Rio Grande de Arecibo PR (C)

May 2023


Rio Grande de Arecibo PR (C)
Construction (C)
Congressional District: Puerto Rico


The Rio Grande de Arecibo (RGDA) Flood Risk Management (FRM) Project was authorized by the Water Resources Development Act of 1996, Section 101(a)(26). The ~189 square mile drainage basin is characterized by steep mountains and an associated high-velocity run-off. Severe flooding has occurred with overflows of the Río Grande de Arecibo, Río Tanamá, and Río Santiago during hurricanes, tropical events, and stationary fronts. Historical records indicate extensive flooding in August 1899, September 1928, October 1954, May and October 1985, January 1992, September 1996 with Hurricane Hortense, September 1998 with Hurricane Georges, and September 2017 with back-to-back hurricanes Irma and Maria. During Hurricane Georges, the City of Arecibo experienced a 100-year flood event with significant damages to commercial and residential properties, and the loss of the Victor Rojas Bridge. Hurricane Maria’s rainfall caused record-breaking flows and flooding with damages estimated at over $100 million. The RGDA FRM Project will provide 100-year risk reduction of overflows from the Arecibo River, lower Rio Santiago, and Rio Tanama into the Central Los Caños area. The recommended plan combines a floodwall, levee along the Arecibo River, Rio Santiago channel improvements, three (3) bridge replacements, and a wetland mitigation area for the creation of a mangrove habitat.


Estimated Total Cost $205,200,000
Estimated Federal Cost $195,200,000

a. Regular Civil Works Funds:

Allocation thru FY22 $20,423,000
Allocation for FY23 $0
President's Budget FY24 $0


b. P.L. 115-123: Bi-Partisan Budget Act of 2018, Supplemental:

Current Working Estimate $174,100,000
Allocation thru FY22 $17,261,000
Allocation for FY23 $1,308,000



Puerto Rico Department of Natural and Environmental Resources (DNER)
P.O. Box 366147
San Juan, Puerto Rico 00936


RGDA Contract 1, which included the Rio Tanamá levee and channel improvements, PR-22 levee, PR-10 culvert and the Rio Santiago diversion channel, was turned over to the non-federal sponsor for continued operation and maintenance (O&M) on 10 January 2012. The remaining RGDA project segments are being funded under the Bipartisan Budget Act (BBA) of 2018 (P.L. 115-123). Plans and specifications (P&S) for the new Supplemental Contract 1 (consisting of segments 2A and 3) was brokered to the St. Louis District (MVS).

P&S of the intermediate design package for the RGDA Project was completed in July 2021. As the 95% P&S design efforts progressed in the summer of 2022, additional scour and bend scour analysis identified a high risk with the current terminal wall design at the mouth of the Arecibo River. It was determined that due to dynamic hydraulic conditions at the project site (area geology, intense velocities, change in flow direction) and the increased scour levels during a 100-year storm event, scour would be down to -45' along the entire terminal wall instead of the -35’ scour initially estimated and designed for. Currently, the alignment options being evaluated by the Project Delivery Team (PDT) will realize over 80% of the overall project benefits.

Click for full-sized Rio Grande de Arecibo Project Map