Dearne Reach is a 4.4-hectare integrated constructed wetland (ICW) designed to enhance water quality along 4 km of the River Dearne by reducing ammonia levels and improving storm flow treatment. To deliver this nature-based solution, MMB excavated 13 wetland cells covering over 44,000 m² (equivalent of 7 football pitches!), creating space to house more than 350,000 wetland species. An alternative to traditional grey infrastructure which initially would have entailed 7,000 m³ of additional storm storage and a 4.5 km diversion of final effluent to a lower river reach—this ICW offers a sustainable approach to pollution mitigation. The largest ICW developed in the UK to improve water quality, the project pioneers a low-carbon stormwater management solution. Harnessing the power of natural pollutant removal processes such as sedimentation, filtration, and biological uptake the ICW will reduce pollutants including ammonia, micropollutants and emerging contaminants. Aligning with Yorkshire Waters WFD drivers and Net Zero ambitions, this project pioneers an ICW tailored for intermittent storm overflows, distinguishing itself from conventional ICWs that require constant inflow. Its innovative design ensures effective management of stormwater variability and will contribute to driving continuous innovation in nature-based solutions across the water industry.