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Flooding + Tallahassee

Flooding in Tallahassee generally occurs along four waterways: the West Drainage Ditch, the Central Drainage Ditch, the East Drainage Ditch, and the Northeast Drainage Ditch. The volume of runoff in certain areas exceeds the capacity of these channels, during heavy storms, and floods adjacent structures and lands. The West Drainage Ditch floods areas in the vicinity of Springhill Road and Lake Bradford Road. Frequent flooding of the Northeast Drainage Ditch occurs near Centerville Road in the vicinity of Capital Circle NE, Doomar Drive, and Potts Road. The Central Drainage Ditch floods areas in the vicinity of Stadium Drive, Eppes Drive, and Pepper Drive. Flooding of the East Drainage Ditch occurs in the vicinity of Orange Avenue, Blair Stone Drive, and Fleetwood Street. Although the floodwaters are not very deep, they cover streets and yards and can flood garages, cars, basements, and lower floors. Flooding also occurs due to local drainage problems and in several closed basins in our City.

Flooding in all of these areas can come with little warning. Floodwaters of the St. Augustine Branch, a tributary of the Central Drainage Ditch, have been observed to leave its banks and flood Franklin Boulevard within one-half hour after a thunderstorm started. Flooding can be dangerous. Even though the floodwaters appear to be moving slowly, a flood two feet deep moving at three feet per second can knock people off their feet or float a car off the road.

If your property is in the floodplain, the odds are that someday your property will be damaged by flooding. Your property may be high enough that it has not flooded recently. However, it can still be flooded in the future because the next flood could be worse.

Floodplain Management

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.

Floodplain Mapping Amendments

Flood Insurance Rate Maps (FIRMs) are issued by the federal government, through the Federal Flood Insurance Program, to facilitate the issuance of flood insurance policies to property owners. The City of Tallahassee does not prepare or issue the flood maps for the insurance program. As a result, amendment to the flood maps is a process between the property owner and the Federal Emergency Management Agency (FEMA).

Prior to initiating a flood map revision, FEMA requires that sufficient evidence be provided to indicate a change is warranted. FEMA places the burden of providing that evidence on the property owner, because it has previously gone to considerable expense to analyze flood hazard areas and generate the flood maps.

Two types of map changes are most commonly requested for minor modifications. These are a Letter of Map Amendment (LOMA) and a Letter of Map Revision (LOMR). A LOMA is the final result of an administrative procedure in which FEMA reviews scientific and technical data -- certified topographic data and/or hydrologic and hydraulic analyses -- submitted by the owner or lessee of property who believes the property has incorrectly been included in a designated Special Flood Hazard Area (SFHA). A LOMA is FEMA's comment whether the natural ground adjacent to a structure is above the base (100-year) flood elevation (BFE), and amends the currently effective FEMA map and establishes that a structure is not located in a SFHA.

A LOMR is FEMA's modification to an effective FIRM based on the placement of fill, or other physical measures that have been implemented that support changes in the SFHA, BFEs, or floodway. The LOMR officially revises the FIRM and includes a description of the modifications. In addition, the LOMR is generally accompanied by an annotated copy of the affected FIRM.

Procedure

  1. Use this link to obtain forms and directions.
  2. Retain a registered professional engineer to determine the BFE in the unnumbered SFHA. He/she must prepare and seal a letter report (or a more detailed study for complicated cases) documenting how the BFE is determined.
  3. Retain a registered land surveyor to prepare a FEMA Elevation Certificate (EC). This EC must be prepared according to the instructions provided.
  4. Complete the FEMA forms and include the necessary documentation supporting them.
  5. Submit the entire package to the Stormwater Management Department of the City of Tallahassee for review.
  6. The City of Tallahassee will review it, and if it is determined that the applicant's engineer's determination is the best available BFE information, a letter to that effect will be provided.
  7. The applicant can then submit the entire package, including the City's letter, to FEMA.
  8. FEMA will review and make a determination whether amend (LOMA) or revise (LOMR) the FIRM and will issue a letter to that effect.