Investigation of flow hydraulic gradient through self-spillway dams

Dams are hydraulic structures constructed across rivers in order to store or rise water level for multi-purposes such as irrigation and power generation. The upstream face of the dam is subjected to water drag force which makes possible of flow seepage through the dam body. In the present study, the difference in water level between upstream and downstream sides of a rock-fill dam is investigated under different flow conditions demonstrating the flow behavior through the dam body. Two well graded samples of river aggregates with d50 of 56 mm and 40 mm are used to build the dam model. One sample of poor graded crushed rocks of d50 33 mm is included as well. The obtained results show that due to the porosity of the gabion containing the aggregates, the hydraulic gradient line dropped down significantly where it is inversely proportional to the porosity non-linear relationships for all. In addition, a linear relationship has dominated on the relation between upstream water depth and discharge through the self-spillway dam with and without impermeable core.