APPLICATIONS OF LIDAR TO ALLUVIAL CHANNEL DYNAMICS IN RESPONSE TO GREAT SALT LAKE LEVEL FLUCTUATIONS

Studies relating changes in base level to fluvial processes may provide a link between geomorphology, sedimentology, stratigraphy and economic geology. However, few field studies have examined the effects of base level changes on modern fluvial systems. The purpose of this investigation is to examine alluvial channel dynamics of two streams, the Lee Creek and the Goggin Drain, which flow into the Great Salt Lake, a lacustrine environment in which base level fluctuates frequently. An historic regression has been in progress since 1986, exposing remnants of avulsive channels. The ultimate objectives of this study are to determine the timing and possible mechanisms of recent channel avulsions, and to asses the usefulness of LiDAR data both in geomorphic mapping and in providing input for erosional models. The primary research tools are historical aerial photographs, airborne and ground-based bare-earth LiDAR DEMs, and field measurements. Preliminary research suggests that channel avulsions have primarily occurred during rises in lake level, and that major avulsions may be linked to instabilities caused by channelization in upper reaches. LiDAR DEMs of the system have been valuable in revealing subtle fluvial sedimentary features, but challenges have arisen in using these data to measure basic channel parameters such as gradients and cross sections. Ongoing research will integrate these measurements into erosional models in order to investigate the likely timing and location of future avulsions.