We are delivering a range of emergency repairs and long-term works to help manage, maintain and preserve Stockton's coastline.
The Stockton CMP 2020 outlined a series of short and long-term actions. These actions include construction of more permanent protection structures, which are required to shield the shoreline and reduce the chance of inundation during large swells.
One of these structures is a new buried seawall at the southern end of the Mitchell Street rock seawall.
What are we building?
The new terminal structure we are planning to build is a buried seawall constructed with vertical, overlapping concrete beams. When completed, the top of the wall will be buried as shown below.
The new seawall in this location is 126 metres long, and the base of the overlapping beams (piles) that form the wall will extend 8.5m below ground.
What will it look like?
Why is a seawall the best option?
Before designing these structures, we studied and compared a range of potential design options to determine which solution best suited this location. We assessed each option's ability to address both storm erosion and long-term beach recession, access and amenity, cost to construct and to maintain over time, environmental impact, ease of construction and availability of materials.
Compared to other terminal protection solutions our design, known as a vertical secant pile seawall, requires less excavation during construction, which is more cost efficient and leads to less disruption during construction than other options. They also present the ability to increase the structure’s height in the future if required.
When will construction start?
We are currently seeking tenders for construction of the new structure, and we are planning to start construction in early 2023.
In the interim, emergency sandbags at the southern end of the Mitchell Street rock seawall are currently being repaired, and an additional two layers of rock bags will be placed at the base of the emergency structure to provide stability until the new vertical structure is complete.