Performance analysis of trench weirs

Most of the small hydropower projects (SHP) in hilly regions are run of river schemes using stream water by diverting through suitable diversion structure and other civil structures. There are many types diversion structures used in small hydropower projects and their selection dependon quantity of water withdrawal, characteristics of incoming sediment and stream topology. The trench type of diversion weir is commonly used in the small hydropower schemes in the hilly regions of India for last 3- 4 decades. The paper presents performance analysis of trench weirs constructed for different SHP stations by carrying out field investigations. Comparative study of the trench weirs in terms of water withdrawal, diverted sediment and downstream scour have been carried out. The clogging of trash racks and maintenance of the weirs have been also studied and compared.