Water resources for irrigation:
- Nepal’s rivers contribute 45% of the Ganges annual flow, and 75% of the driest month’s average.
- It is estimated that the 200,000 million cubic meter annual runoff from Nepalese rivers is underused and, at times, causes a severe, hazardous flood in Nepal, India and Bangladesh (Still and Kirkby, 1991).
- Despite a huge potential of hydropower generation, a limited number of hydropower stations are established in few areas only.
- Nepal rivers are classified into three classes based on their origin. Rivers in class I originate in the high Himalayas above the snow line and have a sustained dry season flow due to snow melt. The class II rivers originate below the snow line in the slopes of the Mahabharat mountains which are perennial but have a low dry season flow. The class III rivers originate in the Siwalik ranges and southern slopes of the Mahabharat mountains.
- These rivers are ephemeral and flashy with watersheds that are geologically fragile, erodible and are deteriorating fast due to population pressure.
- Nepal’s Terai belt has rechargeable ground water potential, which occurs in both artesian and non-artesian aquifers.