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Home My WebLink AboutBRUIN TERRACE S12506Onsite File p Engineer's Soils Report Bruin Terrace, Block 9, Lots 1 & 2 Proposed Subdivision of Bruin Park First Addition, Block 9, Tract A, Less NW Corner 512506 Municipality of Anchorage Prepared for: Hultquist Homes Inc. 12570 Old Seward Highway, Ste. 204 Anchorage, AK 99515 Prepared By: Pannone Engineering Services, LLC P.O.B. 100217 Anchorage, AK 99510 Submitted By: Steven R. Pannone, P.E. Principal, Civil Engineer October 7, 2019 Bruin Terrace, Block 9, Lots 1 & 2 Proposed Subdivision of Bruin Park First Addition, Block 9, Tract A, Less NW Corner Engineering Report Project Description This soils report is to identify the suitability of the soils on the lot being subdivided for an on-site septic system. This subdivision is part of Bruin Park First Addition, Block 9, Tract A, Less NW Corner. This report will detail the soils encountered during the soils investigation, existing topography, impact to surrounding wells and septic system and the suitability of the soils encountered for the use of an on-site wastewater disposal system and water supply system. The two (2) proposed lots will be 1.13 and 1.01 acres in size respectively. The lots are undeveloped, with the exception of an existing well. We were unable to locate a well log for the subject well. Soils Investigation Pannone Engineering Services performed a soils investigation on July 12, 2019, in the area that the subdivided lots will be located. The test pits were excavated by the White Raven Development and were excavated to the maximum extent of the excavator. The test pits revealed a variety of soils. We encountered in Test Hole one (TH-1) a layer of organics to a depth of one point five feet (1.5'), underlain with fine sand with silt to a depth of eighteen feet (18.0'). The layer of sand and gravel was found to have a percolation rate of 45 minutes per inch. Based on the percolation rate and the appearance of the soil an application rate of 0.45 gallons per day/ square foot may be used as an application rate with a trench type disposal field. We did not encounter bedrock or impermeable soils in the Test Hole one (TH-1). Permafrost was not encountered in the test pit nor is it suspected in this area. Groundwater was not encountered to a depth of eighteen feet (18.0') during excavation or after the 7 -day monitoring period or during October high groundwater. We encountered in Test Hole two (TH-2) a layer of organics to a depth of one point five feet (15), underlain with fine silty sand gravel to a depth of fourteen feet (14.0'). The layer of fine silty sand and gravel was found to have a percolation rate of 18.0 minutes per inch. The SM layer was underlain by a layer of SP (sand) from fourteen feet (14.0') to a depth of twenty-one feet (21.0'). A sieve analysis was performed on the sand and it was found to have 96% passing a #4 sieve and only 6% passing a #40 sieve. Based on the percolation rate and the appearance Bruin Terrace, Block 9, Lots 1 & 2 Proposed Subdivision of Bruin Park First Addition, Block 9, Tract A, Less NW Corner of the soil an application rate of 0.6 gallon per day/ square foot may be used as an application rate. We did not encounter bedrock or impermeable soils in the Test Hole Two (TH-2). Permafrost was not encountered in the test pit nor is it suspected in this area. Groundwater was not encountered to a depth of twenty-one feet (21.0') during excavation or after the 7 -day monitoring period or during October high groundwater. Topography The proposed Subdivision is located on the lower portion of Rabbit Creek Road and is surrounded by developed lots. The slope is generally from the northeast to the southwest. The subject area slopes at approximately 5% with a slope of about 20%-25% just downhill of the lot line and a slope of about 10% below. The area surrounding the test holes and the septic reserve areas slopes at about 5%. There is an area on the southeast corner of Lot 2 within the septic reserve area that is shown on the surveyors drawing to slope between 25% and 46%. In the area of this slope the steep -slope provision in the 15.65 code should be used in the design of the drain field. No slopes exceeding 46% exist within 100' of the proposed septic reserve area. Existing water and wastewater systems The proposed subdivision is located in the triangle formed by the intersection of Forest Road and Reader Road, in Anchorage. There is an existing well that was installed at an unknown time. The current status of the well is unknown. The existing water supply systems on the surrounding lots to the west, north, and east are private wells and have a 100 foot protective radius around them (i.e. a new wastewater disposal system may not be located less than 100 feet from these private water wells.) The lots to the south are served by AWWU. Water Availability This subdivision will be located, on the lower Anchorage hillside where water is readily available. The surrounding wells are typically between 100 and 250 feet deep. The static water levels range between 55 and 75 feet deep. The existing well flow data that was available showed that the wells with record data could produce approximately at least 5 gallons per minute. Based on the record research and field data we collected, there appears to be adequate water available for the proposed subdivision without affecting the surrounding wells. The well will be approximately 200 feet deep or less and will likely produce at least 5 gallons a minute. Installing these wells will not affect the production of water wells on the surrounding property. Bruin Terrace, Block 9, Lots 1 & 2 Proposed Subdivision of Bruin Park First Addition, Block 9, Tract A, Less NW Corner Legal Description Well Depth Static Water Level Production Nitrates Freeman, Lot 8 Unk (55+) 55 6.8+ gpm 0.5 (6/26/2001) Freeman, Lot 4 236 75 5.8+ gpm 0.382 (3/13/2014) Bruin Park First Addn, B9, Tr A, NW Corner 113 56 5.4+ gpm ND (5/6/2013) Bruin Park, Block 4, Lot 13 99 72 10 gpm ND (7/21/1987) Bruin Park, Block 5, Lot 14 61+ 61 5.7+ gpm ND (3/12/2018) Bruin Park, Block 4, Lot 14 Unk 67+ 62 3.3+ ND (5/11/2007) Bruin Park, Block 5, Lot 13 181 92 5.1 0.50 (8/17/2000) Surface water There are no wetlands or surface water within 100' of this subdivision. Engineering Criteria The soils in this area are typically organics underlain by silty sand and gravel. PES conducted a percolation test on the proposed lots and found percolation rates as shown above, and on the soils logs. The soils encountered in this area are generally medium percolating soils (around 18-45 mpi). An application rate of 0.45 gpd/sf should be used for the design of a wastewater disposal system on the proposed lot 1 and an application rate of 0.60 gpd/sf should be used for the design of a wastewater disposal system on the proposed lot 2 as shown on the soils logs and in this report. Groundwater was not encountered on this subdivision. Site Information For a subdivision, a site plan stamped by an engineer must show specific areas for the septic system based on the observed percolation rate and Title 15.65.180, Table 2. These areas must meet all set.back requirements of Title 15.65. According to Table 2, and area of 10,000 sf must be shown for areas with a percolation rate of 1-5 MPI, an area of 12,000 sf must be shown for areas with a percolation rate of 5-12 MPI, and an area of 14,000 sf must be shown for areas with a percolation rate of 12-24 MPI. The attached site plan shows the reserve areas per these requirements. Bruin Terrace, Block 9, Lots 1 & 2 Proposed Subdivision of Bruin Park First Addition, Block 9, Tract A, Less NW Corner The Municipality of Anchorage (Moa) Regulations (15.65) govern for single-family homes. These regulations require a minimum of four (4) feet vertical separation between the bottom of a soil absorption system and ground water for a conventional wastewater disposal system, six feet (6') to bedrock or other impermeable layers (tight silts and clays with a percolation rate greater than 120 minutes per inch) and must be located greater than 100 feet horizontally from any surface water (Creeks and ponds). Additionally, the accepting soils must have a percolation rate of less than 120 minutes per inch. A lot must have room for a primary and reserve soil absorption system. - -SF I P A Rl A WELL (P 0l 16 -OTS SERVED BY AINMU 14 NO WELL OR SEPTICS -SEPTIC AREA WELL 15 -7- �R 4" ------ --- 13 12 Uj 16,000 S F. f .0 < LaJ. RESERVE AREA 3 W L 13 . vi_l`l_.�.'. - -1.1 Li WELL 14,000� S.F. 18 14 /- TIC A WELL (E IS Vv- - -SF I P A Rl A WELL (P 0l 16 -OTS SERVED BY AINMU NO WELL OR SEPTICS WELL 15 -7- LOT 2 Uj 16,000 S F. .0 < LaJ. RESERVE AREA 3 . vi_l`l_.�.'. - -1.1 Li 14,000� S.F. 3; RESERVE ARE < TI -i --- 2 D 0 UTI_ FY EAC-t-Mn.N I LOTS SERVED BY AWWU NO WELL OR SEPTICS r -A Ww______w_-____w- w W_ ... . ........ MONA AVENUE ss — ss $3 ss — ss — ss -- ss --o— ss ss ss ss ss ss - - - - - - - - - - - - - - — - — - — - — - — - — - NOTES: PAMONE ENG SVC, LLC ........ 1) E/21 ,,'200 1 SOILS Fes' P.O. BOX 100217 ANCHORAGE, AK 99510 III PHONE (907) 272-8218 FAX (907) 272-8211 :49TH .... .. .. ....... iP.0� NO 2 BRUIN TERRACE, BLOCK 9, LOTS I & i . . . . . ........ 1 01-6-112-18 ---------- SUBDIVISION OF BRUIN PARK 1S1** ADDN, TR A e PERMIT NO. HULTQUIST �IOIVIES M_-. CE 8149 S12506 FOREST DRIVE jSheet PI -AN ANCHORAGEL-, AK F r. RESERVE ARE < TI -i --- 2 D 0 UTI_ FY EAC-t-Mn.N I LOTS SERVED BY AWWU NO WELL OR SEPTICS r -A Ww______w_-____w- w W_ ... . ........ MONA AVENUE ss — ss $3 ss — ss — ss -- ss --o— ss ss ss ss ss ss - - - - - - - - - - - - - - — - — - — - — - — - — - NOTES: PAMONE ENG SVC, LLC ........ 1) E/21 ,,'200 1 SOILS Fes' P.O. BOX 100217 ANCHORAGE, AK 99510 III PHONE (907) 272-8218 FAX (907) 272-8211 :49TH .... .. .. ....... iP.0� NO 2 BRUIN TERRACE, BLOCK 9, LOTS I & i . . . . . ........ 1 01-6-112-18 ---------- SUBDIVISION OF BRUIN PARK 1S1** ADDN, TR A e PERMIT NO. HULTQUIST �IOIVIES M_-. CE 8149 S12506 FOREST DRIVE jSheet PI -AN ANCHORAGEL-, AK F TEST HOLE 1 OR ORGANICS 1 2 3 4 5 6 7 FINE SILTY SM SAND 8 9 10 11 12 13 14 15 16 17 18 BOH DATE PERFORMED: 7/12/19 SOILS LOG - PERCOLATION TEST SLOPE X TH WAS GROUND WATER ENCOUNTERED? N IF YES, AT WHAT DEPTH? -DRY DEPTH TO WATER AFTER MONITORING? -DRY DATE: 7/19/19 DEPTH TO WATER AFTER MONITORING? -DRY DATE: 10/1/19 .SITE PLAN 1 \iy LOT 2 —2 TH —1 TH SLOPE TH X READING DATE CLOCK NETTIME WATERTIME LEVEL READING NETDROP 1 7/12/19 8:30 -- 6.39 -- 2 9:00 30 MIN 7.30 0.91 3 9:00 __ 6.39 -- 4 9:30 30 MIN 7.06 0.67 5 9:30 --- 6.39 -- 6 10:00 1 30 MIN 7.05 0.66 PEROLATION RATE 45_ (min/inch) PERC HOLE DIAMETER 6 inches TEST RUN BETWEEN 3 FT AND 4 FT COMMENTS: Test hole excavated by WHITE RAVEN DEVELOPMENT. PERFORMED BY: Dan Moran. I CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDLINES IN EFFECT ON THE DATE OF THIS TEST. NOTES: 7- T � .�-o'�•a SOILS REPORT PAMONE ENG SVC, LLC OF Q� �� DO/7/2019 P.O. BOX 102954 ANCHORAGE, AK 99510 '�� ' ' ' ' ' 'qcS' �t PHONE (907) 272-8218 FAX (907) 272-8211 �Gj�P 'Fy}� Scale ��•: �� NTS BRUIN TERRACE, BLOCK 9, LOTS 1 & 2 0 P.I.D. NO SUBDIVISION OF BRUIN PARK 1ST ADDN, T "Ste'ven 'R: 'Pannone HULTQUIST HOMES INC. ��CE 8149 PERMIT N0 S125�' FOREST DRIVE � Vis."• •'•�"'� SOILS LOG ANCHORAGE, AK ��/'ROFESSSN� �— sheet �0�0 2 OF 3 TEST HOLE 2 1 2 3 4 5 ORGANICS 6 7 SM/ FINE SILTY GM SAND WITH 8 SOME GRAVEL 9 10 11 12 13 14 15 16 17 SP SAND 18 19 20 21 ' ' BOH DATE PERFORMED: 7/12/19 SOILS LOG - PERCOLATION TEST St4�E PLAN � � 3 3 R- I \ . ...LOT 1 \ LOT 2 TH-1 TH-2 SLOPE WAS GROUND WATER ENCOUNTERED? N IF YES, AT WHAT DEPTH? -DRY DEPTH TO WATER AFTER MONITORING? -DRY DATE: 7/19/19 DEPTH TO WATER AFTER MONITORING? -DRY DATE: 10/1/19 SLOPE TH X READING DATE CLOCK NET TIME WATERTIME LEVEL READING NET DROP 1 7/12/19 11:45 --- 6.65 --- 2 12:15 30 MIN 8.25 1.60 3 12:15 -- 6.65 --- a 1 12:45 1 30 MIN 1 8.31 1 1.66 512.45 — 6.65 -- 6 1:15 MIN 30 8.28 1.63 PEROLATION RATE 18 (min/inch) PERC HOLE DIAMETER 6 inches TEST RUN BETWEEN 3 FT AND 4 FT COMMENTS: Test hole excavated bV WHITE RAVEN DEVELOPMENT. PERFORMED BY: Dan Moran. I CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDLINES IN EFFECT ON THE DATE OF THIS TEST. NOTES: LLC T � �•�`� SOILS REPORT PANNONE ENG SVC, LLC ��>� Dote P.O. BOX 102954 ANCHORAGE, AK 99510 'C� OF A�,Qs�,, 10/7/2019 PHONE (907) 272-8218 FAX (907) 272-8211 d�oj�p �y�� Scale :+dO NTS BRUIN TERRACE, BLOCK 9, LOTS 1 & 2 . . P.J.D. ils .112°$ SUBDIVISION OF BRUIN PARK 1ST ADDN, TR S'tev'en •R. Pon none ' HULTQUIST HOMES INC. CE 8149 PERMIT NO. FOREST DRIVE ��csjFp• �s'� Sheet506 SOILS LOG ANCHORAGE, AK �d F�PROFESSOO 3 OF 3 040.002 Client: Pannone Engineering Services Project: Bruin Terrace Block 9 Lot 2 Date: ,luly 14; 2019 Crowther Associates Particle Size Distribution Table (percent passing sieve size) Sample Source Block 9 Lot 2 Sieve Size Percent Finer Percent Finer Percent Finer Percent Finer 3 inch 100 1-1/2 inch 100 3/4 inch 100 #4 96 #10 93 #40 6 #100 4 #200 3 0.02 mm Classification Sand (SP) 1632 Bellevue Circle /Anchorage, Alaska 99515 Telephone (907) 349-2195/E )?rail: croi>>then alaska.net