Geochemical studies of some thermal springs in Nepal

Abstract

Most of the major geothermal springs of Nepal are located close to and north of the Main Central Thrust and south of the Main Boundary Fault. The geothermometer temperatures of eight springs at Darchula, Jumla, Jomsom, Tatopani-Mustang, Sadhu Khola, Rior, Mayangdi, Chilime and Bajhang-Tapoban are in the range of 85 to 115°C and these thermal springs are not found to be mixed with cold ground water. Most of the spring waters seem to be peripheral but those at Tatopani-Mustang and Sadhu Khola are mature with respect to major anion concentrations. A combination of the results of previous isotope studies and the present ones suggests that a large geothermal reservoir exists in the Sadhu Khola - Jomsom area in central Nepal. Many thermal springs in Nepal are yet unexplored for their potential use, except for bathing and laundering purposes. Detailed scientific studies should be conducted to gain more information about these and estimate the prospective reservoirs. The location of many of the springs in sparsely populated areas, mostly in the remote, steep Himalayan terrain, and the absence of adequate knowledge of the utilization of low- temperature thermal waters have been the major impediments to the promotion of this resource. In view of the comparatively good accessibility, relatively high population density, and the possibility of a large reservoir, the central region of Nepal should be given priority. Thermal waters can be used in Nepal for a wide range of economically productive purposes and for reducing environmental pollution.