In arid and semi-arid regions, collection of surface and subsurface waters in small seasonal rivers is very crucial, particularly in dry seasons. The cost of construction and maintenance of the classical water intakes makes them inappropriate for such rivers. In this study a rather new method to divert surface and subsurface water is experimentally evaluated. In this kind of intakes, a couple of trenches are excavated and the drain pipes are installed in them and then filled with very porous materials. Indeed the system acts as a river drainage network. This method not only reduces the construction and maintenance costs but also minimize the disturbance of river topology and morphology. Therefore this intake is also suitable for rivers with high sedimentary loads. In this study an experimental model of the subsurface intake was constructed and the effective parameters such as water head, installation depth, drains interval, porous media length, and drains arrangement (10, 20, 30, 40, 50, 60, and 150 cm) was evaluated. The results showed that the drains flow rate changes along the porous media depending on the hydraulic head above each drain so that in constant up- and down-stream head, the minimum discharge was observed in the central drain. The assessment of different drains arrangement indicated that bilevel installation was superior to mono-level drains. Finally the regression equations were established to estimate the discharge of each drain based on dimensional analysis, which facilitate the design of this structure.

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