During the spring of 2002, water levels were measured in 737 wells completed in the Mississippi River Valley alluvial aquifer in eastern Arkansas. The regional direction of groundwater flow is generally to the south and east except where affected by intense ground-water withdrawals. In 2002, the highest water-level altitude measured was 287 feet above National Geodetic Vertical Datum of 1929 in northeastern Clay County. The lowest water-level altitude measured was 78 feet above National Geodetic Vertical Datum of 1929 in southwestern Ashley County. Comparisons of water-level changes in cones of depression from 1998 to 2002 show increases and decreases in depth or areal extent. A large depression in the potentiometric surface was located in Arkansas, Lonoke, and Prairie Counties during 1998 and persisted in 2002. Water levels generally declined in this depression in Lonoke County but rose in Arkansas County. Two shallower cones of depressions were located in Craighead, Cross, and Poinsett Counties and St. Francis, Woodruff, Lee, and Monroe Counties west of Crowleys Ridge during 1998. These coalesced into a single depression by 2002. Water-level data from 143 wells with 26 or more years of record indicate long-term water levels in the alluvial aquifer declined an average of about 0.3 foot per year from 1977 to 2002. Water levels generally declined throughout most of the aquifer from 1998 to 2002.
Specific conductance measurements made on water samples collected from 64 wells ranged from 262 microsiemens per centimeter in a well in Randolph County to 2,730 microsiemens per centimeter in a well in Chicot County.
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USGS Numbered Series
Status of water levels and selected water-quality conditions in the Mississippi River Valley Alluvial Aquifer in Eastern Arkansas, 2002