Learn the facts about flood zones in Missouri and learn how to prepare for potential flooding. Floodplains are low, flat, periodically flooded lands adjacent to lakes, rivers, and oceans. These areas are protected by levees and serve vital functions within the natural environment. Floodplain maps can be found at FEMA.gov/floodplains. Learn about floodplains in Missouri and how you can protect your home from them.
Floodplains are low, flat, periodically flooded lands adjacent to rivers, lakes and oceans
Hundreds of thousands of homes and businesses have been built on floodplains in the St. Louis area since the Great Flood of 1993 submerged land by 10 feet. However, floodwaters overtopped the levee in Valmeyer, Ill., which was only two miles above the Mississippi floodplain. Today, the floodplains are protected by miles of levees.
The Water Resources Planning Act of 1965 and Executive Order 12319 issued by the Federal Insurance Administration establish a River Basin Commission to manage floodplains. This plan requires states to study floodplain hazards and develop a floodplain management plan for each region. However, floodplains do not always flood, and some areas are more susceptible to flooding than others.
A watershed is a large area of land that drains to a river. A river’s watershed is its trunk and includes individual streams. These streams carry sediment, which nourishes plants and animals. Watersheds are also called catchments and drainage basins. Soil erosion from rivers affects floodplains, and floodplains play a major role in protecting a river.
The floodplains are often overlooked. Yet the floodplain is an important place for ecosystem health. In fact, the state of Missouri has some of the most beautiful and diverse ecosystems in the world. However, the development of new buildings has impacted the floodplain. It has also paved the way for acres of warehouses. Consequently, the floodplain ecosystems are more threatened than ever.
They provide important functions in the natural environment
The Missouri River ecosystem has experienced marked changes over the last century, with the Missouri River once famous for its large floods and a sinuous river channel that flowed freely across the floodplain. By the end of the century, the river bore little resemblance to its former self. This chapter describes the ecological changes in the Missouri River ecosystem during this century, and compares the ecological status of the river before and after the construction of large mainstem dams.
Missouri’s floodplains are vital to Missouri’s ecosystem, providing a range of important functions. These areas provide temporary flood storage, habitat for a variety of animals, and they prevent heavy erosion caused by fast-moving water. In addition, floodplains recharge groundwater and filter contaminants. For these reasons, MoDOT strives to avoid encroaching into floodplains by conducting engineering analyses of proposed projects. In addition, proposed roads are located adjacent to existing roads, so that construction does not disrupt these ecosystems.
The floodplain also slows overland runoff, which helps recharge groundwater aquifers. Floodplain vegetation also helps protect back-lying areas from erosion. Floodplains are integral to healthy rivers and lakes, and can protect homes and businesses from flooding. They also help prevent erosion of land and provide multiple functions to society. They help maintain the health of rivers and lakes by serving as natural barriers.
They are protected by levees
In the past, the modern 500-year levees have been the gold standard for flood protection in major cities. However, recent larger floods have called into question the effectiveness of these structures, requiring the Corps of Engineers to reinforce some areas, including Riverport and downtown St. Louis. A 1,000-year levee is the next logical step, and the Corps has proposed building it to protect all major cities and communities along the upper Mississippi River.
The First Street Foundation has calculated that about 280,000 properties in Missouri are vulnerable to flooding, which is almost double the number estimated by the federal government. In addition to the large number of properties that are at risk, Missouri has the largest flood plain in the country, covering more than 6,400 square miles. The flood plain in Illinois and Iowa is much smaller, covering about 4,000 square miles. The nonprofit group, which tracks flood plain issues, says the state is at risk of a one-in-500-year flood, and the risk could rise to as much as 1.8% in the next half century.
The historic flood of 1993 flooded many Missouri river towns, including Kansas City. Today, this river is a major economic and transportation hub. Yet, the trust in engineered flood control is waning. The Midwest flooding in 1993 killed 50 people and caused US$15 billion in damages. The government and state governments were forced to provide financial aid to move homes and communities to higher ground. After the flooding in 1993, however, the trend changed. The state of Missouri approved a two-billion-dollar plan to allow development in floodplains and protect the Missouri river.
They are mapped by FEMA
When a community is in an area that is in danger of flooding, flood insurance rates may be higher than they would otherwise be. To find out which areas of Missouri are considered flood-prone, consult a FEMA Flood Map. Depending on the level of risk in a given area, different zones are created for different risks. The maps are updated as needed to reflect changes and are based on the latest flood information.
The flood map is used by mortgage lenders to determine the insurance coverage requirements of homes and to develop strategies for reducing risk. FEMA and the state emergency management agency collaborate to develop flood maps. Floodplain administrators work with FEMA to develop flood maps in Missouri. FEMA provides the technology while local leaders provide information and plans. FEMA also collaborates with local surveyors and engineers. These maps provide vital information to mortgage lenders and community leaders.
If you’re looking to buy a home in an area where flooding is more likely to occur, you’ll want to look at the latest maps. Missouri’s maps have flood zones, but these maps aren’t definitive. Floods do not respect city limits. If you’re interested in knowing whether or not your property is in a flood-prone zone, you can view the preliminary proposed rates. The preliminary proposed flood insurance rate maps are available online.
They are regulated
The State Emergency Management Agency (SEMA) regulates flood zones in Missouri. If you are planning to build on land that is within a floodplain, you will need a floodplain development permit. This permit is required for any project within a regulated floodway. A ‘no-rise’ certificate is also necessary for projects that are located within a floodplain. The state has a number of floodplain development permits available.
Preliminary flood maps are important because they show potential flood risk. They are updated often and may reflect changes in flood hazards since the last map was created. These maps can be obtained from your city’s Community Development Department or from a Registered Missouri Land Surveyor. In addition, a FIRM can be obtained from FEMA or the NRDC. Flood risk maps and information are useful for homeowners, business owners, and developers.
When zoning for flood plains, a comprehensive land use plan is necessary. This plan must identify how flood plains will be used in the future. For example, it may be logical to build a quarry in a flood plain, but it should not become a nuisance for the residential areas that are adjacent to the area. Further, the zoning ordinance must specify a range of acceptable uses for flood plains.
They are protected by ordinances
Flood zones are areas of land subject to periodic flooding. During these times, floodwaters can cause substantial property damage and health risks. Moreover, they disrupt commerce and governmental services. They may also result in extraordinary public expenses and reduce the tax base. Many factors contribute to the severity of flood damages, including inadequate elevation of land, obstructions in flood plains, and the occupancy of vulnerable uses. Here are some of the most common reasons why your property may fall into a flood zone:
Zoning ordinances in floodplains are designed to protect properties from flooding. These ordinances may be strict or lax, and they specify what types of buildings are allowed on the land. In some cases, flood plain ordinances prohibit any structure altogether, while others allow less expensive, more transient structures. Some are based on engineering or scientific criteria. In any case, floodplain ordinances protect people, property, and infrastructure from the effects of severe flooding.