Developing a mathematical framework in preliminary designing of detention rockfill dams for flood peak reduction

Hydraulic designing of rockfill detention dam is based on the treatment of nondarcian and non-linear turbulence flow in coarse porous media. Previous literature focused only on the regular outlet ponds, and there is a shortcoming in the design methodology for detention rockfill dams. So, this paper develops a simple novel design framework by combining the governing equation of non-linear and non-darcian flow through rockfill dams with the hydrologic flood routing in reservoirs and hydraulic rules of storage dams. An innovative mathematical framework developed for preliminary designing of detention rockfill dams. The effects of type and size of rock fill materials, the shape of reservoir, shape, and intensity of inflow hydrograph on the peak of outflow, the volume of a stored flood, coefficients of flood peak and storage are investigated by parametric study in 36000 simulations. A simple design equation for preliminary designing of detention rockfill dams is provided and its applications in two design examples are presented. Its results indicate that the developed design equation (with R² = 0.996, MAE = 0.008, and RMSE = 0.0041) is superior to the previous equations and can be used in preliminary designing of detention rockfill dams for flood peak reduction.