2.4-Discharge measurement of river Teesta in Sikkim using tracer dilution technique

Abstract

River Teesta is a perennial river with substantial flow even in lean season. It flows in North-South direction along the length of the state of Sikkim and forms the single major river in the state drawing water from 95% of the total area of the state.

There is a programme to install micro hydels on this river. The information about the flow rates of river during the lean period was required for designing the microhydels .The discharge of river Teesta was measured at four sites viz. Chungthang, Mangan(Sanklang), Dikchu and Sirwani using tracer dilution technique. These sites were chosen according to the proposed programme for the installation of microhydels.

Methodology, details of the experimental work carried out and the results are discussed in this paper. The discharge values obtained using conventional techniques at different sites are 40% to 50% higher than those obtained by tracer dilution technique except at site Chungthang.