MAPPING AND INTERPRETING SOIL TEXTURAL LAYERS TO ASSESS AGRI-CHEMICALMOVEMENT AT SEVERAL SCALES ALONG THE EASTERN SEABOARD (USA)

Despite numerous cases of groundwater contamination with agricultural chemicals on layered sandy soils, monitoring and prediction of the fat e of these chemicals in the vadose zone has eluded researchers and bur eaucrats alike so far. To aid in a better understanding of this phenom ena, the movement and fate of agricultural chemicals were assessed at different scales for the (sandy and layered) floodplain soil occurring along the Eastern Seaboard. At the point and field scale ground penet rating radar was used to locate the coarse sand lenses and tracer expe riments were initiated to study the How pattern of the chemicals. Resu lts show that water and solutes moved over the coarse layers and were funneled into fingers bypassing most of the soil matrix and reaching t he groundwater much faster than when the solute would move evenly thro ugh the vadose zone. At field scale a computer simulation indicated th at the exact location of the layers does not have to be known for calc ulating travel times, indicating that pedo-transfer functions could be developed for calculating groundwater pollution potential for differe nt combinations of soil and chemicals. In the future, groundwater poll ution on a regional scale can be predicted by using these pedo-transfe r functions in a Geographic Information System.