The City of Delray Beach experiences Tidal flooding on its streets more than a dozen times a year. Whether it’s due to a higher High tide, like a King Tide event or whether it’s a storm off the Atlantic that pushes more water than normal into the Intracoastal Waterway during a high tide, several of Delray’s streets and right of ways become inundated during that high tide cycle. Tides only stay high for 3 hours at a time. The problem with tidal waters on the streets and grassed areas is the salt content in the water. It does damage to vegetation within the City’s right of way or private yards. Over time the water will damage the sub base of the City’s roadways.
Delray Beach has experienced noticeable increases in flooding episodes in recent years, often referred to as nuisance flooding. In addition to the notable flooding in the Marina Historic District and low lying areas on either side of the Intracoastal during the Fall and Spring King Tides, impacts from such storms as Hurricane Wilma and most recently Hurricane Mathew have resulted in damage along the coastline. The reported damage from Wilma in Delray Beach was between $100 million and $150 million with $8 million of damage to public buildings. While the specific impacts of rising water in Delray Beach require further study, the Southeast Florida Regional Climate Change Compact’s Unified SLR Projection, described below, makes clear that nuisance flooding will continue to occur and intensify.
When the water elevation of the waterbody that the drainage systems outfalls into, is higher than the drainage system itself.
Type of Prevention
Flooding for coastal communities has always been an issue, but sea level rise has increased the frequency and severity of inland impacts from tidal flooding. The City of Delray Beach has included infrastructure projects within our Capital Improvement Plan that aim to reduce the effects of flooding to our residents and business owners.
In-line check valves
Inline check valves are an effective and aesthetic method employed to prevent tidal backflow in a drainage system. Due to the ease of installation, low maintenance requirement and low head-loss, in-line check valves have become the City’s preferred stormwater backflow prevention measure.
Flap Gates are typically installed at stormwater discharge points directly downstream of stormwater pump stations. They must be periodically maintained to ensure a thorough seal to prevent tidal backflow.
Similar to flap gates, duckbill valves are installed to a headwall or seawall at stormwater discharge points. They require a relative low flow or hydraulic head condition to function, but their exposure to the environment can cause a higher level of maintenance to function properly. The City is currently replacing duckbill valves with in-line check valves.
Located along the western shore of the Intracoastal Waterway directly north of Atlantic Avenue is comprised of over 650 linear feet of seawall
The City’s municipal marina is located along the western shore of the Intracoastal Waterway between South East 1st Street and South East 2nd Street