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HomeMy WebLinkAboutEngineer's Report 08.20.2020P.O. Box 1908 1011 Grand Avenue Glenwood Springs, CO 81602 elZANCANELLA ANA 4550CI4TE5, INC. / ENGINEERING CONSULTANTS August 20, 2020 Mr. Ted White Garfield County Environmental Health 108 8th Street, Suite 401 Glenwood Springs, CO 81601 Re: Cattle Creek Commercial Center, Building "Q", OWTS [Z&A: 97404.01] Mr. White: (970) 945-5700 (970) 945-1253 Fax This report is regarding the proposed OWTS to be located on Parcel C of the Midland Subdivision, aka Garfield County Parcel Number 239318100359. Investigations and design were performed by personnel from HP Geotech and Zancanella & Associates. Various geotechnical investigations were performed by HP Kumar on 2/25/1999 (job no. 198 819), 2/15/2018 (project no. 17-7-858) , and on 10/25/2019 (project no. 17-7-858.A) and by Zancanella in 2000, on 11/17/2017, and on 4/13/2020. General soil boring Togs are included in the HP Kumar Reports, the most recent from 2018, and the proposed infiltration area lies between Borings 10 and 11 of that report. Detailed information for the proposed site of the OWTS was obtained by Zancanella on the above noted dates and included profile excavations, percolation testing, and verification of soil type. The purpose of the 2020 evaluation was to verify that the soils expected from the borings were present in the actual location of the proposed bed. The results of the tactile evaluation indicated that the soils were more silty than clayey, which agreed with the "Summary of Laboratory Test Results" (attached to this letter). Thus, indicating sandy loam or silt loam and an 0.6 LTAR. This also agrees in general with the various percolation tests in the area. See the infiltrative area calculations attached to this report and included on Sheet 4 of the building permit (civil) drawings. Specific setback distances of interest include the distance to a well on the northwest area of the property which is in excess of 600 feet from the absorptions area, and the (minimum) distance from the property line for the absorption area which is in excess of 30 feet. Other items included in Tables 7-1 and 7-2 of the County OWTS Regulations can be derived from the drawings. Garco Env. Health August 20, 2020 Page 2 A drawing showing the location of the proposed OWTS on the parcel, an elevation benchmark, and other pertinent information is attached to this report. Other design and layout information can be found on Sheets 1, 3, and 4 of the building permit (civil) drawings. No limiting layers or features, or groundwater were encountered in any of the exploratory excavations. The proposed site is far above any established 100 year flood plain. The only construction/operational issue foreseen would be some possible settlement due to hydrocompactive soils. However, the native material has a fair amount of included rock and the sand bed is proposed to be set on top of pit run material. The native rock material and the pit run material will combine to disperse the wastewater flows which will mitigate any tendency toward piping which could lead to some settlement, and in addition, the pit run material will act as bridging to support the bed and mitigate settlement. The fact that the bed will be pressure dosed and thus will evenly disperse the wastewater will further reduce the possibility of excessive flow to any one area. The design parameters for the pumping system are shown in the attached calculation sheet based on the Orenco Pump Select software. If you have any questions, or need additional information, please contact our office at (970) 945-5700. Very truly yours, Zancanella & Associates Inc. 7 &el Timothy P. Beck, P.E. cc: Wayne Rudd Eric Rudd Chris Jung Z:\97000's\97404 Rudd, Wayne\97404.01 Cattle Creek\2019\Bldg Q ISDS\ISDS Report letter -SW bench.doc 0 100 SeA N hod / / /' i /' / ' GARFIELD COUNTY PARCEL NUMBER: 239318100359 C WIN .113 n .a p owns PROPERTY LOCATION MAP Wayne Rudd Cattle Creek Commercial Center I e�n le"Az• IMiez J lJNCAM1Euw ,atl 11xmr.ve aomm ol 11 ..r.•.y. PR nn »� 1,11 o 4.4 TO EXISTING COMMERCIAL BUILDING Jr- 50 0 50 100 APPROXIMATE SCALE —FEET NOTE: BORINGS 1 —4 DRILLED AT PROPOSED BUILDING K TO HOUSE SITES (BORINGS 11 AND 12) 17-7-858 H-P KUMAR LOCATION OF EXPLORATORY BORINGS Fig. 1 TO COMMERCIAL BUILDING SITES (BORINGS 5-10) ti 30 0 30 60 APPROXIMATE SCALE —FEET 17-7-858 H-PKCUMAR LOCATION OF EXPLORATORY BORINGS Fig. 1 A TABLE 1 SUMMARY OF LABORATORY TEST RESULTS Project No. 17-7-858 Paae3of3 SAMPLE LOCATION NATURAL MOISTURE CONTENT (%) NATURAL DRY DENSITY (poi) GRADATION PERCENT PASSING NO.200 SIEVE ATTERBERG LIMITS UNCONFINED COMPRESSIVE STRENGTH 1PSF) SOIL TYPE BORING DEPTH (ft) GRAVEL (%) SAND lob) LIQUID LIMIT (%) PLASTIC INDEX 1%) 9 21/2 3.1 100 Gypsiferous Silty Sand with Gravel 5 3.7 97 39 Gypsiferous Silty Sand with Gravel 15 5.6 111 Silty Sand with Gravel 10 21/2 9.3 37 31 32 Silty Clayey Sand and Gravel 10 11.7 42 26 32 Silty Sand and Gravel 20 22.5 70 Silty Sandy Clay with Gypsum 11 10 11.3 23 28 49 Very Silty Clayey Sand and Gravel 25 2.9 3 65 32 Silty Clayey Sand with Gravel 45 4.9 23 46 31 Silty Clayey Sand with Gravel 12 5 3.5 101 34 Silty Clayey Sand 10 2.4 114 Silty Clayey Sand with Gravel and Gypsum 15 12.6 90 Silty Sandy Clay 20 3.9 104 47 Very Silty Clayey Sand 1. NEW ISDS FOR BUILDING Q - AND FUTURE BUILDINGS TO NORTH: A. THE NEW ISDS WILL BE BASED ON AN AVERAGE DAILY FLOW OF 3.4 GALLONS PER DAY PER 100 SQ. FT. AND FOR A TOTAL OF 1920 GALLONS PER DAY TO ALLOW FOR FUTURE BUILDINGS TO THE SOUTH. B. THE SEPTIC TANK FOR BUILDING Q WILL BE 1000 GALLON (MINIMUM) AND WILL BE LOCATED ADJACENT TO THE BUILDING. THE ABSORPTION AREA FOR BUILDING Q WILL BE LOCATED AS SHOWN ON SHEET 2 OF THESE PLANS. ABSORPTION AREA WILL BE SIZED FOR AN AVERAGE DAILY FLOW OF 1920 GALLONS PER DAY WHICH WOULD BE EQUIVALENT TO 120,000 SQUARE FEET OF BUILDING. BUILDING Q IS 3200 SQUARE FEET, THIS LEAVES 116,800 SQUARE FEET IN RESERVE (OR AN EQUIVALENT USAGE OR FLOW). ALTERNATIVELY, 1920 GALLONS/DAY - 52 GALLONS/DAY = 1868 GALLONS/DAY IN RESERVE. 2. SOIL IS TYPICALLY SILTY SAND, PER TABLE 1-SUMMARY OF LABORATORY TEST RESULTS, FOR BORINGS 10 AND 11, IN ATTACHED GEOTECHNICAL REPORT (HP-KUMAR GEOTECH - PROJECT NO. 17-7-858, 15 FEB 2018, AND SITE SPECIFIC TACTILE TESTING. (ON -SITE VERIFICATION OF SOILS BY ENGINEER WAS PERFORMED ON 13 MAR 2020, AND ADDITIONAL VERIFICATION IS REQUIRED DURING EXCAVATION.) MINIMUM FOOTPRINT AREA OF GRAVEL TO SAND INTERFACE: (1920 GAL/DAY-SQ.FT) * (DAY-SQ.FT./0.8 GAL) = 2400 SQ. FT. MINIMUM FOOTPRINT AREA OF SAND TO INFILTRATIVE SURFACE INTERFACE: (1920 GAL/DAY-SQ.FT) * (DAY-SQ.FT./0.6 GAL) = 3200 SQ. FT. SEE PLAN AND CROSS SECTION OF BED ON DRAWING FOR DETAILS. Pump Selection for a Pressurized System - Commerical Project cattle ck sw bench Parameters Discharge Assembly Size Transport Length Transport Pipe Class Transport Line Size Distributing Valve Model Max Elevation Lift Manifold Length Manifold Pipe Class Manifold Pipe Size Number of Laterals per Cell Lateral Length Lateral Pipe Class Lateral Pipe Size Orifice Size Orifice Spacing Residual Head Flow Meter 'Add -on' Friction Losses Calculations 2.00 inches 150 feet 40 2.00 inches None 5 feet 16 feet 40 2.00 inches 12 50 feet 40 1.50 inches 1/6 inches 5 feet 5 feet None inches 0 feet Minimum Flow Rate per Orifice Number of Orifices per Zone Total Flow Rate per Zone NuMberorL fatsperzone % Flow Differential 1sULast Orifice Transport Velocity Frictional Head Losses 0,43 132 57,1 12 0.3 5.5 gpm gpm fps Loss through Discharge Loss in Transport Loss through Valve Loss in Manifold Loss in Laterals Loss through Flowmeter 'Add -on' Friction Losses Pipe Volumes 6.5 feet 7.7 feet 0.0 feet 0.3 feet 0_0 feet 0_0 feet 0.0 feet Vol of Transport Line Vol of Manifold Vol of Laterals per Zone Total Volume Minimum Pump Requirements 26.1 3.1 63.5 92,7 Os gals gals gals Design Flow Rate Total Dynamic Head ()ne.° i C M S 57.1 gpm 24.5 feet Total Dynamic Head, TDH (Feet) 50 45 40 35 30 25 20 15 10 5 .■■.. ■■■■ .■■■■■■N■■■■.■.....■■■■■■ ■■■..C■■■..■■■■.■r.■■.■■■■......■.■. ■■■■■....■ ■■■■■.■ i■■ ■■■■■.■■■.■■■■■ ■■■■■M■■.■■■..■...■■■■■■■■.■■■■■..■■ ■ ■■. ■ ■ ■■■ ■ ■■■ ■ ■1!■ ■ ■...■■ ■■■■■ ■■■■. ■■..■■■..■;•■■■■Irt■■■■.■■■�.....■.■■ ■■■■■C■■■■■.■■.Ur1U■■.■■■■■■■■■■■■■l '=mom .■■■■ ■■■.■t,.■■..■....t .■.■.. dig -a 4l ..t� ■■■■■■!�fri■■■■■■■■■■...■.■■■. .■■t.■.■■u■ ■■■■■fi■■■■■■im■■■■■■.■■■. ■.■■■■■■..■.■.■■■I'ar■■■■■■■■■■■■■ ■■.■■ t►■■■■.■■■■. u>■■■■ ■■■■■■■■...... .. ■.■.■.■■■■......■■....■.■■■■.■■.. ..O..U..■■.■■■L■■■■■ ■■■■■■U■.■ ■■■■■ .■■► ■.■... ■■.■ri ■■■■■ ■■■■■ ■■■■. ■■■■■ .■.■■■■■■■ ■■■■ ■ ■■■■.....■..■■■ ■■■■■ ■■■■■►\....■■f■■■■■■■■■■■■■...M■■■■ C:::::C::::::M:::::UC:::::::::::UEM ■■■■■ ■■■■\.■■'j■ ■■■■■ ■■■■■ ■■■■■■■■■■ ■.... ■■■■■\ ■. ■■.■..■ ■■....■■■■.■■.. ■■ ■ ■. ■.■ ■ ■ !ii■■ ■■■■ ■ ■ ■■■■ ■■ ■■■ ■■■■. .■tii■®.■■�■.Ei r.■..■■■■■■■■■■■■■■■■■. ■■■.■■■■■■.■M..M■■■■.■.■■.■..■.■■■. .■■■■ ......A'!■■O. ■■■■ MEMO■ ■..■..■■■. ;i■■.M\.■■.....■■■■.■■■.. ■■.MAIM■■■ ■CAM■■ .■O■. ....■ .■■■M■■■■. ■■■■■■A.■■It.■■■■■■:\■.....■■A. ■■■■■ C■■■■ ■■■■■►u..■■■■■■■ ■■■■■■■■■■.I.M■■ ■■■■■■.■■.I.■■■.■■■►.■■■■■.M■■■■.■. •.■■■■■■.I,.1R.■........■■■■■■■■.■... ■■■u ■u ■■►i ■t.■■ ■ ■■■.E.� ■M ■ ■■ ■■ ■■ ■■■ .■■■ ..iMi.■■■■■■■■ ■■•■■■■M..■■■■ /■■■■I ►i ■■■I►■ ■I�r■ .■M■M■■■E■■■►■■■■■ ■■■M. .■AM ■■■■■I ■■■.■A■ ■MA.II`l..■■.■M.. ..■....I.■ ■II..■■.■■■■..■■■O'...■■.■ ■■■■■■■► MMIN.■■■.M■■■■■■■■■■■i.■■■M. ■■/■■ ■.'r■■ ■I.■■■■..■■luau..■■t ■■■■■ ■■■■■■►A..■■MMEMM■■■■■■■■■■■■■O►.■■■ ■■.■■..■■■■MMMEM■■.■■■■■■■■■■ ■\■■It ■■■■■G4■■.■■N■■■■■■■■■■■■■■■MM■■■■■■ ■■■■I■■■.■ui..■M■■■■■■■■■■■■■■.■■■■■ ■.■/a ■■■■■ ■It■■...■■■.■■■■ ■■■■■ ■■.UII ■■..•.•.u••iuu............uuu.uuuuuu ■■.■■.■■.■■1.■■■■■■...■.■ ■■■...■■■ ■■■■■■.■■■■1.■■■■■■■u■■■■uu■■■..■■■ ■■■■■■■■.■■1....■■■■ .■■■■ ■■■■.■..■ ■■■■■■■■■■■1.■■■..MM.=■■■■C■■■■.■■I.M ■■.........11.■.■.... ■... ...M.■■.■ 00 25 50 75 100 Net Discharge (gpm) 125 150 175 PumpData PFSW50 Sewage Pump 1/2HP, 115/230V 10 Legend System Curve: PumgQurve: Pump Oplini ange: DeslPPolnt