Morphometric analysis and hydrogeomorphology for delineating groundwater potential zones of Western Doon Valley, Uttarakhand, India

Remote Sensing and Geographical Information System (GIS) techniques have been effectively used for the analyses of the morphometric analysis of the Western Doon Valley. The drainage network of the watershed was delineated using satellite data IRS-ID (LISS-III data) and Survey of India toposheets were used as reference. The morphometric analysis of the watershed has been carried out using ERDAS Imagine 9.2 and ARC GIS-9.2 version. The drainage network of the study area covering 789.26 km².which exhibits dendritic drainage pattern. The stream order ranges from first to sixth order. The drainage density of the study area varies between 1.12 to 3.75 km/km2 which observed that area is highly permeable and structurally controlled. The bifurcation ratio varies from 2.47 to 4.49 and the elongation ratio vary from 0.37 to 0.68 which reveals that Western Doon Valley is an asymmetrical longitudinal synclinal valley which extends for about 34 km. in length and 20 km in width and lies between two major rivers of Indian sub-continent. Hydrogeomorphologically the Western Doon Valley is classified into different zones covered by denudational hills, residual hills, high dissected hills, moderately dissected structural hills, upper piedmont, lower piedmont, older terrace, younger terrace and flood plain. The excellent groundwater potential zones are associated with the younger terraces and flood plains of Tons river, Asan river and Yamuna river and parts of adjacent lower piedmont unit. Good groundwater potential zones are associated with the part of older terrace (alluvium) and lower piedmont unit. Moderate groundwater potential zones fall in the lower part of the upper piedmont. Low groundwater potential zone falls in the upper part of the upper piedmont units, adjacent to structural hills. Very low potential zone includes residual hills, denudational hills, and structural hills with high slope are grouped together as runoff zone in the study area.