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Dr. Melissa Foster is a fluvial geomorphologist with the US Bureau of Reclamation. She is an interdisciplinary scientist and much of her work focuses on the crossover between engineering and river science. Her professional interests include reservoir sedimentation, hydraulic modeling, Quaternary dating techniques, and landscape evolution. Prior to joining Reclamation, she received her Ph.D. from CU Boulder in Geological Sciences and worked as a consultant in river restoration and sedimentation.

Abstract

Developing a semi-automated method to estimate reservoir sedimentation at ~30,000 reservoirs across the United States

Melissa A. Foster¹, Aaron A. Hurst¹, Abigail Eckland²

¹U.S. Bureau of Reclamation, Technical Service Center, Denver, babyÖ±²¥app. ² University of babyÖ±²¥app at Boulder, Geological Sciences Department.

Water resource management in the US is reliant upon aging reservoirs for critical storage and flood mitigation. Sediment accumulation in reservoirs limits resource availability and storage. The rates of sedimentation vary due to natural stochastic events, such as floods or wildfire. However, in many cases the emplacement of upstream dams is the dominant control on downstream sediment availability. Our work seeks to automate the calculation for reservoir sediment yield, accounting for the emplacement of upstream dams and their sediment-trapping efficiency (similar to methods detailed in Minear and Kondolf, 2009).

We acquired reservoir survey data for 535 sites across the United States. Within the drainage basins for our sites, the National Inventory of Dams (NID) listed approximately 30,000 registered dams. We manually cleaned the data to remove duplicate dams, dikes, and off-stream storage facilities. We used ESRI ArcPro to snap the NID-registered dams to the National Hydrography Dataset (NHD) High Resolution, Version 2.1 flowlines. Each NHD flowline lists the downstream Hydro-Sequence, allowing us link flowlines and order dams from upstream to downstream. Once the dams were ordered, we adjusted the sediment-contributing drainage area at our sites through time, to calculate sediment yield rates. Preliminary data indicate that study sites will lose approximately 11% of total design storage by year 2050. Our next steps include modeling the sedimentation of the ~30,000 upstream NID-registered dams, based on basin sediment-production rates inferred from site data. In addition, we will analyze site data for trends on how basin sediment production correlates with environmental parameters (e.g., geology, soil type, relief, millennial-scale denudation); if trends exist, we will use these relations to infer sedimentation in NID-registered dams that lie outside of our study basins.