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Kimley»>Horn <br />Page 3 <br />• Pump removal efforts to date have caused visible damage to the S4 PVC well casing <br />at depths between 7 feet and 46 feet BPL, exposing the well to groundwater <br />infiltration and potential sanitary hazards. <br />• Damage to the S4 well casing has been present since the pump was removed using <br />a vibratory hammer and crane as reported in the Phase I report (2002). <br />• Observations from the 2009 and 2016 well videos demonstrate growth of scale or <br />organic material on the interior PVC well casing has increased. The downward growth <br />of scaling observed in the 2016 well video from casing cracks and casing joint <br />separations between 38 feet and 46 feet BPL indicates leakage of fluid from behind <br />the PVC well casing and represents a sanitary seal hazard. <br />• Potential repairs needed to fix the well casing cracks including out of plumbness are <br />cost prohibitive and not guaranteed to resolve the casing integrity and alignment <br />issues. <br />Given the fact that there are numerous casing breaches and the well is extremely out of <br />plumb in several areas, there are limited corrective actions available to restore the well to <br />usable capacity. Most of these include the following: <br />1. Continue to rehabilitate the well and do nothing to the casing. <br />a. Previously scheduled well acidization will be dangerous due to the casing <br />failures and may not safely handle pressures generated during the procedure. <br />Jetting and cleaning off the existing casing is all that could be performed. <br />b. Pumping water levels would have to remain above the water table elevation to <br />prevent further seepage into the existing PVC well casing. This would reduce <br />the pumping rate of S4 to less than 500 gallons per minute (GPM) based on <br />the current specific capacity of 16 GPM/Ft at 535 GPM measured during the <br />pre -rehabilitation well video. <br />c. A design rate of less the 500 GPM is not sufficient for the South Oslo Road <br />WTP needs, and a reduction in capacity would require other wells to <br />overproduce. <br />d. NO COST (Rehabilitation already budgeted) <br />2. Line the well casing to seal off sanitary hazards and install a smaller/different <br />type pump. <br />a. Installation of a stainless steel liner should be completed to the total depth of <br />the existing PVC well casing and should include squeeze grouting behind the <br />kimley-horn.com <br />1920 Wekiva Way, Suite 200, West Palm Beach, FL 33411 <br />561 845 0665 <br />P103 <br />