The flood forecasting and warning system
Flood forecast formulation and management involves the following processes:
- Observation and collection of data from field stations and satellites;
- Transmission of data from field stations to forecasting centers;
- Data processing and formulation of forecasts at the forecasting centers.
- Dissemination of forecast; and
- ]forecast monitoring and evaluation.
A pilot project for improvement of river and flood forecasting system in India was commenced in 1980 as a UNDP/WMO aided project for the Yamuna up to Delhi. Data acquisition systems using sensors have been in stalled and further improvement using satellite communication technology has been introduced. Regarding formulation of forecast, various models have been tailor-made, calibrated and utilized for forecasting purposes.
The Upper Yamuna Division of the Central Water Commission keeps hydrological observations in the upper Yamaha basin from the origin of the river upto Delhi Railway Bridge. Flood forecast are issued during the monsoon season (June 15 to October 15) when the water level at Delhi Railway Bridge crosses 204 m or is likely to cross this level, which is marked as the danger level. The forecast is disseminated to Delhi Administration, concerned Ministries, Military and para-military forces 48 to 53 hours before the incoming flood so that they can make flood fighting plans and arrange evacuation from low lying areas.
Communicating warnings to communities
At the end of the resource intensive flood forecasting and warning process, the warning that reaches the most vulnerably community, the hutment dwellers in the riverbed, is a cryptic one line statement, saying "the water level is expected to rise, make your arrangements". This community is from the lower most economic strata of the society, and as such, access to televisions and radios is low as is the level of literacy. The issued warning comes through the local police, and a policemen goes around the settlement, making the announcement. The warning includes no element of expected time of flooding, quantity of water being released from the headworks, areas expected to be submerged, or duration of high flow. As such, it hods little information or meaning.
Besides, since the water level in the river crosses its danger mark almost every year, and the warning is issued whenever the level crosses this mark, or is likely to cross it, the community ends up receiving this same flood warning virtually every year. Since the warning holds no information on the probability or severity of the expected flood, time it has come to lose its significance. The technology rich flood forecasting and warning system established, and constantly upgraded, to serve them, goes a waste.
Conclusions
The case of flood warnings in the Yumuna river-bed slums in Delhi is representative of the general state of warning dissemination regarding all disasters, all over the city. In order to make the warnings more effective, and make best use of developments achieved in the area of disaster forecasting and communication technology, there is an urgent need to strengthen the public dissemination link of the disaster warning systems, particularly with reference to vulnerable communities with weaker economic backgrounds.
The warnings issued need to be precise, yet provide all relevant information regarding the impeding disaster such as expected time, magnitude and specific areas to be worst hit. It needs to be reliable, and should not be resorted to regularly and casually. To achieve this, a two-way link between the scientific community engaged in technology developments and application and communities at risk is a must. The above factors hold good not only for pre-disaster warnings, but also for during and post-disaster public instructions and information dissemination.
Finally, awareness of the communities regarding interpretation of disaster communication, and appropriate action to be taken on these, is a crucial need.
References
- Delhi Development Authority. 1993. Planning of River Yamuna Bed, New Delhi: DDA.
- Government of India: 1994. Flood Forecasting and warning Network Performance Appraisal. Central Water Commission.
- Irrigation and Flood Control Department. 1995. Report on Effects of 1995 Floods in River Yamuna in Delhi and Proposed Remedial Measures. Govt. of Delhi.
- Kukreja P.B. 1995. Flood Forecasting and Warning System in India. Indian Institute of Public Administration.
- Ministry of Agriculture. 1994. Natural Disaster Reduction- South Asian Regional Report. Government of India.
- Office of the Deputy Commissioner. 1997. Flood Control Order. Govt. of NCT of Delhi.
- Sharma, K.K. 1996. An Appraisal of Structural Measures for Flood Control in Delhi. Unpublished Dissertation. Indian Institute of Public Administration.
- Singh Rajesh, Jha Suniti Kumar. 1996. Problems of the Flood Prone Squatter Settlements in Delhi: A Case Study. Indian Institute of Public Administration.