What is Floodplain Management?
Floodplain Management is the operation of a community program of corrective and preventative measures for minimizing the damaging effects of flooding.
The Floodplain Management and Disaster Mitigation Services Program aims to protect human life, health, minimize property damage, promote the practice of wise development in areas subject to flooding, and encourage appropriate construction practices to reduce future damage, prevent future displacement from disasters and suffering of its residents by increasing public awareness and implementing the proper programs.
Floodplain Website Pages
Geographically, the City of Birmingham sits in a valley in the western foothills of the Appalachian Mountains. The general flow of ground water is westward, away from the higher points in the City, towards the Black Warrior and Cahaba Rivers. Other major creeks in the area include Shades and Little Shades Creeks which drain into the Cahaba River and Five Mile, Valley, and Village Creeks which drain into the Black Warrior River. These creeks, rivers, and tributaries, along with additional waterways, contribute to the makeup of several watersheds that have some portion located within the city limits of Birmingham. The watersheds are: Cane Creek, Valley Creek, Turkey Creek, Five Mile Creek, Village Creek, Little Shades Creek, Shades Creek, Big Black Creek, Cahaba River, and Little Cahaba River. Each of the 10 watersheds contains at least some portion of 100-year floodplain. In the city limits of Birmingham, approximately 8,000+acres of the 100-Year floodplain are located within the boundaries of the 10 identified watersheds.
The City of Birmingham is affected by several natural events; however the most frequent are flooding and wind events (including Hurricanes). Flash flooding resulting from rising creeks / rivers during a storm event and localized flooding due to inadequate capacity or maintenance of the storm sewer drainage systems. According to the National Oceanographic and Atmospheric Administration (NOAA), the normal rainfall for the City of Birmingham is approximately 53.99 inches per year. This average rain fall amount is spread out over the course of a year and varies from event to event.
Flash flooding is dependent on the amount and duration of the rainfall as well as the condition of the watershed. High amounts of rain received over relatively short periods of time (usually hours) result in fast rising waters. The condition of the watershed also plays an important role in how local waterways react to storm events. Previously saturated areas or land covered by impervious materials, such as asphalt, will produce higher runoff rates, contributing a larger volume of water reaching the local waterways.
The risk of flooding is often associated with the terms, base floodplain and 100-Year Floodplain. The Federal Emergency Management Agency, through the National Flood Insurance Program (NFIP) and the development of Flood Insurance Rate Maps (FIRM) has delineated the 100-Year floodplain for communities participating in the NFIP. The base floodplain, or 100-Year floodplain is the area of land that would be inundated by a 1-percent-annual-chance flood. It is used by FEMA as the basis for administering their floodplain management programs, through regulatory requirements as well as for settings for flood insurance rates.
The second type natural event experienced frequently in Birmingham is straight lined-winds is wind that comes out of a thunderstorm once the winds meet and exceed 58 miles per hours then the storm is classified as severe by the National Weather Service. These winds are produced by the downward momentum in the downdraft region of a thunderstorm. A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as twisters or cyclones, although the word cyclone is used in meteorology, in a wider sense, to name any closed low pressure circulation. Tornadoes come in many shapes and sizes, but they are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust.
Floodplains serve a beneficial purpose to our quality of life. These low lying areas are where rainfall goes to drain and are adjacent to rivers and subject to flooding. Some examples of the major rivers in the City limits of Birmingham with surrounding floodplain areas include Little Shades Creek, Village Creek, Valley Creek and Five Mile Creek.
Floodplains also serve as filters of stormwater runoff as it seeps through the ground and into our aquifer. The natural vegetation filters out impurities and uses excess nutrients. This aquifer is our only source of drinking water, and filtering helps contain pollution before it reaches our aquifer! It is important that we appreciate our floodplains, and try to maintain, preserve and restore these areas whenever possible. These benefits range from providing aesthetic pleasure to reducing the number and severity of floods, helping handle stormwater runoff and minimizing non-point water pollution. Such natural processes cost far less money than it would take to build facilities to correct flood, stormwater, water quality and other community problems.