Rewrite the following text to be coherent.
Hydropower is considered a renewable and clean energy source. Large dams, such as the Three Gorges Dam or the Xiluodu Dam have had environmental impacts on the areas surrounding dam reservoirs.
Hydropower is considered a renewable and clean energy source. However large dams, such as the Three Gorges Dam or the Xiluodu Dam have had environmental impacts on the areas surrounding dam reservoirs.