The “Watershed project” is one of the research projects carried out at the Indo-French Cell for Water Sciences (IFCWS),which was created five years ago in the Indian Institute of Science (IISc), Bangalore. The “Watershed Project” involves Indian researchers and students from the Civil Engineering Department, IISc, and French researchers from the Research Institute for the Development (IRD). It aims to understand and quantify the effect of the environmental parameters on the hydrological and geochemical cycles in southern India, and more particularly in the Kabini River basin.
The Karnataka state presents in its south-eastern part a unique context to carry out comparative studies on the effect of environmental parameters. The Ghâts range, stretching parallel to the west coast of the peninsula, form an orographic barrier: from west to east indeed the annual rainfall decreases progressively within a distance of about 50 km from high values (between 2000 mm and 6600 mm/yr) to only 500 mm/yr. The transition area corresponds to a narrow strip of forest protected from human activities: the Bandipur National Park.
The Kabini River drainage basin contains the three climatic areas and is a unique laboratory for studying the physical and chemical erosion fluxes with respect to the soil cover and the hydroclimatic conditions. In order to identify the major reservoirs regulating the cycles and to quantify the fluxes between these reservoirs, two small experimental watersheds have been delineated in the Bandipur National Park, near the villages of Moole Hole and Maddur. They are being equipped with different devices (borewells, pluviometers, gauging stations, rain samplers…) and sensors (weather station, tensionics,…) to allow the monitoring of data.
Both are located in a hard rock weathered fissured aquifer and can be considered to be representative of the main media hydrogeological context as more than 70% of the country are covered by plutonic, volcanic and metamorphic rocks (BOURNET 2004).