Scenario 3

Scenario 3 presents a model simulation conducted to determine the effects of increased pumpage throughout most of the model area with removal of selected industrial withdrawals in Pine Bluff and El Dorado for the period 1998-2027. This scenario provides information on aquifer conditions in the region if the water withdrawal rates continue to increase while conservation initiatives in Pine Bluff and El Dorado support a reduction in industrial use as in scenario 2. The baseline 1990-97 withdrawal rate was linearly increased by 25 percent over the 30-year period from 1998 to 2027. The simulation period was segmented into six stress periods of 5 years each. Withdrawal rates at each well were multiplied by an appropriate percentage for each stress period that totals a 25 percent increase over 30 years.

The results of scenario 3 show that throughout most of the model area the predicted hydraulic heads for this scenario are higher than levels predicted for scenario 1 and that substantial recovery results in the cones of depression located in the Pine Bluff and El Dorado areas. Similar to scenario 2, the removal of selected withdrawals in the Pine Bluff and El Dorado areas results in shallower, less expansive cones of depression relative to scenario 1, however; recovery is less because of continued increases in pumping elsewhere in the aquifer. Hydraulic heads recover more than 100 ft by 2027 in Pine Bluff. In El Dorado, hydraulic heads recover more than 124 ft by 2027. Hydraulic heads also recover above the top of the Sparta Sand, as in Scenario 2, by 2027 over most of Union County. However, the percentage area of Union County where hydraulic heads are below the top of the Sparta Sand is greater compared to Scenario 2 (16.6 percent compared to 7.3 percent in 2027).