Tamiami Trail Bridges

The River of Grass used to be much larger than it is today; in the wet season, the shallow sheet flow was up to 60 miles wide, supporting a massive sawgrass marsh punctuated by tree islands, areas of open water, and stands of cypress trees. The ecosystem was home to populations of alligators, limpkins, marsh rabbits, and fish. But over the last century, a network of canals, gates, and pumps was built to get rid of excess water and drain land for agriculture—particularly sugar cane. The result was a highly compartmentalized system of disconnected habitats. In the late 1920s, construction of the Tamiami Trail, which cut across the River of Grass, effectively dammed the system, cutting off the lower Everglades from its headwaters. The reduction of fresh water flowing through Everglades National Park to Florida Bay began to affect habitat diversity and the salinity of the bay.

In 2008, the U.S. Army Corps of Engineers built a one-mile bridge at the eastern end of Tamiami Trail to allow some water to pass through and into Everglades National Park, and in 2019, the Florida Department of Transportation removed part of the existing roadbed and constructed two new, longer bridges. Increasing the amount of water flowing through the lower Everglades will strengthen grassland and mangrove ecosystems that can play an important role in carbon sequestration, storing carbon in soils and plants instead of releasing it into the atmosphere. Healthy mangrove forests will also help mitigate upcoming climate-caused disturbances, such as sea-level rise. Scientists are now studying how best to manage this water—how much and at what times of year—to achieve the biggest positive effects. The goal is to return the Everglades to a resilient system that can respond to change by itself, naturally, as much as possible.