The UK should re-think the way it assesses and manages river water quality following our exit from the EU, a Lancaster University professor tells an influential committee of MPs.

The notion of returning rivers to "a natural state" is inherently problematic, Professor Nigel Watson told the opening session of an inquiry into Water Quality, by the House of Commons Environmental Audit Committee.

The inquiry is exploring the best approach to maintaining and improving water quality, as the UK transitions away from the European Water Framework Directive (WFD) post Brexit. Currently only 14% of UK rivers reach EU water quality standards.

"The context of the enquiry is that there is now a key question about what elements of the WFD should be carried over, and what new targets and alternative approaches are needed to realise the ambitions of the Government’s 25 Year Environment Plan," explains Nigel, Professor of Geography and Environmental Management at the Lancaster Environment Centre.

Nigel, an environmental social scientist and expert in water governance, told MPs that what is needed is an approach founded on ecosystem functions and services, and including humans as parts of those systems. This contrasts with the WFD approach which sets standards based on the assumption that there is a fixed natural condition for rivers which we are trying to meet.

"Rivers are open dynamic systems, they are always changing, so we shouldn’t be aiming for a static condition or one particular fixed state. What’s more important is that rivers maintain their fundamental ecological functions and are able to evolve from one healthy configuration to the next. We need resilient rivers, that can cope with disruption and change, and continue to evolve over time from one semi-stable state to the next.

"The ecosystem services approach could help to identify more clearly what people and nature require from our rivers, and enable more effective targeting of investment in remediation, restoration and protection.

"So if a community wants inland recreational swimming for example, what are the corresponding water quality standards that we need to enable that to happen safely, and how can that function or service be accommodated alongside other requirements for nature and people?"

Nigel championed the catchment partnership-based approach, which he has helped to develop over the past decade. Catchment partnerships bring together interested parties such as the Environment Agency with conservation groups, water companies and farming organisations.

Nigel, who has been chair of the River Ribble Catchment Management Partnership for the past ten years, argued that focussing on water quality at this one river system scale could help to get over some of the challenges experienced with the implementation of the Water Framework Directive, which focusses on much larger regions known as River Basin Districts.

"If you focus on one river and its tributaries, you can be much more confident of the analysis and of identifying the actions that need to be taken and, critically, who should be responsible for taking them," he explains.

He recommended that these partnerships should be move from their current voluntary status to being a fuller and more integral part of the institutional system for managing land and water.

He also suggested that the MPs could learn from best practice in Canada, where he lived and worked for several years. He highlighted Canada’s use of "catchment or watershed-scale institutions" that bring together local and regional government officials and representatives from community interests and resource user groups. Their focus encompasses land, water and related natural resources, with the aim of protecting water quality and managing hazards such as flooding and drought.

Nigel hopes that the Committee’s report, including his evidence, will feed into the finalisation and eventual implementation of the Environment Bill, which is waiting to be considered by Parliament.

Watch Nigel giving evidence on Parliamentlive.tv - Environmental Audit Committee