Vegetation affects water movement in the Florida Everglades

Abstract

Introduction The Florida Everglades is a vast, diverse wetland ecosystem characterized by small ground-surface slopes, slowly moving surface waters, and dense aquatic vegetation. Both submersed and emergent vegetation are found in sawgrass and cattail marshes, wet prairies, and sloughs. The south Florida ecosystem has been greatly altered during the last 100 years. A complex water-management system that includes levees, canals, pumps, and water-control structures now regulates flooding and provides a steady supply of fresh water to urban areas and agriculture. Drainage projects have diverted much of the water that originally flowed slowly southward from Lake Okeechobee through the Everglades. Restoration and management of the Everglades ecosystem requires understanding and manipulating the amount and timing of water flows throughout the ecosystem. The spatial and temporal distribution of water and water-borne contaminants in the Everglades must be understood if degradation of the ecosystem is to be halted and reversed. To understand how water moves through the Everglades, it is necessary to quantify the forces affecting the flow. The resistance exerted on the flow by the vegetation through which the water moves is one of the dominant but least understood forces affecting Everglades surface-water flows. The aquatic vegetation of the Everglades affects both the depth of water and the rate at which it moves. The presence of living and dead plant material in the water column creates drag forces on the moving water. Water flows most slowly and the water-surface slope is largest in areas where vegetation is most dense.