R2002-79 AUTHORIZING AGREEMENT - Laserfiche WebLink

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Scope of Work To accomplish the project goals, the ISWS will perform an instrumented, 30-day aquifer test using Decatur's well #2 at the Cisco well field. The ISWS will dri117-9 observation wells in the area at optimal locations to collect necessary water level data to quantify the response of the aquifer to the pumpage. The data collected by the ISGS in the area will be utilized to assist in the selection of sites. The observation wells will be outfitted with recorders to monitor water levels during the test. Additional wells may be monitored using steel tapes by ISWS staff if the data will be beneficial in the analysis of the results. The effect of the Sangamon River will be quantified by the observation well data and by the installation of seepage meters in the streambed. A step test will be conducted for 3 hours to evaluate the pumping capacity and to test both the equipment and method to be used for the 30 day aquifer test. The well pump will be turned off for 2 days, then, once any needed changes or adjustments are made, the well pump will be tumed back on and operated at a constant rate for 30 days. After 30 days, the pump will be turned off and data on water level recovery will be collected for an additiona130 days. The modifications to the well head and installation of a valve will be completed by the Ciry of Decatur prior to the commencement of pumping. Project Tasks The following tasks outline the role of the ISWS: Task 1: Install seepage meters in the Sangamon River. These meters consist of bladders attached to cutoff drums which when placed in the streambed can measure the flow rate of groundwater into or out of the stream. These meters will be placed in 3-5 locations along the Sangamon River where there are outcrops of sandy aquifer material. Measurements will be made before and during the aquifer test. Changes in the river stage will also monitored Task 2: Modify the outflow for Decatur #2 to permit control of the flow rate. The ISWS will coordinate the temporary piping changes needed at Decatur#2 for conducting the aquifer test. The City of Decatur will modify the wellhead for ISWS use and install a valve for regulating the flow rate from the well. The ISWS will install the temporary piping to the valve and install the necessary testing equipment for use m morutoring the flow rate during the test. The ISWS will work with the land owner to monitor the discharge from the test to avoid any flooding problems on private property. Task 3: Identify existing wells that may be candidates for water level monitoring and identify well logs to be used to evaluate the known geologic characterization. Water well records are maintained by the ISWS. These data provide the basis for regional hydrologic and geologic characterizations. To help ensure that the data are as accurate as possible, each record should be verified in the field for correct location, well depth, static water level, and use. The following services will be performed. Subtask 3.1: Notify public of the project and the intent to monitor several private wells in study area, and solicit their cooperation. We will contact the well owners in the vicinity of Decatur #2 and seek their cooperation in allowing us access to measure their well water levels during the 30-day �,