At Salix, we’re proud to have played a key role in delivering the new Integrated Constructed Wetland (ICW) at Staplefield Wastewater Treatment Works in West Sussex.
An innovative nature-based solution for Southern Water that combines smart engineering with ecological design to improve water quality, support biodiversity, and enhance local flood resilience.
Over an eighteen-week period, Salix undertook earthworks, drainage, and planting, ensuring a fully integrated approach from design through to completion. The system operates by pumping water from the existing sewage treatment works into a distribution chamber at Cell 1, where it begins its journey through the three wetland cells. As the water passes through each stage, it is naturally filtered. By the time it exits the final cell, the water has reached a sufficiently high quality to be safely returned to the nearby watercourse.
To establish the wetlands, Salix supplied and installed over 100,000 native plants, representing around 25 different species carefully selected to balance treatment performance with ecological value. Some species were chosen for their role in nutrient removal and water purification, while others were introduced to promote biodiversity, providing nectar, shelter, and habitats for a wide range of invertebrates, birds, and small mammals. Together, these species form a thriving ecosystem that not only contributes to water treatment but also enhances the visual and ecological richness of the surrounding landscape.
Collaboration played a key role throughout the project, with Vessi Environmental acting as a valued supply chain partner and contributing to the successful delivery of the ICW. The concept at Staplefield was developed to fit naturally within the existing environment, complementing local habitats while adding long-term ecological and hydrological value.
The completed wetland now provides multiple benefits by improving water quality, supporting biodiversity, and offering a low maintenance solution to the treatment works, all while creating a resilient and visually appealing landscape. The project exemplifies Salix’s commitment to delivering sustainable, nature-based infrastructure that works in harmony with the environment while providing tangible long-term benefits for wildlife and the local communities.
