Which federal agency is primarily responsible for the implementation of the Clean Water Act (CWA)?

The Environmental Protection Agency (EPA) is primarily responsible for the implementation of the Clean Water Act (CWA). This legislation, enacted in 1972, aims to restore and maintain the integrity of the nation's waters by preventing point and non-point source pollution. The EPA's responsibilities under the CWA include setting water quality standards, issuing permits for discharges into waters, and enforcing compliance with those standards and permits.

The agency plays a critical role in regulating pollutants and managing water quality, ensuring that waterways are protected for public health and the environment. It also collaborates with state and local governments to enforce regulations and promote initiatives that support clean water goals.

Other agencies, while involved in aspects of water management and protection, do not have the primary role in implementing the CWA. For instance, NOAA focuses on oceanic and atmospheric conditions and managing marine resources, while the Department of Energy concentrates on energy policies and technologies. The U.S. Army Corps of Engineers has responsibilities related to water resources and infrastructure but does not lead the implementation of the CWA itself. In summary, the EPA's central role in enforcing and regulating water quality standards makes it the correct choice for this question.