Vol. 2, Issue 6, Part P (2016)

Abstract
Present investigation deals with assessing the impact of barrage construction on macrobenthic invertebrate population of river Tawi and its comparison with the previous studies on the diversity of macrobenthic invertebrates reported from river Tawi. Dams and barrage regardless of the purpose they are made for, impede and regulate the river. This brings about changes in physical and chemical parameters along with biotic parameters of regulated river as compared to untamed rivers. The process of river degradation begins as soon as any physical disturbance is imposed upon natural course of river. Changes in river ecosystem may be temporary or permanent depending upon the severity and time duration of disturbance. In the present study, four stations on river Tawi, which flows through the centre of Jammu city were selected to study the impacts, two upstream Gujjar Nagar bridge (Station-I) & Near Mosque (Station-II), one on the site of barrage (Station-III) and one downstream the barrage ahead of Bhagwati Nagar bridge (Station-IV). Samples were collected from all the four stations on monthly basis for a period of one year (August, 2013 to July, 2014). Since the construction was still ongoing, and is still in initial stages, so no permanent standing water system had been created but repeated changes in flow regimes of river were observed, huge water diversions, disturbances to river bed (sand extraction, load carriers and tractors passing through the river, machinery for construction purposes etc.) along with pollution load from city. A river which is already dying due to pollution load and continuously decreasing water levels will definitely succumb to such disturbances especially in the stretch that flows through the city.