Comparison Seepage Performance for Different Drainage Systems of Rainwater Harvesting Dam

Abstract

In arid and semi-Arid regions, rainwater harvesting (RWH) system may achieve a new water source. RWH dam can be constructed, based on criteria of small earth dam, at the out let of the selected catchment area to store the harvested rainwater in its reservoir. RWH dam may suffered by seepage problem (the flow of water through dam body). Seepage problem represents a major problem that may cause dam failure if it is not controlled. Dam failure is very dangerous resulting in property destruction and loss of life. In this study, the characteristics of seepage analysis are investigated through the proposed Al-Khoser RWH dam. Seepage modelling based on finite element method and numerical analysis has carried out using SEEP/W, a sub-program of Geo Studio. The analysis is covered eight scenarios for two types of dam (homogeneous and zoned) with different filters types (toe, horizontal, chimney, and without filter) for each dam type. In order to, make suitable decision of using core and filter including specifying filter type, seepage parameters such as total head, pore water pressure, seepage discharge, velocity and the gradient are computed. The phreatic line and factor of safety against vertical and horizontal piping are also studied and presented.