Conference Papers

The streamflow regime and sand supply of the Colorado River have been affected by the presence and operations of Glen Canyon Dam since filling of Lake Powell began in March 1963. Consequent changes in river morphology have included decreases in the size and abundance of sandbars used as campsites in Grand Canyon National Park (Dolan and others, 1974; Schmidt and Graf, 1990; Kearsley and...

Flood events have historically had a strong impact on riparian vegetation within Grand Canyon. Pre-dam sandbars were nearly devoid of perennial riparian vegetation due to the magnitude and frequency of periodic floods (Turner and Karpiscak, 1980). Vegetation has increased since dam closure (Waring, 1995), particularly since the early 1990s (Sankey and others, 2015). This increase in...

Forage fish are small, abundant, schooling planktivores that form a critical link in marine food webs by transferring energy from plankton up to birds, fishes, and marine mammals. Forage fishes in Puget Sound include the iconic Pacific herring as well as lesser known species such as surf smelt and the Pacific sand lance. There are significant knowledge gaps regarding the basic life...

Glen Canyon Dam has reduced downstream sediment supply to the Colorado River by about 95% in the reach upstream of the Little Colorado River confluence and by about 85% below the confluence (Topping and others, 2000). Operation of the dam for hydropower generation has additionally altered the flow regime of the river in Grand Canyon, largely eliminating pre-dam low flows (i.e., below 8...

Sediment-transport theory and field measurements indicate that the greatest or most efficient deposition of sand in eddies occurs during controlled floods (a.k.a. High-Flow Experiments or HFEs) when the greatest amount of the finest sand is available on the bed of the Colorado River (Topping and others, 2010). Conducting HFEs when the sand on the bed of the Colorado River is depleted and...

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