The Environment Agency identified that Rookery Brook was failing the Water Framework Directive (WFD) status for Phosphorus. Hafren Water collaborated with Reaseheath Agricultural Development Academy (RADA) in a CPAF-funded project to undertake an assessment of Rookery Brook, to ascertain the causes of the deteriorating water quality.
Extensive water quality monitoring and engagement with landowners was carried out to identify notable pollution sources, and appropriate mitigation measures. Off-line and on-line attenuation features were subsequently installed to slow flow and trap sediment.
The Water Framework Directive (WFD) status of the Rookery Brook, Cheshire, deteriorated from ‘moderate’ to ‘poor’ between 2009 and 2015. Phosphorus levels were particularly high, along with raised pesticides and low invertebrate and macrophyte populations, indicating poor physico-chemical status. Agricultural fertiliser was identified by the Environment Agency as the main cause of the failure.
Funding from the Catchment Partnership Action Fund was obtained in April 2015 for a collaborative project between Reaseheath Agricultural Development Academy (RADA) and Hafren Water, to undertake a detailed assessment to identify agricultural sources causing the worsening water quality. Recommendations and implementation of the intervention measures to improve WFD status was also undertaken.
Following a review of existing data and walkover surveys to identify potential issues (including point and diffuse pollution sources), extensive water quality and flow monitoring was undertaken to supplement existing Environment Agency data.
The field-derived data was used to engage with farmers and landowners to inform discussion and support adoption of mitigation measures to reduce or help control nutrients entering the watercourse. A number of attenuation features were designed by Hafren Water, including online and offline works, to trap sediment and reduce flow during peak rainfall events.
Three attenuation features were constructed at various points along the Rookery Brook following the meetings between landowners, farmers, RADA and Hafren Water. Appropriate consents were obtained from the Environment Agency and Local Authority for their construction.