Home Preface Synopsis History of the Study Regional System Ecosystems >Hydrologic Systems > Importance of Water - Aquifers - Water Balance - Hydrologic Changes - Quantity Problems - Resource Limits - Quality Final Word References Appendices PDF version

Water is the major controlling factor and a common denominator for all ecologic systems of south Florida. The sole source of freshwater for south Florida is its rainfall, 1,270 to 1,524 mm (50 to 60 in) each year, most of which occurs from June through October. Rainfall recharges shallow aquifers and provides surface runoff by slow sheet flow to the ocean through the Everglades and the Big Cypress Swamp. The natural plant and animal communities are mostly adapted to and depend on wetland conditions and have adjusted to the cyclic nature of the rainfall.

Man has degraded the ecosystem by manipulating the water systems through increased ground-water withdrawals along the urban coastal areas and by canal drainage from the interior to the coast. Drainage by canals has upset the natural flow system by accelerating the runoff and has shortened the periods of inundation and sheet flow in the wetlands. Since recharge to the shallow aquifers occurs in the wetlands, the accelerated runoff from there has reduced the quantities of water available for recharge. Consequences of the drainage were seawater intrusion in the coastal parts of the shallow aquifers and biological alteration in the interior areas. In addition, water-quality deterioration in the canal systems resulted from increased runoff from agricultural and urban lands.

Regional water management since the early 1960's has tended to slow down the rate of change in the interior, but increased demands for water in the rapidly expanding urban areas have continued. The problem becomes one of acceptable distribution of water supply where people demands and environmental demands are satisfied to the extent that the stresses upon each are minimized.