MEASURING CHANNEL AND GULLY CROSS-SECTIONS WITH AN AIRBORNE LASER ALTIMETER

A laser altimeter, making 4000 measurements per second, was used to me asure channel and gully morphology. The laser measurements provide qui ck, accurate and readily obtained data on the cross-section and morpho logy of channels and gullies in relation to the adjacent landscape. Al though ground based techniques can be used to make these measurements, using a laser altimeter mounted in an aircraft allows data to be coll ected faster, with greater density and detail, and in areas with limit ed access for ground surveys. The laser altimeter data are valuable fo r measuring channel and gully cross-sections and roughness in relation to the surrounding landscape, for assessing soil loss from gullies an d channels, and for providing input to the understanding of gully and channel dynamics in the landscape.