Cross sections illustrating the process of sediment mobilization and redeposition for the controlled flood release of 1996 from Glen Canyon Dam Recent high flows on the Paria River and other Colorado River tributaries have provided an opportunity to test new techniques for managing the Lower Colorado River ecosystem. These recent flows have deposited large amounts of sediment in the main channel of the Colorado River. This high flow experiment, which is a controlled release from Glen Canyon Dam, is intended to move the sediment from the bottom of the main channel and rebuild sandbars, beaches, and backwater areas in the Grand Canyon. Since the closure of Glen Canyon Dam, sandbars have been eroded as a result of reduced sediment load in the river. Sandbars, beaches, and backwater areas are important parts of the Grand Canyon ecosystem and are important for wildlife and recreational use . Sediment sampling on the Colorado River above Diamond Creek Sediment sampling on the Paria River at Lees Ferry Pre flood Pre flood Post flood Post flood Controlled Controlled flood flood Sand on channel bed Sand suspended Ri Ri v e r Lees Ferry Lit Lit tle tle do do ra ra Colo Colo Glen Canyon Dam Glen Canyon Dam Grand Grand Canyon Canyon National National Park Park 50 KILOMETERS 0 50 MILES 0 C o l o r a d o R i v e r C o l o r a d o 35 ˚ Flagstaff 111 ˚ 114 ˚ UTAH ARIZONA Paria ver Lake Powell Lake Mead 113 ˚ 37 ˚ 36 ˚ 52’30’’ 36 ˚ 50’ Base from U.S. Geological Survey, 1:500,000, State base map 36 ˚ Ri Ri v e r 09380000 09380000 09382000 09382000 09404200 09404200 Pearce Ferry U.S.G.S. STREAMFLOW-GAGING STATION AND NUMBER EXPLANATION C OLORADO R IVER H IGH F LOW E XPERIMENT 09382000 09382000 09383100 09383100 09402000 09402000 09379910 09379910 09402500 09402500 Ri Di C a r k ee ond m Page 112 ˚ P a r i a R i v e r 111 ˚ 37’30’’ 111 ˚ 35’ Lees Ferry 09380000 09380000 C o l o r a d o Ri Ri v e r 1/2 MILE 0 0 1/2 KILOMETER 09382000 09382000 Real-time data of Paria River discharge retrieved from the U.S. Geological Survey Web homepage Arizona URL: http://az.water.usgs.gov Sand bars deposited on river banks 09404120 09404120