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Title: Model study of RCC stepped spillways with sloped converging training walls

Author
item WOOLBRIGHT, RYAN - OKLAHOMA STATE UNIV
item Hunt, Sherry
item Hanson, Gregory

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2008
Publication Date: 6/29/2008
Citation: Woolbright, R.W., Hunt, S., Hanson, G.J. 2008. Model study of RCC stepped spillways with sloped converging training walls. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). June 29 - July 2, 2008, Providence, Rhode Island. Paper No. 084149.

Interpretive Summary: By 2018, approximately half of the 11,000 small watershed dams designed and constructed with the assistance of the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) will reach the end of their planned service life. Environmental changes including urbanization and topography surrounding many of these dams have resulted in inadequate spillway capacities. In many cases, urbanization of surrounding areas limits the rehabilitation options of these dams. Roller compacted concrete (RCC) stepped spillways provide an effective solution to this problem. Research and application of stepped spillways has been on the rise, but readily available generalized design guidelines are still limited, especially in areas of spillway convergence and application of stepped spillways on relatively flat slopes. Research has been performed on converging spillway chutes with vertical training walls; however, public safety, aesthetics, and construction efficiency suggest sloped training walls are a more desirable option. A generalized study of converging stepped spillways with sloped training walls was conducted at the USDA-Agricultural Research Service (ARS) Hydraulic Engineering Research Unit in Stillwater, Oklahoma. The study utilized a three-dimensional small scale physical model. Model configurations consisted of a spillway chute having a slope of 3(H):1(V) and training walls with slopes ranging from 1(H):1(V) to 3(H):1(V). Water surface profiles and flow information were recorded for each configuration. Run-up along the wall was observed to be the controlling factor for determining necessary dimensions of the sloped training walls. The objective of this study was to increase the general knowledge of and help develop a generalized equation for stepped sloping training walls.

Technical Abstract: Approximately half of the over 11,000 small watershed dams designed and constructed under the supervision of the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) will reach the end of their planned service life within the next 10 years. Many of these dams have inadequate spillway capacity due to changes in hazard classification and revised dam safety laws. Urbanization of surrounding areas limits the rehabilitation options of these dams. Roller compacted concrete (RCC) stepped spillways provide an effective solution to this problem. Recent years have seen a growth in the research and application of RCC, but there are no readily available generalized guidelines. Research has been performed on converging spillway chutes with vertical training walls. Public safety, aesthetics, and construction efficiency suggest sloped training walls are often a more desirable option. A generalized study of converging stepped spillways with sloped training walls was conducted at the USDA-Agricultural Research Service (ARS) Hydraulic Engineering Research Unit in Stillwater, Oklahoma. The study utilized a three-dimensional small scale physical model. Model configurations consisted of a spillway chute having a slope of 3(H):1(V) and training walls with slopes ranging from 1(H):1(V) to 3(H):1(V). Water surface profiles and flow information were recorded for each configuration. Run-up along the wall was observed to be the controlling factor for determining necessary dimensions of this type of structure. The objective of this study was to increase the general knowledge of and help develop a generalized equation for stepped sloping training walls.