Flood Design of Kholongchu Hydroelectric Project

Abstract

The Royal Government of Bhutan (RGoB) is proposing to harness the country’s vast hydro power potential. Hydro power generation has been identified as one of the core area of cooperation between India & Bhutan. In this context, RGoB has assigned the task of investigation and preparation of Detailed Project Report (DPR) of various Hydro Electric Projects to India. The work for the investigation and preparation of DPR of Kholongchu Hydro-Electric Project on Kholongchu, a tributary of Dramengchu (Gongrichu) in Manas river basin has been assigned to Satluj Jal Vidyut Nigam Limited (SJVNL). The following development alternatives for the project have been considered: i) Diversion Dam at D-3 This alternative envisages the construction of diversion dam across river Kholongchu about 11 km upstream of its confluence with Dramengchu (Gongrichu) at Duksum. The diversion site is located in Trashiyantse District in the North – Eastern part of Bhutan at Latitude 27⁰ 30’ 32’’ N and Longitude 91⁰ 31’ 10’’ E. It is proposed to utilize a net head of about 550 m for development of hydro power. The power house is located about 4.5 km downstream of Duksum. The project catchment lies between Latitude 27⁰ 27’ 00’’ N to 27⁰ 57’ 36’’ N and Longitude 91⁰ 18’ 36’’ E to 91⁰ 39’ 36’’ E. Catchment area upto the diversion site is 1120 sq km, out of which about 15 sq km is snowfed above an elevation of 5000 m.