Flood protection is among the St. Johns River Water Management District’s four core missions. To meet this mission, the district employs both structural and non-structural techniques.
Structural flood protection includes constructed levees, water control structures and pump stations to physically hold back potential floodwaters from downstream areas and control the water levels in the areas behind these structures.
Non-structural flood protection is achieved through management of water control structures to ensure compliance with regulation schedules and to minimize upstream and downstream flooding, implementation of stormwater management rules, purchase and conservation of floodplain wetlands to provide floodwater storage, and the collection and dissemination of hydrologic data to guide flood preparedness and responses.
We all have a role in helping to prevent flooding.
The district’s role
The district works with local governments and other agencies before, during and after a flood event. The district operates and maintains major and minor water control structures, including 11 spillways, three navigational locks, approximately 300 miles of federal and farm/project levees, and 30 pump stations.
In the Upper St. Johns River Basin, the district operates and maintains several major water control structures in Indian River, Brevard and Osceola counties. In the Ocklawaha River Basin, the district operates and maintains the Moss Bluff dam in Marion County and the Burrell dam, Harris Bayou water control structure, and Apopka-Beauclair dam in Lake County. Those structures are the only controls the district has of water levels in the St. Johns and Ocklawaha rivers. The combination of federal and district projects’ benefits do not reduce flooding in east-central Florida (the St. Johns River’s middle basin), including Lake Monroe, nor further downstream in the St. Johns River’s lower basin in north Florida. This is because prior to the St. Johns River reaching central and northern Florida, the many tributaries to the St. Johns contribute to the river’s flows.
The district also restores wetlands and floodplain areas that provide flood water storage. Through its permitting program, the district ensures that stormwater is managed on development sites and that new drainage ditches or significant changes to existing ditches are coordinated regionally. The district and the Florida Department of Environmental Protection issue permits to install stormwater systems, but it is often the responsibility of a developer or homeowners association to maintain the systems. In addition, the district assists local governments in emergency response during disasters and to incorporate flood protection elements into their comprehensive land use plans.
Your local government’s role
Local governments are responsible for emergency responses during storms, land use planning, maintaining stormwater/drainage systems, implementing a master stormwater plan for solving flooding, implementing stormwater retrofit projects in older communities that were built prior to stormwater rules, and adopting local laws that focus on building and road elevations, setbacks from waterbodies, fill limitations, sanitary codes and structures allowed in floodplains.
Individuals can protect themselves from flooding by being proactive ahead of storm season and conducting periodic maintenance. As an individual, you can protect yourself and your property by keeping debris out of storm drains and ditches, reporting clogged ditches to your local government, obtaining flood insurance through the National Flood Insurance Program, determining whether a home or land you are considering buying is in a floodplain or flood-prone area, and by flood proofing your home.
District flood control operations
A key element in the district’s flood control mission is operation of flood-control structures in the Upper Ocklawaha River Basin and in the St. Johns River’s upper basin. However, the district does not control water levels in the St. Johns River itself.
Overlapping our routine flood control mission is the district’s role as local sponsor for the U.S. Army Corps of Engineers (USACE) federal flood protection projects, located in the Upper St. Johns River and Upper Ocklawaha River basins. In our role as local sponsor, the district is responsible for the operation and maintenance of the levees and water control structures that provide flood protection, environmental benefits and habitat restoration.
As with any flood protection project, there are limits to the level of flood protection benefits and the areas benefited by the project. While these federal projects reduce flooding in much of the Upper St. Johns and Ocklawaha river basins, they do not reduce flooding in the St. Johns River’s middle basin in east-central Florida, including Lake Monroe, 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.
Federal flood control project information
We take our responsibility as local sponsor for the federal flood protection projects seriously and we work closely with USACE to ensure that the levee systems that comprise these projects are maintained and operated to reduce risk to human life and property damage associated with flooding. For additional information about the federal levees, USACE has developed “Levee System Summaries”, which include a project description, risk information and additional details.
- Jane Green Detention, South Levee System Summary
- Impacts Brevard, Osceola and Orange counties
- Upper St. Johns River Basin, North Levee System Summary
- Impacts Brevard County
- Upper St. Johns River Basin, South Levee System Summary
- Impacts Indian River and St. Lucie counties
- Ocklawaha River Bain, C-231 Levee Summary
- Impacts Marion County
Flood risk reduction, federal levee system webinar
(recorded Jan. 28, 2021)
Flooding issues: The upper basin, C-54 canal
Extreme rainfall can cause rivers and streams — such as the north-flowing, 310-mile-long St. Johns River — to surge beyond their banks, damaging homes and businesses. While the St. Johns River Water Management District operates flood-control structures in the Upper Ocklawaha River Basin — the Apopka-Beauclair Lock and Dam, Apopka Dam, Moss Bluff Dam and the Burrell Dam — and restored St. Johns River headwaters marshes used for water storage, the district does not control water levels in the St. Johns River.
The district’s largest flood control project is the Upper St. Johns River Basin Project.
The Upper St. Johns River Basin Project at the river’s headwaters was planned to control flooding on the St. Johns River in Osceola, Brevard and Indian River counties following a devastating flood in the 1940s. One component of this project, Canal 54 (C-54), was designed to divert water from the upper St. Johns River into the Indian River Lagoon. However, the upper basin project was redesigned in the 1980s to address environmental concerns with the original design and the role of C-54 changed.
As part of the original upper basin project, C-54 discharged directly from the St. Johns River to the lagoon. Now, C-54 is no longer directly connected to the St. Johns River, but instead serves only as an emergency overflow for the St. Johns Water Management Area to ensure that extreme flood events do not overtop the flood protection levees.
Contrary to popular belief, the use of C-54 to release water from the headwaters of the St. Johns River provides no measurable flood relief to the river’s middle basin (east-central Florida), including Lake Monroe, 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 at C-54 canal. Also, middle basin tributaries do not have comparable flood control facilities as are used in the upper basin. Downstream of the upper basin project area, flood levels are reduced as far north as Lake Poinsett. For example, flood elevations on Lake Washington can be reduced by about half a foot for a 100-year flood event.
Hurricanes and historic rain events have tested the flood storage capabilities of the Upper Basin Project — such as the heavy rains that arrived with hurricanes Irma in 2017 and Matthew in 2016.
During Hurricane Irma and the subsequent nor’easter, (September to October 2017), a foot of rain fell over the St. Johns River’s upper basin over a 30-day period. People as far north as Mayport and Jacksonville called for relief from local flooding along the St. Johns River, believing that discharges from C-54 canal would help. Discharges up to 2,200 cubic feet per second (cfs) were made through the C-54 canal over a period of 11 days following the hurricane, and an additional seven days following the subsequent nor’easter. This resulted in a diversion of nearly 15 billion gallons of water away from the St. Johns River.
During Hurricane Matthew (October 2016), nearly three inches of rain fell over the upper basin project over a two-week period. Discharges up to 1,300 cfs were made through the C-54 canal for nine days. This resulted in a diversion of nearly six billion gallons of water away from the St. Johns River.
During the 2004 hurricane season, nearly four feet of rain fell on east-central Florida during a 60-day period, statistically a one-in-200-year rain event. When the river overran its banks in the Middle St. Johns River Basin (Lake Harney north to Lake George, including lakes Jesup and Monroe), some called for the district to provide flood relief by releasing water from C-54 canal, located about 120 miles to the south.
Following Hurricane Frances (September 2004) when discharges were made through C-54, the result was a reduction in flow to the St. Johns River of only 600 cubic feet per second (cfs). Water management district engineers estimate that a 600-cfs reduction in flow from the upper basin project would have resulted in less than a half-inch reduction in the water level on Lake Monroe. Why such a small impact? Because flows out of the uncontrolled tributaries of the middle St. Johns River are much larger than this. For example, flow out of the Econlockhatchee River has been measured at more than 10,000 cfs, and this is only one of several tributaries of the middle St. Johns River.
Water management district engineers have concluded that the flooding that occurred on lakes Monroe and Harney in 2004 was due primarily to local rainfall conditions and that greater use of C-54 would not have reduced the damage caused by these floods.