District focus on flood protection heightens as Dorian approaches

Working with Mother Nature: Flood control in the Upper St. Johns River Basin

What you can do: Maintain your stormwater system before hurricane arrives

PALATKA, Fla., Aug. 30, 2019 — When hurricanes and other storms bring high volumes of rain in short periods of time, flooding can result. The St. Johns River Water Management District’s water control structures in the Upper St. Johns River Basin (USJRB) and Upper Ocklawaha River Basin (UORB) are important federal flood protection projects. Currently, both have ample water storage available.

As Hurricane Dorian begins to bring heavy rainfall to Florida’s east coast, it is important to understand what these water control structures, as well as district-permitted stormwater systems, can and can’t do.

Locks, spillways, pump stations, levees and canals in the headwaters of the St. Johns River in Brevard and Indian River counties (USJRB Project) and in the Harris Chain of Lakes in Lake County (UORB) are the district’s only structural controls of water levels. The district does not control water levels in the rest of the St. Johns River.

The USJRB Project has proven itself several times over the past two decades, protecting the region from flooding during hurricanes Matthew in 2016 and Irma in 2017, as well as the unprecedented 2004 hurricane season. But as with any flood protection project, there are limits to the level of flood protection benefits and the areas benefited by the project.

The USJRB Project does not reduce flooding in the river’s middle basin in east-central Florida, including lake Monroe and Harney, nor further downstream in the river’s lower basin in north Florida. This is because tributaries such as the Econlockhatchee River drain much more water to the middle St. Johns River than the amount that can be drained from the headwaters. Also, middle basin tributaries do not have comparable flood control facilities as are used in the upper basin.

The district also operates flood-control structures in the UORB — the Apopka-Beauclair Dam, Moss Bluff Dam, Harris Bayou Spillway, Nutrient Reduction Facility (NuRF) and the Burrell Dam.

What you can do

If you are experiencing flooding, immediately contact your local government. Local governments are the primary entities responsible for emergency responses during storms, such as implementing state-of-emergency declarations, evacuations and rescue efforts during flood-related disasters.

Understanding that water control structures do not address flooding in the middle or lower St. Johns River basins, the best time to prepare for the storm is before weather conditions begin to deteriorate. Maintenance of a neighborhood stormwater system will help homeowners be ready for copious rainfall associated with many tropical systems.

Stormwater systems, like natural ponds or wetlands, help control flooding by slowing down surges and absorbing rainwater before it reaches water bodies. They also help filter out nutrients and sediments collected by storm water as it runs over the earth’s surface before pollutants can reach natural waterways.

Stormwater systems come in a variety of shapes, sizes and forms. Very generally, some systems can handle 4–5 inches of rainfall, while others can handle up to 8–9 inches of rain.

Maintenance of private stormwater systems permitted by the district or the Florida Department of Environmental Protection may be the responsibility of a homeowner association. In some planned subdivisions, the homeowner association may legally have responsibility for routine and periodic maintenance of the stormwater system.

Maintenance may include clearing or cleaning inflow/outflow structures, removing nuisance and excess vegetation, repairing eroded slopes, and cleaning up trash and yard waste in your yard and gutters and around storm drains. The district’s website contains a section on stormwater systems and how they work that addresses the most effective methods of keeping stormwater systems working properly.