Protecting U.S. Water Resources under the Clean Water Act

The U.S. Environmental Protection Agency requires technical support to enforce the Clean Water Act, particularly regarding the protection of waters of the United States (WOTUS) and implementation of CWA Section 404, which regulates the discharge of dredge and fill material. This work involves complex geospatial analysis, field assessments, and enforcement across diverse geographic regions and environmental conditions. 

Since 2011, ERG has supported EPA in protecting our nation’s water resources, including rivers, streams, and wetlands, under the Clean Water Act. ERG conducts geospatial and modeling analyses using aerial photography, topography, and LIDAR to determine impacts to waters. We compile data required by EPA to target stream crossings for inspections. We also perform inspections of dredge-and-fill impacts to wetlands, as well as field assessments to determine the discharge of hazardous substances to WOTUS. To determine jurisdictional status, we evaluate physical, chemical, and biological indicators of water bodies. We also provide EPA with technical reports and publication-quality map products for use in determining impacts to WOTUS. ERG has supported WOTUS and 404 enforcement cases in many states, including Alabama, Alaska, Arkansas, California, Florida, Hawaii, Indiana, Illinois, Louisiana, Mississippi, Montana, Nevada, New York, North Dakota, Ohio, South Carolina, South Dakota, and Texas. In one example, we helped EPA evaluate a 410-mile-long oil and gas pipeline by assessing over 100 wetland and stream crossings.