How to Use the Atlas 

            The Digital Watershed Atlas of India embodies maps showing spatial distribution of watersheds with extent, its river systems and administrative coverage (state/district) in the country. The Atlas delineates 3851 watersheds in the country with distinct spatial extent and unique National code. The Atlas has been developed using Geographic Information System (GIS) and Relational Data Base Management System (RDBMS).

The Atlas also contains compendium of regions with associated river systems and administrative units, distribution of Catchments, Subcatchments and Watersheds within Basins and Water Resources Regions. A Plate Index to watersheds has been appended in the Atlas for the benefit of the user. The administrative index displayed on each map plate indicates the district falling in the respective plate or a particular watershed.

The delineation and codification of watersheds have been done using a well defined systematic approach starting from bigger to successively smaller hydrological unit. The delineation is carried out from down-stream to upward considering a river system as discrete. The next river system is taken for delineation after completion of the previous one. The codification is done from left to right banks following alpha-numeric system. Thus, in the watershed level code 5D5A6, 5 stands for Water Resource Region, 5D denotes Basin, 5D5 as Catchment, 5D5A as Subcatchment and 5D5A6 as Watershed.

For further clarification and explanation, communication may be addressed to: