During the past century, river and tidal creeks throughout the coastal wetlands of the Everglades have filled with sediment and vegetation from surrounding landscapes to the point that many have greatly diminished or disappeared entirely. Restoration plans are under consideration to redirect additional freshwater inflow from the Everglades to open and sustain these waterways to a level that closely resembles historical patterns.

The South Florida Water Management District (SFWMD) has developed hydrodynamic numerical models to help define the restoration plan and oversees monitoring of the restoration efforts to assess the impacts.

This study had two objectives:

• Establishing protocols for channel-characteristic mapping that will provide adequate, consistent information about different channels, and changes in channels, through time that can be used in the Everglades processes modeling. Hydrodynamic models require high-resolution boundary conditions to produce accurate results.
• Evaluating the accuracy and cost of various techniques for assessing changes in geomorphic features of tidal rivers and creeks along the coastal ecotone of the southern Everglades for restoration impact monitoring. These surveys will characterize the longitudinal gradient and cross-profiles of the tidal river networks.

SFWMD requested that the U.S. Geological Survey USGS develop a strategy for defining mapping protocols appropriate for tidal rivers and creeks located in south Florida. Shark River (Gulf of Mexico side) and Trout Creek (Florida Bay side) were identified as representative study sites for this project (fig. 32). Field tests were conducted to evaluate mapping protocols for their accuracy, precision, and cost effectiveness. Two boat-based acoustic techniques were assessed: single-beam and interferometric swath systems. Figure 33 is a color-coded example bathymetry map of the Shark River produced from data acquired with the interferometric swath system.

Figure 33. Example of swath data collected in the Shark River, Florida. [Click to enlarge]