Location: Hydraulic Engineering ResearchTitle: Earthen embankment overtopping analysis using the WinDAM B software Author
|Visser, Karl - Natural Resources Conservation Service (NRCS, USDA)|
|Hanson, Gregory - Retired ARS Employee|
|Temple, Darrel - Retired ARS Employee|
|Tejral, Ronald - Ron|
|Neilsen, Mitchell - Kansas State University|
Submitted to: Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/14/2013
Publication Date: 2/21/2013
Citation: Visser, K., Hanson, G.J., Temple, D.M., Tejral, R.D., Neilsen, M. 2013. Earthen embankment overtopping analysis using the WinDAM B software. In: National Dam Safety Technical Seminar #20: Overtopping Protection for Dams, February 20-21, 2013, Emmitsburg, MD. 11 p.
Interpretive Summary: Over 11,000 earthen embankment dams nationwide were constructed with Federal involvement during the last seventy years. Many dams were constructed in rural areas and originally classified as low hazard. Increases in number of people living near dams and new dam safety rules have changed the hazard classification for a large number of these dams. As a result, it is predicted that the storm for which a new dam should be designed, would cause water to flow over existing dams. WinDAM B software predicts the resulting erosion if water flows over the dam. Results from WinDAM B analyses can be used to prioritize dam rehabilitation efforts. The paper briefly discusses suggested capability of the software and its use within existing USDA-NRCS dam safety policy.
Technical Abstract: Over 11,000 earthen embankment dams nationwide were constructed with Federal involvement during the last seventy years. Many dams were constructed in rural areas and originally classified as low hazard. With increased development near the dams and changing dam safety criteria the hazard classification for a large number of these dams has changed. As a result, the current design storm event overtops the existing earthen embankment. WinDAM B software predicts the resulting erosion from an overtopping event. Results from WinDAM B analyses can be used to prioritize dam rehabilitation efforts. WinDAM B includes erosion failure of a homogeneous embankment through overtopping and drainage of stored water. Future expansion includes internal erosion, non-homogeneous embankments, and embankment protection analysis. Agency Policy The paper briefly discusses suggested use of this model within existing USDA-NRCS dam safety policy. WINDAM B CAPABILITIES Primary Purpose of Software •Hydraulically routes one input hydrograph through, around, and over a single earthen dam. •Estimates auxiliary spillway erosion in up to three earthen or vegetated auxiliary spillways. •Estimates erosion of the earthen embankment caused by overtopping of the dam embankment. The user must import an inflow hydrograph into WinDAM B. Overtopping Homogenous Earthen Embankment: WinDAM B assumes the embankment of the dam is a homogenous earthen material. Future versions will address zoned-fill dams where each zone exhibits markedly different erosion resistance from other zones. Embankment Slope Protection: The WinDAM B overtopping/breach analysis evaluates possible failure of the surface of the embankment's downstream slope. Initial slope conditions can be vegetal (grass), riprap, and no protection (bare soil).