Central Water Commission (CWC) compiles the flood damage data every year reported by the States/ UTs in the predefined proforma.
As per the assessment done by CWC in the year 1993, the river basin-wise average annual water availability in the country is 1869 billion cubic meters (BCM). It is estimated that owing to topographic, hydrological and other constraints, the utilizable water with conventional approach is 1123 BCM which comprises of 690 BCM of surface water and 433 BCM of replenishable ground water resources. Further, it has been estimated in the year 2009 by CWC that about 450 BCM of surface water is being utilized for various purposes. Also, as per the July 2014 report of CGWB titled ground water draft for irrigation, domestic and industrial uses is 245 BCM. Thus, the quantity of water flowing down to the sea can be approximately considered as 1174 BCM.
This information was given by Union Minister of State for Water Resources, River Development and Ganga Rejuvenation Dr. Sanjeev Kumar Balyan in a written reply in Lok Sabha today.