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South Platte Decision Support System Groundwater Component Task 33 Field Study Work Plan <br />for Alluvial and Bedrock Well Installation, Testing, and Water Level Monitoring <br />observation wells, multi-well tests will be performed if feasible. Test locations within <br />the Denver Basin Region bedrock aquifers will be determined as described in <br />Section 2.4. <br />If the production well has a sounding tube and it is not already equipped with a <br />water level measurement device, the production wells and any available observation <br />wells will be outfitted with continuous water level recording devices to monitor <br />changes in groundwater levels during the aquifer pumping test. It is anticipated that <br />water levels in each pumping well and in one other well that can serve as an <br />observation well, if present, will be monitored for at least one week prior to the start <br />of the aquifer test and for a total of up to 1 month. <br />The aquifer test will consist of water level measurements recorded in three phases: <br />pre-test, pumping, and recovery. During the pre-test phase, water level <br />measurements will define ambient conditions. During the pumping phase, the high- <br />capacity bedrock well will pump at a constant rate over the duration of this phase and <br />water levels in the observation well will decline as a cone of depression forms around <br />the pumped well. During the recovery phase, the high-capacity well will be shut <br />down and water levels allowed to rise back towards pre-pumping levels. <br />Discharge will be measured periodically during the test to ensure that a constant <br />pumping rate is maintained. Discharge measurements will be made with an in-line <br />flow meter or other method acceptable to the State Engineer's Office. The pumping <br />phase will last for at least 8 hours and may extend up to 1 week in duration. Up to <br />1 week may be required to measure the recovery in aquifer water levels once <br />pumping stops. <br />The water level drawdown and recovery data will be analyzed using standard aquifer <br />test analysis methods that are appropriate for the type of aquifer being tested <br />(unconfined, confined, or leaky). The data analysis will be used to obtain estimates of <br />aquifer transmissivity, storage coefficient (for tests with observation wells), and <br />hydraulic conductivity. <br />3.4 Task 39, Collect Water Level Data <br />This task will enhance the State's groundwater database by continuing the Phase 1 <br />collection of water level measurements during the fall season after agricultural <br />pumping has ceased and will add to the understanding of seasonal changes in <br />groundwater levels when compared to the SEO's spring season measurements. It is <br />anticipated that this task will involve approximately 60 wells at a minimum and that <br />up to 60 more wells will be added to the program using resources saved from the <br />alluvial drilling and testing tasks. The final number and locations of wells will be <br />determined by the outcome of well evaluations performed under this task. <br />~.~.-~ <br />19 <br />Z:\SPDSS\10-CDM DELIVERABLES\PHASE 2 FIELD WORKPLAN\FINAL DRAFT\FINAL SPDSS TASK 33 2 WORK PLAN.DOC <br />