1. Flood Mitigation Methods

2. Flood Risk Management Measures
Structural measures
Modify flood behavior
Nonstructural measures
Modify damage susceptibility

3. Structural Measures
1.Embankments/Banks, Flood Walls, Flood Levees(may be natural leeve)
The embankment system in the river restricts the river to its existing course and prevents it from overflowing the banks.
Embankments are constructed generally with earth easily available from nearby areas.
In developed areas where adequate space is not available or land is very expensive, concrete or masonry floodwalls are constructed.

6. Natural leeves

8. Hard engineering technique Description Advantages Disadvantages
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9. Hard engineering technique Description Advantages Disadvantages

10. Advantages and Disadvantages
Embankments have provided positive benefits by ensuring protection against floods and river spills.
Embankments with proper roads have provided useful communication link in the area. These are generally the only means of communication during floods and thereafter.
However, breaches in them have resulted in large-scale flooding in the protected areas. Poor drainage in the protected area also leads to drainage congestion.
The embankments may lead to deposition of silt and rise in bed levels, thus decreasing the carrying capacity of the river and aggravating drainage congestion
They interfere with natural drainage and deprive protected areas of fertile soil and groundwater recharge.
They are also generally unable to withstand erosion unless adequately protected

11. Dams, Reservoirs and other Water Storages
Lakes, low lying depressions, tanks, dams and reservoirs store significant proportions of flood water and the stored water can be released subsequently when the flood has receded.
The stored water can also be used subsequently for irrigation, power generation, and meeting industrial and drinking water needs.
In the case of large multipurpose reservoirs, a proper reservoir regulation schedule can be worked out for optimum benefit from the project as a whole.

12. Dams and Reservoirs Mt. Morris Dam McCook, Ill.
Center Hill Lake, Tenn.
Yatesville Lake, Ky.

14. Channel Improvement
A channel can be made to carry flood discharge at levels lower than its prevailing high flood level by improving its discharge carrying capacity.
Channel improvement aims at increasing the area of flow or the velocity of flow (or both) to increase its carrying capacity.
Channel improvement has not been resorted to widely in India mainly because of the high costs involved and topographical constraints.
However, it is of advantage to take up such work for local reaches.

15. Channel Modification Projects
Martins Fork, KY, diversion
Minnesota River, MN, diversion
Harlan, KY, tunnels
River Rouge, MI, channelization

16. Drainage Improvement
Surface water drainage congestion due to inadequacy of natural or manmade drainage channels results in flooding in many areas.
In such cases constructing new channels and/or improving the capacity of existing channels constitute an effective means of flood control.
The system of ‘dhars’ or ‘old channels’, efficiently serve the function of draining away the spillage and surface flows generated by local rains.
The blocking of these natural drainage channels, which is normally done in the name of ‘reclamation for development’, may result in drainage congestion/ water- logging.

17. Catchment Area Treatment/ Af-forestation
Watershed management measures such as developing the vegetative cover i.e. afforestation and conservation of soil cover in conjunction with structural works like check dams(small and temporary dam constructed to reduce the erosion), detention basins(surface storage system) etc. serve as an effective measure in reducing flood peaks and controlling the suddenness of the runoff.
This, however is not very effective during a large flood although, it does help in reducing the siltation of reservoirs and to some extent, silt load in the rivers as well.

18. Anti-erosion Works
Alluvial rivers are usually meandering in nature and, therefore, raise problems of erosion and silting at various locations.
Bank erosion can be minimised by adopting measures that aim at deflecting the current away from the river bank or which aim at reducing the current along the bank of the river and induce silt.
Geo-synthetic material (woven geotextile) available in various forms like big bags and tubes etc. can be filled in-site with riverbed sand to form the groynes(barrier bulit into sea), spurs(bulit with stones as barrier)&revetments(sloping barrier)
the bank and bed protection were carried out with MacBags .

19. GEOSYNTHETIC MATERIAL

20. SPURS

21. Revetment

22. Groynes

23. Alignment, Location, Design and Provision of Waterway
Roads and railway embankments cut across the drainage lines and may lead to increase in vulnerability of the area, through which they pass, to flooding and drainage congestion, if they are not properly aligned, located and designed.
Alignment, Location, Design and Provision of Waterway i.e. Vents, Culverts(tunnel carrying opendrain under road or railway), Bridges and Causeways in National Highways, State Highways, District and Other Roads and Railways Embankments.

24. Non-Structural Measures
Non-structural measures strive to keep people away from flood waters. It contemplates the use of flood plains judiciously, simultaneously permitting vacating of the same for use by the river whenever the situation demands. This technique allows the use of flood plains by reducing the disaster dimension, while retaining its beneficial effects.

25. A floodplain or flood plain is an area of land adjacent to a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge.

26. Flood Plain Zoning
It is natural for a river to overflow its banks in the event of heavy rainfall in its upper catchments and spill into the flood plains(low lying area near the river), which are basically its domain. Extensive and often unplanned use of flood plains by man disregarding the basic fact that it is part and parcel of the river leads to damage.
The basic concept of flood plain zoning is to regulate land use in the flood plains in order to restrict the damage due to floods, while deriving maximum benefits from the same.

28. Flood Proofing
Flood proofing measures help greatly in the mitigation of distress and provide immediate relief to the population in flood prone areas.
It is essentially a combination of structural change and emergency action, not involving any evacuation.
The techniques adopted consist of providing raised platforms for flood shelter for men and cattle, raising the public utility installation especially the platforms for drinking water hand pumps and bore wells above flood level

30. Flood Forecasting and Warning
Flood forecasting enables us to be forewarned as to when the river is going to use its flood plain, to what extent and for how long.

31. Medical Preparedness
There is the risk of drowning and physical trauma along with the threat of diseases associated with contamination of water and the creation of mosquito breeding sites.
Direct health effects of a flood may include: drowning; injuries like cuts, sprains, fractures, electric shocks; diarrhoea, vector-and rodent-borne diseases like malaria, leptospirosis; skin and eye infections; and psychological stress.
The indirect health consequences of floods are usually due to damage caused to health care infrastructure and loss of essential drugs, damage to water and sanitation infrastructure.