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Home My WebLink AboutGeo-Revoli-Yarmouth-Discharge Plan-09302024 Dewatering Discharge Plan Wastewater Collection and Water Resource Recovery Facilities Phase 1, Contract No. 3 Yarmouth, Massachusetts for Revoli Construction Company, Inc. September 20, 2024 153 Cordaville Road, Suite 300 Southborough, Massachusetts 01772 508.283.6354 09/20/2024 153 Cordaville Road, Suite 300 Southborough, Massachusetts 01772 508.283.6354 September 20, 2024 Revoli Construction Company, Inc. 90 Earls Way Franklin, Massachusetts 02038 Attention: Alfredo Palumbo Subject: Dewatering Discharge Plan Wastewater Collection and Water Resource Recovery Facilities Phase 1, Contract No. 3 Yarmouth, Massachusetts File No. 27340-001-00 GeoEngineers USA, P.C. (GeoEngineers) has prepared the attached design calculations for groundwater discharge of the previously-designed temporary dewatering system at the above referenced project located in Yarmouth, Massachusetts. Background GeoEngineers previously designed deep wells along S. Shore Drive to facilitate construction of the proposed sewer. Per this design, the estimated groundwater flow per well is about 300 gallons per minute (gpm) to achieve adequate drawdown; when a factor of safety of 2 is considered, the Contractor shall be prepared to pump and discharge up to 600 gpm per well. Groundwater Discharge & Monitoring Treatment and monitoring of groundwater shall be conducted in accordance with the Contract Specifications. A 12” HDPE header pipe will connect each dewatering well to one of three discharge locations along S. Shore Drive, as shown in the attached figures. A maximum of eight (8) wells are planned to be in operation at any given time. At each discharge location, a sedimentation tank will receive the dewatering effluent. This tank shall have a minimum capacity of 18,100 gallons and be equipped with an inner baffle. Sediments will settle from the effluent in the sedimentation tank before being discharged along 12” HDPE pipe lines to the beach, beyond the low tide line; refer to Detail A for more information. The discharge point into the ocean will be located at least 10’ past the low tide line, below the low tide water level, and elevated above the sea floor. This discharge point will consist of a 90-degree pipe bend ending vertically beyond a concrete barrier to hold the pipe in place. Refer to Detail B for more information. Details A and B comprise part of our stamped submittal. The Contractor shall monitor groundwater flow rates and the discharge system for the duration of pumping. Each 12” pipe can handle a maximum flow of approximately 3,000 gpm; discharge through the pipes must either be limited to this number, or a second, parallel 12” pipe must be installed to handle additional flow Revoli Construction | September 20, 2024 File No. 27340-001-00 beyond this limit. In addition, the proposed 18,100-gallon sedimentation tank can handle approximately 300 gpm of steady-state flow. If the Contractor wishes to discharge more than this at one time, additional tanks must be placed in parallel to handle an additional 300 gpm each. The Contractor may use larger tanks if desired once approved by GeoEngineers. Refer to the attached calculations for more information. Since the discharge outlet pipe is located off of the sea floor, scour of the beach material is not anticipated at the ocean discharge points. The Contractor shall monitor each discharge point at least weekly to ensure no scour occurs. Closing We trust that this satisfies the needs of the project at this time. Please contact Collin Sweeney at (317) 437-0652 with any questions or comments. Sincerely, GeoEngineers USA, P.C. Collin Sweeney, E.I.T. Michael T. Flynn, P.E. Staff Geostructural Engineer Associate Geostructural Engineer Attachments: Discharge Pipe and Tank Calculations; Discharge Plan and Details Wastewater Collection and Water Resource Recovery Facilities Yarmouth, Massachusetts Discharge Pipe Sizing Calculation By: CES 09/17/2024 Chk: MTF 09/20/2024Job No. 27340-001-00 Subject:Discharge Pipe Sizing for Dewatering System Effluent at the Wastewater Collection and Water Resource Recovery Facility in Yarmouth, Massachusetts. References: Contract Plans - Bid Set by CDM Smith, dated March 29, 2023. TM 5-818-5 Dewatering and Groundwater Control Manual. PE Civil Reference Manual, 16th Edition, M.R. Lindeburg, 2021. Check 12" HDPE Discharge Pipe Proposed pipe diameter ≔D 12 in Manning's n for HDPE pipe ≔n 0.012 ――s ft ―1 3 Length of pipe (approximate)≔L 300 ft Parking lot elevation (elevation of tank discharge into HDPE pipe; approximate) ≔z0 10 ft Discharge elevation (assume sea level)≔z1 0 ft Pipe Slope ≔S =――-z0 z1 L 0.033 Pipe flow depth (assume pipe-full condition)≔d 12 in Angle of flow area (from circle geometry)≔θ =⋅2 acos ⎛ ⎜⎝-1 ――⋅2 d D ⎞ ⎟⎠6.283 rad Flow Area ≔A =⋅⋅―1 8 ((-θ sin((θ))))D2 0.8 ft2 Hydraulic Radius ≔R =⋅⋅―1 4 ⎛ ⎜⎝-1 ―――sin ((θ)) θ ⎞ ⎟⎠D 0.3 ft Flow rate at flow depth=d 1 ft ≔Q =⋅⋅⋅――1.49 n A R ―2 3 S ―1 2 7.07 ――ft3 s Design Discharge (from Dewatering Design submittal) ≔qdes 300 gpm Consider a maximum of pumps ≔n 8 running simultaneously =n 8 Page 1 of 2 Wastewater Collection and Water Resource Recovery Facilities Yarmouth, Massachusetts Discharge Pipe Sizing Calculation By: CES 09/17/2024 Chk: MTF 09/20/2024Job No. 27340-001-00 Compare to pipe capacity ≔Qdes =⋅n qdes 2400 gpm <=Q 3171 gpm Check flow velocity for pipe self-cleaning ≔V =―Q A 9 ―ft s >2 ―ft s OK Check maximum allowable flow velocity to protect against long-term pipe damage ≔V =―Q A 9 ―ft s <10 ―ft s OK Summary: Provide one (1) 12" HDPE pipe for discharge between pumps and tank and between tank and discharge point. Limit system discharge to a maximum of into a single =Q 3171 gpm pipe. Add additional pipes in parallel if flow rate exceeds per pump. Pipes must be =―Q n 396 gpm installed at a slope of at least .=S 0.4 ―in ft Size Sedimentation Tank Limit flow into sedimentation tanks to avoid overflow of tank and to allow settling of sediments. Limited flow value ≔Qmax 300 gpm Minimum Required Basin Surface Area ≔Areq =―――Qmax 1.0 ――gpm ft2 300 ft2 Consider 18,100 Gallon Weir Tank ≔V 18100 gal Inner Length of Tank ≔L 40 ft Width of Tank ≔W 8 ft Depth of Tank ≔D 9 ft Check Tank Surface Area ≔A =⋅L W 320 ft2 >=Areq 300 ft2 OK Check Settling Time for Discharge Detention Time in Tank ≔T =――V Qmax 1.006 hr Settling Velocity (assume a fine sand/silt - Lindeburg 26-5) ≔vs =0.001 ―m s 0.003 ―ft s Minimum Required Settling Time ≔t =―D vs 0.762 hr <=T 1.006 hr OK Summary:Provide one (1) sedimentation tank with a minimum volume of about 18,100 gallons and inner baffle height of 9 feet (or equivalent) per of flow. Additional =Qmax 300 gpm sedimentation tanks are necessary if flow exceeds this number (min. 2 tanks recommended). Page 2 of 2 Detail A - Discharge Location Plan Detail A - Discharge Location Plan Detail A - Discharge Location Plan Detail B - Discharge Point Detail Steel Tank Overview: Features: Specs: Store liquids with confidence with Rain for Rent’s 18,100-gallon Open-Top Wier Tank. The over and under weirs allow for separation of oils or particulates. Permanently attached axles, for maximum maneuverability, allows this tank to be moved with ease on the jobsite. The staircase ensures proper protection for workers on site. 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