The total measured rate of alluvial sediment accretion in the agricultural
Coon Creek Basin for the period 1975-93 was only about 6 percent of the rat
e that occurred in the 1930s, but the distributed changes within the basin
were highly variable and systematic. Sediment yield (efflux), however, rema
ined relatively constant despite Large stream and valley changes within the
basin. These observations demonstrate (i) that sediment sources, sinks, an
d fluxes vary widely over time and space and (ii) that, although improved s
oil conservation measures have decreased soil erosion, the downstream effec
ts are complex.