associates. Sheet ~ of 5 t~ig N~ En2ineers -- Surveyors . Total Dapth / ~. ~9 , Anchorage, . Alaska . Ground Water Table Time 9ate f','~/d Pa~x ,~.:,,j,~-~.~ ZT,,z~.,-.,..~ ..,-'~ : Geoto~i$, .~ 1.~'. ~-~. Time Wealhew Dote Sampling ' DESCRIPTION Local/on Notes £ Diagram; Soil type, color~ te~d,~we, ' ' ~ ~timated particle size~ '~ ~ ' ~ sampler driving note~ ~ ~ depths circulation lo~t~ , .... I · '~o ~ ~-~,~J~- I~~ .~/~ ~f ~ptaPY~J~-- , .... ~,~ -- _ _ I~ ..... I 9 ~ ~ x/, ' .... C ,, g GOV T L.OT 3 ,o/ TRACT CURVE SCHEDULE GOV'T ~ ~ NE '/,~* NE '~ UNSUBDCv' DEE) LEGEND DTIO01134 MOUNTAIN TERRACE ESTATES UNIT NO. 2 SEC. GOV'T LOT S 9 8 7 6 TRACT A SE l/4 c.~ ..... Ijl~¢UdLltV DEl- -EGEND MOUNTAIN TERRACE ESTATES UNIT NO. 2 HE'41TT V. LOUNSBUR¥ '[ R$SOCIRTE$ 5 PAINE RJ~CE )0 78.36 LEGEND ESTAI'ES UNll' NO, ~'