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HomeMy WebLinkAboutNEAR POINT S12022Onsite File Near Point Lot 1B-1 &Lot 1B-2 #512022 ANDERSON ENGINEERING P.O. BOX 240773 ANCHORAGE, AK 99524 522-7773 677-7766 (FAX) December 9, 2013 Building Safety Division On Site Water and Wastewater Program 4700 Elmore Street Anchorage, AK 99507 Attention: Debbie Wockenfuss Subject: Nearpoint Subdivision — S12022-1 Septic System Feasibility Study Dear Debbie: The owner of Lot 1B, Near Point Subdivision intends to subdivide the lot into two lots. The two lots are fronted by Nearpoint Drive in the Stuckagain Heights area of Anchorage. The new subdivision will be known as Nearpoint Subdivision. Lot 113 is currently developed with a well and septic system constructed years ago under a permit from the State of Alaska Department of Environmental Conservation (ADEC). The Certificates to Operate both the well and septic system are attached for your review. The ground surface of the lots slopes to the west and northwest in the areas proposed for septic system development. The slope varies and ranges from 10% to 20%. No surface water is found in the area and sufficient area is available on each lot for the septic system reserve areas and the wells either in place or proposed for construction. Test holes were placed on the proposed lots in August of 2013. Water monitoring has been ongoing with readings last taken on October 15, 2013. At that time both test holes were dry. The purpose of the test holes was to assess the underlying soil conditions and to determine whether septic systems could be placed on the lots to serve single- family homes. The test holes were placed to depths of 14' with no bedrock or impermeable lenses of material encountered. The locations of the test holes were determined in the field for use in the future for developing septic systems. Percolation benches were constructed at various depths in the holes, but primarily 3.0' to 4.0' below the original ground surface. A percolation cavity was prepared to determine the absorptive characteristics of the soils encountered. The cavity was presoaked in accordance with Municipal requirements and a percolation test performed. The results of the tests are included in the attached documentation. In every case well graded gravel (GW) with varying degrees of sand was encountered to the bottom of each test hole. The percolation rate in this material ranged from 1.4 to 1.5 minutes per inch. All work was completed under the direction of technicians and engineers at Anderson Engineering. The results of the percolation tests and test hole logs are included as well Nearpoint Subdivision December 9, 2012 Page 2 as the water monitoring results. No groundwater was found in either test hole and none has been detected during the monitoring period. Based on our field study and water monitoring completed to date it appears both lots of the proposed subdivision are capable of supporting an onsite septic system and well. We hereby request your approval of the subdivision as designed with the septic systems and reserve area at the locations shown. Sincerely, Michael E. Anderson, P.E. Attachments 2 R ur Interval 2' LE B Well Location with top' Prolective Radius ,C ® Test Hole Designation and Location A 1 /1 NEAR POINT SUBDIVISION LOTS 1131 AND 1132 1\ p7 �C) WELL AND SEPTIC SYSTEM PLAN •I fM'C No. EE -.381 DERSOM -- �e Jam•.••.. T' S•'' 4 SCALE 1" = 100' MUNICIPALITY OF ANCHORAGE DEVELOPMENT SERVICES DEPARTMENT 4700 BRAGAW STREET ANCHORAGE, AK 99519-6650 DEPTH Irmo 1- 2 3 4 5- 6 7 8 9 10- 11 12- 13- 14- 15- 16- 17- 18- 19 - SOILS LOG - PERCOLATION TEST LEGAL DESCRIPTION: LOT IB -I, NEAR POINT SUBDIVISION PERFORMED FOR: JOE HENRI DATE: 8/14/2013 PROJECTNo.: PARCELID#: TECHNICIAN: M. ANDERSON TEST HOLE 1 OB/OG d O 4 d d e d a WELL GRADED GRAVEL WITH SAND a GW/GP e d _ a e BOH @ 14' SLOHE 2% 49th i1EL E. ANDERSON No. CE -4381 Pmlessioml SITE PLAN SEE SITE PLAN i WAS GROUND WATER ENCOUNTERED" IF YES @ WHAT DEPTH? .S DEPTH OF WATER AFTER MONITORING: Nur+: (EPL) 5% DATE OF MONITORING: 10, 3, 2013 DATE READING GROSS TIME (MINUTES) NET TIME (MINUTES) DEPTH TO (INCHES) NET DROP (INCHES) TEST HOLE PRESOAKED PRIOR TO TESTING: 8/16 1 8:13/8:23 10 .75"/7.50" 6.75" 2 8:24/8:34 10 .63"/7.38" 6.75" 3 8:35/8:45 10 .75"/7.38" 6.63" 4 8:46/8:56 10 .63"/7.38" 6.75" 5 8:57/9:07 10 .63"/7.38" 6.75" 6 9:08/9:18 10 .75"/7.50" 6.75" PERCOLATION RATE:1.5 (MIN/INCH) PERC. HOLE DIA. g (INCHES) TEST RUN BETWEEN: 3.0 FT. and 4.0 FT. COMMENTS: TEST HOLE PRE SOAKED PRIOR TO TEST. TEST PERFORMED BY ANDERSON ENGINEERING. 1, MICHAEL E. ANDERSON CERTIFY THAT THIS WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPLE GUIDELINES IN EFFECT ON THIS DATE: 8/23/13 MUNICIPALITY OF ANCHORAGE DEVELOPMENT SERVICES DEPARTMENT 4700 BRAGAW STREET ANCHORAGE, AK 99519-6650 DEPTH (feet) 1- 2 i - 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 SOILS LOG - PERCOLATION TEST LEGAL DESCRIPTION: LOT IB -2, NEAR POINT SUBDIVISION PERFORMED FOR: JOE HENRI DATE: 8/14/2013 PROJECTNo.: PARCEL ID#: TECHNICIAN: M. ANDERSON TEST HOLE 2 OB/OG a a e b D 4 a WELL GRADED GRAVEL WITH SAND a GW/GP a a a a BOH @ 14' SLOPE 2% 49th_•: MICHAEL E. ANDERSON NO. CE -4381 SI I L KLAN SFF SITE PLAN Y i 9 WAS GROUND WATER ENCOUNTERED? NO IF YES @ WHAT DEPTH? DEPTH OF WATER AFTER MONITORING'. NONE 5% DATE OF MONITORING'. 10/3/2013 DATE READING GROSS TIME (MINUTES) NET TIME (MINUTES) WATER D (INCHES) NET DROP I (INCHES) TEST HOLE PRESOAKED PRIOR TO TESTING: 8/16 1 10:02/10:12 10 .50"/7.75" 7.25" 2 10:13/10:23 10 .38"/7.50" 7.12" 3 10:24/10:44 10 .50"/7.62" 7.12" 4 10:45/10:55 10 .63"/7.75" 7.12" 5 10:56/11:06 10 .38"/7.50" 7.12" 6 11:07/11:17 10 .50"/7.62" 7.12" PERCOLATION RATE: 1.4 (MINANCH) PERC. HOLE DIA. 611 (INCHES) TEST RUN BETWEEN: 2.5 FT. and 3.5 FT. COMMENTS: TEST HOLE PRE SOAKED PRIOR TO TEST. TEST PERFORMED BY ANDERSON ENGINEERING. I, MICHAEL E. ANDERSON CERTIFY THAT THIS WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPLE GUIDELINES IN EFFECT ON THIS DATE: 8/23/13 ;/- I --� Municipality of Anchorage "` s,� P.O. Box 196650 • 4700 Elmore Road n i" Anchorage, Alaska 99519-6650 • (90 3437904 • Fax 907) 343-7997 71 -ax ( 'n 9 lli p.0 anent hftp:/Iwww.muni.org/Onsite Development Services Division On -Site Water and Wastewater Program **** VARIANCE/WAIVER REVIEW **** Waiver#: OSP141038 COSA#: Permit#: _ PID#: Legal Description: 512022-1 proposed Nearpoint Lot 113 Engineer: Anderson Engineering Applicant: Your request for a waiver of the required 10 feet horizontal separation from the existing absorption field for Lot 1B-2 to the proposed property line has been approved. The approved separation distance is 2.0 feet. In addition, the proposed subdivision septic reserved area is approved to be within 50' of an excessive slope. See the engineers letter and site plan. Any future upgrade to the on-site wastewater disposal system will require all separation distances be met or another approval from this department. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I Waiver is Granted: X Waiver is not Granted: Date: /( / Approved by: a Name of Revie r .......................................................... ................... **** VARIANCE/WAIVER REVIEW **** ANDERSON ENGINEERING P.O. BOX 240773 ANCHORAGE, AK 99524 522-7773 677.7766 (FAX) March 9, 2014 Municipality of Anchorage Development Services Department On -Site Water and Wastewater Program P.O. Box 196650 Anchorage, AK 99519-6650 Subject: Nearpoint Subdivision — S12022-1 Separation Distance Waiver Absorption Trench to Lot Line Dear On Site Services Engineer: The existing absorption trench on Lot 113-2 of the proposed Nearpoint Subdivision is located 2' from the southwest corner of Lot 1 B-1. A lot line waiver is therefore required. Soils on these lots are clean gravel with sand and silt with percolation rates less than 5 minutes per inch. Migration of effluent is unlikely. Placement of the trench in this area does not impact Lot 1 B-1 as the septic reserve area is more than 35' from the trench. In addition, the location of the trench does not impact the proposed location of the well on that lot. We recommend a waiver be issued allowing the trench to be 2' from the property line. Sincerely, n Michael E. Anderson, P.E. ANDERSON ENGINEERING P.O. BOX 240773 ANCHORAGE, AK 99524 522-7773 677-7766(FAX) March 7, 2014 Building Safety Division On Site Water and Wastewater Program 4700 Elmore Street Anchorage, AK 99507 Attention: Debbie Wockenfuss Subject: Nearpoint Subdivision — S12022-1 Septic System Feasibility Study Reserve Area to Slope Waiver Dear Debbie: Test holes placed in the proposed Nearpoint Subdivision for Lots 1 B1 and 1 B2 indicate clean well graded gravel with sand (GW/GP) and no groundwater. This material is typically considered excellent for the treatment and disposal of septic effluent. We have therefore established a 10,000 square foot reserve area for septic systems on each lot. Unfortunately a small portion of the reserve area on Lot 1 B1 is less than 50' from a break in grade greater than 25%. We are therefore requesting a waiver be granted allowing the reserve area to be at the location proposed. It is likely the septic absorption trench will be constructed more than 50' from the break in grade and further assessment can be made with the permit for development of the lot. The 25% slope from 2.5' above the invert of a distribution line of a trench constructed at the limit of the reserve area will not daylight. This is the worst case condition along the reserve area boundary. We therefore recommend the waiver be issued allowing the reserve area as shown on the attached drawing. Sincerely, Michael E. Anderson, P.E. :'• 49th S. MICHAEL E ANCER50N No CE -4781 1 < '1� AROF SS��i' in 955'rA J J J 2.5' �S� 950' J J J I J 945' J J J J J J 940' J J J J J 935' 930' 70' 65' 60' 55' 50' 45' 40' 35' 30' 25' 20' 15' 10' 5' 0' OF•A4 4 NEAR POINT SUBDIVISION v AN '"� *�; LOTS 1131 AND 1132 .49T" S• .. ....... A •• SLOPE ASSESSMENT • MKNAEL F. AND"' ,� fl •, JE -4381 �'� SECTION A — A ° ��j9�o'•... y' (WORST CASE) ANDERSON ENGINEERING P.O. BOX 240773 ANCHORAGE, AK 99524 522-7773 677-7766 (FAX) November 17, 2013 Municipality of Anchorage Building Safety Division On Site Water and Wastewater Program 4700 Elmore Street Anchorage, AK 99507 Attention: Debbie Wockenfuss Subject: Near Point Subdivision, S-12022-1 Water Availability Study Dear Debbie: We have collected information on several wells in the area of the proposed Near Point Subdivision to estimate the possible depths and production rates of wells to be constructed in the future on Lots 1 B1 and 1 B2. A well is currently in place on Lot 1 B2 and is producing sufficient water to serve the home on the lot. The lot is currently identified as Lot 1 B, Near Point Subdivision. Our study indicates all of the wells were constructed without the presence of bedrock and cased the entire depth. In all cases the well are shallow in comparison to most wells in the Anchorage area with the deepest at 197' and the shallowest at 120'. NEARPOINT SUBDIVISION WATER AVAILABILITY STUDY WELL LEGAL DESCRIPTION DEPTH PRODUCTION - LOG COMMENTS Hillside North #7,Block 2, Not Stated on Well Bedrock from 19' to Lot 6 400' Log 400'. Stuckagain Heights, Bedrock from 37' to Block 2, Lot 4C 128' 2.5 GPM 128'. Stuckagain Heights, Well Deepened from Block 2, Lot 5 595' 2.9 GPM 300' to Improve GPM Bedrock from 88' to Stuckagain Heights # 2 370'. Well Flow Test Block 1, Lot 8 1 129' 2.5-3 GPM 1997 - 2.0 GPM Neat: Point Subdivision November 17, 2013 Page 2 Stuckagain Heights # 2 Bedrock from 87' to Block 1, Lot 7 300' 2 GPM 300'. Stuckagain Heights # 2 Bedrock from 99' to Block 1, Lot 6 305' 4.5-5 GPM 305'. Stuckagain Heights # 2 Weathered Bedrock Block 1, Lot 5 124' 20 GPM from 115' to 124'. Bedrock from 46' to Near Point, Lot 1 B 355' 3.5 GPM 355'. Stuckagain Heights # 2 Well Flow Test 2009 — Block 2, Lot 2 1 294'+' No Well Log 2.6 GPM It is difficult from our study to predict the depth of the well to be constructed on Lot 1B1, Near Point Subdivision. Lots to the east are shallow to depths from 124' to 129' with production rates of 2.5 GPM to 20 GPM. Other wells in the area are up to 400' in depth and constructed primarily in bedrock. The production rates in these wells range from 2.9 to 3.0 GPM. We estimate the well on Lot 161 will range in depth from 160' to 350' and will produce approximately 2.0 GPM. The production rate will be sufficient to support a four bedroom home. Sincerely, ww"'.d E Com, Michael E. Anderson, P.E. Attachments VIA 41 � J 0 49th '• ••" MICHAEL EANDER30N. � n No cE-a}ai ff ��� E r 3 ur Interval 2 Well Location with 100' Protective Radius ® Test Hole Designation and Location 1 NEAR POINT SUBDIVISION LOTS 1131 AND 1132 A SUBDIVISION OF TRACT A, BLM LOT 40 (PLAT NO. 70-377), AND BLM LOT 33, LOCATED WITHIN THE NE 1/4, SECTION 22, T12N, R3W, S.M., ALASKA, ANCHORAGE RECORDING DISTRICT, THIRD JUDICIAL DISTRICT, AND CONTAINING 5.41 ACRES, MORE OR LESS. WELL AND SEPTIC SYSTEM PLAN SCALE 1" = 100' 11 t■ 2 4,.° 49th ! y . . * REL E. MIDERSON No. CE -4381