Geological Disasters
Earthquakes may be caused by changes in the river and dam systems (Refer to the ANSI standard N170-1976, replaced by the ANSI / ANS 2.8, "Determining the basis of the design of the power reactor site flood", July 28, 1992)[10]. After the dam is removed, floods in the flood season may affect the downstream towns, such as Safford, endangering the safety of the residents. After the decline of water level in the detention area, the original detention area was submerged. A large amount of land released, the formation of large tracts of desolate wetlands, if not treated and used, will produce landslides, debris flow and other natural disasters.
Ecological Environment Impact
Dam removal will change the upstream and downstream aquatic ecosystems. This effect varies with time and space. After the demolition of the dam, the water environment will face the dynamic state of the reservoir from the static state of the reservoir to the river, which is opposite to the static water state of the river when the river water environment is changed from the dynamic state of the river to the dam. "Reverse ecological environment". The reverse ecological environment problems faced by the project will bring great influence to the ecological environment of the reservoir area and downstream. Dam removal will damage the just-formed reservoir ecological environment balance, a variety of fish habits will be broken, facing the problem of adapting to the new environment. The treatment of sediment deposition in the reservoir area and the series of ecological and environmental problems caused by the sediment discharge to the downstream flora and fauna and the production and life; the effect of dam removal on the ecological environment near the dam site and how to restore the construction problem.
Pollution
The main causes of water pollution in the reservoir area are as follows: pollution of the construction itself; flooding of various pollution sources; water heterogeneous layer effect; changes in hydrogeological conditions and human factors. During the construction period, a large amount of engineering and living waste is generated, resulting in an increase in the degree of pollution of the river water body in the demolition project. Even after the completion of the project within a few years after the rain will still wash the scene of a large number of pollutants into the river body. After the demolition of the reservoir will cause the lower reaches of the groundwater level, pressure, temperature changes. The dissolved power of the groundwater eruption will increase, the number of subsurface increases, especially in the rainy season. Will increase the suspended solids and dissolved solids in the water. In addition, the analysis needs to take into account the bulk of the dam after the demolition of a large number of dam material and the disposal of harmful substances.
