In scenario 2, pumpage was increased according to current
water-use trends to simulate likely demands in the future.
A regression was developed to determine a trend in the rate
of increase for each county using water-use data from 1988
through 2000 (Holland, 1993, Holland, 1999, T. W. Holland written
commun., 2002 U.S. Geological Survey). Pumpage for each county
for future years was estimated from the regression. This trend
was applied to the 1997 pumpage to supply increased pumpage for
successive stress periods to a maximum value of 1.25 times the
estimated pumpage for each county in 2000.
The simulated water-level map (fig. 23 in report) and the animation
for Scenario 2 indicate enlargement and deepening of previously
described depressed potentiometric surface areas and the presence of dry
cells in Desha County in 2019. A total of 10 dry cells appears
in the 2019 timeframe. The pumpage-induced area of depressed
simulated hydraulic heads in Desha County elongates further to the
southeast and northwest into Lincoln County. An area in southern
Desha County that was previously greater than 50 percent saturated
formation thickness drops below the 50 percent saturated formation
thickness level to a total thickness of 11 to 30 feet in 2019.