Project History

The Río Puerto Nuevo Flood Risk Management Project is in the Río Piedras Watershed, a 26 square mile urban watershed in San Juan. The watershed begins in the foothills of the central mountains south of San Juan. Flowing north from the Caimito District to the San Juan Bay, the watershed's main river, the Río Piedras, is joined by the following tributaries: Quebrada Margarita, Bechara Canal, Quebrada Josefina, Quebrada Doña Ana, Quebrada Buena Vista, and Quebrada Guaracanal.

Over the past century, all the rivers, streams, and canals in the watershed were heavily modified and channelized. Until the 1950s, the Río Puerto Nuevo flowed into the San Juan Bay at the location that is now the Puerto Rico Port Authority (PRPA) docks. In the late 1950s, the mouth of the river and the lowermost three-quarter mile of the channel were diverted to the east to empty into Caño Martín Peña.

After this diversion, PRPA began to build the Port of San Juan complex and USACE dredged the newly formed Navigation Project in San Juan Harbor to serve these docks. Creation of the port and the diversion of Río Puerto Nuevo stimulated public, commercial, and industrial development along John F. Kennedy Avenue and this road became a major artery for commercial and industrial development.

Comparison of two historic maps of San Juan, Puerto Rico. The first map is dated 1940 and shows the river flowing into the bay. The second map is dated 1957 and shows the river diverted away from the bay and into another river.

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Río Puerto Nuevo Diversion
Before the 1950s, the Río Puerto Nuevo flowed directly into the San Juan Bay near what is now the Puerto Nuevo docks. During the 1950s, the river was diverted to the east to empty into Caño Martín Peña, forming the u-shaped channel that exists today.

The problem occurred when development of the lower basin, the port complex, constructed north of the diverted Río Puerto Nuevo channel, was built over wetlands that had been filled with deposited soil from the area north of Kennedy Avenue. This effectively "plugged" the river's natural drainage path, resulting in flooding along Kennedy Avenue, the Bechara Industrial Area, and the port itself.

Flooding was further intensified by the rapid urbanization of San Juan. As roads, businesses, and residential developments expanded across the watershed, impervious surfaces like parking lots, roads, and buildings increased stormwater runoff. Critically, much of this development, including commercial and residential construction, occurred directly within the river's natural floodplain.

Although the channel naturally could convey small, frequent storm events (such as those classified as 1-3-year storm events), larger flows resulted in hazardous flooding. Without a natural floodplain to flow into and temporarily store the floodwater, the Río Puerto Nuevo and its tributaries would overtop their banks during large storms and flood roads, homes, and businesses. Adding to this problem undersized bridges and other barriers in the channels trapped debris during storms, further obstructing flow and creating hazardous conditions on surrounding roadways. Development within a floodplain reduces the river's ability to convey and store floodwaters during storms, resulting in an increased risk of localized flooding.

This flooding along the Río Puerto Nuevo and its tributaries became a major public concern following the floods of June 1970. The Commonwealth of Puerto Rico requested that USACE complete a survey investigation to develop a project that would do the following:

Safeguard the lives of those living in the floodplain;
Minimize the financial and personal property losses from flooding;
Minimize economic and social disruption to San Juan;
Revitalize the area's urban core and enhance opportunities for further economic development;
Facilitate the use of existing infrastructure in the study area;
Preserve existing habitat of local species;

The sections below provide a brief overview of the project's history starting with this request from the Commonwealth of Puerto Rico.

1978–1993

Project Authorization

The Río Puerto Nuevo Risk Management Project began in 1978 as a feasibility study requested by the Commonwealth of Puerto Rico. Conducted under the authority of Section 204 of the Flood Control Act of 1970 (Public Law 91-611), the study, which included an Environmental Impact Statement, was completed in October 1984 and subsequently revised in June 1985.

In 1986, Congress authorized the construction of the project under Section 401(a) of the Water Resource Development Act (WRDA) of 1986 (Public Law 99-662). Under WRDA 1986, USACE would build the project, but the non-Federal sponsor for the project, the Puerto Rico Department of Natural and Environmental Resources would be responsible for operating and maintaining the project after construction.

Authorization by Congress, however, did not mean that the project immediately began construction. Between 1986 and 1993, a General Design Memorandum and Environmental Assessment were completed (1991-1992) and a Water Quality Certification was issued by the Puerto Rico Environmental Quality Board in conformity with Section 401(a)(1) of the Clean Water Act. During this time, funding for the project was appropriated by Congress and the Puerto Rico Department of Natural and Environmental Resources secured the necessary cost-shared funds.

1978

Río Puerto Nuevo Survey Investigation Begins
1984

Survey Report
1985

Environmental Impact Statement
1986

Congressional Authorization
1992

General Design Memorandum
1993

Flood Control Environmental Assessment and Water Quality Certification

1993–2020

Puerto Nuevo Construction and Environmental Studies

After over a decade of feasibility studies, an Environmental Impact Statement, a Chief of Engineers Report, the completion of a General Design Memorandum and Environmental Assessment, and a Water Quality Certification, construction on the project began in 1995. Located in the u-shaped area where Quebrada Margarita meets the Río Piedras to flow via the Río Puerto Nuevo and Caño Martín Peña into the San Juan Bay, the first phase of the project included 1.3 miles of improvements to the river and several structural upgrades to the De Diego Expressway and Kennedy Avenue Bridges.

Originally just a small creek-sized river, the project widened the channel to several hundred feet to reduce flooding impacts. The De Diego Expressway and Kennedy Avenue Bridges were modified to match the new width of the river and built to withstand strong earthquakes.

In March 2010, a Wetland Mitigation Plan was completed which called for the planting of 28 acres of wetlands and mangroves along Quebrada Margarita. The planting was completed in 2014, and monitoring of the sites has shown that the trees and wetland plants are thriving and spreading throughout the area.

Additionally, between 2013-2014, in consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, USACE identified plans and processes to protect endangered species that may live in the project area. This consultation determined that the project would not impact or would not likely adversely affect endangered species like the yellow shouldered blackbird, the green sea turtle, the Puerto Rican boa, and the Antillean manatee.

Sewer overflows from the existing sewer lines also were a major concern in this area. To help the Puerto Rico Aqueduct and Sewer Authority reduce the overflow of raw sewage into the rivers and the bay via leaking, broken pipes, USACE partnered with the local agency to design and construct new, larger pipes to carry wastewater from the area to the treatment facility. Since completing this phase of the project, sewer overflows have been reduced and the mangrove forests along the river have flourished, resulting in better water quality, protection against erosion, and increased habitat for many types of birds, fish, and other animals who shelter and feed in the wetland.

1995

Puerto Nuevo Construction Begins
2002

Bechara Industrial Area Environmental Assessment
2010

Wetland Mitigation Plan
2013

Endangered Species Act Consultations
2014

Revised Wetland Mitigation Plan and Planting
2015

Essential Fish Habitat Consultation

2017–2018

Hurricanes and New Project Funding

On September 6, 2017, Hurricane Irma, a Category 5 hurricane, passed northeast of the island. With peak winds of over 120 miles per hour (mph) on the island, over 10-15 inches of rainfall were recorded over 36 hours, resulting in severe flooding and over $1 billion in damages.

Two weeks later, on September 20, 2017, Hurricane María made landfall on the island as a Category 4 hurricane, with sustained winds of over 155 mph. Classified as the tenth most intense Atlantic hurricane on record, it was the strongest hurricane to make landfall in Puerto Rico since 1928. During this storm, over 35 inches of rainfall were recorded in 48 hours and a storm surge of over six feet was estimated. Hundreds of thousands of buildings were damaged and the power grid failed, causing long-lasting interruptions to essential services. Overall, the hurricane resulted in $90 billion in damages, making it the third-costliest hurricane (as of 2017) in U.S. history.

On February 9, 2018, the Bipartisan Budget Act of 2018 was signed into law. Within the bill, $90 billion was allocated to assist with hurricane relief efforts nationwide. This funding provided over $1.6 billion for the Río Puerto Nuevo Flood Risk Management Project to be completed solely by USACE funds. As a result, the Commonwealth of Puerto Rico and its local municipalities no longer needed to contribute funding to assist with the design and construction of the project. DNER continues to be the project's non-federal sponsor and USACE coordinates closely with the agency to execute the project.

2017

Hurricanes Irma and Maria
2018

Bipartisan Budget Act of 2018
2019

Design and Stakeholder/ Community Outreach
2020

Continuing Construction Validation Report
2023

Historic Preservation Act Consultation
2024

Roosevelt Avenue Bridge Construction Begins

Current and Future Project Phases

The Río Puerto Nuevo Flood Risk Management Project is broken down into multiple phases which will be completed over the next decade. To learn more about design, construction, and schedule for these phases, visit Current and Future Project Phases.

Last Updated: July 2025