HR: 1340h
AN: H53B-0470    [Abstracts]
TI: Using an Integrated, Remote-Sensing Methodology to Evaluate the Effects of Dam Operations on Fine-Grained Sediment Storage and Sand Bar Restoration in Marble Canyon
AU: * Breedlove, M J
EM: mbreedlove@usgs.gov
AF: USGS - GCMRC, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AU: Hazel, J E
EM: joseph.hazel@nau.edu
AF: Northern Arizona University, Dept. of Geology, Flagstaff, AZ 86001 United States
AU: Kaplinski, M A
EM: matt.kaplinski@nau.edu
AF: Northern Arizona University, Dept. of Geology, Flagstaff, AZ 86001 United States
AU: Schmidt, J C
EM: jschmidt@cc.usu.edu
AF: Utah State University, Box 5280 Geography, Room 132, Logan, UT 84322 United States
AU: Topping, D J
EM: dtopping@usgs.gov
AF: USGS - GCMRC, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AU: Rubin, D M
EM: drubin@usgs.gov
AF: USGS - WR, Western Coastal & Marine Geology, Santa Cruz, CA 86001 United States
AU: Fuller, A E
EM: afuller@usgs.gov
AF: USGS - GCMRC, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AU: Tusso, R
EM: robert.tusso@nau.edu
AF: Northern Arizona University, Dept. of Geology, Flagstaff, AZ 86001 United States
AU: Gonzales, F M
EM: fgonzales@usgs.gov
AF: USGS - GCMRC, 2255 N. Gemini Dr., Flagstaff, AZ 86001 United States
AB: Eddy sand bars and other sandy deposits in and along the Colorado River in Grand Canyon National Park (GCNP) were an integral part of the pre-dam riverscape, and are still important for habitat, protection of archeological sites, and recreation. These deposits began eroding following the 1963 closure of Glen Canyon Dam that reduced the supply of sand at the upstream boundary of GCNP by about 94 % and are still eroding today. In the 1990s, resource managers and scientists began a long series of experiments and monitoring aimed at answering one primary science question. Given existing sand inputs to the ecosystem, can any set of dam operations actually restore and maintain sand bars within the Canyon? In order to test this question, a reach-based approach was developed to examine temporal and longitudinal trends in sediment storage and composition in six, 3 to 6-km reaches of the channel in Eastern GCNP. The reach-based approach integrates various remote-sensing technologies to supplement historical survey techniques. These include: LiDAR and multi-beam sonar for measuring the elevations of subaerial and subaqueous surfaces; an underwater microscope (the flying eyeball) and its subaerial sister, the beachball, for measuring the composition of sediment surfaces; and traditional surveys to provide fine-level control. Between 2000-2005, 7 distinct measurements were made for all reaches. These bracketed two high-flow experiments (controlled floods) and intermediate periods characterized by normal Dam operations. Sediment-surface changes will allow scientists to quantify system responses to specific Dam operations in attempting to address the primary science question.
DE: 1808 Dams
DE: 1815 Erosion
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: Fall Meeting 2005