Quantifying Long-Term Geomorphological Change In Dry Valley Streams: Integrating Survey Data With Subsequent LiDAR Surveys
Crisp, Steven W 1 ; McKnight, Diane 2 ; Jaros, Chris 3 ; Cullis, James 4
1 INSTAAR
2 INSTAAR
3 INSTAAR
4 INSTAAR
In 1994, 16 stream transects were established in Taylor Valley representing different flow regimes and substrates. Contour plots were created by manually and exhaustively surveying individual points and then applying an interpolation technique known as kriging to present basic channel morphology. The locations of algal mats in the channel were included in the surveys. We plan to refine the geospatial models of our transects to gain a better understanding of algal mat dynamics with regards to stream flows. We have used LiDAR (Light Detection and Ranging) to scan most of these transects with very high resolution. Within minutes, millions of points are meshed to create a three-dimensional terrain plot. The plots allow us to digitally represent channel geometry and bed roughness. Using these parameters, we can find shearing stresses at the bed interface which can have broad impacts on POM transport, nutrient availability, and algal mat population dynamics. In addition, the flood of the 2001/02 season may have substantially changed stream channels and has caused algal species dominance to shift in some streams. The new scans will be overlaid on the pre-flood contour plots to allow us to determine the extent of any scouring or deposition that occurred during the flood and provide insight on what caused the shifts.
James D.S. Cullis, Lee F. Stanish and Diane M. McKnight. 2014. Diel flow pulses drive particulate organic matter transport from microbial mats in a glacial meltwater stream in the McMurdo Dry Valleys. Water Resources Research, published online: 7 JAN 2014, DOI: 10.1002/2013WR014061