DESIGN, DEVELOPMENT OF AN AUTOMATIC FLAPE GATE FOR CONTROLLING EXCESS WATER AT THE HEAD OF IRRIGATION SOURCE.

The purpose of this study was to control undesirable discharge on the downstream of irrigation inlet during floods in the river/streams. To study this an automatic flape gate was designed and tested at Malakandhare farm of N-W.F.P University of Agricultural, Pakistan. The gate was made of mild steal. The experiments were conducted by storing and releasing upstream water. The downstream discharge was measured by cut throat flume. The upstream movement of Flape Gate was checked at 23° with horizontal water surface and sustained by 1701 grams weight with the surface area of gate as 529 cm3 and gate mass of 1.41 Kg. The increase in hydraulic pressure pushes the gate downwards. The gate then collapse with prefixed frame below which the desirable discharge was allowed to flow from the inlet. When flood recedes, manually the gate was brought back to its original position. The flap gate could be kept at 23° inclination by a sustaining mass of 1701 gms. The desirable discharge of 22 liter per second can be obtained when the upstream head varied from 23 cm to 49 cm, then the adjusted gate opening varied from 23 cm to 25 cm. The gate skeletons was simple and economical. Therefore, keeping in view the operational easiness and enormous economic benefits Flap Gate is recommended for adoption in the country.