In August 2008, Tropical Storm Fay inundated the City of Port St. Lucie with as much as 14 inches of rainfall during a 48-hour period. It was more rain than the City got in 2004 from Hurricanes Frances and Jeanne combined. This amount of rainfall exceeded the South Florida Water Management District's (SFWMD) criteria for a 100-year, 3-day storm event and caused flooding of streets, businesses and residences in eastern Port St. Lucie and also flooded one of the City's main transportation corridors, U.S. Highway 1.
As a response to the heavy flooding, the City Council approved a multi-million dollar drainage improvement project that is now under construction in the east side of the City. It is called the Eastern Watershed Improvement Project (EWIP), and it is expected to cost the City about $35 million to complete. This Web page will help residents affected by the project to stay informed about the status of the project. The Engineering Department will also be sending a printed newsletter called "EWIP News" to affected residents on a monthly basis.
The Eastern Watershed Improvement Project is the construction and installation of a system of drainage ditches, stormwater ponds, piping, pumps and other structures that work together to manage stormwater runoff on the east side of the City. It includes all of the City east of U.S. 1 as well a small portion west of U.S. 1 generally around Howard's Creek, just north and south of Westmoreland Boulevard.
View/download a map of the City's eastern watershed area and the proposed improvements that are planned to minimize potential flooding problems in future heavy rain storms.
The Eastern Watershed Area was developed in the 1980s by General Development Corporation (GDC), which was the original developer of the City. The South Florida Water Management District (SFWMD) permitted the stormwater system utilizing criteria that were acceptable during that time. The 1980s permit criteria for minimum building and roadway elevations were less stringent than current requirements. The original permits allowed more storage of stormwater in roadways and swales, while current SFWMD and City criteria require detention ponds to store runoff and do not allow significant roadway storage.
Within the Eastern Watershed Area are four drainage basins that were planned and defined under the SFWMD permits obtained in the 1980s. The four basins are:
The natural grade of the land for these four drainage basins slopes generally from north to south, and from east to west, or from the Eastport Phase 2/Blackwell Basin through the Eastport Phase 1/Tiffany Basin to the Howard Creek Basin.
The Eastport Phase 1/Tiffany Basin and the Eastport Phase 2/Blackwell Basin were designed and permitted to utilize two large pump stations to overcome the natural slope of the land, which also limited the volume of runoff directed toward Howard Creek.
These stormwater systems are designed and permitted to store significant amounts of water in the streets, and if the capacities of these pump stations are exceeded, they will overflow toward the low lying areas of the Howard Creek Basin. The difference in average elevation between the Blackwell Basin and the Howard Creek Basin is approximately seven feet.
The Howard Creek Basin is divided into two sub-basins by U.S. 1. Because U.S. 1 is a primary evacuation route, it was constructed at a higher elevation than the adjacent properties (this becomes especially important during hurricanes). Two large drainage structures near the Lennard Road intersection allow water to flow under U.S. 1, but they have not been used to their full capacity because other drainage systems upstream and downstream were designed to lesser capacities.
In heavy rainfalls, this leads to the Howard Creek Basin becoming inundated with water from the other basins, and the problem was made worse because of an overgrowth of vegetation along Howard Creek where it moves toward the St. Lucie River.
Improvements to the City's eastside drainage problems will include several design changes. Those changes include the creation of additional stormwater retention ponds and treatment areas, additional alternative basin discharges, the modification of existing canals, improvements to existing pump facilities and the addition of new pump systems.
The first of this series of improvements is underway, including debris and vegetation removal and dredging along Howard Creek.
The next improvement to begin will be the construction of a 19-acre stormwater treatment area on City-owned property just south of the WalMart on U.S. 1 and the realignment of the Howard Creek channel into the stormwater treatment area.
Then crews will begin improvements to reduce flooding along Giffen Avenue, where homeowners experienced flood waters backing up into homes during Tropical Storm Fay. This will include the construction of a 3.7-acre pond east of Bur Street, the installation of culverts and ditches in the Giffen neighborhood, and improvements in the Dalhart and Van Kleef waterways.
|Before and after|
In addition to flood control, EWIP also serves to improve water quality through the creation of stormwater treatment marshes, or wetlands, and to provide passive recreational areas and places for residents and visitors to explore the environment.
The wetlands improve the quality of stormwater before it flows to the North Fork of the St. Lucie River. The system is designed to move water coming off buildings, driveways, roads and other surfaces that are impervious to water, into a network of swales, ditches, canals and ponds leading to the treatment marshes.
People often think of these bodies of water as lakes, but their primary purpose is to serve as retention ponds and stormwater treatment areas. In places where there are no impervious surfaces, rain water is usually absorbed into the ground. But when impervious surfaces are constructed, rain falling on those places will create flooding if not directed into the City's drainage system. That is the purpose of the City's open swale and canal network-to channel water away from roads, homes and businesses and into the St. Lucie River.
But as water flows over concrete and asphalt surfaces, it picks up not only debris, but also road oils, chemicals and substances that could harm one of the area's greatest assets—the River. Even fertilizer intended to help lawns can run into the river and disrupt its delicate ecosystem. However, as the water flows through the canals and sits in retention ponds and stormwater treatment areas—the places many people think of as lakes—various types of vegetation growing within the system breakdown the harmful chemicals, purifying the water before it moves on to the River.
The City monitors the vegetation, making sure that specific species are growing in proper proportion and that they are not displaced by unwanted species that do not filter the water or that obstruct flow.
With this in mind, the EWIP engineers designed improvements that work not only to reduce flooding, but to preserve the environment and natural resources as well.
We plan to update this page frequently with the latest project developments. Add this page to your favorites or click on the EWIP graphic on the left side of the city's home page.
E-mailed to subscribers every Friday, the City's weekly e-newsletter, PSL Mail, will include any significant developments on the project. Sign up today.
Still have questions? Feel free to call the City's Engineering Department at (772) 871-5177.