As background to Everglades restoration planning, historical sources were extensively researched to characterize and map the major Everglades landscapes which existed prior to canal development. Vegetation, soil type, topographic relief, and hydrology were estimated for each landscape. Particular attention was placed on hydrology, including water depths, hydroperiods, flow directions and velocities.

The research consisted of three major components: determination of the lateral extent of each of the landscapes during pre-canal conditions; description of each landscape; and estimation of long-term average annual low and high water depths. The major wetland landscapes are closely linked to specific soil types. The extent of each pre-canal landscape was therefore estimated by "hindcasting" a 1940's soil map to 1880's conditions, using knowledge of patterns of soil and vegetation change in response to canal drainage. Direct observations made at identifiable locations and taken from Township surveys, expedition accounts, and early maps, enhanced the accuracy of the "hindcasting" effort.

Landscape descriptions were synthesized from multiple sources. Three key base maps, a 1948 soil map and a 1943 and 1948 vegetation map, were used, along with information gathered from scientific discussions of patterns of drainage-induced change. Considerable material was gathered to quantitatively estimate widths and elevations of the components of the most topographically diverse landscape, the Ridge and Slough mosaic.

The third component of the research, estimation of average water depths for each pre-canal landscape, was based on direct point observations, navigable routes, vegetation requirements, and general information from the landscape descriptions. Water depth observations were classified by landscape and plotted versus time of year. They were then compared against a simple linear model of hydropattern, consisting of an average annual low water depth in May and an average annual high in October. Other information suggested an average annual range of approximately two feet. Average hydroperiod was estimated, using these models, as the months per year with above-ground water levels.

The most laterally extensive Everglades landscape was a Ridge and Slough mosaic, somewhat like the southern portion of the present Water Conservation Area 3A, with the important exception that in the former, water was in a natural flowing system while in the latter, water is impounded. In addition to tree islands, sloughs and sawgrass ridges, narrow channels or creeks were reported, usually with perceptible flow. Average annual low and high water depths in the sloughs were 1 and 3 feet, respectively. Water was deeper in the channels. Water depths on the sawgrass ridges were slightly lower than for the extensive sawgrass plain to the north. Depths were approximately 1 foot below ridge surface for the annual low, and 1 foot above for the annual high.

Estimates of Everglades water depths were somewhat deeper and hydroperiods somewhat longer in this study than was previously simulated by the South Florida Natural System Model (NSM v.4.4). Spatial patterns were similar between this study and the NSM. Although this study provides useful estimates of average annual low and high water depths, models such as the NSM can probably best simulate the ecologically important patterns of weather-driven hydrologic variability, which were not addressed in this study.

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