United Utilities and partners have worked to transform the water quality of the River Petteril in Cumbria through innovative new trials which have seen phosphorus levels in Calthwaite Beck reduced by 63% in 2022.
In order to positively impact the health of the River Petteril, in 2019 the UK’s first Catchment Nutrient Balancing (CNB) trial was initiated at Calthwaite wastewater treatment works (which discharged into the Calthwaite Beck – a major tributary of the River Petteril).
This project initially aimed to remove 150kg of phosphorus load through integrated catchment and treatment works solutions – in turn creating a 9% reduction in phosphorus in the catchment area. The trial exceeded expectations as, in 2022, it achieved a 63% reduction in phosphorus.
The trial saw an improved treatment process, using innovative reactive filter media, polonite at the treatment plant – to reduce phosphorus levels from that source.
United Utilities then worked with sectors such as agriculture, businesses, and environmental NGOs, to deliver even greater value for customers, communities, and the environment.
These wider catchment measures included hedges, buffer strips and sediment ponds delivered at farm level to reduce agriculture contribution – to achieve results beyond regulatory obligations.
Jo Harrison, Environment, Planning and Innovation Director, from United Utilities, commented:
“We are thrilled with the results that the CNB trial has produced. They clearly evidence the enhanced benefit that can be achieved with an integrated catchment approach that addresses all sources of pollution within the catchment, rather than focusing on a one-size-fits-all solution.”
“Through tackling the problem of phosphorus pollution in a new way, we have taken into account the dynamic nature of the catchment, how pollution into the River Petteril is driven by multiple sources and how it is exacerbated by storm and flooding events, in order to completely transform the Petteril’s water quality.”
The innovative approach is part of United Utilities’ Catchment Systems Thinking Strategy (CaST) in the Petteril, in which they aim to work with others to address specific catchment needs in a more sustainable and holistic way.
United Utilities worked together with the following partners: Eden Rivers Trust, Carlisle City Council, Cumbria County Council, Lancaster University, Natural England’s Catchment Sensitive Farming, The National Farmers Union, the Environment Agency, and Nestle and their fellow stakeholders, making joint decisions through co-creation and co-delivery of interventions.
The activity has been supercharged by additional funding of £120k, achieved through match-funding and collaborative working with farmers (landowners and tenants) in the area, which will deliver greater environmental outcomes for the River Petteril.
Jo Harrison added: “The activity across the River Petteril is part of our ‘Better Rivers, Better North West’ programme, by working alongside our partners, we are looking forward to continuing to transform river health in the North West.”
Moving forward, United Utilities is set to keep up the momentum on the River Petteril by expanding the CNB trial across three further wastewater treatment works in the Petteril catchment – Greystoke, Motherby and Southwaite. This will target phosphorus load reductions totalling 566kg/year by September 2024, where 98kg of this reduction is achieved through catchment interventions.
