Rivers, Lakes and Water Systems

Puerto Rico's hydrography includes a complex network of rivers, reservoirs, wetlands, lagoons, and coastal waters that play an essential role in the island's environment and water supply.

The island's central mountain range, La Cordillera Central, divides Puerto Rico into northern and southern watersheds. Rivers originating in these mountains flow either toward the Atlantic Ocean in the north or the Caribbean Sea in the south.

Although Puerto Rico is relatively small and does not have long rivers or natural lakes, the island contains more than 1,200 bodies of water, including approximately 50 rivers, numerous reservoirs, and several coastal lagoons that support wildlife and recreation.

Rivers of Puerto Rico

Puerto Rico's rivers vary greatly depending on their location and rainfall patterns.

Northern Rivers

Rivers flowing north toward the Atlantic Ocean tend to be longer and slower moving, supported by higher rainfall and broader coastal plains.

Important northern rivers include:

• R&icute;o Grande de Arecibo – the longest river in Puerto Rico
• Río La Plata – one of the island's largest, running from the mountains to the Atlantic
• Río Cibuco – a significant waterway for northern agriculture
• Río Loíza – the largest river by water volume
• Río Bayamón – supports urban and industrial areas

Several major rivers also flow westward toward the Mona Passage, including Río Grande de Añasco, Río Guanajibo, and Río Culebrinas.

Many northern rivers maintain perennial (year-round) flow.

Southern Rivers

Rivers flowing south toward the Caribbean Sea are generally shorter, steeper, and faster flowing due to lower rainfall and steeper terrain.

Many southern rivers are seasonal, occasionally drying out before filling rapidly during heavy rains.

Examples include:

• Río Portugués – one of the few perennial rivers in the south
• Río Loco – known for its seasonal flow
• Río Coamo – famous for its nearby hot springs
• Río Grande de Patillas – a vital water source for the southeastern region

Subterranean rivers are also common in the island's karst region, particularly in northwestern Puerto Rico.

Lakes and Reservoirs

Puerto Rico does not have natural lakes. Instead, the island has artificial reservoirs created by dams to supply drinking water, irrigation, and hydroelectric power.

Major reservoirs include:

• Lago La Plata – one of the island's largest reservoirs, supplying water to San Juan
• Lago Dos Bocas – a scenic lake popular for boat tours
• Lago Carraízo – a primary water source for the metropolitan area
• Lago Guajataca – provides drinking water to northwestern Puerto Rico
• Lago Lucchetti – important for irrigation and hydroelectric power

Although hydroelectric facilities exist, they provide less than 1% of Puerto Rico's electricity production.

Wetlands and Lagoons

Puerto Rico also contains several important coastal lagoons and wetlands, which support marine ecosystems and wildlife habitats.

Important lagoons include:

• Laguna del Condado (San Juan) – a popular spot for kayaking and paddleboarding
• Laguna San José (San Juan) – a significant mangrove ecosystem
• Laguna Piñones & Laguna Torrecillas (Carolina) – both located in a protected coastal area with rich biodiversity
• Laguna Joyuda (Cabo Rojo) – the largest coastal lagoon in Puerto Rico, known for its fishing industry
• Laguna Tortuguero (Manatí) – the largest freshwater lagoon on the island, home to many endangered species

Water Conservation & Climate Impact

These ecosystems provide habitats for fish, birds, and mangrove forests.

Marine Environment

Puerto Rico's surrounding waters contain coral reefs, seagrass beds, and deep ocean environments. Just north of the island lies the Puerto Rico Trench, the deepest part of the Atlantic Ocean.

Puerto Rico's rivers, reservoirs, and coastal ecosystems play a vital role in supporting the island's communities, agriculture, wildlife, and natural landscapes.

From mountain rivers and freshwater reservoirs to mangrove lagoons and coastal estuaries, these waterways are an essential part of Puerto Rico's geography and ecological balance.