Overview of Historical Reservoir Flushing Events and Screening Guidance
Abstract
Reservoirs are an important component of water resource systems around the world. Sediment trapped in reservoirs threatens their usefulness while also having the potential to cause problems upstream and downstream of the reservoir itself (Kondolf et al. 2014). The U.S. Army Corps of Engineers (USACE) maintains and operates more than 350 reservoirs within the United States, and many of those reservoirs are experiencing decreased project benefits due to sediment deposition (Pinson et al. 2016; USACE 2016). Existing and continued sediment deposition will result in a reduction of reservoir storage available for project uses such as flood control, water supply, hydropower, recreation, and environmental purposes (e.g., minimum flows). To achieve long-term sustainable performance of reservoirs, it is necessary to find and understand sediment management techniques that could be effective for each reservoir. Flushing is one simple technique for managing sediment in reservoirs. In general, reservoir flushing involves opening low-level gates in a dam and allowing the water to remove sediment from the reservoir. There are two general cases of this technique. Pressure flushes are conducted for a short time, thereby limiting the drawdown of water in the reservoir while also restricting the affected area to a relatively small area immediately upstream from the gate. Drawdown flushes lower the water level in the reservoir, using both the increased flow of water and the increased water surface slope to erode large quantities of sediment throughout the reservoir. When a drawdown flush is timed to coincide with a large, sediment-laden inflow, it may be referred to as sluicing or drawdown routing (ICOLD 1999).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2019
- Accession Number
- AD1075972
Entities
People
- Marielys Ramos--villanueva
- Travis Dahl
Organizations
- Engineer Research and Development Center