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Large-scale stepped spillway testing

Hunt, Sherry L, Kadavy, Kem C
Dam Safety 2010. Proceedings of the Association of State Dam Safety Officials Annual Conference 2010 pp. 10
Agricultural Research Service, agricultural land, concrete, dams (hydrology), demographic statistics, energy, infrastructure, models, Oklahoma
Hazard classifications for many earthen embankment dams have changed due to shifting demographics surrounding the structures. Originally designed to protect agricultural land, these embankments are now surrounded by residential communities and other infrastructure. To meet federal and state dam safety regulations as set by the new hazard classification, dam rehabilitation is often required. The USDA-ARS Hydraulic Engineering Research Unit (HERU) in Stillwater, OK, is conducting generalized research on roller compacted concrete (RCC) stepped spillways to address rehabilitation needs. Stepped spillways are typically placed as a retrofit over the existing embankment and used to increase spillway capacity. Practical design guidance on stepped spillways is limited, so researchers at HERU have developed a large-scale testing facility to determine useful design parameters like the inception point location, flow depth, velocities, and energy dissipation in stepped spillways with slopes flatter than 22 degrees. The scope of this paper is to discuss the new large-scale 3(H):1(V) stepped spillway testing facility, the objectives of the large-scale generalized stepped spillway research, and preliminary results of inception point obtained from this large-scale model. Preliminary results show that the inception point data location may be directly manipulated by changing the step height; thereby changing the energy dissipation within the stepped spillway and the design parameters of the stilling basin.