Floods are often a result of heavy rains associated with the natural course of surplus water flow being hindered by encroachments, unplanned development and the like. Heavy rainfall in excess of normal capacity to manage the quantity of water can also result in floods in cityscapes historically built on flat levels. The Central Water Commission has developed a network of flood forecasting stations and issues Daily Flood Bulletins to all designated Authorities/Agencies of the Central Government and State Governments/ District Administration during the Monsoon seasons for all the major river basins in the following categories:
- Category IV: Low Flood stage (Water level of the river is flowing between Warning Level and Danger Level)
- Category III: Medium Flood (Water Level below 0.50m. less than HFL and above Danger Level)
- Category II: High Flood (Water Level less than Highest Flood Level, but still within 0.50m. of the HFL)
- Category I: Unprecedented Flood (Water Level equal and above Highest Flood Level (HFL)
Pre – Disaster
- Effective early warning shall be given when a decision has been taken to release water from a reservoir/dam.
- Public Address System/sirens and other methods should be planned for all habitations that are in the course of the river.
- All the sirens/hooters should be connected by laying cable or other modern techniques/systems so that they will ring simultaneously at the press of a button.
- Flood warning mechanism should be ensured. Activate flood warning to vulnerable communities and stakeholders.
- Evacuation of vulnerable people to safe areas and pre-designated shelters to be done.
- If Flood risk is reduced, a Flood de-warning may be issued in consultation with PWD(WRD)
- Boats become an essentially on account of the flooding and hence need to be sourced from various sources. The problem is more acute when the flooding occurs inland.
- In case Flood occurs, rescue and relief activities shall be initiated immediately (to be read along with Chapter 6) Police/Fire – Rescue teams/Ambulances will need to be pressed into service. Citizen Rescue and swimming teams will need to be put to work.
- The District Collector must arrange for a full-fledged review of PWD tanks and dams separately to ensure that the flood level release protocol is fully understood by the officers themselves. Maintenance issues of the lakes and dams will also need to be looked along with surplus run off.
Declaration of Stages of Flood
The standard stages of the flood situation are as follows:
- Flood Alert: Flooding is possible. Be prepared
- Flood Warning : Flood is expected require immediate action
- Severe Flood Warning : Danger to life and property
- De Warning : Flood warning /Flood alert is withdrawn