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<br />01788 <br /> <br />. <br /> <br />. Research is needed in both fine sediment modeling and sediment <br />augmentation. <br /> <br />. Development of a predictive fine sediment model will continue, perhaps at a <br />reduced level after 2 years. Model development should result in a computer <br />program that can be queried for such issues as: 1) Long-term effects of Glen <br />Canyon Dam; 2) effects of tributary floods on sand volumes and sediment <br />availability for beach building flows; 3) estimated size and areal coveragc of <br />bed sediment (sand and gravel); and 4) effects of possible future sediment <br />augmentation. This program should be able to distinguish between effects <br />within different reaches of the river, such as above Lees Ferry, within Marble <br />Canyon, the open reach below the Little Colorado River, etc. The program <br />should be targeted for completion by 2006 and no later than 2008. A <br />continuing budget item should be included for validation of the model with <br />new sediment data. <br /> <br />Monitoring of the fine sediment budget will need to be continued and further <br />developed with regard to new technologies and implementation procedures, but possibly <br />at a reduced level of effort and frequency. Possibilities for more efficient sediment <br />monitoring will be evaluated as follows: <br /> <br />. <br /> <br />. Fewer monitoring sites for measuring sand volumes and/or less frequent <br />resurveYIng. <br /> <br />. Less frequent collection of physical samples of suspended sediment, with <br />greater reliance on automated turbidity measurements. <br /> <br />. Less frequent routine collection of images and topography from overflights. <br /> <br />. Development of a sampling and sand inventory survey protocol that is <br />partially event-triggered, such as after major tributary floods (e.g. floods with <br />>5 to 10 year recurrence interval), with less frequent resurveys or samples <br />during normal dam release periods. - ~ <br /> <br />However, the number of sediment concentration measurement sites will not be <br />reduced. A provision will be included in either the core monitoring or research budgets to <br />permit sediment sampling and sand inventory surveying after experimental flows. <br /> <br />Question: <br /> <br />How are Riparian and Spring Communities and Habitats Effected by <br />Flow Regimes? <br />What are the physical and biotic relationships of flows and terrestrial <br />vegetation? <br />How does the occurrence and state of marsh and backwater <br /> <br />Question: <br /> <br />Question: <br /> <br />. <br /> <br />USGS SBSC GCMRC Strategic Science Plan - FY 2005-2009 <br />Draft, October 22, 2004 <br /> <br />21 <br />