Quantifying USACE reservoir sedimentation knowledge gaps by expanding the Reservoir Sedimentation Information Portal

<jats:p>The Reservoir Sedimentation Information (RSI) Portal provides a database of US Army Corps of Engineers (USACE)–managed reservoir information, including estimates of storage capacity loss. However, the portal lacks critical data regarding acute or localized sedimentation, its impact on reservoir function, and the availability or quality of pre-impoundment surveys. This absence of information hampers a manager's ability to project how unplanned changes in sedimentation may impact reservoir capacity. To quantify these challenges, we surveyed 291 of the 445 reservoirs listed in the RSI Portal at the time of this study. Our results showed that 46% reported moderate-to-major sedimentation issues. Furthermore, 77% reported issues with pre-impoundment surveys. This means 224 of the USACE reservoirs surveyed lack sufficient historical data to evaluate the impact of unplanned increases in postconstruction sedimentation. Our assessment also provided a first-order estimate of the number of reservoirs that could benefit from targeted research, such as sub-bottom profiling. Our analyses were hampered by the size and complexity of the dataset, highlighting the critical importance of incorporating these missing datasets directly into the RSI Portal to better manage reservoir resources and safety.</jats:p>