Some methods of flood control have been practiced since ancient times.[1] These methods include planting vegetation to retain extra water, terracing hillsides to slow flow downhill, and the construction of floodways (man-made channels to divert floodwater).[1] Other techniques include the construction of levees, lakes, dams, reservoirs,[1] retention ponds to hold extra water during times of flooding.
Methods of detection[edit]This is the method used for remote sensing the disasters. Detection of disasters such as floods, Earthquakes, Explosions are quite complex in previous days and range of detection is inappropriate. But it came to possibilities by using Multi temporal visualization of Synthetic Aperture Radar (SAR)images. But to obtain the good SAR images perfect spatial registration and very precise calibration are necessary to specify changes that have occurred. Calibration of SAR is very complex and also a sensitive problem. Possibly errors may occur after calibration that involves data fusion and visualization process. Traditional image pre-processing cannot be used here due to the on-Gaussian of radar back scattering, but a processing method called "cross calibration/normalization" is used to solve this problem. The application generates a single disaster image called "fast-ready disaster map" from multitemporal SAR images. These maps are generated without user interaction and helps in providing immediate first aid to the people. This process also provides image enhancement and comparison between numerous images using data fusion and visualization process. This proposed processing includes filtering, histogram truncation and equalization steps. The process also helps in identifying the permanent waters and other classes by combined composition of pre-disaster and post-disaster images into a color image for better identity.[2]