MAPPING OF SAND DEPOSITION FROM 1993 MIDWEST FLOODS WITH ELECTROMAGNETIC INDUCTION MEASUREMENTS

Sand deposition on river-bottom farmland was extensive from the 1993 M idwest floods. A technique coupling electromagnetic induction (EM) gro und conductivity sensing and Global Positioning System (GPS) location data was wed to map sand deposition depth at four sites in Missouri al ong the Missouri River. A strong relationship between EM redding and p robe-measured depth of sand deposition (r(2) values between 0.73-0.94) was found. This relationship differed significantly between sites, so calibration by ground-truthing was required for each sand deposition survey. An example of the sand deposition mapping wing the EM/GPS syst em is shown for two 50-60 ha (125-150 ac) sites. Such maps can provide valuable detailed information for developing restoration plans for la nd affected by 1993 Midwest floods.