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Home My WebLink AboutHILLSBORRO S4693I__t il IS boxrO D iii JML John M. Lambe, P.E. 4303 North Star Street II Anchorage, Alaska 99503 907.276.4113 January 15, 1979 H. V. Lounsbury & Associates 723 West 6th Avenue Anchorage, AK 99501 Attention: Darrell Kvasager Subject: Preliminary Soils Exploration Hillsborro Subdivision S.W. ~ S.E. ~., Section ll~ T. ll N.~ R. 3 W., S.M. AK Dear Mr. Kvasager: Transmitted ~th this letter are the results of the subsurface investigation that we performed to provide preliminary soils infor- mation to aid your engineers and the Municipality of Anchorage, Department of Environmental Quality in evaluating the proposed subdivision of the referenced property into Hillsborro Subdivision. At your request~ we drilled twelve test holes in the approximate locations shown on the Boring Location Sketch, Plate Ohe, fourteen to twenty feet deep, with a Nodwell mounted "Mobile B-50" drill fitted ~th 6" O.D. continuous flight auger. Samples were taken at 5' intervals by removing the auger from the boring, then removing a sample of the cuttings from the flights of the auger from near the bit. All soils observed were visually classified in the field by the writer who was present on the site full time to locate the borings, direct the drilling~ log the borings, and obtain the samples. The logs of the borings are presented on Plates 2-.ll follov~ng the text of this letter. At your request~ one sample of the soil strata most likely to accept on site sewage effluent from the proposed development from each boring was analyzed in the laboratory to determine the particle size distribution. The analyses of these samples are Page 2 H. V. Lounsbury & Associates Attention: Darrell Kvasager January 15, 1979 presented on Plates 12-23 following the text. The classification of the remainder of the strata was done visually and is subject to change upon further testing of the samples, if required. All samples were classified in accordance with the Unified Soils Classification System presented on ?late 25 and the Textural Classification Soils Triangle presented on Plate 24. The samples will be stored for three months for further testing. The purpose of the investigation was to provide subsurface information to your engineers and to the Municipality of Anchorage for review of the proposed plat. Included in the necessary infor- mation is the depth to seasonal free water. This information was obtained by placing 4" nominal perforated PVC pipe in the borings, then monitoring the free water level within the pipe after the level had stabilized, typically one or two days after drilling. The information obtained is presented on the boring logs and on the boring location sketch. The water levels were again observed on 12 January 1979 with the following results; BORING DEPTH TO FREE WATER BORING DEPTH TO FREE WATER I l' 7 More than 8' (slough below) 2 4.5' 8 Slough below 5' 3 5.5' 9 4' 4 5.5' 10 4.5' 5 4.5' ll 7' 6 More than 9' (Slough below) 12 4.8' In many instances the borings sloughed at or above the free water level precluding the installation of the pipe sufficiently deep to observe the stabilized free water level. In these instances the depth to the free water level was estimated from observation of the cuttings and performance of the drill rig. Please note that the water level observations were made late in December at a time when the water level may have been approaching a lower seasonal level. However~ it is possible to monitor the water levels in the stand pipes throughout the seasons, if care is taken to observe the levels Page 3 i~ · H. V. Lounsbury & Associates Attention: Darrell Kvasager January 15, 1979 at times when surface water entering through the top of the boring is not temporarily affecting the observation. Drilling refusal was encountered in several borings. Drilling refusal is defined for the purposes of this report as when signifi- cant resistance to drilling is encountered, as if drilling through rock, with little or no gain in depth with significant effort. Please note that this loose definition defines fairly competent igneous or metsmlorphic boulders or bedrock. Drilling refusal is not likely to be encountered in highly fractured or weathered rock, nor in sedimentary nor soft metsmorphic rock. To try to define the nature of refusal where above 15' deep, a second attempt at the boring was made 5' to lO' from the original boring location. ~'~en refusal was encountered at approximately the.same depth the writer would assume either large boulders at that depth, or bedrock. If no refusal was encountered in the second boring, the writer would assume the first boring encountered a boulder~ although a highly irregular bedrock profile could also account for the discrepancy. Due to the bit design and sampling techniques accurate determination of the nature and profile of underlying bedrock is not always possible. Three conditions most directly affect the development of this property; l) Relatively high apparent free water. 2) Relatively permeable soils in areas where the free water level is sufficiently deep for development. 3) Relatively impermeable soils and/or bedrock at depth. State ordinance requires the lowest portion of an on-site sewer system be separated from any water table by 4 feet. The high water level will prohibit construction of conventional on-site sewer systems in areas where the depth to the free water level is less than 6 feet; and will cause concern in areas where less than 8 feet. Additionally, due to the stratigraphy of the soils and area drainage features, it is possible that the free water level may fluctuate sig- nificantly in response to spring melt or heavy rain. ill Page 4 H. V. Lounsbury & Associates Attention: Darrell Kvasager January 15, 1979 While the permeable sandy gravel soils overlying the more impervious soils at depth will provide for hydraulic design of absorption systems with probably 100 square feet of absorption area required per bedroom~ high density development of the area is not likely to be acceptable to the Municipality due to possible contamination of the shallow~ probably perched water table which may find its way to surface water sources due to the relatively deep natural ravine and stream to the north of the development. As you recall, this factor was mentioned by Mr. Les Buchholz during our meeting of January 12, 1979. The liability of contaminating the surface source can be reduced by installing reliable package treatment plants in lots where the free water level allows con- struction of drainfields; maximizing the possible number of lots in this area which can be developed. Unsuitable lots may be made into a large tract for park or recreation or future development. One might also consider collecting sewage from the lots at a common treatment facility then discharging the treated effluent in a common drainfield or into the creek with proper treatment and clearance from significantly more governmental agencies. It is not likely the community treatment plant alternative will be cost effective for i acre lots and may not be acceptable to the Municipality. As you are well aware discharge of the effluent into the creek will require a high quality, probably chlorinated effluent, and careful supervision and monitoring of the treatment facility. The scope of this effort did not include analysis of the treatment alternatives; and I am not aware of the most current state and federal regulations in this field. We trust the foregoing is sufficient to your immediate needs° While intended to be comprehensive within the scope of a preliminary soil investigation~ it may not be exhaustive of the possibilities. Therefore, please feel free to call should questions arise o~ if we can be of further service. Very truly yours, ' John M. Lambe, P'E. Civil Engineer 4254-E ~ ~. LOG OF BORING 1 ~--~ Equipment 6" Continuous Auger .... ~ ~ g~ ~ EI,vatlonExist. Grnd. ~,, 12/18/78 ~ ~ FREE WATER LEVEL OBSERVED __~:= IN STAND PIPE ON 12/21/78 ~ F-4, Brown PEAT, PT --' soft, saturated ' F-4~ Grey GRAVELLY SANDY SILT,MI ~ [ stiff, saturated, PI+ ~0-~ ~ F-~, Grey CLAYEY SILT, C~ML stiff, saturated, PI+ ~;~'~ F-3, Grey SILTY SANDY GRAVEL,GM ]5- ~' dense, saturated~ plastic ~ fines~ becomes much harder ~ . to drill at 17' i~ I ~11 ~I ~k~i TOTAL DEPTH 3~ LOG OF BORING 1 JOHN M. LAMBE, P.E. . HILLSBO~RO SUBDIVISION 2 Job No. 78-180.01 Appr: JML Date 1/11/79 Anchorage~ Alaska ..., 04, ,._o,,:. LOG OF BORING 2. ~°':' · '~ ~ ~c .~ Equipment 6" Continuous Auger La~rotory Te,t, ~ ~ ~ ~ O' 5- F-2 SILTY GRAVELLY SAND SM dense~ saturated 10- E-3~ Grey SILTY GRAVELLY SAND~SM dense~ saturated~ with cobbles and boulders~ many cobbles anc boulders below ~2'~ plastic 15- fines F-~ Grey GRAVELLY SANDY SILT~ME hard~ moist~ PI-~ with cobbles 20- TOTAL DEPTH 19' 3~ 4~ LOG OF 50~ING 2 PLATE , JOHN LA aE, K E. HILLSBO~RO SUBDIVISION 3 JobNo, 78-~80.O1 Ap~r:JML Oatel/11/78 Anchorage~ Alaska ~ ~. ~ LOG OF BORING ~ ~ c ~"~ Equipment 6" Continuous Auger Loboro,oryTe,,, ~ ~ ~ ~ ~r~ E,.¥e~ion Exist. Grnd. D~,e 12/18/78 0 ~ F-t, DUFF, PT -- ~ F-l, Bro~a~ SANDY GRAVEL, GW-GM ~',~.."~', dense moist to saturated ~ with cobbles Mechanical ~ ~ '~"__'~..i:~ Analysis 5- I..'.1:';~ ~ FREE WATER LEVEL OBSERVED ~....~ ~N STAND ~I?E O~ ~ a/a ~/78 10- F-l/F-5 Brown SILTY SANDY GRAVEl ~,~, GM, medium dense, saturated I F-3, Bro'ma SILTY GRAVELLY SAND 1~_~-.~ SM, medium dense, saturated plastic fines TOTAL DEPTH 15' 20- 25- ~OG OS 50~ING 3 JOItN g. P.E. -- HILLSBORRO SUBDIVISION ~ob~o 78-180.01 A~: Anchor~ge~ Alaska ~.. ,~ LOG OF BORING 4- --~ --~ ~ ~--~ Equipment 6" Continuous Auger F-~ Bro~m SANDY SILT~ ML stifE~ wet Si~e Analysis ~ ~EE WATER LEVEL OBS~RV~D IN STUD PIPE ON F-3~ Bro~ SILTY G~AV~LY SAND~ SM dense~ saturated~ with cobbles 10 F-~ Brown GRAVELLY SANDY SILT~ML hard~ wet 15 F-3~ Brown SILTY GRAVELLY oA~D~ very dense~ moist 20 TOTAL DEPTH ~O, LOG OF BORING ~ ~LAT~ J0 N M. LAMBE, P.E. ~~ HILLSBORRO SUBDIVISION JobNo~ 78-180.0~ ADDr~~L Oa~e ~/]~/79 Anchorage~ Alaska ~ ._a,.z. __LOG OF BORING ~5 -- ~ ~ Z ~ ~ Equlpm~nt 6" Continuous Auger La~ratoryTes~ ~ ~m ~ ~ ~ ElevationExist, Grnd.~te~/~9/78 0--~ F-~ Brown SILT~ ML [':,~k,:,]f~ F-ls Bro~ SANDY G~AV~ GW-GM dense~ moist~ with cobbles Mech~ical ~] ~d boulders Analysis "~ ~"'~ ~EE WATER LEVEL OBSERVED 5-[ ;,:~x IN STAND PIPE ON 12/2~/78 ~, i~ F- 1~ Brown SILTY SANDY GRAVEL, GM l, medium dense~ saturated d~ 4~ 15 ~ .,~ TOTAL DEPTH ~ 5' 20- NOTE: ~rst attempt at this location met drilling refusal at 5'~ second attempt at 2.5' i all attempts within 10' radius i LOG OF BORING 5 PLAT~ JOHH M. I. AM E, Al~s~ ~ ~- '~ ~ LOG OF BORING 6 ~:]~ F-1 Brown SANDY GRAVEL GW-GM Analysis 5- ~'.~)]~. medium dense~ moist Analysis lOJ ' i F-]~ Grey SILTY SANDY G~AVEL~ ~,~ ~ ~,~ dense, saturated, plastic ~ ~ fines i ~ TOTAL DEPTH 19' 20- ~ NOTE: Boring sloughed below 10' ' unable to install stand pipe below that depth to observe ~- stabilized water level 3~ I 4~ LOG OF BORING 6 ~LATE JOHN M. I. AMBE, HILLSBORRO SUBDIVISION Job No.78'180.01 Appr: JML Date 1/11/7~ Anchorage, Alaska ~ ~ ~"~ ,.D.'~u t. OG OF BORING Lc~ratory Tes~ ~ ~ ~ ~ ~ _ . 0~' ~ ~-~ DU~s ~ Bro~ SANDY ML F-~ SILT~ Mechanic~ 5- ""' ~alysis ~;[;;t ~ ~EE WAT~ L~VLL OBSERVED I0-I'' ' ~ WHILE D~ILLING ... F-2~ Brov~ G~AVELLY SAND~ SW-SM ..'.'. medium dense, saturated !~ F-4, Grey SILT, ML " 'i stiff, saturated ' TOTAL DEPTH ]9' 2O- I I . ~ ~ NOTE: Boring sloughed below 8' ~ i ~ unable to install stand pipe . ~ ' below that depth to observe I~ stabilized water level I 4~ LOG OF BO~ING 7 PLATE JOH M. LA,SI, P.E. HILLSBORO SUBDIVISION gob No. 78-180.O~ AoDr: JML ease 1/~ 1/78 Anchorage, Alaska ~o~ '~ $ ~ ~~ ~ ~.-~ ~ hOG OF BORING 8 ~ ~ '~ - ~_'~ Equ;pm.n~ 6" Continuous Auger ha~ratory Te,~ E ~ ~ ~ ~ ElevaHonExist. Grnd.~e 12/26/78 ~ F-4, DUFF, PT '. F-l, Bro~ S~DY GRAVEL, GW-GM ~sdium dense, moist, with MechaniC~~alysis ~ cobbles * WHILE DRILLING ~ F-4, Brovm SANDY SILT, ML stiff, saturated, NP F-4, Grey CLAYEY SILT~ C~ML stiff~ moist ~ TOTAL DEPTH 16' Boring sloughed belo~ 7.5' _~OG O~ BORING 9 [q~ 6" Continuous Auger ~ew~o~ Exist. GrndJ~2/26/78 0 ~ F-4, DUFF, PT ~ F-l, BroYm SILTY S~DY GRAVEL, ~ F-l, Bro~ SANDY ~RAVEL, GW-GM Mechanical ~TW~ medium de~se~ wet Analysis 5' ~[~ FREE WATER LEVEL OBSERVED WHILE D~ILLING J lIIIF-4, Grey GRAVELLY SANDY SILT, ML ~0-~ hard, saturated, Pl+ IIIII TOTAL DEPTH 12' ~_ ~ ~ Boring sloughed below 4' LOG OF,,~Q~IN~S 8&? Pt, ATE JOHN M LAM E P.E. HILLSBO~O SUBDIVISION ~No. 78-~80.01 ~:~(L Oa~e1/11/78 Anchorage, Alaska L ~ ~ ~ ~ ~--~ Equipment 6" Continuou~ Auger Left,tory Tes~ ~ ~ ~ ~ ~ Elevetlon Exist. Gr~d~te 12/~7/78 F-l, Brown SILTY SANDY GRAVEL, ~ F-l, Brown SANDY G~AVEL~ GW-GM Mechanical 5 d~.: ~ ~EE WATER LEVEL OBSERVED Analysis IN STAND PIPE ON 12/29/78 F-1/F-~ Brown SILTY SANDY GRAVEL GM, medium dense~ saturated ]0 F-3, Brown SILTY GRAVELLY SAND, SM saturated~ 15,, [ DRILLING REFUSAL ~ 14' NOTE: Rock probe drilled 10' north east of boring also encountered refusal ~ 14' LOG O~ BOMING 11 EquSp~nt 6" Continuous Auger ElevoHonExist. Grnd.~te12/27/78 0 ~.:.~ F-4, DUFF, PT ' ~.~. F-l, Brown SANDY GRAVEL, G,~.~-GM Mechanical ~'~J~ F-2~ Bro~m SILTY SAND~ SM An~ysis ~'~? -~ wet ~0~~~~ F-2~ Brown GRAVELLY SAND, S~V-SM saturated ~.]] F-4~saturatedGrey SANDY SILT~ ML 15 TOTAL DEPTH 15' ~No. 78-180.01 _~: JML~te 1/11/7~ ~chorage, Alaska LOG OF BC)RING Equipment ~IT 10- 15_ 20- 30- 4O JOHN M. LAMBE, P.E. Job No2 ':!-~ ,2C~ '2 ! _Appr ~]~ll Date LO() OF BORING PLAI'[ J. S. Standard Sieve Openin9 Size J U.S. Standard Sieve Numbers J Hydromete¢ 5 I 0.5 CI 00.5 GRAIN SIZE IN MILLIMETERS C~OI 0.005 I GRAVEL COBBLES COARSE J F~NE Symbol Sample Source SAND - MEDIUM FINE SILT OR CLAY BORING JOHN M. LAMBE P.E. Job No.78-180'O1 Appr: JML Date 1 / 11/7~9 Classification F-2~ SILTY GRAVELLY SAND~ SM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage~ Alaska PLATE 12 U. S. Standard Sieve Opening Size I U.S.Standard Sieve Numbers I Hydrometer /llll ' - [111 Ill l ' - i 0.5 Ot 00~ - OOt000~ O~l ~RAIN SIZE IN ~ILLI~ETE~5 COBBL[S COARSE I FINE COARSq MEDIUM J FINE SIt. T OR CLAY Symbol Sample Source Classification BORING ~ ~ ~.O' F-I~ SANDY GRAVEL~ GW-GM PARTICLE SIZE ANALYSIS PI. ATE JOHN ~LLS~OR~O Job No78- 180. O 1 Appr'. ~4L Oate 1 / 11/79 Anchorage~ Alaska U.S. Stondord Sieve Opening Size I U.S.Standord Sieve Numbers I Hydrometer' ~ 4 3 / ~/,~ ~ 4 8/o ~6 2030 405060 ~ 200 270 5 I 0,5 C GRXtlN SIZE IN MILLIMETERS 0.005 I GRAVEL [ SAND COBSL£S COARSE I FINE COARSI~ MEDIUM i FINE SILT OR CLAY Somple Source BORING 4 @ 5.0' JOHN M. LAMBE P.E. JobNo, 78-180,01 Appr:JML Oate1/i1/79 Closs[ficotion SILTY GRAVELLY SAND~ SM PARTICLE SIZE ANALYSIS HILLSBOR])O SUBDIVISION Anchorage, Alaska PLATE 14 U.S. Stondard Sieve Opening Size I U.S.Standard Sieve Numbers I Hydrometm' 5 I 0,5 OI 005 GRAIN SIZE IN MILLIMETERS QOI 0.005 COBBLES O COARSE FINE MEDIUM FINE SILT OR CLAY Symbol Somple Source BORING 5A @ 2.5' JOHN M. LAMBE P.E. Clossificotion F-I~ SANDY GRAVEL~ GW-GM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchora~e~ Alaska PLATE 15 Job No. 78- 180.01 Appr:_JML Date 1/11/79 U. S. Stondard Sieve Opening Size U.S. Stondard Sieve Numbers $ I0 16 20,.'30 405060 /00 I Hydrornetet 200 270 I 0.5 OI GRAIN SIZE IN MILLIMETERS 0 05 001 0,005 COARSE FINE MEDIUM I FINE SILT OR CLAY Symbol Sample Source BORING 5B @ 2.5' JOHN M. LAMBE P.E. Job No. 78-180.01 Appr:_ EHT, Date]/11/78 Classification F-I~ SANDY GRAVEL, GW-GM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage~ Alaska PLA 'rE 16 U.S. Stondard Sieve Opening Size J U.$.Standard Sieve Numbers J Hydrometer 5 I 0.5 0 005 GRAIN SIZE IN MILLIMETERS O OI 0 005 COBBLES COARSE I FINE COARSE[ MEDIUM J FINE SILT OR CLAY J Symbol Somple Source BORING 6 @ 4.5' JOHN M. LAMBE P.E. JobNo. 78-180.O1 Appr: JMLDate 1/11/78 Clossification F- 1 , SANDY' GRAVEL, GW-GM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage, Alaska PLATE 17 U. S. Stondard Sieve Openin9 Size J U.S.Sfandord Sieve Numbers I Hydrometer I 0.5 CH Q05 GRAIN SIZE IN MILLIMETERS QOI 0005 C08I~LES COARSE I FINE COARSE~ MEDIUM J ,FINE S~LT OR CLAY Symbol Sample Source BORING 6 @ 9.0' JOHN /~. LAMBE P.E. Job No. 78-180.01 _Aopr:_JTIL Date 1/11/78 Classification F-I~ SANDY GRAVEL~ GW-GM PARTICLE SIZE ANALYSIS HILLSBO~O SUBDIVISION Anchorage, Alaska. PLATE 18 U. S, Standard Sieve Opening Size J U,S,Standard Sieve Numbere I Hydrometer 5 I 0,5 OI 005 GRAIN SIZE IN MILLIMETERS OOI O. O05 SAND GRAVEL ICDARS~ MEDIUM J FINE COBBLESI COARSE [ FINE ] SILT OR CLAY Symbol Sample Source BORING ? @ ~.5' JOHN M. LAMBE PoE. Classification F-l~ SANDY GRAVEL~ GW-GM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage~ Alaska PLATE 19 JobNo, 78-180.01 Appr: JML_Date 1/11/78 U. S, Standard Sieve Opening Size U.S.Stondord Sieve Numbers 4 810 16 2050 405060 5 I 0.5 C GRIIIN SIZE IN MILLIMETERS J Hydrometer 200 270 005 001 0.005 Symbol Sample Source BORING JOHN M. LAMBE P.E. Classification SANDYGRAV~,L~V' GW-GM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage, Alaska PLATE 2O JobNo. 78-180.01 Appr:_JML Date 1/11/78 U. S. Standard Sieve Opening Size J U.S.Standard Sieve Numbers J Hydrometer I 0.5 OI 005 GRAIN SIZE IN MILLIMETERS , COBBLES COARSE [ FINE COARSE~ MEDIUM J FINE Symbol 001 0.005 SiLT OR CLAY Sample Source BORING 9 @ 6.0' JOHN M. LAMBE P.E. Classification F-8~ SILTY GRAVELLY SAND~ SM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage~ Alaska PLATE 21 JobNo. 78-180.01 Appr:d~L.Date 1/11/7~ U.S. Stondard Sieve Opening Size I U.S.S/andord Sieve Numbers I Hydrometgr 5 I 0.5 0 005 GRAIN SIZE IN MILLIMETERS GRAVEL COARSI~ 'MEDI uMSAND~ FINE COBBLESI COARSE I FINE I SILT Symbol 0.005 OR CLAY Somple Source M. LAMBE P.E. ApprLJMT' Date 1 / 1 1/?_____~8 BORING 10 ~ 3.5' JOHN Clasdfication F-2~ GRAVELLY SAND~ SW-SM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage~ Alaska PLATE 22 Job No. 78-180.01 U. S. Stanclard Sieve Openin9 Size J U.S.Standard Sieve Numbers I Hydrometer 5 I 0.5 G I 005 GRAIN SIZE IN MILLIMETERS QOI 0.005 QO0~ COBSL£S COARSE I FINE COARSE~ MEDIUSANo M J FINE SILT OR CLAY Symbol Sample Source BORING JOHN M. LAMBE P.E. JobNo. 78-180.01 Appr: d~____~% Date 1/11/78 Classification F-2~ GRAVELLY SANDs SW-SM PARTICLE SIZE ANALYSIS HILLSBORRO SUBDIVISION Anchorage? Alaska PLATE 23 JML I John M. Lambe, P.E. 4303 North Star Street Anchorage, Alaska, 99503 907-279-8056 )0% GRAVEL ~ CLAYEY ~,/ CLAY EY \ / OR c::>/ SILTY eX SI LTY x \ SAND \ DY ~GRAVE l. \ \ \ GRAVELLY \ SAND \ 0 I0 20 30 40 50 60 70 80 90 GRAVEL (+~4SCREEN) % BY WEIGHT L I00 NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% FINER THAN O.O~mm, GROUPS OF FROST-SUSCEPTIBLE SOILS: FI F2 F4 a. b. C. d. GRAVELLY SOILS CONTAINING BETWEEN 3, AND 20% FINER THAN O,02mm. SANDY SOILS CONTAINING BETWEEN 3 AND 15% FINER THAN O.02mm. GRAVELLY SOILS CONTAINING MORE THAN 20°,~ FINER THAN O,02mm. AND SANDY SOILS (EXCEPT FINE SILTY~ SANDS) CONTAINING MORE THAN 15°/o FINER THAN O.02mm. CLAYS WITH PLASTICITY INDEXES OF MORE THAN 12. EXCEPT VARVED CLAYS. ALL SILTS INCLUDING SANDY SILTS. FINE SILTY SANDS CONTAINING MORE THAN 15% FINER THAN O,02mm. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN 12, VARVED CLAYS. 24 MAdOR DM~ION$ TYPICAL NAMES C~ Q~AVIL$ <]W::/.]~::, , WILL O~A~D O~VILS. G~AVIL o rAND MIX.El ~C~ C~YW ~, ~LY ~0 ~ND- ~Y C~Y StoL. W~TH SUOH~ ~ ~ ~ mN~OANrC C~ O~ ~ ~o ~m~ ~CHY, , gILTS AND CLAYS CL ~VELLY C~, ~ C~YI, SIL~ C~Y$, ' Z~ lill ~I~T8 AND CLAY8 ~ z CH~ IN~GANIC C~ ~ HIGH ~i OH ~ ~GANICC~DI~TOHIOHP,~TICI~, HIGHLY ORGANIC ~OIL~ P~ ~ P~ANDOm~HIGHLY~NICS~ UNIFIED 501L CLASSIFICATION SYSTEM KEY TO TEST 0ATA JOHN M LAMBE P.E. CLASSIFICATION CHART PLATE AND KEY TO TE~6TA 25 Job No._ ADDr:_ Dine MAdOR DM~ION$ TYPICAL NAMES C~ Q~AVI[S OW WILL O~AI~D O~VILS. ~VEL - ~NO MIX.El WI~ LITT~ ~ )~ ~N HA~ ~ 51L,Y ~VELS, ~LY C~O O~VJL - ~1 ~N ~Vl~ Wl~ 4 II~l II~ ~ I~ /INl$ CL~N~N~ ~W · · WILL~DSAN~, O~VELLY lANDS NO ~INES SP Ieee P~LY ORA~D SlNffi, ~VILLY 4 Sl~l SiZE ~IR I~ FINES IN~OANiC SlL~ AND YEIY FI~ ~N~, C~Y SIL~ WITH SLIGHT ~ INmO~N~C C~ OF ~e~ tO 31LT~ AND CLAY~ aL ~VILLY C~, ~ C~YI, SlL~ C~YS, 0L ~GANIC C~ A~D ~C~NIC ~ ~Cl~ ~ILTS AND CLAYS CH~ IN~GANIC C~ ~ HIGH OH ~ ~GANICC~DI~TOHIOHP,~TICI~, HIGHLY ORGANIC ~OIL~ PI ~ P~tANDOm~HIOHLY~NICS~ r DATE: TO: FROM: SUBJECT: ] umcipality Anchorage MEMORANDUM January 31, 1979 Planning Department~ Health and Environmental Protection Hillsborro Subdivision Tracts A - F This department concurs with the plat submitted regarding the subject property. T~act A is relatively small(2.32 acres), do to existing dwellings and property holdings, which have set precedence for Tract B and C. Le . . . Senior Environmental Specialist LNB/ljw attach: submitted plat 91.010 (4/76) JML John M. Lambe, P.E. 4303 North Star Street Anchorage, Alaska 99503 LETTER OF TRANSMI'I~FAL 907.276.4113 TO: ATTENTION: SUBJECT: OUR JOB NO. Transmitted herewith is/are the following: CC: