The Bureau of Reclamation (Reclamation) has authority for maintenance of the Rio Grande river-channel between Velarde, New Mexico and Caballo Reservoir, under the Flood Control Acts of 1948 and 1950. Under this authority, Reclamation monitors locations where there is danger of river erosion causing damage to levees, roads, ditches, and other riverside facilities; these locations are referred to by Reclamation as "priority sites." Two priority sites that have been identified are called the San Acacia priority sites at River Miles 114 and 113, hereinafter referred to simply as "San Acacia."

At the present time, the Rio Grande is eroding the west-side of the levee downstream of the San Acacia Diversion Dam. Historically, the river was a wide and braided channel with a sand bed and low banks. The river also experienced larger floods and higher sediment loads. Since the Low Flow Conveyance Channel (LFCC) was built in the 1950's, this section of the river was straightened. In addition, two channel bends were cut off in this section of the river. The river is currently incising, narrowing, coarsening, and migrating to the west. The meandering and incising characteristics are causing bank failure and erosion that is threatening the levee at the priority sites previously mentioned.

The federal action addressed in this Environmental Assessment would be the funding and execution of levee and LFCC relocation activities at San Acacia by Reclamation. The proposed action would provide space for the river to migrate naturally toward the west in the vicinity of River Miles 114 and 113. The relocation would prevent severe damage to the levee and LFCC.