What do we know about pre-drainage conditions in the 1800's? (Part 2)

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Township Survey  (1847)

Township Survey field notes

Exploration routes in relation to landscapes

"During the late Seminole War I was repeatedly in the Everglades and on the rim or margin at various points, and crossed it from Miami to Shark River. It is a vast, fresh-water lake, of shallow depth, from 60 to 90 miles in length, and from 25 to 50 miles in width. Its general depth is from 2 1/2 to 6 feet of water, over (say from 2 to 6 feet of) soft mud, or vegetable deposit. It is interspersed with thousands of islands, from a quarter of an acre to several acres in area and generally having a few trees on them. Water grasses of several feet in height above the water cover its entire surface, except in a few channels or where there are small ponds of water with sand bottom from 3 to 5 feet deep. There are no trees in the waters of the interior of the Everglades, but the margin of the "Glades," running out about on an average 1 mile, is full of fine cypress trees."

- Col. Harney (1848)

Aerial Photo Loxahatchee Slough (1940)

Davis Vegetation Map (1943)

Soils Map - 38 sheets (1948)

A

B

(Click on images above for larger versions.) Soil Subsidence, 1910-1940

Drainage History...   2° Plant Succession...   Org. Soil Changes...   Topographic Changes...

Coherent picture of the pre-drainage Everglades emerges from extensive mapping of all available observations, combined with mechanistic understanding of processes of drainage-induced change.   Changes in soils, vegetation, topography,  and hydrology each have distinct time constants.

Pond Apple Swamp Pond Apple Swamp - frequent overflows, regular wash in of silt.

Eastern Flatwoods Eastern Flatwoods - numerous seasonal ponds, year-round cypress domes.

Sawgrass Plains Sawgrass:  -0.5 to 1.5 ft deep

Marl Transverse Glade Transverse Glades: wet ca. 50% of year

Ridge & Slough Landscape

Mechanism that maintained sloughs (i.e ., prevented fill-in)?   Water flow??

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