Secondly, create a new dam decrease in quality geography resources. Erosion and the buildup of sediment at the base of the river. One of the first problems with dams is the erosion of land. Dams hold back the sediment load normally found in a river flow, depriving the downstream of this. In order to make up for the sediments, the downstream water erodes its channels. As a Dam construction across the river, the water flows over the dam, and accumulated in the area as a result of land area over the dam is flooding for a long time, most of the area is forest land. Which is considered a land that is rich, so that the flooding in the area. There are a lot of fertile land will be made to the loss of resources.