HIGH-PRECISION MEASUREMENTS OF SEDIMENT ELEVATION IN SHALLOW COASTAL AREAS USING A SEDIMENTATION-EROSION TABLE

The use of a sedimentation-erosion table (SET) for the measurement of small changes in sediment surface elevation in intertidal and shallow subtidal areas is described. The SET provides a constant reference plane in space from which the distance to the sediment surface can be measured by lowering pins to the surface. The precision of the method was determined by repeated measurements in coastal marshes, mudflats, and subtidal areas in Louisiana and Georgia. The confidence interval of the SET is about +/- 1.5 mm. The SET is more accurate if pins are lowered manually and the sediment surface is determined visually than if pins are lowered by gravity and the sediment surface is determined by soil resistance.