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Urban Waters Partnership

Where and Why of Caño Martín Peña

Background: Where and Why

Caño Martín Peña (Martín Peña Channel; MPC) is a 3.75 miles long channel that provides a natural connection between San José Lagoon and San Juan Bay. In the early 20th century, as the Puerto Rican economy evolved, impoverished squatters began filling the wetlands at the margins of the canal with garbage and debris to build their homes. This practice continued for decades. In the 1980’s, a major urban redevelopment plan resulted in the relocation of residents from the eastern portion of MPC. The channel was widened to 400 feet and dredged to a depth of ten feet. This area is now fringed by red mangroves and includes a concrete boardwalk for pedestrians along one of its banks.

The canal also provides a waterway for the operation of an aquatic mass transit system. However, the continued practice of filling in the banks of MPC with trash and other refuse reduced eastern half of MPC to a width of two to three feet and a depth of a few inches in some areas. This has resulted in a severe disruption of the natural water flow and circulation within the San Juan Bay estuary system. Furthermore, over 3,000 structures discharge raw sewage into MPC through direct pipes, ditches and the stormwater system. Mercury, lead and PCBs have been detected in concentrations of concern. The frequent flash flooding of the area during rain events directly expose residents to these contaminated waters on a regular basis.

Since EPA designated the San Juan Bay Estuary as an Estuary of National Importance in 1992, data on MPC’s hydrodynamics, water quality and point source pollution has been steadily collected. The San Juan Bay Estuary Program (SJBEP) was instrumental in raising awareness among government agencies, communities and the general public about how the restoration of the MPC could have a positive impact on the whole San Juan Metropolitan area. In 2007, the Governor of Puerto Rico signed a Land Use and Comprehensive Development Plan for MPC. The Plan incorporates dredging the MPC to improve flow and reduce flooding hazards, promote biodiversity, and restore the SJBE. The implementation of the Plan would allow for waterway connections among strategic locations, an opportunity for economic development and a new waterfront for San Juan.