United States Section; Notice of Availability of a Final Environmental Assessment and Finding of No Significant Impact for Improvements to the Lateral A/Retamal Dike Levee System, in the Lower Rio Grande Flood Control Project, Hidalgo County, TX

AGENCY:

United States Section, International Boundary and Water Commission, United States and Mexico.

ACTION:

Notice of Availability of Final Environmental Assessment (EA) and Finding of No Significant Impact (FONSI).

SUMMARY:

Pursuant to Section 102(2)(c) of the National Environmental Policy Act of 1969; the Council on Environmental Quality Final Regulations (40 CFR parts 1500 through 1508); and the United States Section's Operational Procedures for Implementing Section 102 of NEPA, published in the Federal Register September 2, 1981, (46 FR 44083); the United States Section hereby gives notice that the Final Environmental Assessment and Finding of No Significant Impact for Improvements to the Lateral A/Retamal Dike Levee System, in the Lower Rio Grande Flood Control Project, located in Hidalgo County, Texas are available. A notice of finding of no significant impact dated January 8, 2007 provided a thirty (30) day comment period before making the finding final. The Notice was published in the Federal Register on January 8, 2007 (Federal Register Notice, Vol. 72, No. 4, Pages 797-798).

For Further Information Contact:

Daniel Borunda, Environmental Protection Specialist; Environmental Management Division; United States Section, International Boundary and Water Commission; 4171 N. Mesa, C-100; El Paso, Texas 79902. Telephone: (915) 832-4767, e-mail: danielborunda@ibwc.state.gov.

Backgound: The USIBWC, in cooperation with the U.S. Fish and Wildlife Service (USFWS), prepared this Environmental Assessment for the proposed action of raising the Lateral A/Retamal Dike Levee System located in Hidalgo County, Texas to improve flood control. This levee system is part of the LRGFCP that extends approximately 180 miles from the Town of Peñitas in south Texas to the Gulf of Mexico. The Lateral A/Retamal Dike Levee System extends approximately 14 miles, from the Carlson Settling Basin to Retamal Diversion Dam.

The Proposed Action would increase the flood containment capacity of the Lateral A/Retamal Dike System to meet the 3-foot freeboard design criterion for flood protection. Throughout the approximately 11.5-mile Lateral A segment, height increases between 1.5 and 4 feet are typically needed to reach the design freeboard value. For the 3.5-mile Retamal Dike segment, typical increases in levee height range from 0 to 2 feet. The increase in levee height will result in an expansion to the levee footprint by lateral extension of the structure. Structural improvements, such as a slurry cutoff barrier or a riverside impermeable liner, may be required for some levee segments where seepage is a potential problem.

The Environmental Assessment assesses potential environmental impacts of the Proposed Action and the No Action Alternative. Potential impacts on natural, cultural, and other resources were evaluated and mitigation measures were incorporated into the Proposed Action. A Finding of No Significant Impact was issued for the Proposed Action based on a review of the facts and analyses contained in the Environmental Assessment.

The USIBWC is authorized to construct, operate, and maintain any project or works projected by the United States of America on the Lower Rio Grande Flood Control Project (LRGFCP) as authorized by the Act of the 74th Congress, Sess. I Ch. 561 (H.R. 6453), approved August 19, 1935 (49 Stat. 660), and codified at 22 U.S.C. Section 277, 277a, 277b, 277c, and Acts amendatory thereof and supplementary thereto. The LRGFCP was constructed to protect urban, suburban, and highly developed irrigated farmland along the Rio Grande delta in the United States and Mexico.

Availability: Electronic copies of the Final EA and FONSI are available from the USIBWC Home Page at http://www.ibwc.state.gov.