In this article of flood disaster management , we will try to introspect the main steps that could be taken to contain the Disaster:
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1) Reduction of Runoff
Runoff can be reduced by increasing infiltration of the surface water into the ground in the catchment area.This can be done by large scale afforestation in the catchment area.
The canopy of the forest cover intercepts the falling rain droplets and the roots,the leaf litter and humus are capable of holding Water.Together these induce infiltration and reduce runoff.
Runoff reduction helps in reducing soil erosion which leads to reduced sediment load of the streams which in turn reduces siltation and helps in maintaining the water accommodating capacity of the rivers.
2) Construction Of Embankments
Most of the embankments have been constructed in north India where Brahmaputra valley of Assam, northern parts of Bihar, U.P(Ganga,Yamuna & Ghaghara) and Punjab (Satluj, Baes & Ravi).
In South India, embankments have been constructed mainly on the deltaic parts of Mahanadi, the Godavari, Krishna and along the banks of Penneru.
These embankments have provided considerable protection to large areas.
Limitations of Embankments:
a- Often cause flood in downstream areas.
b- In case of heavy rain, embankments may develop breaches thereby causing heavy damage ti life and property.
c- Construction of embankments put limits to the river channel.In the presence of embankments the sediment is deposited in a limited river channel.It causes the river bed to rise at an accelerated rate and as a result flood water level increases.
3- Flood Forecasting
It means giving prior information regarding the occurrence of floods. It enables the people to take necessary action to prevent loss of human lives and livestock.
It involves following activities:
a) Observation and collection of hydrological and hydrometeorological data.
b)Transmission of data to forecasting centers.
c) Analysis of data and formulation of forecast.
d) Dissemination of forecast
4- Construction of Dams and Detention Basins
Dams have the capacity of holding huge quantity of flood waters, which could be later released down stream under controlled conditions. Dams have helped in mitigating flood peak in the down stream reaches. Notable among them are Bhakra Nangal Dam on Satluj, Hirakund Dam on mahanadi, Sardar Sarovar Dam on Narmada , Tungbhadra Dam on Krishna etc.
Apart from dams, ponds, tanks and surface storage structures etc also help in checking flood which can be used for harvesting during dryer seasons.