Connectivity and Jurisdictional Issues for Rocky Mountains and Great Plains Aquatic Resources

Understanding the connectivity between wetlands and headwater intermittent and ephemeral streams with downstream navigable waters has become a critical focus for U.S. Clean Water Act protection. Recent Supreme Court decisions resulted in a new interpretation and federal agency guidance for how to assess jurisdiction over waters of the U.S. under Section 404 (dredge and fill permits). For jurisdictional determinations (JDs) of waters considered to be 'geographically isolated' or requiring an evaluation of their 'significant nexus' to navigable waters, coordination between the U. S. Environmental Protection Agency (EPA) and Army Corps of Engineers (COE) is required. EPA Region 8 evaluated all coordinated JDs during the first year of guidance implementation from June 2007 to June 2008. The region includes the Rocky Mountains, Great Plains, and parts of the Colorado Plateau, including portions of 20 Level III Ecoregions. Approximately 54% of all stream miles are 1st-order channels, and 77% are intermittent. During the period, JDs for 1,265 individual waters from three COE districts were evaluated, resulting in 793 wetlands, 12 streams, and 18 water bodies considered non-jurisdictional due to isolation. Significant nexus evaluation was required for 441 waters, of which 49 wetlands, 66 streams and 14 other water bodies were considered non-jurisdictional.