The document summarizes some of the negative environmental impacts of the Hoover Dam on the Colorado River ecosystem. It discusses how the dam led to lowering of the riverbed downstream, releasing of greenhouse gases from the reservoir, and destruction of local ecosystems and fish species. Specific impacts included endangering plants that could no longer reach the lowered water table, competition and temperature changes negatively impacting native fish populations, and significant bank erosion reducing habitat. While providing hydroelectric power, the dam fundamentally altered the natural environment of the Colorado River.