The Role of Flow in the Everglades Ridge and Slough Landscape

Science Coordination Team

South Florida Ecosystem Restoration Working Group

(Approved by the SCT: January 14, 2003)

Executive Summary

The Everglades has at the core of its identity the slow movement of water across the vast, low gradient, wetland landscape. Marjory Stoneman Douglas eloquently immortalized this identity in her descriptions of the “River of Grass” (Douglas 1947). Drainage and compartmentalization efforts during the 20th century for flood control and water supply purposes interrupted this flow, as well as altering water levels, distribution, and seasonal timing. Water flows are closely linked to water levels, and their alterations have caused environmental damage. Efforts to restore the Everglades have focused on re-establishing more natural hydropatterns – the appropriate water levels, and the location, timing, and duration of these water levels. While these natural hydropatterns are widely recognized as being extremely important, much less attention has been paid to the importance of the actual movement of water, the physical and ecological roles that movement of this water plays, and how management activities have altered that flow. Thus, the Science Coordination Team has chosen understanding the science of the role of flow in the Everglades as one of its priorities. The purpose of this paper is to provide a stimulus for increasing the level of understanding and awareness of the role of flow in restoration activities, and to highlight the urgent need for research in this area.

Pre-drainage Everglades hydrology was dominated by a remarkable flow regime – a 30- milewide expanse of water moving down the low-gradient wetland landscape from north to south. Surprisingly, although Everglades hydrology has flow as one of its defining characteristics, most discussions of hydrology in the Everglades exclude mention of the role of water movement. The movement of water in aquatic ecosystems such as wetlands is a fundamental construct of ecosystem structure and function, and its ecosystem role is well- established. It is likely that water movement plays a similar vital role in the Everglades.

The ridge and slough landscape, one of several major habitat types in the Everglades, originally consisted of a peat-based system of dense sawgrass ridges interspersed with adjacent and relatively open sloughs. These parallel ridges and sloughs existed in an organized pattern, oriented parallel to the flow direction, on a slightly sloping peatland. Unfortunately, compartmentalization and related water management activities are resulting in the loss of this ridge and slough landscape. This loss is evidenced by replacement of the characteristic ridge and slough landscape with a landscape that is more topographically and vegetationally uniform. It is clear that 1) the Everglades ridge and slough landscape has changed, and is continuing to change significantly; and 2) the landscape changes are having detrimental ecological effects on Everglades plants and animals. It is likely that these changes are the result of altered water flow and hydropattern caused by human-made barriers

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