Hydrologic and terrain variables to aid strategic location of riparian buffers

ABSTRACT:

Methods for mapping hydrologic variables to locate vegetated riparian buffers were explored using examples from the Deep Loess Region of the Midwest. Elevation and stream-flow data were used to define wetness, baseflow, sediment transport, and discharge indices. Groundwater dominates discharge in very small streams and through riparian areas in the region. All indices showed that riparian areas along first order streams have greater potential to intercept groundwater or runoff than similar areas along larger streams. A wetness index, used to indicate saturated soils, defined a significantly (p<0.05) greater probability of saturation along smaller streams, enhancing the potential for groundwater interception. Significantly smaller values of the sediment transport index along smaller streams provide enhanced opportunities for deposition of sediment and associated contaminants. A discharge index shows that buffers along first order streams have orders of magnitude greater opportunities to intercept water passing through riparian areas than reaches of larger streams.