Abstract: The Himalayan mountain range extends in a broad arc from Pakistan through India, Nepal, Bhutan and China. With elevations ranging from approximately 300 meters in the plains at the base of the mountains to the peaks well over 8,000 meters (Mt Everest 8,848 m). The Himalaya is the tallest and most complex of the world mountain regions (Striffler, 1985). The Himalaya can be divided into three physiographic zones. These includes the lower foothills usually describe as sub-Himalaya and represented by the Siwalik Hills which extend along most of the Himalaya with elevation seldom exceeding 1000 m. The second zone is the middle Himalaya also called Outer Himalaya or the lesser Himalaya with elevation ranges from 600 meters to over 3000 m. Interspersed within the middle zone are occasional larger to small valleys and river basins. The third zone is the great Himalaya or Inner Himalaya zone that covers higher mountain areas, the snow clad peaks and trans-Himalayan harsh climatic dry areas (HMG Nepal, 1977; Kaith, 1960). The glaciers and natural springs have drained the whole area and created a vast area as wetlands supplemented by different lake system in different elevations.