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HomeMy WebLinkAboutRevised - OWTS Design Report 03.04.2020i REVISED PERCOLATION TEST AND ON-SITE WASTEWATER TREATMENT SYSTEM DESIGN 886 MESA DRIVE RIFLE, CO Prepared For: Pinnacle Homes Prepared By: CApsT0NE ENTERPRISES WEST, LLC GEOTECHNICAL AND MINING ENGINEERING TESTING AND INSPECTION SERVICES 618 PARTEE DRIVE GRAND JUNCTION, CO 81504 PHONE (970) 250-3331 March 4, 2020 Job No. 4439 CAPSTONE ENTERPRISES WEST, LLC GEOTECHNICAL AND MINING ENGINEERING TESTING AND INSPECTION SERVICES March JOB # 4439 Attn: 618 PARTEE DRIVE GRAND JUNCTION, CO 81504 PHONE (970) 250-3331 Pinnacle Homes 2755 North Ave #105 Grand Junction, CO 81501 Subject: Percolation Test and On -Site Wastewater Treatment System Design for 886 Mesa Drive Rifle, CO 81650 At your request Capstone Enterprises West, LLC directed and observed the excavation of the test pit to evaluate onsite soils for design of an additional On -Site Wastewater Treatment System (OWTS). The suitability of soils was evaluated by soil classification as prescribed by the Garfield County Health Department, and confirm by performing a percolation test, The results of investigation and the percolation test with the OWTS design are presented in this report. If you have any questions, or if we may be of further assistance, please do not hesitate to contact us. Respectfully Submitted: CAPSTONE ENTERPRISES WEST, LLC Martin W. Chenoweth, PE Registered Professional Engineer MWC CAPSTONE ENTERPRISES WEST, LLC 2 JOB NUMBER 4439 PERCOLATION TEST Per your request, Capstone Enterprises West, LLC performed a percolation test for your 4 bedroom residence. The test was performed as prescribed by the Garfield County Department of Public Works' regulations updated on July 2nd, 2018. The property is located in the southeast quarter of Section 24 Township 5S Range 93W. The following images show the site location as well as the location of the profile hole and perc holes. "P"'"'"11,111C44W G --Site Location 44110-417,k..ippr # ,t. . ' „• .11Nr *el lkipst: c or tti lkir , 1 • * - ' ' II ' t I.4 - 2,2,24 y. 129] 4403001 PH•2 PH -1 TP -1 o PH -3 TP -2 CAPSTONE ENTERPRISES WEST, LLC 3 JOB NUMBER 4439 SITE DESCRIPTION The property is a 3.73 acre parcel that was undisturbed grazing land until the development of the subdivision. The eastern half of the property generally flat with a gentle slope to the east of "2%. Two test pits were excavated to determine the soil types at this location. The profile hole was excavated to a depth of 8 feet. No free water was encountered to that depth, nor was there evidence of a seasonal high water table. The geologic log of the profile hole is presented below. TP -1 1101 46004 4046 00 o 0000400 000406 41101 I/4°0:1:01;i 00000 100004 011.10001 11111111 10 TEST PIT GEOLOGY TP -2 Topsoil- Silt wf Roots Reddish Tan Silt Firm Dry Clayey Silt PI = 13 Dry Density= 117.1 pa Moisture = 11.5% 10 00100 0 44 10401 4000 11111111 0000000 1004000 11111111 Topsoil- wf Roots Reddish -Tan Silt Brown Silty Clay PI = 10 Dry Density = 100.4 pd Moisture = 7.6% The soils at the site were consistent between the two excavations. The soils that will utilized for the absorption bed are a firm, very fine grain clayey silt (GR) with moderate structure (2). To confirm this classification a abbreviated percolation test was performed. A total of 3 perk holes (PH -1, PH -2 and PH -3) were dug to evaluate the percolation rates. All holes were moisture conditioned as prescribed by Garfield County Health Department. And the percolation test was performed 24 hours after the initial conditioning. The results for the percolation test are presented on the following page. CAPSTONE ENTERPRISES WEST, LLC 4 JOB NUMBER 4439 HOLE ID & DEPTH ELAPSED TIME min. WATER LEVEL in. WATER DROP in. PERCOLATION RATE min./in. PH -1 0.0 0.00 0.00 20 - 36" 30.0 0.50 0.50 60.0 0.75 0.75 90.0 1.00 1.00 120.0 1.38 1.38 80.00 PH -2 0.0 0.00 0.00 36 - 52" 30.0 0.75 0.75 60.0 1.25 1.25 90.0 1.63 1.63 120.0 2.00 2.00 80.00 PH -3 0.0 0.00 0.00 0 - 16" 30.0 2.63 2.63 60.0 4.75 4.75 90.0 7.13 7.13 120.0 8.38 8.38 24.00 AVERAGE 61.3 20.00 18.00 16.00 14.00 6.00 4.00 2.00 Water Drop Vs. Elapsed Time SPH 1 t PH 2 -4,- PH -3 Limits 0.00 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Elapsed Time (minutes) Job No.4439 886 Mesa Drive CAPSTONE ENTERPRISES WEST, LLC 5 JOB NUMBER 4439 The average of the for the last 30 minutes of the two-hour test was 61.3 minutes per inch. However, the 80 minutes per inch for the 2 lower Perc Holes was judged to be governing layer. Capstone believes that the un -official percolation test confirms the classification as a type 4 soil. Based Garfield County Guidelines, the system has been designed based on a Long Term Acceptance Rate (LTAR) 0.20. Table 10 -term Acceptance Ratea by Soil Texture, Soil Structure, Percolation Rate and Treatment Level Soil Type, Texture, Structure and Percolation Rate Range Lang -tent Acceptance Rate (LTAR); Gallons per day per square foot Soil Type USDA Soil Texture USDA Soil Structure- Shape USDA Soll Structure- Grade Percolation Rate (MPI) Treatment Level 1' Treatment Level 2.1 Treatment Level 2N' Treatment Level 3' Treatment Level 3N'' 0 Sall Type 1 with more then 35% Rock (r2mm); Soll Types 2-5 with more than 5096 Rode (r2mm) 0 (Slagle Grain) c 5 Mi tum 3--tofo ott deep unlined sand filter required' Minimum 2 tod deep unlined nand Hier required' 1 Sand, Loamy Sand - 3 5-15 0.60 1.25 1.23 1.40 1.40 2 Sandy Loam, Loam, Silt Loam PR (Prismatic) BK (Blocky) GR (Granular) 2 (Moderate) 3 (Strong) 16-25 0.60 0.90 0.60 1.00 1.00 2A Sandy Loam, Loam, Silt Loam0 PR GRBK, (none) 1 (Weak) Massive 28.40 0.50 0.70 0.70 0.60 0.80 3 Sandy Clay Loam, Clay Loam. Silty Clay Loam PR, BK, GR 2 3 41-60 0.35 0.50 0.50 0.60 0.60 Sandy Clay Loem, Clay Loam, Sly Clay Loam PR. BK, OR 1 Mes ve 01.75 0.30 0.40 0.40 0.50 0.00 4 SendyClay, Cloy , Gley Cloy PR. BRK, 2, 3 76.00 0.20 0.30 0.30 0.30 0.30 4A &Indy Clay, Clay Slay Clay PR BK GR 0 Massive 91-120 0.15 0.20 0.20 0.20 0.20 5 Soll Types 2.4A Platy 1, 2, 3 121+ 0.10 0.15 0.16 0.16 0.15 NOTE: Shaded areas require system design by a professicna engineer. 1 Treatment levels are defined in Table 6-3. 2 Unlined send fitters in these soil types shall provide pathogen removal. Design shall Conform to section 11.C.2.c, Unlined Sand Filters Higher lorg-term acceptance rates for Treatment Level 3N may be allowed for CW15 required to nava a discharge permit, if the capability of the design to achieve a higher long-term acceptance rate can be substantiated_ CAPSTONE ENTERPRISES WEST, LLC 6 JOB NUMBER 4439 WASTE WATER TREATMENT SYSTEM DESIGN The proposed residence for this site is planned to be a four (4) bedroom dwelling. Using the guidelines in the Garfield County On -Site Wastewater Treatment System Regulations, Effective Date: July 2, 2018 (OWTSR) the following sewage flow calculations were prepared: 4 Bedroom Residence Table 6-1 Q =525 gal. /day Once again using the OWTSR the absorption area was calculated. Where: A = Absorption Area in square feet Q = Design Flow of sewage in gallons/day LTAR = Long Term Acceptance Rate (From Table 10-1, OWTSR) Q 525 AREA= _=2,625sgft LTAR 0.20 Base Area Size Adjustment Factors Gravity Bed Chambers 2,625 sq. ft. 1.2 0.7 Total Absorption Bed Area 2,205 sq. ft. To obtain 2,205 square feet of absorption area two 12 foot wide beds 92 feet long (92 Chambers plus end caps) are required. A two compartment 1,250 -gallon septic tank is required for this system. Capstone recommends that a concrete tank approved by Garfield County be used for this system. Detailed plans are attached. The following table shows the distance pertinent to this system. CAPSTONE ENTERPRISES WEST, LLC 7 JOB NUMBER 4439 FEATURE DISTANCE FROM FEATURE Septic Tank & Tank Discharge Lines Absorption Bed Potable Water Well or spring 50 100 Potable water supply 10 25 Cistern 50 50 Non-potable Water Lined/piped irrigation Ditch 10 10 Flood irrigated field 10 25 Lake, water course, un-lined ditch,stream or wetlands 50 50 Intermittent irrigation ditch, storm drain or dry well. 10 25 Structures Structure w/ Crawlspace 5 20 Structure w/o Crawlspace 5 10 Misc. Property line. 10 10 Trees 10 15 Pool (water's edge) 10 20 Geo-thermal lines. 10 25 Dry gulch, cut bank or fill area from crest 10 25 Septic Tank 6 Garfield requires that every OWTS be inspected by the to receive an occupancy clearance for the new construction. Please make arrangements with the engineer to schedule an inspection once the system is installed but before the bed is backfilled. The installer is responsible to maintain the appropriate offsets and grades. Any deviation from the plans must be approved by the engineer. The recommendations contained in this report are made in a manner consistent with the level of care and skill used by geotechnical engineers practicing in this area at this time. This report contains no warranty either express or implied. CAPSTONE ENTERPRISES WEST, LLC 8 JOB NUMBER 4439 I 70 rn CL CO 3 3 O 0 rn 70 0 0 n n woo lsaMaumsdeo u©unJew c) =za o o- z M cm n '0o� orn N Ol ' o nA 0 < 04 co 0) ON 10]CO2id ON _LHS 0 m MON3HO M W 0 rn W n r rn — OD a)� mmcw 0W0 o>m ppm ><D pmr O > Z O m m Z v W a O O (r) Cn ,!¢ L .Z6 IRA %S'0= aS9 AO SdO1S (n(no0-1--0-Imz r r m>> O r o OOozzm,,GH mmz© II DU) OOmH�H O H�Hm.z m> m 3 O T 0z°i-1 O V Lo > II V r r r 11 bo 1 o N ((fl (p W O O 01 O O N O O O U) Inspection Ports Capped 12" Above Ground UNCOMPACTED SOIL CAP (MOUND 5%) Max Depth 4.0 Ft Distribution Box FILTER FABRIC OVER CHAMBERS 4" PERFORATED DISTRIBUTION LINES ENTIRE LENGTH OF BED PERFORATIONS DOWN NOTES ELEVATION FOR OWTS TOF = 100.0 PIPE @ STEMWALL = 98.0 TANK INLET = 97.1 TANK OUTLET = 96.85 BED INLET 96.51 SLOPE TO TANK >= 2% SLOPE TO BED >= 1% SLOPE OF BED =0.2% Inspection Ports Distribution Box BED IN SECTION rn NK • Distribution Box • N V 92 0 EACH BED MADE UP OF 92 QUICK -4 INFILTRATOR CHAMBERS (OR EQUIV.) BED TO SLOPE DOWN 0.2% FROM D -BOX Inspection Ports REV. DATE DESCRIPTION BY CK 1 3/4/2020 Added Elevation Notes Referenced off TOF MWC CAPSTONE ENTERPRISES WEST, LLC 618 PARTEE DRIVE GRAND JUNCTION, CO 81504 PHONE (970) 250-3331 martin@capstonewest.com OWTS CONSTRUCTION DETAILS 886 MESA DRIVE RIFLE, COLORADO BY M W CHENOWETH DATE 8/13/19 SCALE NTS PROJECT Na 4439 SHEET NO. 20F2