Central Water Commission (CWC) is the Nodal Organisation entrusted with the task of flood forecasting & early flood warnings in the country. Presently, CWC issues flood forecasts for 332 forecasting stations (199 river level forecast stations & 133 dam/ barrage inflow forecast stations). These stations cover 20 major river basins in 23 States & 2 Union Territories. In order to provide more lead time to the local authorities to plan evacuation of people & take other remedial measures, Central Water Commission (CWC) has developed basin wise flood forecasting model based on rainfall-runoff mathematical modeling for 5 days advance flood forecast advisory at identified flood forecasting and inflow forecasting stations. As per flood forecasting network of CWC, during the last five years, in addition to existing flood prone states of Assam, Bihar Uttar Pradesh & West Bengal extreme floods were witnessed in the states of Kerala, Karnataka, Tamil Nadu, Andhra Pradesh, Telangana, Odisha, Maharashtra, Chhattisgarh, Madhya Pradesh & Rajasthan due to excess to large excess rainfall in these states combined with extremely heavy rainfall in short duration. While giving reply to a question, the Minister of State for Jal Shakti, Bishweswar Tudu informed that dams, in general, aid in moderating the floods. However, faulty operations of reservoirs may sometimes result in flooding of downstream region. The CWC has prepared Guidelines for Preparing Operation and Maintenance Manuals, 2018 for dams which contain various aspects of project operation including normal operation and emergency operation. These serve as guidance for dam owners on various protocols and responsibilities for managing water releases during a year including flood seasons. Details for preparation of operational rule curve (both for reservoir filling and release) are also part of the guidelines. In accordance to the provisions of Disaster Management Act, 2005, directions have been issued to the State Governments and the State authorities mandating them to give intimation to the adjacent States immediately after a decision is taken by the authorities of the State to release water from the reservoirs/dams. Data on flooding caused due to faulty operations of reservoirs is not maintained centrally. As per the National Register of Large Dams, 2019 of Central Water Commission, India has 5745 large dams, of which 5334 are completed and operational while 411 are under construction stage. Further, there are 227 large dams which are more than 100 years old and about 18% of dams are having age between 50 to 100 years. Under, Dam Rehabilitation and Improvement Project (DRIP), Design flood review of 250 large dams located in 7 States was carried out under Phase-I, implemented during 2012-2021 with World Bank funding. Further, rehabilitation measures (structural interventions) or operational procedures (non-structural methods of coping with design floods) were undertaken under the Project ensuring safety of the dam and reservoir with the revised design flood. In addition, design flood review of 267 large dams has been carried out under DRIP Phase-II, which has become operational in October 2021. Dam Safety Act 2021 very comprehensively provides for surveillance, inspection, operation and maintenance of the dams for prevention of dam failure related disasters and to provide for institutional mechanism to ensure their safe functioning and for matters connected therewith or incidental thereto.
