Many of the millennium is the true human energy contained in flowing water. Inventories tsieyi energy are enormous. People learned to use this power before all others. When night came electricity, water wheel again revived, but now in the form of water turbine. We can say that even in 1891 started adding hydropower.

     Hydroelectric power plants have many advantages: constant supply of energy recovery, ease of use, the relative absence of environmental contamination. But to build a large dam is much harder than the water wheel. To get powerful turbines rotate, you nakopyty huge energy reserves by dams. So you want to flood certain areas, which in turn may lead to irreparable consequences. So building dams requires very precise engineering calculations, and any mistake can lead to environmental disaster. Even when accurate calculations dam construction is an important environmental factor in large areas. Nothing is taken from nowhere: Dam reduces the flow velocity, taking away her energy, and it can cause waterlogging and "flowering" of water in the floodplains. Imbalance can cause the most unpredictable consequences.

      Now China is built on r.Yandzy Dam is the biggest in the world. Predbachayetsya that the water level to rise in 2004 at 220 pm This is despite the fact that every second he makes the sea Yandzy 34,000 m3 of water, and Dam will have to pass 25 000 m3. It really will help produce enormous amounts of energy and immediately solve energy problems in China. But half of all rural hospolarstva China uses water, the Yandzy and its tributaries. Half of Agriculture of China - is 8-10% of the world's agriculture. Even scary to imagine what would happen if engineers made the fatal error. In addition to plan the project will be flooded 13 major and 70 small towns, 1300 villages. Flooding is also subject to many cultural and archaeological sites, tourist attractions, including vsesvitno famous "Three." So full transition to extract energy only from the river flows may be less dangerous than the use of fuel resources. Now we can tell only part of the rivers of energy use in places where regular flooding are real natural disasters. In regions such dangerous flooding converted through dams to useful energy. How can cite prykad cascade dams Corporation "TVA" on the river Tennessee, USA. 51 Dam protect arable land. In 38 of them are hydroelectric. Before construction of the dams of agricultural activity was almost impossible.