| | | | Title: | | | | | Volume/Number: | 1950 | | | | Issuing Agency: | | | | | Description: | This investigation is part of a state - wide investigation of groundwater resources being conducted by the State Water Survey Division. Records of more than 1400 wells have been tabulated. These wells penetrate one or more of three separate and distinct aquifers within the glacial drift . The three aquifers penetrated by wells in this are a have unrelated hydrostatic heads. The average daily pumpage from the middle deposits, the major producing aquifer considered in this report, was 7.917 million gallons. It was estimated that a total of 67,812 million gallons of water has been pumped from this aquifer. Water level pressure contour maps of the upper and middle waterbearing deposits show no similarity. Sufficient data are not available to permit the construction of a pressure contour map of the lower deposits. Values of the coefficients of transmissibility and storage have been determined. Values of the coefficient of transmissibility ranged from 10,000 to 400,000 and averaged about 40,000. Values of the coefficient of storage ranged from 0.00024 for short periods to 0.0065 for a 46 year period, the longest for which records are available. Using a coefficient of storage of 0.0065 it was determined that the amount of water removed from storage since pumping began was about 3,187 million gallons or about 5 percent of the total amount of groundwater withdrawn. The amount of inflow into the heavily pumped area at Champaign-Urbana is about equal to the 1948 rate of withdrawal indicating little if any recharge within the 630 contour of the cone of depression. The steep hydraulic gradient and low water levels near the area of heavy withdrawal, together with continued water level recession, suggests that the middle deposits at Champaign-Urbana have been developed to their maximum transmission rate and that some lessening of the rate of withdrawal would be necessary to maintain constant operating water levels. | | | | Date Created: | 1 9 2006 | | | | Agency ID: | RI-6 | | | | ISL ID: | 000000000917 Original UID: 999999993871 FIRST WORD: Groundwater | |
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