HR: 1340h
AN: H53F-1481 [Abstracts]
TI: Potential for Recharge in Agricultural Soils of the Mississippi Delta
AU: * Perkins, K S
EM: kperkins@usgs.gov
AF: US Geological Survey, 345 Middlefield Rd., MS-421, Menlo Park, CA 94025,
AU: Nimmo, J R
EM: jrnimmo@usgs.gov
AF: US Geological Survey, 345 Middlefield Rd., MS-421, Menlo Park, CA 94025,
AU: Coupe, R H
EM: rhcoupe@usgs.gov
AF: US Geological Survey, 308 South Airport Rd., Jackson, MS 39208,
AU: Rose, C E
EM: cerose@usgs.gov
AF: US Geological Survey, 308 South Airport Rd., Jackson, MS 39208,
AU: Manning, M A
EM: mmanning@usgs.gov
AF: US Geological Survey, 308 South Airport Rd., Jackson, MS 39208,
AB:
Ground water models predict that 5 percent or less of precipitation in the Mississippi Delta region recharges the
heavily-used alluvial aquifer; however the presence of agricultural chemicals in ground water suggests more
substantial recharge. In a preliminary assessment of the potential for aerial recharge through the agricultural
soils of the Bogue Phalia basin in the Mississippi Delta, we applied a method for rapidly measuring field-
saturated hydraulic conductivity (Kfs) in 26 locations in cotton and soybean fields. The technique makes use
of a portable falling-head, small-diameter, single-ring infiltrometer and an analytical formula for Kfs that
compensates both for falling head and for subsurface radial spreading. Soil samples were also collected at the
surface and at about 6 cm depth at each location for particle size analysis. Kfs values are generally higher
than anticipated and vary over more than three orders of magnitude from 1x10-2 to 5x10-6 cm/s. There
is also a correlation between Kfs and mean particle size which may prove useful in generalizing recharge
rates over larger areas. A 2-m ring infiltration test is planned that will include the use of tracers and subsurface
instruments for measuring water content and matric potential from the near surface to about 5 m to evaluate flow
and transport below the root zone.
DE: 1838 Infiltration
DE: 1865 Soils (0486)
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: 2007 Fall Meeting