Storm overflows: helping nature and society thrive through the design of innovative wetlands

Reducing storm overflows (SOs) and improving water quality is a core part of the largest infrastructure investment in UK history, as stated in the UK government’s Storm Overflows Discharge Reduction Plan (SORP). To address this, Wessex Water Services Limited (WWSL) is integrating nature-based solutions (NbS) as key interventions into the company’s asset base through their commitment to restoring the environment. Building on its successful monitoring programme of reedbed treatment systems installed to treat groundwater-influenced SOs at two sites, WWSL is trialling NbS schemes across the region. Working towards achieving targets set out in the SORP, these trials shall inform the long-term NbS plans of WWSL. Mott MacDonald Limited (MML) has worked closely with WWSL to assess several of their SO sites for installation of constructed treatment wetlands. MML is designing both traditional and innovative wetland approaches to deliver schemes at different scales and approaches, while maximising sustainability through retrofitting existing and decommissioned infrastructure. MML and WWSL are working collaboratively with stakeholders to develop inclusive designs that maximise biodiversity and social opportunities, benefitting the environment and wider communities. Installed systems will be monitored and lessons learnt captured to inform best practice and deliver targets while incorporating wider benefits.