Water levels in aquifers in the Nacatoch Sand of southwestern and northeastern Arkansas and the Tokio Formation of southwestern Arkansas, spring 2008

Water-level trends and potentiometric surfaces in the Nacatoch Aquifer in northeastern and southwestern Arkansas and in the Tokio Aquifer in southwestern Arkansas, 2014–15

“…4;Holland, 1993Holland, , 1999Holland, , 2004Holland, , 2007Schrader and Rodgers, 2013;Pugh and Holland, 2015). Withdrawals from the southwestern study area reached a peak of 4.75 Mgal/d in 1980 (fig.…”

“…9) [Schrader and Rodgers, 2013]; and 156 ft above NGVD 29 in 2014). Water-level changes in other wells screened in the aquifer are minor in comparison to those published in previous studies.…”

“…5) and declined by 85 percent to less than 1 Mgal/d by 2010. This decline has been attributed to public water supplies converting to surface-water sources and relying less on groundwater sources (Holland and Ludwig, 1981;Holland, 1987Holland, , 1993Holland, , 1999Holland, , 2004Holland, , 2007Schrader and Rodgers, 2013). Withdrawal data from the aquifer were not reported for several counties and appear as 0.00 Mgal/d in the record.…”

“…6), groundwater flows southeasterly toward the Mississippi River from a potentiometric high of 275 ft above NGVD 29 in northcentral Clay County to a potentiometric low of 230 ft above NGVD 29 in northeastern Greene County (table 1). The direction of groundwater flow has not changed since the 2013 potentiometric mapping of the northeastern Nacatoch aquifer (Schrader and Rodgers, 2013).…”

“…11D) indicates an annual decline of 0.18 ft/yr since 1986. Withdrawals in Miller County have remained relatively stable since 2005 (Holland, 2007;Schrader and Rodgers, 2013). 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 2015 Water level, in feet,above National Geodetic Vertical Datum of 1929 YEAR…”