Floodplain Management
Background
Human history in Florida is replete with flooding experiences, most notably the devastating hurricanes of the early 20th century that brought about the systems of canals and dikes that make much of the central and south Florida habitable. It is not surprising that flooding frequently occurs in a state that originally was one-half wetlands. Without proper land use controls, flood protection measures can actually contribute to increased flood risks by creating a false sense of security which encourages unwise development in areas subject to flooding. Also, as new development further modifies stormwater runoff patterns, flood risks are often increased for areas that were not previously flood prone.
Flooding can occur in either floodplains (low-lying lands around rivers and streams, lakes, and wetlands), or in other low-lying, poorly drained areas. Flooding occurs when rainfall is too intensive for the land to absorb the extra runoff, when natural or artificial waterways are inadequate to accommodate runoff. The Federal Emergency Management Agency (FEMA) estimates about 14.25 million acres, or 41 percent, of Florida is flood prone -- the highest percentage of all 50 states. The Department of Community Affairs (DCA) estimates that about 1.3 million people live in areas subject to flooding.
Flooding in Florida typically is caused by heavy or prolonged rainfall from tropical storms and hurricanes. Rainfall in Alabama and Georgia can cause significant flooding problems in North Florida as shown during tropical storms Alberto and Beryl in 1994. Florida's high vulnerability to flooding demands an adequate response to protect the public health, safety, and welfare. The economic and social impacts of flooding events can be staggering. For instance, statewide damage from three tropical storms and two tropical disturbances in 1993 was approximately 500 million dollars. Future public liabilities related to flood losses can be greatly reduced through proper control of development in floodplains and floodprone areas and maintenance of the existing flood protection infrastructure.
Flooding Issues
Human occupancy of and alteration of floodplains and floodprone areas are threatening public safety, health, and welfare.
The cornerstone of any floodplain management strategy is adequate mapping of floodplains and flood prone areas. However, because floodplain mapping is a complex, expensive, and time-consuming endeavor, many areas are not adequately mapped. Many floodplain mapping efforts have occurred in response to specific needs in specific areas, but a coordinated, comprehensive approach has not been undertaken. Adequate mapping is an important link between landuse and water resources planning.
For the subject area of the flooding, the best current formal recognition of such areas is the 10- and 100-year floodplains mapped by various agencies. Protecting the functions of unaltered floodplains is a critical aspect of statewide ecosystem
management efforts. As many floodplain areas have been altered, restoring their natural functions is also an important issue. Land acquisition and management through various programs provides a very effective tool for protecting and restoring floodplains.
Floodplain management responsibilities are shared among federal, state, regional, and local governments. Local governments have the most direct control in floodplain management through landuse planning and regulation, land acquisition and management, and as sponsors for the flood insurance program administered by FEMA. Water Management Districts (WMDs) and the DEP, through surface water management regulations also regulate development activities in floodplains and flood prone areas.
Inadequate preparation for flood disasters and response have increased property damage and risks to human safety.
The State of Florida Comprehensive Emergency Management Plan, administered by the DCA, Division of Emergency Management, coordinates the activities and responsibilities of 23 state agencies, 5 WMDs, school districts, and numerous private organizations during declared emergencies. The experience of Hurricane Andrew in 1992 sharpened the state's awareness of the need to be prepared for, and respond to, flooding and other natural disasters.
The most effective opportunity to improve emergency management procedures, however, is after emergency situations occur and emergency procedures are completed. An ongoing procedure to evaluate the effectiveness of emergency management procedures, after the emergency has passed, needs to be coordinated among all responsible entities.