The Río Antón Ruíz Continuing Authorities Program (CAP) Section 1135 project located in the Humacao Natural Reserve (HNR) in Humacao, Puerto Rico.
The purpose of the project is to provide a permanent solution to reduce the saltwater intrusion into the HNR system. The need of the project is driven by the increased salinity levels which have occurred following con of the 205 flood control project, which was completed in 2001.
The Corps of Engineers has conducted a supplemental environmental assessment (EA) in accordance with the National Environmental Policy Act of 1969, as amended, (NEPA) in order to evaluate changed construction methodologies.
The Corps previously assessed the effects of the 2018 Recommended Plan in the Final Integrated Feasibility Report and Environmental Assessment (IFR/EA) for the Río Antón Ruíz Continuing Authorities Program (CAP) Section 1135 project in Puerto Rico. A Finding of No Significant Impact (FONSI) was signed on February 9, 2018.
The 2018 final recommendation is contained in the IFR/EA and is incorporated to the current supplemental EA by reference. Based on changed site conditions, the 2018 Recommended Plan has been updated to develop the 2020 Recommended Plan, which consists of the following:
- Installation of two sheetpile notched concrete cap weirs at the location of the temporary salt water intrusion measure (SWIM) structures. Weir #1 will be approximately 180 linear feet. Weir #2 will be approximately 140 linear feet.
- Both weirs will have a notch that is 3 feet deep by 15 feet wide with a 2 feet by 1 foot concrete cap to allow for continued vessel and fauna transit.
- Placement of riprap at the weirs starting from the location of the weir wall and extending approximately 25 feet downstream to protect from potential scouring.
- Use of a vibration or impact hammer to drive the sheetpile from the streambanks and/or temporary work platforms, constructed of either soil or geobags full of soil, within the diversion canal and Río Antón Ruíz.
- Permanent filling of scour holes adjacent to the weir in the diversion canal.
Details on the 2020 Recommended Plan can be found in the project’s draft supplemental EA.