Coastal structures like seawalls play a crucial role in stabilizing shorelines and protecting waterfront properties. They are designed to mitigate erosion, minimize flooding, and provide defense against extreme weather events, including hurricanes. However, with the ongoing rise in sea levels, it is important to consider the long-term effects of sea level rise on seawall design, especially in low-lying coastal areas like Florida.
Many municipalities have started implementing minimum seawall elevations in their ordinances and building codes to account for sea level rise. These requirements may impact your seawall project, depending on its scope. It is advisable to consult with a licensed engineer or contractor who can incorporate the new seawall design requirements into your project.
For instance, Broward County in Florida implemented a seawall ordinance on April 1, 2020. It mandates that all new or substantially rehabilitated seawalls have a minimum elevation of +5.0 feet (NAVD). However, applications submitted before January 1, 2035, for new or substantially repaired seawalls may be permitted with a minimum elevation of +4.0 feet (NAVD), provided they are designed and constructed to accommodate an elevation increase to +5.0 feet (NAVD) by January 1, 2050.
It is essential to stay informed about these evolving regulations and ensure compliance with the latest seawall design requirements to safeguard your property against the impacts of sea level rise.
Here is what you will need to know about proper seawall maintenance:
Seawalls endure significant exposure to various environmental forces throughout their lifespan, leading to deterioration over time. In Southeast Florida, numerous seawalls were constructed during the development surge of the 1950s and 1960s. As a result, many of these waterfront structures, including seawalls, have surpassed their intended service life of 60 years due to the effects of long-term exposure to saltwater, tides, vessel impacts, storms, and excessive loads.
It is common for older seawalls to exhibit signs of wear and damage, compromising their effectiveness in providing shoreline protection. Regular inspections and maintenance are crucial to identify and address issues such as cracks, erosion, or structural weaknesses that may have developed over the years. By evaluating the condition of the seawall and implementing appropriate repair or replacement measures, property owners can ensure the continued functionality and safety of their coastal structures.
Properly maintaining and addressing the deterioration of seawalls is essential to safeguarding waterfront properties and mitigating potential risks associated with ongoing exposure to environmental forces.
Implementing periodic inspections is a valuable practice for seawall owners to proactively identify deterioration and carry out necessary repairs before replacement becomes necessary. Repairing deteriorated sections of a seawall can effectively extend its useful service life and is generally a more cost-effective option than complete replacement. The American Society of Civil Engineers recommends that coastal structures, including seawalls, undergo inspections at least once every 5 years.
Certain signs of deterioration serve as indicators for an owner to initiate an inspection. These signs include cracking, corrosion, rotation, and settlement or soil loss along the upland area. Such forms of deterioration can signify a decline in the seawall's structural integrity, safety, and ability to provide shoreline protection. It is essential to involve a professional with expertise in seawall inspections to address these issues before they lead to failure.
Regular maintenance and timely repairs contribute to extending the service life of a seawall and maintaining its functionality for an extended period. Neglected deterioration will accelerate due to increased exposure to the harsh marine environment and potential further damage.
A thorough seawall inspection should encompass both above-water and underwater observations to assess the extent of deterioration, which may occur even at the seabed level. For instance, clearing marine growth in the tidal zone could reveal cracks, while probing below the water surface can confirm upland sinkholes resulting from soil washout through the seawall. It is crucial to engage a licensed Professional Engineer experienced in seawall inspections, familiar with common types of deterioration, aware of where to look for them, and capable of designing appropriate repair or replacement strategies to address them effectively.
The information gathered during a seawall inspection serves as the basis for designing the appropriate repair or replacement strategy. When designing and constructing a seawall, careful consideration must be given to its location and the various forces it will encounter throughout its service life. Seawalls can be constructed using different materials such as steel, concrete, timber, aluminum, vinyl, and composites, each offering its own set of advantages. Factors such as cost, service life, constructability, and durability should be taken into account when selecting a design that suits the specific site conditions. For instance, seawalls along the Atlantic Ocean are typically constructed using steel or concrete due to the high forces they may experience during storms.
By engaging in proper planning, conducting routine inspections, implementing proactive maintenance measures, and employing thoughtful design practices, seawall owners can effectively maintain shoreline stabilization and protection for their properties in the present and in the future. This approach ensures that the seawall remains resilient and capable of withstanding the environmental challenges it may face, thus safeguarding the property and preserving its value.