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HomeMy WebLinkAboutSOUTHPARK Soils Information Job No. 5941 BESSE, EPPS POl-rS Engineering, Planning & Surveying 2220 E. 88th Ave. Anchorage, Ak. 99507 Telephone (907) 349-6451, 344-1352 June 24, 1981 MUNrCIPALffY OF ANCHORAGE DEPT. OF HEALI'H & FNVIRONMENTAL PROTECTION State of Alaska Department of Environmental 437 E Street, 2nd Floor Anchorage, Alaska 99501 Conservation J'.N 2 9 1981 RECEIVED Attention: Mr. 'rom Murrell Dear Mr. Murrell: Subject: Proposed Infiltration Gallery to serve Southpark Subdivision Attached please find a copy of the proposed location of the infiltration gallery to serve Southpark Subdivision which we discussed last week. It is our intention to construct the gallery this week and begin test pumping and monitoring of water quality upon completion. As we discussed, the final design will depend upon amount of water and actual field conditions encountered. As-builts of the gallery will be submitted upon completion. Actual usage of the water from the gallery will probably not occur until next year. During this time, monitoring, testing and final design of the pump house and distribution system will be taking place. If you have any questions or desire additional information, please advise. DAG/jl cc: John Lynn, DHEP John Berggren June 30, 1980 338 Denali Street Macl(ay Bldg., Room 1206 Anchorage, Alaska 99501 (907) 274-5527 P.O. 8ox 1207 Soldotna, Alaska 99669 (907) 262-5210 P.O, Box 1064 Wasilla, Alaska 99687 (907) 376-5038 18-06LH Department of Health and Environmental Protection Municipality of Anchorage 825 L Street Anchorage, AK 99501 Attention Mr. John W. Lynn MUNICIPALITY OF ANCHORAGE ENVIRONMLNi'AL ~,,©i~CTION JUl. :[ 1980 RECEIVED Subject: South Park Water System Dear Mr. Lynn: We have reviewed the preliminary plans for the proposed Southpark Subdivision, phase I (23 lots). We hereby give our conceptual ap- proval for the use of well #1 in conjunction with 87 gallon hydronu- matic storage tanks in each home for use as an initial water system. Our comments follow: (i) Our calculations show that the proposed system will meet the minimum water requirements for the 23 homes proposed in phase I. Experience however, has shown that when sub- divisions are built around small yield wells that are pumped at or near their rated capacity, water shortages will occur in the future. Well yields nearly always drops with time. (2) A centralized water storage tank is usually preferable in the long run as opposed to individual storage tanks. (3) Fire protection under the proposed system will be limited. (4) Expansion of the subdivision beyond 23 houses under the pro- posed system will be severely limited without additional water from another source. In reviewing this project we noted that the percolation tests conducted within the subdivision were not in accordance with the U.S.D.H.E.W. Department of Health & page 2 June 30, 1980 Environmental Protection Manual of Septic-Tank Practice. Results from these tests may not accurately determine the suitability of the soils for the use of septic systems. If you have any questions concerning our conceptual review of this project, please fee]. free to contact me. Tom Murrell Environmental Engineer cc: imc David A. Grenier Tryck, Nyman & Hayes NYMAN Street Anchorage, Alaska 99501 /907 279-05 Cable TNHANCAK/Telex 090-25332 8171.0 June 20, 1980 Department of Health & Environmental Protection Municipality of Anchorage 825 "L" Street Anchorage, AK 99501 Attention: Mr. John W. Lynn Subject: Sou~hpark Subdivision Dear John: In response to your letter dated June 17, 1980, regarding the proposed subdivision plat for Southpark, the following additional information is submitted: Item No. 1---Lot 4, Block l: An additional soils test was taken on this lot located within the proposed drain field. This additional test answers the concerns expressed about this 'lot. Item No. 2.--Lot l, Block 3: A soils test was also taken on this lot in the revised proposed drain field location. Item No. 3: The drain field location for Lot 2, Block 3 has been revised as recommended. (The existing cut bank will be to a minimum of 2 to 1 or less.) Item No. 4: The drain field for Lot 3, Block 3 has also been revised as recommended. Item No. 5: Please regard this letter as acknowledgment for the need of proper abandonment of the existing wells within Phase I. This will be accomplished as per DHEP requirements within the next six to eight weeks. Item No. 6: The design of the water system to serve Phase I is nearing completion and will be submitted to the State Department of TIRYG( NYMAN "2- Mr. John W. Lynn June 20, 1980 8171.0 Environmental Conservation as well as DHEP for review and approval. Attached, please find a letter addressed to the Municipality of Anchorage Planning Department dated June '16, 1980, regarding the water system and supply as it is being designed to serve this first phase. Also attached are copies of the additional soils tests that were taken which included Lot 2/3, 4 and 7 of Block 1 and Lot 1, Block 3. If there are any further questions or if we may provide additional information at this time, please advise. Very truly yours, cbh Attachments: As above cc: Mr. John S. Berggren, Bounty Development Co. 825 "L' STREET ANCHORAGE, ALASKA 99501 (907) 264-4111 June 17, 1980 Dave Griener % Tryck, Nyman and Hayes 740 I Street Anchorage, Alaska 99501 Subject: Southpark Subdivision This department has reviewed the requested soils prior to final approval and inspected the site on June 16, 1980. The soils work is adequate and this department finds the following criteria necessary for approval of Southpark Subdivision: (1) Lot 4 Block 1; must be combined with Lot 3 Block 1 due to lot size, high water table, slope and limited area due to 100 foot creek set ])ack. (2) Lot 1 Block 3; has ground water streams crossing or existing from the lot with marshy areas noted. This department requests the lot be incorporated with another lot. (3) Re-design sewer system location on Lot 2 Block 3 due to water seeps at ground level for proposed leach- field area. Water seeps noted at base of the cutbank. (4) Lot 3 Block 3; proposed sewer leachfield area located in fill consisting of root wads and organic material. Sewer system must be relocated. (5) Submit letter of intent guaranteeing proper abandonment of dry wells. Dave Griener % Tryck, Nyman June 17, 1980 Page Two and Hayes (6) Submit ~lans and State approval system and its adequacy. Also, well and water system. of tenative water dispensation of If there are any furLher questions, please call this office at 264-4720.' Sincerely, John W. Lynn Environmental Specialist JWL/ljw cc: Jerry Weaver Planning Department 71.1 June 16, 1980 Municipality of Anchorage Plan~ting Depar tmellt City ilall Annex Ancilorage, AK 99501 Attention: Hr. Jerry Weaver Subject: Southpark Subdivision Water Supply - Jerry: As you know, we are in tile process gl~ completing the final plat for the firs': phase of Sou~hpark Subdivision consisting of 23 'lots and 2 tracts. One of ~he conditions of approval is to provide a come,unity water system. Au adequate supply of water for the first phase can be served by the existing well drilled last sumner, located directly east of the gas line and north of Southpark Bluff Drive. This well has been pump tested and found to have a sustained yield in tile range of lO gallons per mi)lute. The system proposed for this first phase would connect the well directly to the distribution system. Each residence would be required Lo install its own pressure/storage tank (similar to a Well-X-Troll, Model 252) which would allow water flow not only into the house, but also back out to tile main distribution lithe. After completion of the first phase, several options are available for expanding the system, l'he first alternative is to utilize the well drilled this spring located off-site in Little Rabbit Creek Valley, east of the gas line. This well was pump tested with a sustained yield of 14 gallons ))er minute. When tied in with either individual pressure tanks or a centralized storage tank, this well would be capable of serving all of the 53 lots approved within Southpark Subdivision. Another alternative for providing community water to the approved subdivision (or additional surrounding properties) is installing an infiltration gallery along the banks of Little Rabbit Creek. This concept bas been reviewed by the Department of Environmental Conservation -2- Mr. Jerry Weaver 8171.1 June 16, 1980 and }{as received their concept approval. ^ copy of ti)etr letter is attached. The proposed infiltration gallery system would consist of approximately 100 feet of trench backfilled with layered sands and gravels. A perforated pipe would be placed in the bottom of the trench (approximately 20 feet deep) and would be designed to have backwash capability to allow cleaning of tile filter material when required. This trench would collect, filter, and direct the water to a screened well casing similar to that of a typical well. From the well, the water would be pumped directly through a filter which would consist of a fabric screen {Renntngen- Petter type) which would have the capability of filtering out trace contaminents. The water would then be chlorinated and pumped to the distributio)) sysCem. This syst~ would have the capability of producing approxi,,~ately 300 to 400 gallons per minute. If you have any questions or desire additional information at this time, please advise. Very truly yours, TRYCK, IiYMAN & HAYES David A. Grenier, P.E. cbh A~tachmen~: As above cc: Mr. John S. Berggren FLEVATION: FIELD LOG CLIENT DRILLING CONTRACTOR RR~LLER EQUIPMENT SAM~ER SOIL DESCRIPTION W_O. RK~O. RDE R NO. _TIM~ START TIME FINISH WATER LEVELj~*_,I, 'TIME -- SHEET OF COMMENTS FI EVATION: FIELD LOG CLIENT DRILLING CONTRACTOR SAMPLER SOIL DESCRIPTION BORING _N QL "~__~-~ ,-~'i W~ORK ORDER N..O~ TIMF' W_ART TIME FINISH WATER LEVEL//lll ¢TIME SHEET OF COMMENTS ~ALAS K~'~-~T'E$~LA B ELEVATION: FIELD LOG CLIENT DRILLING CONTRACTOR_~' .~,) _O_R!i:_LER EQUIPMENT SAMFA_ER SOIL DESCRIPTION W~ORK~OROER NO. TIM~TART TIME FINISH WATER L EVE LJ~/~_~,/<. TIME SHEET OF COMMENTS ELEVATION: FIELD LOG CLIENT SOIL DESCRIPTION BO_R. iN__G__Ng~__7 - / .... WORK OHDER NO, T~IM~_R T TIME FINISH W~ATER _Lg~.EL/~*,~_TJ_ME_ COMMENTS ,/,.,,/j WELL RESERVE EASEMENT AFFECTING PORTIONS OF TRACTS A; LOT 6, BLOCK 2; LOT 8, BLOCK 3 & LOT 9, BLOCK 3 SOUTHPARK SUBDIVISION An easement is hereby created for the purpose of restricting the use of portions of Tract A; Lot 6, Block 2; Lot 8, Block 3 & Lot 9, Block 3 in Southpark Subdivision, a Subdivision of Tract A, Road Dedication, (Plat No. P77-21) to provide a well reserve within a 200.00 foot radius of a proposed well. The restrictions placed on the use of the above-described tract and lots are in accordance with Title 18 of the State of Alaska Administrative Code, Environmental Conservation, Chapter 80, Drinking Water, whereas the minimum separation between the well and wastewater treatment and disposal systems, sewage pump stations, sewer main clean- outs, sewer line manholes, coinmunity sewer lines, and other potential sources of contaminants, all as defined in said Chapter 80, shall be 200.00 feet (unless a lesser distance is approved by the State), and the minimum separation between the well and private sewer lines shall be 100.00 feet. The limlts of the well reserve easement are shown by attached "Exhibit A, Southpark Well Site" and the easement is described more particularly as follows: The area within a circle having a radius of 200.00 feet and a center point located as follows: Beginning at the southeasterly corner of Lot 6, Block 2, thence South 62° 20' 45" East 119.8 feet more or less, thence North 27° 39' 15" East 34.6 feet more or less to ~]e well casing. IN WITNESS WHEREOF, the persons below as owners and/or representatives of the af~ec~ted tracts~aDd lots hereunto set their hands and their seals this ~r/~day of __(--~/~(/~%~_ , 1980. / GEneRAL ENTERPRISES ~ INC. NOTARY ' S ACKNOWLEDGEMENT ' ' S%[bscribed and sworn to before me this __~_~/~/day o.f , 198o, , ./:--- ~ ~"or' Alaska My commission expires ~.~/62~ rm rn R,::...! IVED JUN 2 7 ]980 To,el<, Nyma;l & Ilayes 4040 "B" STREET ANCHORAGE, ALASKA 99,503 (907) 278-1551 DATi:: I~ROJI=OT / W.O. MEMO su.aECT: SIGNED', May 9, 1980 W.O. #A19218 Bounty Development Company SRA Box 470-B Anchorage, Alaska 99507 Attention: John Berggren Subject: Phase I, Southpark Terrace Estates, Soils Investigation Gentlemen: We herewith transmit four copies of the subject report. The purpose of this investigation was to determine the feasibility of constructing on-site wastewater disposal systems. Design absorp- tion areas for the drain fields are given on a lot-by-lot basis. Sincerely yours, ALASKA TESTLAB James R. Finley, Jr., Geotechnical Engineer PoE. Approved by: Melvin R. Nichols, P.E. Laboratory Manager JRF/mg Attachments cc: Dave Grenier, Tryck, Nyman & Hayes TABLE OF CONTENTS Introduction . General Conclusions Soils and Surficial Geology Ground Water Percolation Rates Field Exploration Program and Percolation Test Methods Pag_~ 1 2 3 6 6 '7 Table A - Percolation Test Results Table B - Recommended Absorption Areas Tables C-O - Test Hole Logs Sheets 1-7 - Grain Size Distribution Curves Sheets 8-10 - Standard Explanatory Information Appendix A - Soils and Recommended Septic System Design Criteria for Individual Lots Appendix B - Report Dated January 26, 1979, Titled "Addendum No. 1 to Subsurface Investigation, 40 Acre Parcel on Old Seward Highway" and Report Dated January 23, 1979, Titled "Subsurface Investigation, 40-Acre Parcel on Old Seward Highway" SOILS INVESTIGATION SOUTHPARK TERRACE ESTATES SUBDIVISION, PHASE I ANCHORAGE, ALASKA Prepared for BOUNTY DEVELOPMENT COMPANY Prepared bY ALASKA TESTLAB SOILS INVESTIGATION SOUTHPARK TERRACE ESTATES SUBDIVISION, ANCHORAGE, ALASKA PHASE I INTRODUCTION This report presents the results of a subsurface investigation and sununarizes the results from two previous investigations conducted in the western one-half proposed Southpark Terrace Estates Subdivision. Southpark Terrace Estates is located south of Anchorage off the Old Seward Highway, south of Little Rabbit Creek and east of Potter Marsh. The 40 acre parcel is in Section SW 1/4 of the NE 1/4, Township 11, Range 3W, Seward Meridian, Alaska. In October 1978, Mr. John Berggren excavated 19 test pits on the property. The purpose of these test pits was to determine soil conditions to evaluate the feasibility of using the property as a gravel pit and aggregate source. In January 1979, Alaska Testlab was retained to determine the suitability of the parcel for a proposed subdivision having on-site wastewater treatment systems. Visual classifications of the 19 test pits dug with the client, Mr. John Berggren, was verified by Mr. James Mack from Alaska Testlab. Verification involved cleaning out the snow and the sluffed soils in the test pits. Then Test Holes 20 through 34 were excavated with a backhoe and logged by Alask~ Testlab. During this same program, Test Holes 35 through 37 were drilled using a Nodwell mounted Mobile B-50 drill rig equipped with a solid flight auger. Percolation tests were performed in these test borings. A report was issued on January 23, 1979 which included the results of the test borings and test pit excavations (Holes 1 through 37). Addendum No. 1, issued on January 26, 1979, contained a map of soils in the proposed subdivision showing estimated percola- tion rates. Further information was required and on September 12, 1979, Alaska Testlab, at the request of the client, attempted to perform percolation tests in Test Pits 2, 6, 7, 10, 14, 15 and 22° These test pits were flooded with water using a water truck. It was planned to conduct the percolation'test the following day. Up to 100 gallons of water was placed in each of the test pits and it was estimated that the percolation rates of the soils was between one and five per inch in every hole. It was concluded that the map in Addendum No. 1 showing estimated percolation rates were representative of values for percolation properties in the test pit areas. The current investigation involved drilling 13 test borings at selected areas within the proposed subdivision for the purpose of performing percolation tests and evaluating the required septic system absorption trench area for each lot. For convenience, each lot is discussed individually in the appendix. A general description of the soils conditions, ground water conditions is presented along with a recommended location for the septic system. A percolation rate is given based on either borings and percolation tests on the lot, or from adjacent lots within the same landform. The following is a generalized discussion and summary of the study. GENERAL CONCLUSIONS Most of the Phase I area of the proposed subdivision is suitable for the construction of on-site wastewater disposal systems. Soils are, for the most part, coarse and free-draining. Percola- tion rates measured by field tests range from 0.5 to 8 minutes per inch. At this time the northern part of~the proposed subdivision is unsuitable for placement of conventional on-site sewage disposal 2 system due to a high ground water table. This includes Lots 7 and 8 of Block 1 and Lots 1, 2 and 3 of Block 2. However, with development of the surface drainage system and the public water system this condition may well be alleviated. Less significant amounts of ground water were detected in Block 1, Lots 1 through 4 where seepage was observed in two test holes after drilling. The amount of down slope seepage in this area is probably small and the condition temporary. Drain fields mos~ probably can be placed on the down slope portion of these lots because the soils are granular in that area. Because of the free-draining charac- teristics, no shallow down slope seepage is expected in this area. Lots 4, 5 and 6 of Block 2 could have ground water, but a drain field system which meets state and municipal regulations can probably be constructed on these lots by using a shallow absorption trench. Table A lists the results of the percolation tests and Table B the recommended design drain field absorption rates per lot. If actual soil conditions vary from the assumed conditions as stated in the discussion in Appendix A, the absorption area requirements may change. A more free-draining soil may result in less absorp- tion area required. A tighter, siltier soil may result in the need for more absorption area. We cannot over emphasize the need for careful lnspectlo of each system as it is constructed. SOILS AND SURFICIAL GEOLOGY The surficial geology of the region has been mapped by the U.S. Geologic Survey(1) on a s~cale of 1 to 24,000. Because of the large scale of the geologic map, a study of the available aerial '(1) Schmoll, H. R. and Dobrovolny, E., 1972, Generalized Geologic Map of Anchorage and vicinity, Alaska, U.S. Geologic Survey. 3 photography and test boring information was initiated to refine the map in the area of concern. Figure 1 shows a generalized surficial geology map of the proposed.subdivision. The U.SiG.S. identified three landforms within the 40 acre parcel including: al - gm - alluvium in abandoned stream channels and terraces along modern streams; gravel and sand generally well bedded and well sorted. Generally excellent material for on-site sewage disposal. glacial and marine deposits consisting chiefly of dimicton, but including some beds of fine sand and silt. Thin beds of gravel and sand occur locally. These soils are generally adequate for on-site sewage disposal. mg - marine, glacial and lacustrine deposits consisting of a variety of interbedded materials with some fine-grained material including dimicton, stoney silt, silt, fine-grained sand and some clay. These soils must be examined closely as to their suitability for on-site sewage disposal. Dimicton is a glacial till consisting of a mixture of silt, sand and gravel. Often it contains scattered cobbles and boulders. Through the center of the property and along the western boundaries in Lots 1, 2, 3, and 4, Block 1, there is a deposit of granular soil which appears to be kame terrace deposits. A kame terrace is an accumulation of stratified drift or a~lluvium layed down by streams between the margin of the glacier and the adjacent valley wall. Upon disappearance of the glacier, the deposit is left as a constructional terrace which differs from a stream terrace in that it does not represent the remnants of a mass of sediment found extending completely across the valley. Kame terraces are usually flat and narrow and is often pitted by kettles. In some areas, as in this subdivision, several terraces occur in a series 4 marking successive positions of ice-marginal streams as a glacier thinned by wasting. Soils in this landform are characterized by Test Pits 19, 22, 28, 32, 15, and 8, also Boring 5-2. Soils are' generally non-frost susceptible and contain only a trace of silt are generally well sorted and well graded. The grain size distribution of typical composite soil samples, Groups B and C, are shown on Sheets 1 through 4. The hill on Lots 5 and 6, Block 1 was mapped as "gm" by the U.S.G.S. Test Pit 23 appears to confirm this, as 12 feet of gravelly silt was found. However, Test Pits 23A and Boring 35 found clean layered sands and gravels. It is probable that this is a glacial alluvium overlying glacial till. Glacial alluvium is defined as material deposited in irregular shaped hills in or near glacial ice consisting chiefly of gravel and sand, moderately well bedded and well sorted. The other hills and slopes are glacial till deposits, either the "mg" or the "gm" landform units. These two units often grade from one to the other and the chief difference is that the "mg" landform is often interbedded with sands and gravels and the "gm" landform is predominantly dimicton, or a mixture of gravel, silt and sand. Soils in these landforms can vary significantly over very short distances. Groups D and E are typical soils in this landform although layers of Group B and C soils can be found. Sheets 5 through 7 show the grain size distribution for these soils. Borings 36, 8-3, 9--3 and 7-3 show typical soil strati- graphy in this landform unit. Lots 1, 2 and 3 in Block 3 and Lot 4 in Block 4 contain some areas of clean fine to medium sand. The limits of these deposits are not well defined by the present available information. 5 GROUND WATER Several areas of high ground water were observed. On Lot 3'of Block 2, five test borings were drilled and high ground water was encountered in all five while drilling. ~our of the borings (Boring I-2, 8-1, 4-1 and 1-1) on the lower or west side of the property were dry when drilling, however, when a percolation test was attempted several days later, the holes were filled with water (1-1/2 to six feet below the surface). Test Pit 23 also encountered water seepage from three to four feet and Test Pit 23A, at eight feet depth. The water present is the result of downstope seepage. Test Pits 19 and 22 encountered clean gravels with no water. However, Test Borings 1-1 and 4-1 were drilled upslope. These test pits were located on the lower part of the slope on a gravel terrace. Lots 4 and 5 may also have water problems. Boring 5-2 encountered ground water at 13 feet while drilling and Boring 3-2A, drilled on the boundary between Lots 3 and 4, encountered water at seven feet. PERCOLATION RATES Percolation rates are quite high in the alluvial deposits because of the high permeability of the soils. Permeability is a physical property of the soil and is a measure of the ease of which water flows through the material. It depends predominantly on the soil grain size. Percolation rates in the granular, clean soils are less than two minutes per inch. Based on design criterJ, a in the "Manual of Septic Tank Practice", published by the U.S. Department of Health, Education and Welfare, Public Health Service, the required absorption area in square feet per bedroom is 85 square feet. It is recommended that the septic systems be designed to provide a minimum absorption area of 100 square feet because the permeability of the soil. can decrease with continued use of the 6 drain field system. The glacial alluvial deposits in Lots 5 and 6 of Blocks 1 also have similar permeability and absorption area requirements. The soil in the glacial till lot. The maximum percolation (gm or mg) deposits vary from lot to rate measured was 0.5 minutes per inch. The boring in which this test was conducted had a thick clean sand layer. The minimum percolation rate was eight minutes per inch in Boring 8-3 and in Boring 36. The absorption area requirements will depend on exactly where the drain field system is placed on the lot and the soils encountered in the drain field trench. Where no percolation test was performed on the lot, the assumed percolation rate in this landform was eight minutes per inch, thus the required absorption area is 150 square feet per bedroom. Table A lists the results of the percolation tests and Table B the recommended design absorption rate for each lot. FIELD EXPLORATION PROGR~34 AND PERCOLATION TEST METHODS The current exploratory program was conducted on April 10 and tl, 1980 and the percolation tests on April 14 and 15, 1980. The test borings were drilled to a depth of 16 feet by a Mobile B-50 drill rig mounted on a Nodwetl carrier and equipped with solid 'flight augers. The drill is owned and operated by Denali Drilling, Inc. The operation was supervised, the test holes were logged, and the percolation tests performed by Mr. O.Mo Hatch, Alaska Testlab engineering geologist. Samples were collected by retrieving them as they were brought to the surface b~ the augers. The samples were classified and placed in plastic bags to preserve the natural moisture content. In the laboratory the samples were again visually classified and the moisture content of each sample was measured. The moisture contents appear on the boring logs, Tables C through O. 7 A slotted PVC pipe was placed in the hole after drilling to keep the test hole open. The pipe in the hole was then filled with water and left to soak overnight. the holes were refilled with water observed for a period of one hour. period of 10 minutes was recorded. Upon returning the next day, and the percolation rate The lowest percolation for a This is not a standard percolation test, but we understand that the Municipality prefers that the test be conducted in this manner. 8 TABLE ~A PERCOLATION TEST RESULTS ~orin~ 1979 Series 35 36 37* 1980 Series 5-2 (Lot 5, 3-3 4-3 5-3 7-3 8-3 9-3 4-4 Block 2) Percolation Rate (Minutes/Inch) 3 8 27 1 0.5 0.5 8 0.5 8 1.6 2 Landform mg/gm mg al al mg/gm mg/gm mg/gm mg/gm mg/gm al *Not in Phase I area TABLE B RECOMMENDED ABSORPTION AREAS Block 1 2 2 2 2 3 3 3 3 3 3 '3 3 4 4 4 4 Lot 1 3 5 6 7' 2~ 3' 4 2 3 4 5 6 7 8 9 2 3 4 Absorption Area (ft /bedroom) Comments 100 100 150 150 Upper part of lot is silt with high water level. DO not install system in this area. Upper part of lot is silt with high water level. Do not install system in this area. Possible high water level due to downslope seepage. Possible high water level due to downslope seepage. 100 100 Possible high ground water. tlon necessary. High ground water. Further explora- High ground water. High ground water. High ground water. 100 Possible seepage (7' to 13' depth) on northeast portion of lot. 100 Water at 13' depth in April 1980. lO0 100 100 150 150 150 150 150 125 Soils conditions may be highly variable. 150 150 150 100 Test ttole #Lot 1, Block 1 Table C WO #A19218 Date: 4/10/80 Logged by: O. Hatch D__epth in Feet From To 0.0 1.0 1.0 2.0 2.0 6.0 6.0 8.0 8.0 16.0 Soil Description Brown Peat, soft, Pt F-4, brown Sandy. Silt, damp, medium dense, non-plastic, ML NFS, brown Sandy Gravel, 45% sand, damp, medium dense, rounded particles to 3", GW F-l, brown Silty Sandy Gravel, damp, medium dense, subrounded particles to 6", GM F-4, brown Gravelly Sandy Silt, very gravelly 13' to 16', damp, stiff, non-plastic, ML Bottom of Test Hole: Frost Lille: Free Water Level: 16.0 Feet 1.0 Foot None Observed While Drilling 5.0 Feet After Drilling (4/14/80) Sa. No. Depth 1 5.0 2 10.0 3 15.0 Type of Dry Blows/6" M% Sample S_trength Group Unified 4.7 G N C GW 8.7 G N D ML 8.9 G N D ML Remarks: 1. 30 50 60 Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 4, Block 1 Table D WO #A19218 Date: 4/11/80 Logged by: O. Hatch Depth in Feet From To 0.0 1.0 1.0 3.0 3.0 10.0 10.0 16.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown Sandy Silt, damp, medium dense, non-plastic, ML F-4, brown Gravelly Sandy. Silt, 20% gravel, damp, dense, non-plastic, subrounded particles to 6", ML F-l, brown very Silty Sandy 30% sand, 40% gravel, damp, to 6", SM/GM Gravel, 30% silt, subrounded particles Bottom of Test Hole: Frost Line: Free Water Level: 16.0 Feet 1.0 Foot None Observed While Drilling 6.0 Feet After Drilling (4/14/80) Sa. No. Depth 1 5.0 2 10.0 3 15.0 Type of Dry Blows/6" M% Sample Strength Group Unified 7.9 G N D ML 8.9 G N D ML 7.9 G N D SM Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, .see Sheet 3. Test Hole #Lot 8, Block 1 Table E WO #A19218 Date: 4/11/80 Logged by: O. Hatch D__epth in Feet From To 0.0 0.5 0.5 3.0 3.0 12.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown Gravelly Sand~ Silt, damp, dense, non-plastic, ML F-4, brown to olive Gravelly Sandy Silt, fine to coarse sand, 15 to 25% gravel, 40 to 50% sand, damp, medium dense, subrounded particles to 3", grades siltier at 12' depth, ML Bottom of Test Hole: Frost Line: Free Water Level: 12.0 Feet 1.0 Foot None Observed While Drilling 2.5 Feet After Drilling (4/14/80) Sa. No. Depth 1 5.0 2 10.0 3 15.0 Type of Dry Blows/6" M% Sample Strength ~roup Unified 7.7 G N D ML 9.4 G N D ML 10.6 G VL D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, . U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 1, Block 2 Table F WO #A19218 Date: 4/11/80 Logged by: O. Hatch Depth in Feet From To 0.0 0.5 0.5 7.0 7.0 16.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown to olive Gravell_~ Sandy Silt, damp, ML F-2/F-4, olive Gravelly. Silty Sand, fine to coarse sand, damp, medium dense, grades to gravelly sandy silt by 15' depth, SM/ML Bottom of Test Hole: Frost Line: Free Water Level: 16.0 Feet 1.0 Foot None Observed While Drilling 1.5 Feet After Drilling (4/14/80) Sa. No. Depth 1 5.0 2 10.0 3 15.0 Type of Dry ~lows/6" M% Sample Strength ~roup Unified 13.6 G VL D ML 9.0 G N E SM. 12.2 G VL D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 3, Block 2 Table G WO #A19218 Date: 4/11/80 Logged by: O. Hatch D__epth in Feet From To 0.0 1.0 1.0 2.0 2.0 8.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown Sandy Silt, damp, stiff, non-plastic, ML F-4, brown very Gravell~ very Sandy Silt, damp to saturated, dense, non-plastic, ML Bottom of Test Hole: Frost Line: Free Water Level: 8.0 Feet 1.0 Foot Boring 3-2 2.0 Feet: Boring 3-2A -'7.0 Feet Boring 3-2B - 6.0 Feet Boring 3-2C - 6.0 Feet . Boring 3-2D - 4.0 Feet Sa. Depth 5.0 Type of Dry Blows/6" M% Sample Strength Group Unified 9.1 .G N D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 5, Block Table H WO ~A19218 Date: 4/11/80 Logged by: O. Hatch D__epth in Feet From To 0.0 0.5 0.5 1.5 1.5 14.0 14.0 16.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown Sandy Silt, damp, dense, non-plastic, NFS, brown very Sand~ Gravel, trace silt, 40 to 5C% sand, damp, medium dense, rounded particles to 3", saturated at ~3' depth, GM/GW F-4, brown Sandy Silt with trace gravel, saturated, non-plastic, ML Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 16.0 Feet 1.0 Foot 13.0 Feet While Drilling 1 minute/inch with water level at 5.0 feet PVC pipe in Sa. No. Depth 1 5.0 2 10.0 3 15.0 Type of Dry ~lows/6" M% Sample ~trength ~roup Unified 13.7 G N C GM/GW 6.3 G N C GW 12.1 G L D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole ~Lot 3, Table I Block 3 WO ~A19218 Date: 4/10/80 Logged by: O. Hatch Depth in Feet From To Soil Description 0.0 1.5 F-4, brown Sandy Silt, damp, dense, non-- plastic, ML 1.5 8.0 NFS, brown Gravelly Sand, fine to coarse, 20% gravel, damp, medium dense, rounded to subrounded particles to 1", SP/SW 8.0 10.0 F-l, brown Silty Gravelly Sand/Sandy Gravel, damp, medium dense, rounded to subrounded particles to 2", GW-GM/GM 10.0 16.0 NFS, brown Sand with traces of gravel and silt, fine to coarse, damp, medium dense, SP/SM Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 0.5 minutes/inch with water level falling 11.5 feet in 70 minutes 16.0 Feet 0.5 Feet None Observed While Drilling in PVC pipe Sa. Type of Dry No. Depth Blows/6" M% Sample Strength Group Unified 1 5.0 5.1 G N B SW 2 10.0 6.5 G N C GM/GW 3 15.0 7.1 G N B SM/SP Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole ~Lot 4, Block 3 Table J WO ~A19218 Date: 4/10/80 Logged by: O. Hatch Depth in Feet From To 0.0 0.5 0.5 1 .5 1.5 3.5 3.5 12.0 12.0 16.0 Soil Description Brown Subsurface Organics, soft, Pt F-4, brown Sa~_~y Silt, damp, dense, non- plastic, ML F-4, brown Gravelly Sandy ~ilt, damp, dense, non,plastic, subrounded particles to 2" F-2, brown silt~ fine Sand with traces gravel, 40 to 45% nbn-plastic silt, damp, medium dense, grades to 30% silt by 10' F-4, brown Gravelly Sand~ ~ilt, 20% gravel, damp, medium dense, non-plastic, ML Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 0.5 minutes/inch with water level falling 7 feet in 45 minutes 16.0 Feet 1.0 Foot None Observed While Drilling in PVC pipe · Sa. Type of Dry No. Depth Blows/6" M% Sample Strengt~ ~roup Unified 1 5.0 14.1 G VL -- ML 2 10.0 9.8 G N -- SM 3 15.0 11.4 G VL D ML Rsmarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 5, Block 3 Table WO #A19218 Date: 4/10/80 Logged by: O. Hatch ~pth in Feet From To 0.0 1.0 1.0 16.0 Soil Description F-4, brown Sandy Silt with trace Peat, damp, medium dense, non-plastic, ML F-4, brown Gravelly Sandy Silt with some cobbles and boulders, damp, stiff, non-plastic, subrounded particles to 8", ML Bottom of Test Hole: Frost Line: Free Water Level: 16.0 Feet Trace Observed None Observed While Drilling Percolation Rate = 8 minutes/inch with water level at 4.0 feet depth in PVC pipe Sa. Type of Dry No. Depth ~$1ows/6" M% S_ample Strength Group Unified 1 5.0 11.4 G VL/N D ML 2 10.0 8.2 G VL/N D ML 3 15.0 10.2 G VL D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot '7, Block 3 Table L WO #A19218 Date: 4/11/80 Logged by: O. Hatch De~)th in Feet From To 0.0 0.5 0.5 1.5 1.5 10.0 10.0 16.0 Soil Description Brown Feat, damp, soft, Pt F--4, brown Sandy Silt, damp, medium dense, non-plastic, ML F-l, brown very Silty Sandy Gravel/Gravell~ Sand, damp, dense, SM/ML F-4, brown Gravelly ~and~ Silt, damp, very dense, 10 to 20% gravel, non-plastic, ML Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 16.0 Feet 1.0 Foot None Observed While Drilling 0.5 minutes/inch with water level in PVC pipe falling 9.0 feet in 50 minutes No. Depth 5.0 10.0 15.0 Type of Dry Blows/6" M% Sample Strength Group Unified 9.7 G N D ML/SM 10.9 G N D SM 10.7 G N D ML Remarks: 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U TM undisturbed. Dry Strength, N=None, L=Low,.M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural ClassJ. fication, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 8 Block 3 Table M WO #A19218 Date: 4/11/80 Logged by: O. Hatch Depth in Feet From To 0.0 0.5 0.5 2.5 2.5 4.0 4.0 7.0 7.0 9.0 9.0 16.0 Soil Description Brown Feat, damp, soft, Pt F-4, brown Gravelly Sandy Silt, damp, dense, non-plastic, subrounded particles to 2", ML F-l, brown Silty Sandy Gravel, damp, dense, rounded and subrounded particles to 3", GM NFS, brown Sandy Gravel with trace silt and cobbles, damp, dense, rounded and subrounded particles to 6", GW/GM NFS, brown Gravelly Sand, fine to coarse sand, damp, dense, rounded particles to 1" F-4, brown Sandy Gravell~ Silt, 30 to 40% coarse sand, damp, medium dense, ML Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 16.0 Feet 1.0 Foot None Observed While Drilling 8 minutes/inch with water level at PVC pipe 6.0 feet in Sa. No. Depth 1 5.0 2 10.0 3 15.0 Type of Dry Blows/6" M% Sample Strength Group Unified 7.3 G N C GW/GM 9.3 G VL D ML 10.5 G VL D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 9, Block Tab].e N WO #A19218 Date: 4/11/80 Logged by: O. Hatch Depth in Feet From To 0.0 0.5 0.5 1.5 1.5 6.0 6.0 8.0 8.0 13.0 13.0 16.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown Sandy Silt, damp, medium dense, non-plastic, ML NFS, brown fine to coarse Sand with traces of gravel and silt, damp, medium dense, SP/SM F-2, brown fine to coarse Silty Sand with -traces of gravel, damp to wet, medium dense, SM ~'-2, brown slightly Silty Gravelly Sand, damp, medium dense, SW/SM F-4, brown Gravelly Sandy Si~t, damp, medium dense, non-plastic, rounded and subrounded particles to 2", ML Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 1.6 minutes/inch with water level in PVC pipe 16.0 Feet 1.0 Foot None Observed While Drilling at 6.0 feet Sa. Type of Dry No. Depth Blows/6" M% Sample Strength Group Unified 1 5.0 8.6 G N B SP/SM '2 10.0 5.7 G N C SW/SM 3 15.0 11.3 G VL D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. Test Hole #Lot 4, Block Table 0 WO #A19218 Date: 4/10/80 Logged by: O. Hatch D_~e~h in Feet From To 0.0 0.5 0.5 1 .5 1 .5 8.0 8.0 16.0 Soil Description Brown Peat, damp, soft, Pt F-4, brown Sandy Silt, damp, medium dense, non-plastic, ML F-4, brown Gravelly Sandy Silk, damp, medium dense, non-plastic, ML NFS, brown fine to medium Sand with traces of silt and gravel, damp, medium dense, rounded particles to 2", grades coarser at 15', SP/SM Bottom of Test Hole: Frost Line: Free Water Level: Percolation Rate = 2 16.0 Feet 1.0 Foot None Observed While Drilling minutes/inch with water level at PVC pipe 6.5 feet in 1 2 3 Depth 5.0 10.0 15.0 Type of Dry Blows/6" M% Sample Strength Group Unified 11.5 G N -- ML 8.9 G N B SP/SM 3.4 G N B SW Remarks: 3. 4. 5. 6. Type of Sample, G=Grab, SPT = Standard Penetration, U = Undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Information, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. g .J g o o ~ ,~ o 3 o o o o o Test Hole Log - Description Guide precision of a laboratory testing procedure. If thc log includes soils samples, to verify the field examination. The logs often iuclude the following items: Depth Intcrva~l - usually shown to 0.1 foot, within that zone no significant change itl soil type wits observed through drill action, direct observation or sampling. Frost Classification - NFS, Fl, F2. F3, F4, see "Soil Classification Chart" Texture of Soil - An engineering classification of the soils by particle size and proportion, see "Soil Classification Chart". hole tile proportions are approximate and modifications to the soil group due to stratification, inclusions aud changes in properties are included. Moisture Content this is a qualitative measure: ~, no or little apparent surface moisture, wet, ilo free water, often soft, if cohesive soil, saturated, free water nla¥ b.e sqtleezcd out, ifa free drainiug soil: sand. ('['he moisture content is further defincdby reference to LW, NP, M%or dilatency.) mixtures with or without a fine fraction, derived from drilbng action and/or sample data; usually described as: very loose, loose, medium Stiffness - refers to nlore-ordess cohesive soils and fine grained silts of the clay-silt groups. Derived from drill action and/or sample data. Very soft, soft, stiff, very stiff and hard are conlntonly used ternls. Particle size - The largest particle recovered by tile split spuott is 1-3/8", Shelhy tube Y', auger flights (minute man)_'~", Auger flights (B-SO hollow stem) 6"-8". Larger particles are descrihed indirectly by action of tile drilbng and are referred to as cobbles, y' to 8", or boullcrs 8 4. Therefore witch reviewing the gradation sheets, il' any, tile description oil tile bole log must be considered for an bldication of larger particles, Unified Soil Cbssi£ication - This is a two letter code. See Unified Classificatkm sheet for further definition, hi some cases AASHO and/or FAA soil classifications may be shown ;ts well as the uniticd. Atterberg Limits - useful for fine grained and other plastic soils. P_l; natural moisture content believed to be less than plastic limit PI+; natural moisture content believed to be between plastic and liquid L~v+; natur,d nloisture content believed to be greater than liquid bnlit NI~; nLm-plastic, useful as a modifying description uf some silty Rock flour finely ground soil that is not plastic but otherwise appears similar to ~ clayey silt. Organic Content -- usually described as Peat, PT, sonlctimesincludes ~iscrcte particles such as wood, co;ti, etc. as a nlodifier to all inorganic soil, Quantity described as; trace, or an estimate of volunle, or, itl case of all organic, - as Peat. Tbis may include tundra, muskeg and bog material. Muck - a modifier used to describe very soft, semi-organic deposits u~, ~ly occuring below a peat deposit. Amorphus peat - organic particles nearly or fully disintegrated. Fibrous Peat organic particles more-or-less intact, Frost Linc - seasonal frost depth as described by drilling action and/or samples at tbe time of drilling. Frozen Ground -- other than frost line, described by samples, usually includes description of ice content, often will include modified Unified Classification for frozen soils - this is it special case re[sled to permafrost studies. Free Water Level - The frcc water level noted during drilling. This is Blow/6" The number of blows of a 1,lO weight free fitlliug 30" to advance a 2" split spoon 6"; the number of blows for a 12" advance is, by definition, the staudard penetration. natural Jnoisture content of the soil sample, usually not pcrfornled on clean sands or grawqs below tile water table. Type of Sample - S~P, refers to 2" split spoon driven into tile soil by 140 pound weight, a disturbed saulple, S, thin wall tube, "Shelby" used to obtain undisturbed samples of fine grained soil, .G, "gr,,h' disturbed sample from auger flights or wall of t~ench, SOIL CLASSIFICATION CHART 30% GRAVEL CLAY CLAYEY CLAYEY CLAYEY CLAYEY DR SILTY SILTY SILTY ~ SAND GRAVELLY SAND SANDY GRAVEL SILTY GRAVEL SAND GRAVELLY SAND SANDY GRAVEL GRAVEL -\ 0 I 0 20 30 40 50 60 70 80 90 100 GRAVEL (+#4 SCREEN) % BY WEIGHT NONFROST SUSCEPTIBLE SOILS ARE INORGANIC SOILS CONTAINING LESS THAN 3% 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 15% FINER TITAN 0.02 mm. F3 a. GRAVE~LLY SOILS CONTAINING MORE THAN 20% FINER THAN 0.02 mm. AND SANDY SOILS (EXCEPT FINE SILTY, SANDS) CONTAINING MORE THAN 15% FINER THAN 0.02 mm, b. CLAYS WITH PLASTICITY INDEXES DP MORE TFIAN 12, EXCEPT VARVED CLAYS, F4 a. ALL SILTS INCLUDING SANDY SILTS, b, FINE SILTY SANI}S CONTAINING MORE THAN 15% FINER THAN 0.02 mm. c, LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN 12, d, VARVED CLAYS. TF1YCK" Office NYMAN ENGINEERS / PLANNERS/SURVEYORS 8]7] .o February 13, 1979 Street Anchorage, Alaska 99501 /907 279-05 Cable TNHANCAK/Telex 090-25332 Department of Health & Environmental Municipality of Anchorage 825 L Street Anchorage, Alaska 99501 Protection Attention: Mr. John W. Lynn Subject: Dear John: Additional Information Regarding /~- ~"~ :Bou~ty:T, er~ace'Subdivision:, Case N°.(50777 "~l Attached please find a preliminary plat of Bounty Terrace which shows topographic information along with proposed well site locations. Also attached is a copy of the sub-surface soil investigation reports dated January 23, 1979 and Addendum No. 1 dated January 26. A community well is proposed for this site along with on-site individual sewer systems. The actual location of the well will depend upon where a successful drilling attempt ]s made. When the well drilling is completed, its location will be verified ]n the field by survey methods and shown on the plat. The lot configuration will then be finalized so that building sites and septic systems will be outside the required 200' radius. In laying out the final plat design all applicable guidelines of the Municipal Health and Environmental Protection Agency regarding on-site septic systems and their relation to lot size and soil type will be followed. We will resubmit the plat to your department which will shown the actual location of the well and final lot layout for your approval. If you have any questions or desire additional information at this time please contact this office. Very truly yours, TRYCF,/~YMAN ~'/~IAYES/~ ]ja encl. cc: John Berggren JAY $. HAMI~OIVD, GOVEIrIIiOIt 338DENALISREET MACKAYBUILDING, ROOM 1206 ANCHORAG~ ALASKA 99501 May 2, 1979 MUNICIPALITY OF ANCHORAGE DEPT. Of ? "1.!:~ & HHVIRONk'ENI'AL i ~ )iiC'I'ION Mr. David A. Grenier Tryck, Nyman & Hayes 740 I St. Anchorage, Alaska 99501 RECEIVED Dear Mr. Grenter: We have received and reviewed a plat showing two proposed locations for exploratory wells in the subject subdivision. If sufficient water is lo- cated, then a community system will be designed and developed. Either location is acceptable to this Department, and a certificate approving con- struction of the exploratory well or wells is en- closed with this letter. The construction approv- al will be expanded to include the wellhouse, distribution systems, and related facilities once those plans are reviewed and approved by this office. If you have any questions pertaining to our review of this proposal, please feel free to contact me at 274-5527. Sincerely, James O. Starr Environmental Engineer Enclosure cc:JDHEP mm 18-06LH LOT l, BLOCK 3 Soils and Ground Water No test borings or test pits were drilled on this lot. Based on the Generalized Geologic Map of Anchorage, the predominant land- form on this lot is "mg" (glacial till). The soil conditions appear to be quite complex. Areas of gravel and sand[ may well be present. Location of Septic System The preferred location for the septic system drain field is on the west, downslope side of the lot near the south property line. D__e.~ign Absorption Area As soils conditions are complex, it would be prudent to design the septic system so as to provide an absorption area of 150 square feet per bedroom. This is the maximum required area for other lots in Blocks 3 and 4. IIf~clean sands are encountered it may be possible to reduce the absorption area requirements. Test Hole ~3 9epth in Feet From To 0.0' 8.0' Table A WO ~A18753 Logged By: Client Date: 10-28-78 Soil Description Peat, wet. Bottom of Test Hole: Frost Line: Free Water Level: Remarks: 8o0I None Observed None Observed Hole filled with water and snow when observed by Alaska Testlabo Test Hole #4 pepth in Feet From To 0.0' -- 1.0' 1.0' - 3.0' 3.0' - 8.0' Table A WO %A18753 Logged By: Client Date: 10-28-78 Soil Description Organic Topsoil. Silty ~and~ Gravel, GM - F-l, damp. Fine Gravelly Silty Sands, SM - F-2/F-3, damp. Bottom of Test Hole: Frost Line: Free Water Level: Remarks: 8.0t None Observed None Observed Test Hole Logged By Client Verified by Alaska Testtab . LOT 2, BLOCK Soils and Ground Water Test Pit 21 was excavated on this lot in 1978. The pit was in relatively clean gravels and sands and Test Pit 21 encountered eight feet of sandy gravel, overlying gravelly silt. No ground water was encountered. Based on these test pits and information from adjacent lots, it appears that two geologic units are present on the lot. The upper part of the lot is the glacial unit "gm" (glacial till) and the lower terraces are probably kame terraces deposited by water flowing along the edge of the glacier as it retreated. Test Pit 21 appears to be on the border between the landform units. These terrace deposits are cleaner and more sorted than the till deposits. Location of Septic System The recommended location for the septic system is on the lower (southwest) portion of the lot on the terraces. Soils on the higher part of the lot are less permeable and possibly have a 'high water level due to downslope seepage. pesign Absorption Area Based on the information available, it is recommended that the system be designed for 1~0 square feet of absorption area per bedroom provided clean gravel or sand (less than 10 percent silt) is encountered. Test Hole ~epth in Feet From To 0.0' - 2.0' 2.0' - 8,.0' 8.0'- 12.0' Table A WO %A18753 Logged By: J.D. Mack Date: 1-9-79 Soil Description Topsoil. Sand~ Gravel with cobbles to 8 inches, G~, Gravell~ Silt, MI,, F-4, damp. Bottom of Test Hole: Frost Line: Free Water Level: 12.0' None Observed None Observed Sample Depth M% 1 2.0'- 8.0' 5.4 2 8.0'-12.0' 12.2 Type of Dry Sample Strength Group Unified G None C GW G Slight D ML Remarks: 1. 3. 4. 5. 6. Type of Sample, G=Grab, SP = Standard Penetration, U = undisturbed. Dry Strength, N=None, L=Low, M=Medium, H=High. Group refers to similar material, this study only. General Info,nation, see Sheet 1. Frost and Textural Classification, see Sheet 2. Unified Classification, see Sheet 3. .I I I 1i ~'~T ',lll"r Ii i ~i " ~iii i~ii ii17'~' "" '~ ' "' ~-, ~ !, , · ~ I,~, ~ iil IIII I!¥1 ..... I :,, ~ ~', .: ,~, ,, ~1 ./~1 '" "' ':" 'l il! ,, , ,' ,,~, .I