5th International Conference on Rain Water Cistern Systems
"Rainwater Catchment for Future Generations"
Keelung, Taiwan, R.O.C. - August 1991

Section 9: Alternative Uses of Cistern Water

Page 521

A Simple Weir for Economical Floodwater Diversion

Ahang Kowsar, Akbar Zargar
Research Institute of Forests and Rangelands, Iran.

Abstract

Diversion dams or weirs sometimes constitute the most expensive and troublesome structures in the design and construction of floodwater spreading (FWS) systems. Many plan for construction of potentially viable FWS systems have bee cancelled in the feasibility stage studies because, on occasions, the expenses involved in the design and construction o a single weir or diversion dam far outweigh the cost of the rest of the project. Thus, justification of the entire project hinges on designing a workable structure at a low cost. Gabion provides a useful material for construction of simple, inexpensive weirs which could be fitted into many designs, and may be. built by unskilled laborers.

Fifteen pieces of 3 0 x 4 0 m, 3 mm diameter galvanized wire netting were used. to construct a.0.60 m high on a 28.0 m wide ephemeral river on a debris cone to diver up to 5m3 s-l of floodwater to a 25 ha FWS system in the Gareh Bygone Plain in, southern Iran. The costs were at least 136 times lower than building a hydraulically efficient, concrete structure having the same capacity.

Although the intake structure behind the weir located on the inside of the river bend, and at a 9° angle to it, no detectable deposition of sediments has--taken-place at this point during 6 years of operation. These hydraulic anomalies deserve further attention.

PDF of full document available to members (8pp,210kb)