Project Number: 6217-13000-009-00
Project Type: Appropriated

Start Date: Jan 19, 2012
End Date: Jan 18, 2017

Objective:
The long-term objective of this project is to develop stand-alone and integrated tools for engineers to evaluate allowable embankment overtopping; predict dam failure from overtopping and internal erosion for homogeneous and zoned embankments with simple and complex downstream embankment slope geometries; design alternative surface protection methods, including vegetation, riprap, and concrete blocks; and develop generalized design criteria for increased spillway capacity for small dams (i.e., less than 20 m high). Specifically, the objectives of this project are: Objective 1: Enhance the WinDAM model to predict erosion and breach of complex earthen embankment geometries and materials. Subobjective 1A: Quantify the impact of complex embankment geometries on erosion processes during overtopping, including: convergence zones at the intersection of the earthen embankment and valley walls, and embankment berms and toes. Subobjective 1B: Quantify the impact of changes in soil materials on erosion processes and rates of earthen embankment erosion and breach. Objective 2: Develop engineering tools for design of earthen embankment protection alternatives and increasing the discharge capacity of small dams. Subobjective 2A: Develop guidelines for dimensioning stilling basins and downstream channel protection for non-converging RCC stepped spillways constructed over existing earth dams. Subobjective 2B: Develop guidelines for dimensioning stilling basins and downstream channel protection for converging RCC stepped spillways constructed over existing earth dams.

Approach:
Large-scale physical models will be used to develop knowledge on the protective capability of vegetation and/or riprap on embankment slopes with convergences and berms. Large and small-scale models will be used to develop knowledge of erosion resistance of zoned embankment materials and to develop key relationships related to earthen embankment erosion. Small-scale and large-scale physical models will also be used to develop knowledge on the impact of discharge, energy dissipation, flow depth, velocities, and downstream tailwater depth on stilling basin and downstream channel protection design for stepped spillways. Data and relationships developed from these physical models coupled with in-depth literature review will be used in the development of predictive and design tools for embankment erosion and spillway and stilling basin design. USDA-ARS HERU scientists will collaborate with other ARS, government, university, international scientists, and consultants to carry-out these objectives. The results from this research will be incorporated into evaluation tools, software, design criteria, and management practices that will allow the continued service and increased benefit of the nation's agricultural flood control infrastructure.