130. Hydraulic Design of Trench Weir on Dabka River – A Case Study

Micro-hydel is the best solution to meet the local power requirements in the far-flung hilly regions particularly in the Himalayas. In recent times the most common type of weir adopted in boulder streams for micro-hydel schemes and also in irrigation and water supply schemes is the “Trench type” or “Drop type” weir. This simple but an ingenious type of structure is an R.C.C. rectangular or trapezoidal shaped trench built across the stream below its bed level. The top of the weir is covered with trash-rack bars. The stream water, while flowing over it, passes through the trash-racks and enters into the trench and collected in a R.C.C. intake well located at one of the banks at the end of the weir. The present paper describes the state-of-the-art of the hydraulic design of trench weir with the particular reference to design of trench weir on the river Dabka near Kaladungi in Nainital district of Uttaranchal.