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JLA Geosciences, Inc. <br />HYDROGEOLOGIC CONSULTANTS <br />1907 Commerce Lane, Suite 104 <br />Jupiter, Florida 33458 <br />(561) 746-0228 <br />fax (561) 746-0119 <br />TECHNICAL MEMORANDUM <br />To: Mark Miller, P.E. <br />Kimley Horn & Associates, Inc. <br />From: Jon Friedrichs, P.G. <br />RE: Summary of Work Completed to Date and Recommendation for <br />South Oslo Road Water Treatment Plant, Upper Floridan Aquifer Well S4 <br />Date: December 9, 2016 <br />As part of JLA Geosciences Inc. (JLA) existing Purchase Order (Job No. 044572026) with Kimley-Horn and <br />Associates (KHA), JLA's scope of work included Rehabilitation Phase Services for four (4) existing Floridan <br />Aquifer supply wells (S3, S4, S5, & S6) located at the Indian River County Utilities Department (IRCUD) <br />South Oslo Road Water Treatment Plant (WTP) in Vero Beach, Florida. Well 54 was selected to be the first <br />well for rehabilitation since it was not regularly used due to poor performance, sand production noted by <br />IRCWUD WTP Staff, and historical records which indicated the well casing was out of alignment and <br />damaged during earlier rehabilitation efforts. This technical memorandum provides a summary of pre - <br />rehabilitation investigation work completed to date and a recommendations based on those findings. <br />SUMMARY OF WORK <br />All Webb's Enterprises (AWE) was contracted by IRCUD to perform rehabilitation services on well S4 and <br />began work by removing the existing well pump, column pipe, and motor on 10/13/16. The S4 pump <br />became lodged in the well casing during removal and required the use of a 50 -ton crane to dislodge and <br />remove the pump and column pipe. <br />Following pump and column pipe removal AWE performed geophysical and video logging of well S4, on <br />October 18, 2016 and October 24, 2016. During the well video, JLA observed damage to the well casing <br />at a depths between 7 feet and 279 feet below pad level (BPL). Casing separations identified in the well <br />video at depths of approximately 27 feet BPL, 46 feet BPL and a casing crack at 38 feet BPL are of particular <br />concern because their size and the scale/growth features at these depths indicate a downward migration <br />of water in the well casing and potentially a sanitary seal failure. <br />JLA also compared observations from the 2016 well video with a 2009 well video performed by Aquifer <br />Maintenance and Performance Systems, Inc. (AMPS). Overall, the majority of observations made during <br />jlageosciences.com <br />P106 <br />