ARTICLES

Storing Water in Dam Reservoirs: Why is it Necessary?

                                                                                 SUMMARY

The world population is growing by leaps and bounds and the impact of this growth on water resources is such that we shall need more water for drinking, agriculture, energy generation, industrial production, and so on. Moreover, life-style is changing all over the world and a direct impact of this trend is a very significant increase in water use. For these reasons, demand for water is steadily increasing throughout the world. However, freshwater resources are limited and unevenly distributed both in time and place. In addition to this, seasonal variations and climatic irregularities in flow lead to the inefficient use of river [1]runoff, with flooding and drought causing problems of catastrophic proportions.

From the beginning of the human history, for almost 5 000 years, dams have served to ensure an adequate supply of water by storing water in times of surplus and releasing it in times of scarcity, thus also preventing or mitigating floods and making a significant contribution to the efficient management of finite water resources that are unevenly distributed and subject to large seasonal fluctuations. In the other words, the construction of dams in the concept of water resources management has always been considered as a basic requirement to harmonize the natural hydrological regime with the human needs for water and water related services. 

Purposes to be served by such a project usually include water supply, irrigation, flood control, hydropower generation, navigation, recreation, pollution abatement, industrial use, fish and wildlife conservation and other environmental considerations, salinity and sediment control, and recharge of groundwater. To meet these purposes, a number of dams are constructed to control and regulate the natural flows. This regulation function is obviously the main reason for creating reservoirs by constructing dams.

Water storage facilities are being constructed in Turkey as in any other country in the world, in order to make benefit of water resources which are not regular in terms of time and space, being aware of the fact that total level of amount may be enough in any given year or long term period. Water storage facilities are also being constructed in order to prevent flood and other water damages.

By the end of 20th century, there were 45000 large dams in over 150 countries. According to the same classification there are 625 large dams in Turkey. All over the world, 50% of the large dams were built mainly for irrigation(16).It is estimated that dams contribute to 12-16% of world food production. Almost all major dams are built for hydropower(16).

Hydropower currently provides 19% of worlds total electricity supply and is used in over 150 countries. Approximately 12<% of large dams are designated as domestic water supply dams (16).

According to DSİ report (17), in Turkey, 629 small[2] and large dams ,384 irrigation schemes ,98 water supply systems has been opened by State Hydraulic Works (DSİ) since 2005. Private sector companies  have  also built  510 river and canal type hydroelectric power plants since 2008.

Giving some figures  from the water resources projects in Turkey, this paper generally presents the  flow regulatory role of dams in water resource management in domestic rivers as well as transboundary rivers.

Keywords : Dams,Turkey, Dam reservoir, Euphrates river.