Quantitative estimation of drainage characteristics of the Pohru Catchment, Kashmir valley, India: a remote sensing and GIS based approach

Abstract

The applicability of remotely sensed data and geographic information systems (GIS) for catchment area characterization are found of enormous utility in soil and water management. Morphometric parameters were evaluated using Digital Elevation Model to characterize the hydrological behaviour. The catchment is seventh order with sub-dendritic to sub-parallel pattern and high drainage density upstream. Youthful geomorphic stage, fine drainage texture and high runoff probability eventually influence the low lying areas. High relief and steep surface gradient makes faster surface water circulation with less water-table recharge resulting into more surface flow towards low lying areas to be severely affected by this extra amount of unusual water. Heavy rainfall and maximization of first-order streams in uplands triggers the likelihood of sudden flash-floods in the downstream areas. The stream order of the catchment is primarily regulated by the lithological and physiographical setting of the locale. The area of study under observation is designated as the seventh order catchment with the calculated drainage density value being as 3.077 km/km2. The changing stream length proportion from lower to higher order explains that the area is yet to reach the phase of geomorphic maturity. The elongation ratio (Re) of Pohru catchment is 0.75, which indicates steep ground slope and high relief. The drainage texture of the Pohru catchment is 34.171 indicating very fine drainage texture, resulting by the impact of various geomorphological processes of the area. To minimize the catchment degradation and future risk, proper treatment should be given to the low lying areas where drainage density is naturally low and death of streams is more common due to human intervention.