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Drought prone area development
Ø Drought-prone areas should be made less vulnerable to drought associated problems through soil conservation measures, water harvesting practices, minimization of evaporation losses, and development of ground water potential including recharging and transfer of surface water from surplus areas where feasible and appropriate.
Ø Flood cushioning: The reservoirs created behind dams may be emptied to some extent, depending on the forecast of impending flood, so that as and when the flood arrives, some of the water gets stored in the reservoir, thus reducing the severity of the flood.
Ø Embankments and dykes: Embankments & dykes also known as levees are earthen banks constructed parallel to the course of river to confine it to a fixed course and limited cross-sectional width. The heights of levees will be higher than the design flood level with sufficient free board. The confinement of the river to a fixed path frees large tracts of land from inundation and consequent damage.
Ø Flood forecast and warning: Forecasting of floods in advance enables a warning to be given to the people likely to be affected and further enables civil-defence measures to be organized. It thus forms a very important and relatively inexpensive nonstructural flood-control measure. However, it must be realized that a flood warning is meaningful if it is given sufficiently in advance. Also, erroneous warnings will cause the populace to loose faith in the system. Thus the dual requirements of reliability and advance notice are the essential ingredients of a flood-forecasting system.
Ø Flood plain zoning: One of the best ways to prevent trouble is to avoid it and one of the best ways to avoid flood damage is to stay out of the flood plain of streams. One of the forms of the zoning is to control the type, construction and use of buildings within their limits by zoning ordinances. Similar ordinances might prescribe areas within which structures which would suffer from floods may not be built. An indirect form of zoning is the creation of parks along streams where frequent flooding makes other uses impracticable.
Ø Flood proofing: In instances where only isolated units of high value are threatened by flooding, they may sometimes by individually flood proofed. An industrial plant comprising buildings, storage yards, roads, etc., may be protected by a ring levee or flood wall. Individual buildings sufficiently strong to resist the dynamic forces of the flood water are sometimes protected by building the lower stories (below the expected high-water mark) without windows and providing some means of watertight closure for the doors. Thus, even though the building may be surrounded by water, the property within it is protected from damage and many normal functions may be carried on.
Ø Soil conservation measures: Soil conservation measures in the catchment when properly planned and effected lead to an all-round improvement in the catchment characteristics affecting abstractions. Increased infiltration, greater evapotranspiration and reduced soil erosion are some of its easily identifiable results. It is believed that while small and medium floods are reduced by soil
Ø conservation measures, the magnitude of extreme floods are unlikely to be affected by these measures.
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