Minute 332 and Joint Report PE.pdf

This document is a Joint Report from the International Boundary and Water Commission (IBWC) for the United States and Mexico, detailing a proposed Composite Cutoff Wall project at the Amistad International Dam to reduce the risk of structural failure. The project focuses on addressing sinkholes and seepage issues in the dam's earthen embankment, specifically on the Mexican side between Stations km 5+393 and 8+000, with a total project length of 2.6 kilometers.

The proposed solution involves constructing a two-part structural measure: a two-line grout curtain (upstream and downstream) and a concrete cutoff wall. The project aims to fill fissures, fractures, and seepage pathways in the karstic limestone foundation, mitigate potential dam failure risks, and improve overall structural integrity. The cost will be distributed between the United States and Mexico in the same proportion as the dam's construction (56.2% and 43.8%, respectively). Technical investigations have revealed 55 sinkholes to date, with 16 new sinkholes discovered in 2024, prompting the need for this remediation project. The work is expected to take approximately 40 months, including solicitation, design, and construction phases.