Water-level changes in the High Plains Aquifer, 1980 to 1994

Water-level changes in the High Plains aquifer, predevelopment to 2009, 2007-08, and 2008-09, and change in water in storage, predevelopment to 2009

“…Since 1988, annual area-weighted, average water-level changes had been calculated using Thiessen polygons (Thiessen, 1911) because a larger number of wells were available with water levels measured in both adjacent reporting years and, therefore, the Thiessen polygon method produced a reasonable value for annual area-weighted, average water-level changes (Kastner and others, 1989;others, 1990 andDugan and Schild, 1992;McGrath and Dugan, 1993;Dugan and Cox, 1994;Dugan and Sharpe, 1996;McGuire and Sharpe, 1997;McGuire and Fischer, 1999;McGuire, , 2004aMcGuire, , 2004bMcGuire, , and 2009. For this report, maps of generalized annual water-level changes, 2007-08 and 2008-09, were constructed using Thiessen polygons (ESRI ® Arc/Info™ version 9.3) to maintain consistency with previous reports.…”

Water-level changes in the high plains aquifer, predevelopment to 2003 and 2002 to 2003

“…For this report, total ground water in storage from 1988 to 2000 ( fig. 4) was calculated by subtracting annual changes in water in storage, 1988 to 2000, from total water in storage in 2000 (Dugan and Cox, 1994;others, 1990, 1994;Dugan and Schild, 1992;Dugan and Sharpe, 1996;Kastner and others, 1989;McGrath and Dugan, 1993;McGuire, , 2003Fischer, 1999, 2000;others, 1999, 2003;McGuire and Sharpe, 1997). The sum of annual changes in water in storage from 1988 to 2000 was a decline of about 47 million acrefeet, based on average area-weighted water-level changes calculated from Thiessen polygons.…”

Transition to Dryland Agriculture

“…The decline has exceeded 30 m in parts tained by using irrigation timing at critical growth stages. of the High Plains area of the Texas and Oklahoma In Minnesota, work by Johnson et al (1987) showed panhandles, and southwest Kansas has averaged about that irrigated corn responded as well to midseason irri-0.13 m yr Ϫ1 since 1980 (Dugan and Sharpe, 1995). The gation as it did to more frequent irrigations at 50% decline has been coupled with rising energy costs.…”

“…Parts of the aquifer have undergone substantial declines since extensive irrigation began about 1940. The decline has exceeded 30 m in parts of the High Plains area of the Texas and Oklahoma panhandles, and southwest Kansas has averaged about 0.13 m yr −1 since 1980 (Dugan and Sharpe, 1995). The decline has been coupled with rising energy costs.…”