Organisation and implementation of operations

Since ancient times floods have been seen as the most terrible calamity. In many world religions they have been described as "God's punishment". Among all natural calamities, flooding heads the list in sheer number of catastrophes, its wide coverage of territory and the most economically destructive.

Floods are caused by spills of rivers in high water, heavy rains, ice blocks on rivers, heavy melting of ice, failure of dams due to earthquakes, bombing or technological catastrophes at hydro facilities and diversions of rivers.

Floods cause rapid inundations of vast territories, where people are injured and lost, agricultural and wild animals are killed, dwelling, industrial buildings and other structures, utility plants, roads, electrical and communication lines are damaged or destroyed.

Agricultural produce is destroyed, the structure of the soil and the relief of the land is changed, productivity is interrupted and storage of raw material fuel, food, forage, fertilizers and construction materials is either destroyed or becomes unusable.

If a basement or underground floors are inundated, the water may cause malfunction of equipment, which in turn, will cause electric accidents and short circuits in electric systems.

In a number of cases floods may result in landslides and mudflows.

The basic characteristic features of floods are water expenditure, its volume and the level to which it rises, the area covered, its duration, the speed and composition of water flow.

During such accidents, people can be affected by the kinetic energy produced by the burst waves. Mechanical injuries of varying severity could be the result of:

Magnitude and structure of population losses vary depending on a density of population in a flooded area, time of a day, velocity of movement and height of a burst wave, temperature of water and others.
At accidents in hydro dynamically hazardous objects, the total losses of population in a burst wave area, can reach 90% at nighttime and 60% in daytime. The irretrievable losses could be 75% at nighttime and 40% in daytime, while the sanitary loses 25% and 60%, respectively.

Frequently, secondary flood effects could cause greater disaster than a flood itself.

Prevention and minimization of adverse flood consequences includes adequate organisational and engineering-technical measures such as: reinforcement of the hydro-technical facilities, construction of additional dams and banks to hold up water flows, accumulation of emergency material (soil) to fill up holes, increase of height of existing dikes and dams, training in emergency swimming, etc. A permanent hydrological forecast is necessary including the estimates on potential and possible water levels in water storages. Transport means has to be allocated and on disposal for organisation of possible evacuation of population and of some significant values (valuable paints, movable historic heritage, archives, etc.). Training of population and special units to operate efficiently under flood condition should be organised.