Sediment control in wadi irrigation systems

Hydraulics research has monitored the design and performance of irrigation off takes for three wadi systems (Rima, Zabid and Mawr) in the Yemen Arab Republic. This paper is drawn from the experience gained during these projeets, and from research into improved design methods for sediment control structures.
The wadis thatcross the Yemen coastal plain (Tihama) have steep, (0.5 to 1 percent) bedslopes.and flow inaseries of multipeaked flash floods. Discharges can rise to more than 1 000 m'/s. returning to less Jtan 1 m'ls in 4 to 10 hours, and stream velocities can exceed 4 m3/s (Lawrence 1982).