Home Introduction Physical Setting - Climate - Drainage > Shape of the Land - Soils - Geology Urbanization Natural Hazards Mineral Resources Water System Environmental Quality Outdoor Recreation Everglades N.P. Coastal Zone Fish & Wildlife Miccosukee Indians Conclusion References

South Dade County is almost flat: the highest points are only 25 feet above the sea, and most of the area is less than 10 feet above high tide. The main drainageways are broad linear depressions only one to two feet deep.

The shape of the land influences the development of soil and vegetation, and is critical in the planning and construction of irrigation and flood-control structures, and in the sitting of communities and their related support facilities. Six natural provinces are recognized and delineated on the accompanying map.

The area of and near the Coastal Ridge has been developed for urban, industrial, and agricultural use. Development of the Everglades, Rocky Glades, and Coastal Marsh has been retarded by poor drainage and a high water table. The Florida Keys [not colored] area series of barrier islands that offer recreational opportunities for water related activities. 1/ [larger image]

The Everglades is a broad expanse of grass-covered marshland dotted with three covered small islands or “hammock” which rise 1 or 2 feet above the surrounding land surface. The Everglades is flat and has almost no slope, hence it floods during rainy seasons.

The Everglades is undeveloped except in a few places along its eastern edge, where flood-control canals have altered drainage. The drained parts of the Everglades are used for industry, agriculture, and homes. A considerable part of the undeveloped Everglades in Dade County has been zoned for industrial use.

The south Dade area is very flat. The shape of the land, however, has greatly influenced the pattern of urban and agricultural development. 2/ [larger image]

Southeast of the Everglades are the Rocky Glades, which look like the Everglades except that hard limestone protrudes through the surface. The scant soil is a few inches thick. The Rocky Glades are fairly well drained by canals. Because the limestone is near the surface, they are easier to convert to urban use than the Everglades.

Rising above the Everglades is a low ridge, the Coastal Ridge, which is nearly parallel to the Atlantic Coast. The ridge is as much as 6 miles wide, and generally 10 to 25 feet above sea level. The highest and best drained land in the area, the ridge was first to be settled, and urbanization has occurred on or near it. In its natural state the ridge was covered by pine and hardwood forests. Today, the vegetation on the urbanized parts of the ridge is luxuriant, in places dense, and includes tropical plants along with pine and palmetto.

The Coastal Ridge is cut by low, narrow valleys or channels called the Transverse Glades in which the soils or and vegetation are similar to those in the Everglades. These were once tidal channels through the Coastal Ridge.

The Transverse Glades are the sites of most major canals and the pathways of saltwater intrusion, storm runoff, and flooding near the coast.

Mangrove Swamp fringes most of the coast. The Mangrove Swamp and the adjacent Coastal Marsh are poorly drained; however, the northern part of the Coastal Marsh is fairly well drained and has many farms and residences.

Biscayne Bay is a shallow tropical lagoon about 35 miles long, as much as 10 miles wide and 12 feet deep. It is bound on the west by the Mangrove Swamp of the mainland and on the east by a series of barrier and coral islands. Near the western mangrove shore, peat, mud, and organic debris are several feet thick. To the east the bottom of much of the bay is hard with little or no sediment. Sea grasses are dense where the sediment is deepest. Algae and other marine organisms grow on the bottom.

The lands of the Coastal Ridge and the Rocky Glades are most readily converted to urban use. The peat soils of the Everglades and the marl soils of the Coastal Marsh are much less readily developed, but are more readily farmed. 3/ [larger image]

Physiographic profile. 4/ [larger image]

PHYSICAL PROVINCES
FEATURES AND CHARACTER- ISTICS	EVERGLADES	ROCKY GLADES	COASTAL RIDGE	TRANSVERSE GLADES	MANGROVE SWAMP AND COASTAL MARSH	BISCAYNE BAY
ORIGINAL GEOLOGIC ENVIRONMENT	Protected embayment	Protected embayment, back slope of barrier bar	Submerged shallow "oolitic" barrier bar	Tide channels through barrier bar	Offshore slope of barrier bar	Basin between coastal island chain and barrier bar
RELIEF	Extremely flat	Very flat	Steep at frontal bluff, flat to very flat on top of ridge	Extremely flat, shallow stream courses	Very flat	Shallow bay
SOIL OR SURFlClAL MATERIAL	Reed and sedge peat, soft freshwater limestone	Thin sandy soft limestone (marl) and hard limestone	Hard limestone with pockets of sand	Soft fresh-water limestone (marl) and sand	Mangrove peat in swamps, marl and peat in coastal marsh	Bay bottom is marine sand and mud

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