GED Seminar Series
Thursday 3rd May 2012
3-4pm, CO304 (NOTE CHANGE OF TIME)
Speaker: Associate Professor
Noah Snyder, Boston College
“Using airborne lidar to map river morphology and habitat”
Much
progress has been made linking the fields of geomorphology, hydrology,
ecology and tectonics over the past 20 years using digital elevation
models (DEMs) to study stream processes. The first-generation DEMs were
generated from topographic maps, and with pixel sizes of 10 to 90
meters on each edge, these grids allowed investigators to make
measurements of parameters such as stream gradient and
contributing drainage area over entire channel networks.
Next-generation DEMs generated from airborne laser elevation (lidar)
surveys open up new opportunities for research on stream processes
because they improve resolution by an order of magnitude compared
to traditional DEMs. With pixel sizes of 0.5 to 5 meters and the
ability to measure height down to 5 to 20 centimeters lidar DEMs enable
researchers to identify channel features, such as the water surface,
bank edges, and floodplains, as well as measure the
slope of channels over short stream reaches. Furthermore, they provide
new types of data about watershed land cover, such as the height and
density of the tree canopy, because the laser instrument receives
returns from both treetops and the land (or water)
surface. In this talk, I will present several applications of airborne
lidar data to study channel processes, morphology and habitat in North
American rivers.
