The award celebrates the successful completion of the project, a collaboration between WWT and the Defence Infrastructure Organisation (DIO), which ran from 2020 to 2024 on the Hampshire Avon, one of the UK's finest chalk streams.

The West Chisenbury project was designed to address two critical objectives for the highly-designated river system, which is a Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC):

• Mitigating Phosphorus Pollution: The project's primary aim was to capture and remove phosphorus from the river through the settlement of sediment-adhered phosphorus in newly created wetland areas. This mitigation was required due to an uplift in phosphorus entering the Avon, which was linked to a planning commitment under the Army Basing Programme (ABP).
   
• Restoring Natural Habitat: The work involved realigning the river channel to its historic course through the centre of the floodplain and restoring natural chalk river geomorphology and floodplain processes. The river had been historically modified, leading to slow-moving water, loss of characteristic species, and siltation of the gravel bed, which limited salmonid spawning.

WWT led the delivery of the project, managing contractors for capital delivery and modelling, compiling essential technical and ecological documents, and providing site supervision. The partnership also involved funding from the MoD and external partners such as National Highways and extensive advice from Natural England and the Environment Agency.

The scheme is notable for its innovative design, which successfully balanced the conflicting needs of creating an effective system for quantifiable phosphorus removal with the SAC conservation objective to deliver a fully natural floodplain wetland. The design maximised water retention time for phosphate uptake and avoided non-natural materials, while incorporating features like gravel riffles to ensure the river's continuing natural processes.

The project's successful delivery, despite significant challenges including the complexity of obtaining multiple permits and licences and construction being hampered by very high rainfall, showcases the dedication and flexibility of all partners.

Beyond its local impact, the project has the potential for national significance:

• A Model for Conservation: The West Chisenbury wetland provides an example for combining large-scale river and floodplain restoration with nutrient capture, particularly in chalk streams.
   
• Refocusing Mitigation: If the current monitoring programme demonstrates sizeable net phosphate uptake, the scheme has "huge potential to refocus and shift the national emphasis" for achieving nutrient neutrality through natural floodplain wetlands.

The project has also enhanced the MoD's environmental reputation, with excellent media coverage including a feature on BBC Countryfile.

This award is a testament to the collaborative effort that has improved the condition of the Salisbury River System SSSI and the River Avon SAC, contributed to the Nature Recovery Network in Wiltshire.

A huge well done to the Water Team! You can learn more about the project here Pioneering river restoration project completed on military land in Wiltshire | Wiltshire Wildlife Trust.