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HomeMy WebLinkAboutPTARMIGAN ADDITION TR B1 RAVENWOOD ELEMENTARY SCHOOL PO L~GI-I 6~650 ANCHORAGE, ALASKA99502-0650 (907) 264-41 ll DEPARTMENT O~ HEALTH AND ENVIRONF,~ENTAL PROTECTION February 24, 1983 Permit ~ 830088 Anchorage School District 4600 De Barr Road Anchorage, Alaska 99504 Subject: Tract B-1 Ptarmigan Subdivision Ravenwood School On-site Sewer Permit This will serve as the Department of Health and Environmental Protection on-site sewer installation permit subject to the conditions outlined below. This permit will be valid for the calendar year of 1983. The specifications and design must adhere to th.e "alternating field design" submitted for the Ravenwood School by the firm of Skilling Ward Rogers Barkshire, Inc. dated January 24, 1983. This design utilizes an alternating dosing technique, and must therefore include the following conditions: (1) The distribution boxes(2) must be set on a concrete pad firmly bedded into stable soil so as to insure that the distribution box is competely level. (2) The distribution boxes(2), dosing tank, and septic tank must be insulated against freezing. (3) Neither system is adequate to handle the entire volume of wastewater effluent, therefore, a comprehensive maintenance program should be prepared and implemented. This program must include mandatory pumping of the septic tank a minimum of once each year, and periodic rejuvenation treatments of the field using hydrogen peroxide. (4) Consideration should be given to extending the length of the trenches from 100' to 130' thereby giving each system the total required area for handling the entire volume of effluent. ~nchorage School District February 24, 1983 Page Two An as-built drawing(s) is required by a registered engineer to be submitted to this office upon completion of the installation of the sewer system° If there are any further questions, please call this office at 264-4720. Sincerely, Robert W. Robison Enviro~nental Engineering Program Manager RWR/ljw MEMORANDUM DATE: T 0: FROM: SUBJECT: February 2,.A983 Planning Department - Attention: Tom Nelson Health and Environmental Protection Ravenwood Elementary School - Soils Data Received January 31, 1983 The review of the subject indicates that [leery, Into {trends to use the septic system design submitted to this de}2arNnent back in August of 1982. At that time, due to dense soils conditions, Douglas L. Huie, Project Manager and two of the Heery's company engineers and I discussed the possibility of connecting to the Eaglewood Subdivision eight(8) inch sewer line about 800 to 1,000 feet northwest of the proposed school site. In general terms, the connection will call for a ~ravJ by from the school to a lift station and a pressure l:]no to Eaglewood Subdivision. ~i '1 ow I am suprised that the possibility of connection inch sewer was not pursued or at lcast addressed January 27, 1983 correspondance to this office. to tho eight(8) This department feels it would be in School District to pursue the public / oonn ~¥t~.~ynn ~%n~121 Specialimt JWL/ljw the best Jntore:3t e~l sewer co]]nec{ lei:. CC: Douglas L. Iluie !leery Program Management, inc. 255 East Firewood Lane, Suite 101 Anchorage, Alaska 99503 January 27, 1983 Department of Health and Environmental Protection 825 L Street Anchorage, Alaska 99501 'HEERY Attention: John Lynne Reference: Ravenwood Elementary School Request for Sewer Permit Dear John: Please find attached documents for a proposed on-site septic system for Ravenwood Elementary School. We have previously submitted this school to you August 31, 1982, for your review. For various reasons, the bidding schedule was postponed. At present, we are preparing to go to bid for start of construction by March, 1983. We would appreciate your reviewing these documents in order that we m~y obtain a permit for sewer. In our previous submission, our con- versations you had indicated a need for additional information on cal- culations and perk test. These are enclosed for your use. We would appreciate your reviewing this information at this time. Please let me know if you have any questions or require additional information. Sincerely, HEERY PROGRAM MANAGEMENT, INC. Douglas L. Huie Project Manager Attachment DHL/lla CC: Bruce Ericson Tom Freeman Terry Hyer 81546-Ravenwood-a Reading File/Ravenwood Heery Program Management, Inc. 255 East Fireweed Lane, Suite 101, Anchorage, Alaska 99503, Telephone (907) 278-4217 DOWL Engineers 4040 '~B" Street Anchorage~ Alaska 99503 Phone (907) 278-1551 ( Telecopier (907) 272-5742 } December 30, 1982 W.O. 9D13964 Area: 1 ECI/Hyer 101 Benson, Suite 306 Anchorage, Alaska 99503 Attention: Subject: Terry Hyer Subsurface Investigation and Percolation Test Addendum for the Eagle River Elementary School Site Dear Mr. Hyer: Transmitted herein are the results of our supplemental sub- surface investigation for the above referenced project. The current field work was conducted December 8, and 9, 1982. This addendum includes six test boring logs, and our labora- tory test results. Two of the borings were drilled for per- colation tests, two were drilled for the extension of Wren Lane, and two were drilled for design of the paved play area. The boring locations were selected for the areas in q%]estion by the client and Ken Walch. The current subsurface exploration was conducted using a track mounted Mobile B-61 drill rig fitted with continuous flight, hollow stem auger. The rig is owned and operated by Denali Drilling, Inc. Test boring locations were located by DOWL Surveyors, except for the two borings in the Wren Lane extension. Those two borings were located with a cloth tape by Mr. Joe Millhouse, geologist with Alaska Testlab. Mr. Millhouse and Carl Bassler, Alaska Testlab geotechnicat Lewis E. Dickinson Maurice P. Oswald Kenneth B. Walch Melvin R. Nichols ECI/Hyer /~ December 30, 19~ page 2 engineer, supervised the drilling, logged the test holes, and performed the percolation tests. The test borings were drilled to a depth of 15 feet, +/- 1.5 feet. Soil samples were taken at 5 foot intervals with a 2.5 inch inside diameter split spoon sampler driven with a 340 pound hammer free falling 30 inches. Penetration tests were performed by driving the sampler 18 inches ahead of the auger or to refusal~ whichever came first. The number of blows required to drive the sampler the last 12 inches or to refusal is recorded on the boring logs, Figures 3 through 8. The blowcount indicates the relative density of the soil. Grab samples were taken near the ground surface in the test borings. All recovered samples were visually clas- sified in the field, sealed in plastic bags to prevent the loss of moisture, and transported to the laboratory for testing. Samples were again visually classified in the laboratory and tested for moisture content. Tests to determine the grain size distributions'were conducted on samples from the perco- lation levels in Test Borings A1 and A2. SUBSURFACE CONDITIONS The soil conditions at the site are illustrated graphically on the test boring logs. The soil conditions described apply only to these test borings, and variation between them should be expected. The current investigation indicates similar soil conditions to those encountered in the previous investigation. ECI/Hyer //'k, December 30, 19'o~ page 3 A layer of topsoil was encountered to a depth of' 1 foot in all the borings drilled for the current investigation except Test Borings A2 and A6. No topsoil was encountered at those boring locations. Gravelly Sand (SM-SP) and Sandy Gravel (GM-GP) with varying silt content were encountered below the topsoil to the limit of our exploration. The sand layer was generally found to overlie the gravel layer, and extend to a depth of approximately 3 feet. Both soil types were gener- ally damp, dense to'very dense, and slightly to moderately frost susceptible (Fl-F2). In Test Borings A5 and A6, non- frost susceptible Sandy Gravel and Gravelly Sand were encountered between 1.5 and 8.0 feet below the ground sur- face. The clean sands and gravels are capped with a thin layer (1.0 to 2.5 feet) of Sandy Silt (ML) at those loca- tions. A groundwater table was not encountered during this sup- plementary field exploration. PERCOLATION TESTS Two percolation tests were conducted during this investiga- tion. Their locations are shown on Figure 2 and the soil logs are shown on Figures 3 and 4. A boring was drilled to a depth of 16 feet at both loca- tions. No groundwater or bedrock was encountered to that depth. A second shallow boring was drilled for percolation tests less than 10 feet away from each of the deep borings. The shallow borings were drilled to a depth of 5 feet, and presoaked over night. Percolation tests were conducted be- tween 4.5 and 5 feet below the ground surface. The water level was measured from a fixed reference point to the ECI/Hyer December 30, 19~z ,Page 4 nearest 1/16-inch at 30 minute intervals. Afte~ each mea- surement, the water level was readjusted to a level 6 inches above the hole bottom. The tests were continued until two successive measurements did not vary by' more than 1/16- inch. At least three measurements were made, and the last was used to calculate the percolation rates. These rates are given below. Test Boring Percolation Rate A1 68.5 minutes/inch A2 41.7 minutes/inch. ~ Should you have any questions regarding this letter or re- quire further assistance, please do not hesitate to call. Sincerely, DOWL ENGINEERS Charles R. Wilson Geotechnical Engineer Approved: Melvin R. Nichols, P.E. Manager CRW:MRN:kf Attachments EAGLE RI EAGLE . RIVER SCALE (MILES): 0 VICINITY MAP EAGLE RIVER SCHOOL SITE *PRO,JECT SITE FIGURE I MA FI~ 9 99 TEST LOCAT i,qN= ELEVATION= BORING,R1 DEPTH TOPSOIL F2, OLIVE BROWN SILLY GRAVELLY SAND,. OCCASIONAL COBBLE, SUBROUNDED GRAVEL TO $", FINE TO COARSE SAND. DAMP. DENSE Fl, BROWNISH GREY SILTy BANDY GRAVEL, OCCASIONAL COBBLE, FINE TO COARSE SAND, SUBROUNDED TO ROUNDED GRAVEL, DAMP, DENSE VERY DENSE TEST BORING COMPLETED 12/8/82 NO GROUND WATER ENCOUNTERED 1.0 3,0 16.5 KEY MA : MECHANICAL ANALYSIS LL : LIOUID LIMIT Pt : PLASTIC INDEX [] : GRAB SAMPLE [] : SPT SAMPLE [] ~ SHELBY TUBE-PUSHED [] : 2,5" I.D. SPOON SAMPLE 340# WEIGHT. 30' FALL DOWL ENGINEERS LOG OF BORING LOGGED BY=JBM W.O, NO.: D13964 FIGURE 3 MA FIG 9 lO0 TEST L OCAT i ELEVATION= IBOR I N O ~'~2 DEP!H F2, OLIVE BROgN SILTY GRAVELLY SAND. SUBROdNDED TO ROUNDED GRAVEL TO 2", FINE TO COARSE SAND, DAMP, DENSE Fi, GREY SANDY GRAVEL, OCCASIONAL COBBLE. FINE TO COARSE SAND. SUBROUNDED TO ROUNDED GRAVEL, DAMP, DENSE Fl, BROWNISH GREY SILTY SANDY GRAVEL, OCCASIONAL COBBLE, FINE TO COARSE SAND, SUBROUNOED TO ROUNDED GRAVEL. DAMP, VERY DENSE TEST BORING COMPLETED ]2/8/82 NO gROUND WATER ENCOUNTERED 3.0 7,5 15-5 KEY MA = MECHANICAL ANALYSIS LL = LIQUID LIMIT Pi = PLASTIC INDEX [] = GRAB SAMPLE [] = SPT SAMPLE [] = SHELBY TUBE-PUSHED [] = 2,5" I,D. SPOOR SAMPLE 340# WEIGHT, 30" FALL DOWL ENGINEERS LOG OF BORING LOGGED BY :.JBM W.O. NO.: D13964 FIGURE 4 23.5 TESTBORING??3 LOCAT1DN~ FLEVAT ION:- DEPlH IOPSOI[ F2. OLIVE BROWN SILLY GRAVELLY SAND,. SUBROUNDED GRAVEL lO 2". F1NE TO COARSE SAND, WET, DENSE FI, BROWNISH GREY SILTY SANDY GRAVEL, OCCASIONAL COBBLES AND BOULDERS, FINE TO COARSE SAND, SUBROUNDED GRAVEL. SATURATED. VERY DENSE REFUSAL GREY, WE~ REFUSAL ON BOULDER TEST BORING COMPLEIED 12/8/82 NO GROUND WATER ENCOUNTERED O.S 3.0 13,0 KEY MA = MECHANICAL ANALYSIS LL = LIOUID LIMIT PI = PLASTIC INDEX [] = GRAB SAMPLE [] = SPT SAMPLE [] = SHELBY TUBE-PUSHED [] = 2.5" I.D- SPOON SAMPLE 340# WEIGHT, 30" FALL DOWL ENGINEERS LOG OF BORING LOGGED BY: JBM W.O. NO,: Dl~9~ FIGURE 5 I00 TEST L OCAT ! EL EVAT i ON= BORING,~.4 TOPSO;L F2, BRONN1SH GREY SiLlY GRAVELLY SAND. GRAVEL TO 2", DAMP, DENSE Fl, CRE¥ SILTY SANDY GRAVEL'. TRACE ORGANICS, OCCASIONAL COBBLE, SUBROUNDED TO ROUNDED GRAVEL, DAMP. VERY DENSE TEST BORING COHPLETED 12/8/82 NO GROUND WATER ENCOUNTERED DFPTH 0.5 15.5 KEY MA : MECHANICAL ANALYSIS LL = LIOUID LIMIT PI = PLASTIC iNDEX [] : GRAB SAMPLE [] = SPT SAMPLE [] = SHELBY lUBE-PUSHED [] : 2.5" I.D. SPOON SAHPLE 340# ~EIGHT, 30' FALL DOWL ENG! NEERS LOG OF BORING LOGGED BY~JBH ~,/-0. NO.: D13964 FIGURE 6 TEST BOR I NG,~'~5 LOCAT ] ON: ELEVAT 1 ON: DEPTH L,,~N CS AND VECETAT10N O.S FA, BROWN SANDY SILT, TRACE ORGANICS. OCCASIONAL GRAVEL, DAMP TO I/ET, MEDIUM DENSE 1.5 NFS. GREY GRAVELLY SAND, SUBROUNDED GRAVEL TO 2", FINE fO MEDIUM SAND, DAMP, MEDIUM DENSE NFS. BROWNISH GREY SANDY GRAVEL, TRACE SILT, OCCASIONAL COBBLE, DAMP, DENSE SOME MOTTLING HARDER DRILLING AT 11' Fl, BROWNISH GREY SILTY SANDY GRAVEL. OCCASIONAL COBBLE. WET, VERY DENSE TEST BORING COMPLETED 12/9/82 NO CROUND WATER ENCOUNTERED B.O 13.8 KEY MA = MECHANICAL ANALYSIS LL : L1OUID LIMIT P1 = PLASTIC INDEX [] = GRAB SAMPLE [] = SPT SAMPLE [] = SHELBY TUBE-PUSHED [] = 2-5" i.D. SPOON SAMPLE 340# WEIGHT. 30" FALL DOWL ENGINEERS LOG OF BORING LOGGED BY:CAB W.O. NO. : DI3964 FIGURE 7 TEST LOCATION~ ELEVATION= O0 BORING,~6 DEPTH F4, BROWN SANDY SILT, SOME CRAVEL AND ORGANICS, DAMP TO WET, LOOSE TO MEDIUm1DENSF EDGE OF ROAD F1LL 2.$ NFS. CREY SANDY GRAVEL, COBBLES, TRACE SILT, DAMP. DENSE 7.0 HARDER DRILLING, MORE S~LT? {'ROUND WATER LEVEL WHILE DRILL1NG I0.S F4, BROWNI,%H GBEY S]LT'Y SAND. FINE SAND, WET TO SATURATED, VERY DENSE 11-0 Fl, BROWN SILTY SANDY GRAVEL, WET 'KO SATURATED, VERY DENSE 15.~ TEST BORING COMPLETED )2/B/B2 KEY MA = MECHANICAL ANALYSIS LL = LiQUiD LIMIT P1 = PLASTIC INDEX [] = CRAB SAMPLE [] = SP? SAMPLE [] = SHELBY TUBE-PUSHED [] : 2.5" I.D. SPOON SAMPLE 340~ WEIGHT, 30" FALL DOWL ENGINEERS LOG OF BORING LOGGED BY:CAB W.O. NO,: D13964 F I CURE 8 o _o o o g ~ o PERFORMED FOR: LEGAL DESCRIPTION: (FEET] 1 2 · 3 4 8- 10 '12 13 COMMENTS / ,~UNICIPALITY OF ANCHORAGE DEPARTMENT OF HEALTH AND ENVIRONMENTAL PROTECTION t~25 L. Street, Anchorage, Alaska 99501 264-4720 SOILS LOG - PERCOLATION TEST [] SOILS LOG PERCOLATION TEST DATE PERFORMED: I'~'-- (~' L,:v;1! / I I I E ENCOUNTERED? IF YES, AT WHAT DEPTH? Gross Net . Depth to Net Reading Date Time Time (¢¢~ n~) Water Drop I I'Z-%,E2 12:0~-~2:1g' l~2. I'~l',~''- i',j,, ~ ~ ,, ~:t~- ~ :0~ ~0 I'f~,[l~ 7/1~" PERCOLATION RATE TEST RUN BETWEEN (Z)(~' ~ {minutes/inchJ ~r-' I~' ETANO I~'~O FT PERFORMED BY: CERTIFIED DATE' FIGURE 1 1 ,v~UNICIPALITY OF ANCHORAGE f;~"~'~.~ DEPARTMENT OF HEALTH AND ENVIRONMENTAL PROTECTION ,~ PERCOLATION TEST 825 L. Street, Anchorage, AIiskl 99501 264-4720 SOILS LOG - PERCOLATION TEST PERFORMED FOR: LEGAL DESCRIPTION: 2 6 y- $- ~6- 20. COMMENTS .See -' ore.' 'q-' DATE PERFORMED: SITE PLAN WAS GROUND WATER ENCOUNTERED? ,IF YES, AT WHAT DEPTH? O P E Gross Net Depth to Net Reading Date Time Time Water Drop ~ ', I:/9 - 1:4~ 3o ~.0~(- ~,f~ . O~ PERCOLATION RATE TEST RUN BETWEEN PERFORMED BY: 72-008 (6/79) ,..Joe. CERTIFIED SY: DATE: ~ZGU~ 12 Test Hole Log - Description Guide The soil descriptions shown on the logs are the best estimate of the soil's characteristics at the time of field examination and as such do not achieve the precision of a laboratory testing procedure. If the log includes soils samples, those samples receive an independent textural classification in the laboratory to verify the field examination. The logs often include the following items: Depth Interval - usually shown to 0.1 foot, within that zone no significant change in soil type was observed through drill action, direct observation or sampling. Frost Classification - NFS, Fl5 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", note the proportious are approximate and m~difications to the soil group due to stratification, inclusious and changes in properties are included. damp, moisture forms portion of color, less than plastic limit, saturated, free water may be squeezed out, ifa free draining soil; sand. (The moisture content is further defined by reference to PI, LW, NP, M%or dilatency.) mixt~es with or without a fine fraction, derived from drilling action and/or sample data; usually described as: very loose, loose, medium characteristics. Stiffness -- refers to more-or-less 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 commonly used terms. P~ticle size -- The largest particle recovered by the split spoon is 1-318", Shelby tube 3", auger flights (minute-man) 2", Auger flights (B-SO hollow stem} 6"-8'. Larger particles are described indirectly by action of the drilling and are referred to as cobbles, Y' to 8', or boulders 8"+. Therefore when reviewing the gradation sheets, if any, che description on the hole log must be considered for ~m:indla~tion of larger particles, Unified Soil Classification - This is a two letter code. See Unified Classification sheet for further definition. Iff some cases AASHO and/or FAA soil classifications may be shown a~ well as the unif~d. Atterberg Limits -- useful for fine grained and other plastic soils. P~; natural moisture content believed to be less than plastic lirait PI-*; rtatmal moisture content believed to be between pL~gic and liquid ~-miss L..._~; r~tura] moisture content believed to be greater thsa liquid limit N__P; ~:on-phstic, useful u · modifying description of some dry Oilatency - is the ability of water to migrate to the surface of · ~atu~azed or nearly sattuated ~oil sample when ~brued necked - u~ Rock flour ~ finely ground soil that is not plastic but otherwise appears similar to a clayey silt. Organic Content -- usually described as Peat, PT. sometimes includes discrete particles such as wood, coal, etc. as a modifier to an inorganic soil. Quantity described as; trace, or an estimate of volume, or, in case of all organic, - as Peat. This may include tundra, muskeg and bog material, Muck - a modifier used to describe very soft, semi.organic deposits usually occuring below a peat deposit. Amorphus peat -- organic particles nearly or fully disintegrated. Fibrous Peat - organic particles more~or-less intact. Bottom of Testbole -- includes last sample interval. Frost Line - seasonal frost depth as described by drilling action and/or samples at the 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 softs -- this is a special case related to permafrost studies. Free W·ter Level -- The flee water level noted during driUing. This is not necessarily the static water table at the time of drilling ot at other seasons, Static water table determination in other than very permeable soils requires observation wells or piezometer installations, used only b~ spe ci~] cases, Blow/6" - The number of blows of a 140 weight free falling 30" to advance a 2" split spoon 6"; the number of blows for a 12" advance is. by definition, the $tandud penetration. · d% - natural moisture content of the soil sample, usually not pe-~'formed on clean sands or gravels below the water table. Type of Sample - SP, refers to 2" split spoon driven into the soil by 140 pound weight, a disturbed sample, S, thin wall tube, "Shelby" used to obtain undistuxbed samples of fine grained soil, G, "grab" disturbed ·ample from auger flights or wall of trench, C. cut sample, undisturbed sample from wall of trench. Dry Strength - a useful indicator of a soil's clayey fraction, N=None, L=Low, M=Medium, H=High ' Group - The samples ue placed into apparently similar groups bared on color and texture and are ubitraxily assigned a group letter. Further disturbed tests including Atterherg Limits, grain size, moisture-density relationship, etc. may be performed on the group and are assumed to reflect the general distrubed characteristics of the soils assigned to the group, This is an important phase of the soil analysis and is used to standardize the various qualitative determinations and to reduce the . __: ::,, TEXTURAL SOIL CLASSIFICATION,,, CHA T .·; ,, CLAYE ;LAYE~ OR SILT~ SILT SAND GRAVEL GRAVELLY SAND GRAVEL O I0 20 :50 40 50 60 70 80 90 GRAVEL (+ ~4 SCREEN) % BY WEIGHT I00 FROST CLASSIFICATION SYSTEM 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 THAN 0.02 mm. F3 a. GRAVELLY 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 OF MORE THAN 12. EXCEPT VARVED CLAYS. F4 a. ALL SILTS INCLUDING'SANDY SILTS. b. FINE SILTY SANDS CONTAINING MORE THAN 15% FINER THAN 0.02 mm. c. LEAN CLAYS WITH PLASTICITY INDEXES OF LESS THAN ]2. d. VARVED CLAYS. 'SKILLING W~dD i~'~ ]t~rDaN~ clv,E eNG,NeeRs · 430 W. 7Ih AVE., SUITE 210, ANCHORAGE, AK 99501 * (907] 276-3633 JAN 261983 HEERY PROGRAM ~/b-'ANAGEMENT, INC. ~anuary 24, 1983 ECI/Hyer, Inc. 101 West Benson, Suite 306 Anchorage, Alaska 99503 Attn: Richard Parrish Re'. Ravenwood Elementary School,Eagle River Wastewater Disposal System Design Dear Richard: ARTHUR J. BARKSHIRE, PRESIDENT WILLIAM M. SMITH, SENIOR VICE PRESIDENT PATRICK W. MOORE. VICE PRESIDENT RECEI.VED EOI/Hyer, Inc. JAN 26 1983 Project # ~.3~2.. Attached herewith are the design calculations for the wastewater disposal system for the Ravenwood Elementary School at Eagle River. Also attached is a site drawing to show the general location of the wastewater disposal system as it is being proposed. You requested us last week to submit final drawings of the wastewater disposal system so that Heery Program Management, Mr. Doug Huie~ can forward the drawings to the Municipality of Anchorage for approval. However~ since our discussion of last week on this matter and our discussion of today~ I would like to suggest that the proposed wastewater disposal system, as shown on the drawing, with the back up design calculations be first' submitted to the Municipality of Anchorage and possibly to the Alaska Department of Environmental Conservation for approval. A wastewater disposal system was originally designed ~or this site and the Municipality of Anchorage expressed concern as to that design. We have made changes to the original design and would like to have the design concept approved prior to completing another design. The original perculation test data provided was for two locations on the playing field~ one of which failed and the other had a low perculation rate. This was the basis of our original design. During December 1982, two additional perculation tests were preformed at the proposed disposal field site and these results also showed a low perculation rate. Therefore, the existing soil at the site required certain design considerations to develop the site into an operational waste disposal field. The disposal field is designed as a deeps wide trench system with two fields such that one field will be dosed and then the next time the other field would be dosed. Thus~ the wastewater disposal system consists of a septic tank with a dosing tank and a siphon system which will provide dosing alternatively to each of the two fields. Flows for the system are based on the student population and a 12 hour day. SEATTLE ANCHORAGE Ravenwood Elementary School, Wastewater Disposal System Dsgn. Page 2 The waste disposal system is considered to be active during a 12 hour segment of each day and inactive for the other 12 hours, thus allowing :[or drying and breathing of the trench absorbtion system during the inactive periods. Due to the low perculation rates o£ the existing soils at the site and to the previous review comments :[rom the Municipality of Anchorage on the original design, I sub,nit the attached schematic of the septic tank, design tank, and two drain fields with supporting calculations :[or your use in submitting to the Municipality of Anchorage for their concurrence of the proposed design. I am not planning to complete the wastewater disposal design and drawings until the Municipality's comments are provided. Should you require any :[urther backup in:[ormation as to this design please advise. Sincerely) SKILLING WARD ROGERS BARKSHIRE INC. Dale A. Nelson~ P.E. Civil Projects Director dll Attachments SKILLING WARD ROGERS BARKSHIRE INC. REC H~R ¢....,¢..~' EIVED 2 61983 · PROGRAM ;EN~ENT, INC. /.),~/~ r__. EiP,q Z:::)~".Sv / Cio, I ,- o. 7s- (4~7s) S~ILLING, HELLE, CHRISTIANSEN, ROBERT~SON, RARKSHIRE, INC. SKILLING. HELLE, CHRISTIANSEN, ROBERTSON, BARKSHIRE, INC. DESIGN SHEET SK]LLING, HELLE, CHRISTIANSEN. ROBERI'i~iON. BARKSHIRE, INC. DESIGN SHEET LOCATION ~ ARC q (( ~-t $~(ILLING, HELLE, CHRISTIANSEN. ROBER, TSON. BARKSHIRE, INC. x = //~ L TABLE 4-7 TYPICAL WAST~WATER FLOWS FROM INSTITUTIONAL SOURCES (18) Source Unit ~ange CTy~tcal~ Hospital, Medical Hospital, Mental Pri son Rest Home SEh~l~,? Day ~, With Cafeteria, Gym, Showers Wi th Cafeteria Only Wi thout~l]a f~ter) 2C' G~'., &Show6r~ School, Boarding Bed 132 - 25! '172 Employee 5.3 - 15.9 10.6 Bed 79.3 - 172 106 Employee 5.3 15.9 10.6 Inmate 79.3 - 159 119 Employee 5.3 - 15.9 10.6 Resident 52.8 - 119 92.5 Employee 5.3 - 15.9 10.6 Student 15.9 - 30.4 21.1 Student 10.6 - 21.1 15.9 ~St~d6ht~ 5.3- 17.2 Student 52.8 - 106 74.0 61 "0 9.5 HA FIG § .0 .B KEY MA = MECHANICAL ANALYSIS LL = LIOUID LIM1T P1 = FLASTJC INDEX [] = CRAB SAMPLE [] = SPI SAMPLE [] = SHELBY TUBE-PUSHED [] = 2.5' 1.D- SPOON SAMPLE 340~ WE1GHI. 30' FALL lEST BORING LO:AT,ON= ELEVATION= A1 DEPTH IDPSOiL 1.O F2. OLIVE BROWN SILlY.GRAVELLY SAND. COBBLE. SUBROUNDED GRAVEL 10 3". COARSF SAND, DAMP. DENSE OCCASIONAL FINE 10 3.0 Fl. BROWNISH GREY SILTY SANDY GRAVEL, OCCASIONAL COBBLE, FiNE TO CO~RSE SAND. SUBROUNDED 10 ROUNDED GRAVEL. DAMP, DENSE VERY DENSE TEST BORING COMPLEIED 12/8z82 NO GROUND WAIER ENCOUNTERED 16-5 DO~4L ENGINEERS LOG OF BORING LDGGED BY~JBM W.O. NO.: DI39G4 F]GURE 3 FIG 9 100 TEST BORING A2 ELEV~.I ION= DEP1H F[', OLIVE BR/,NN SiLlY GRAVELLY SAND. SURkOUNDED ?0 ROdNDED GRAVEL TO 2". FINE TO COARSE SAND. DAMP. DENSE 3.0 Fi. GREY SANDY GRAVEL, OCCASIONAL COBBLE, FiNE lO COARSE SAND. SURROUNDED TO ROUNDED GRAVEL. DAMP. DENSE FI. BROWNISH GREY SILTY SANDY GRAVEL. OCCASIONAL COBBLE, FINE lO COARSE SAND, SURROUNDED ~0 ROUNDED GRAVEL. DAMP. VERY DENSE ........................... 15:5 IESI BORING COMPLETED 12/8/82 NO GROUND ~AIER ENCOUNTERED KEY MA = MECHANICAL ANALYSIS LL = LIOUiD LIMIT Pi : PLASIIC INDEX ~ = CRAB SAMPLE ~ = SPl SAMPL£ ~ = SHELBY TUfiE-PUSHED [~ : 2.5' I.D. SFOON SAMPLE 340~; ~/EiGH'J, 30' FALL DOWL ENGINEERS LOG OF BORING LOGGFD BT: JBH w-O. NO. · Di3964 FIGURE 4 I NI~J, IICIPALITY OF ANCHORAGE DEPARTMENT ft ~HEALTH AND ENVIRONMENTAL PRO'./'-~TION 825 L. Sl~eet, Anchorage, Alaska 99501 264~4720 SOILS LOG - PERCOLATION TEST PERCOLA]ION TEST PEREORMED FOR: . .t~(~ 'r ,./,/~YF~ DATE PERFORMEDi_ ,~ ~/,,,~- ~ ';~ LEGAL DESCRIPTION: Fb SLOPE SITE PLAN I I 181 $~ 20 L~ - GROUNDWATER S L NCOUNTERED? Y~ ~ E YES, AT WHAT Gross Net Depth to Net Reading Date Time Time Waler Drop PERCOLATION RATE Imlnu~eslinch) TEST RUN BETWEEN ~-~- ~ FT AND ~ FT CERTIFIED BY: ~'-, ~',1 ~f DATE:__ MUNICIPALITY OF ANCHORAGE DEPARTMEN~,r'~'i HEALTH AND ENVIRONMENTAL PRC/~iCTION SOILS LOG - PERCOLATION TEST PERCOLATION TEST PERFORMED FOR: E('.'"~ DATE PERFORMED:. LEGAL DESCRIPTION: SLOPE SITE PLAN r WAS GROUND WATER S ENCOUNTERED? ~g'~ {~ P E YES, AT WHAT )EPTH? /7 ' I I COMMENTS PERFORMED BY: 'T, PERCOLATION RATE .~0 ~'r) , minules/inch TEST RUN BE73NEEN --~ '~. FT AND 7 * FT CERTIFIED ~Y: ~ ~N/~y DATE: