United States Army Corps of Engineers May 2017 – Federal Register Recent Federal Regulation Documents

The U.S. Army Corps of Engineers (Corps) intends to prepare a General Reevaluation Report and Supplemental Environmental Impact Statement (GRR/SEIS). This is in compliance with the National Environmental Policy Act (NEPA), for the Middle Rio Grande Flood Protection Bernalillo to Belen, New Mexico Project (Project). This also is the implementation of actions to avoid or minimize potential effects to Endangered Species Act (ESA) listed species and/or associated critical habitat. The GRR/SEIS will supplement the May 1979, Middle Rio Grande Flood Protection Bernalillo to Belen, New Mexico, Final Environmental Impact Statement (FEIS). That document assessed impacts from alternatives to reduce flood risk to structures, infrastructure and life safety. The previously proposed alternative included reconstructing the existing spoil bank system maintained by the Middle Rio Grande Conservancy District (MRGCD) with structurally competent levee system.

Pursuant to the National Environmental Policy Act (NEPA), the U.S. Army Corps of Engineers (Corps), Huntington District has prepared a Supplemental Final Environmental Impact Statement (SFEIS) to disclose potential impacts to the natural, physical, and human environment resulting from modifications to Bluestone Dam. The original EIS was published in 1998 and a Record of Decision (ROD) was signed in 1999 concluding the NEPA process allowing the Corps to initiate implementation of the Bluestone Dam Safety Assurance (DSA) Project. When completed, the current modifications under construction will strengthen the dam's stability and allow for increased discharge capacity through the use of hydropower penstocks substantially reducing risk. However, physical modeling and expert analysis conducted during project construction indicated the downstream bedrock is vulnerable to an unacceptable degree of erosion during high flow events. The Corps has also recognized potential for unacceptable erosion associated with overtopping of areas of the dam not designed to be overtopped. After a full consideration of alternatives to achieve acceptable risk levels, this SFEIS recommends implementing modifications to the existing stilling basin to prevent scour that could result in spillway instability and thus dam failure. Proposed modifications include alteration to the existing stilling basin to include installation of a protective concrete apron and larger baffles among other features described in the SFEIS. This SFEIS also addresses the impacts associated with prolonged construction duration of modification features described in the original EIS and ROD.