Disadvantages of reservoir

1. Increase the frequency of disasters.

The construction of reservoirs may induce earthquakes and increase the frequency of earthquakes in the reservoir area and nearby areas. Because the lower parts of the mountains on both sides will be submerged for a long time in the future, the frequency of landslides, landslides and mudslides will increase.

2. Lead to sediment deposition in the reservoir area.

Due to the interception of the dam and the backwater effect caused by the change of water potential in the reservoir tail area, sediment will inevitably accumulate in the reservoir, especially in the dam and reservoir tail (backwater effect).

3. Soil salinization

Continuous irrigation makes the groundwater level rise and brings the salt in deep soil to the surface. The high content of salt and various chemical residues in irrigation water leads to soil salinization.

4. deterioration of water quality

The water surface area of the reservoir area is large, a large amount of water evaporates, and soil salinization increases the salt and chemical residues in the soil, thus polluting the groundwater and increasing the salt content of the downstream river.

5. Changes of river water quality

Due to the deterioration of water quality, the speed of water flow slows down, and aquatic plants and algae spread everywhere, which not only evaporated a lot of river water, but also blocked the river irrigation channels and so on. These aquatic plants not only spread all over irrigation channels, but also invaded major rivers. They hinder the effective operation of irrigation channels and need to be cleaned by mechanical or chemical methods frequently. This increases the maintenance cost of the irrigation system.

6. Impact on downstream rivers

Due to the change of water potential and sediment concentration, it may also change the river direction and the alluvial degree of the downstream reach, resulting in serious riverbed erosion and the river (sea) mouth retreating towards the land.

7. Increase the incidence rate

The incidence of schistosomiasis and other epidemics in the lower reaches has increased because of the static water flow.

8. Impact of migration

Due to the rising water level, the reservoir area is flooded and needs to be resettled. Moreover, due to the construction of the reservoir, the scenic spots and cultural relics in the reservoir area have been flooded and need to be relocated and restored.

9. Impact on climate

After water storage in the reservoir area, the water area will expand and the water evaporation will increase, which will reduce the temperature difference between day and night in the nearby area and change the climate environment in the reservoir area.

10. Diplomatic influence

Building a reservoir on an international river is tantamount to the redistribution of water resources, which indirectly affects the relationship between the country where the reservoir is located and the downstream countries.

1 1, loss of value

Submerged cultural relics or caused the loss of the original natural landscape ornamental value.