Water chiefs warn CSO data misses harm caused

Senior figures within the water industry have urged MPs not to become tunnel-visioned in their approach to improving river water quality.

While acknowledging that the number of spills from combined sewer overflows (CSOs) must be reduced, heavyweight industry figures said that it was not the only factor impacting river water quality.

Instead river monitoring technology should measure the impact of CSO spills to ensure investment is targeted in the most appropriate places, Welsh Water’s director of wastewater services Steve Wilson has told government.

Speaking to the Welsh Affairs Committee, Wilson admitted the number of spills from CSOs into rivers “is awful”, but argued CSOs were considered a very small reason for not achieving good status (RNAGS).

For the River Usk, Wilson said that CSO spills accounted for 1% of its RNAGS and the Wye only 2%. Elsewhere, Wilson said the impact of CSOs on the River Dee’s RNAGs was 10%, so the company has prioritised investment to this area.

Ofwat chief executive David Black also called for water quality monitoring to measure the impacts of CSO discharges after event duration monitors (EDM) have been added to monitor when CSOs spill.

He said: “We need to technology innovations to move much faster to get a better understanding of the impacts of discharges on rivers. There have been sustained improvements but have to go further.”

Current technology, Black noted does not measure harm done by discharges, which he described as “the ultimate place we would like to get to”. He said adding EDMs was an important step forward but there was still work to do to make sure the data is reliable and understand the impact on public health or the environment.

Ceri Davies, executive director of evidence, policy and permitting, Natural Resources Wales, stressed the need to look at catchments holistically, particularly to remove surface water.

“It’s not just about discharges from CSOs, but to look at what are the root causes of spills elsewhere in the system,” she said, and added this includes the impact customers have on the system that could cause upstream CSOs to discharge.  “There’s a function each of us can be taking to improve the use of systems from households so not to exacerbate problems.”

Black said around 30% of discharges are due to operational issues in companies, rather than matters of capacity across networks. “That’s an early area for a win,” Black said and added that fully addressing the problem would take a sustained  plan with long term targets, actions and understanding of the places CSOs are.

Both sets of regulators denied the need for any further enforcement powers to hold companies, and leaders, to account.

The costs of better river water quality will ultimately fall to billpayers. Wilson said the company was looking to invest more than £1 billion for its environment plans in the next five year period. This will be targeted to tackle sewage works causing phosphorous issues, improving water quality and clean beaches, and addressing overflows causing environmental harm.

The figures to tackle CSOs in Wales are “huge”, Wilson said. Based on drainage schemes already commissioned, he estimated it would cost between £14 billion and £20 billion to get spills down to 10 to 20 times a year.

Within the same session, MP for Clwyd South Simon Baynes also urged regulators to better acknowledge concerns people have over river health.

He said river water quality “arguably should have been a bigger political issue” in Wales than England because problems are proportionately greater in Wales.

“This is a major problem in Wales, it is lagging the rest of the UK and it’s incumbent upon you as the guardians of the water industry to be more up front and open about that,” he added.