United Utilities’ holistic approach to catchments

United Utilities has been engaged in catchment management for more than 15 years to stop pollutants entering water sources. Utility Week talks to catchment advisor Vee Moore about how different catchments are managed and some projects the company has underway.

United Utilities’ (UU) supply area stretches across the north west from Cumbria down to Cheshire, incorporating flood-prone pastureland and river basins as well as swathes of agricultural land.

The company is something of a pioneer in catchment management techniques and has worked with landowners for several years to prevent pollutants entering waterways instead of having to treat and remove them.

In the northerly part of its region, UU owns around 57,000 hectares of land – primarily uplands surrounding reservoirs, but in the south the company owns little and the landscape is more lowland, so the approach to catchment management must vary.

Vee Moore, catchment management advisor, tells Utility Week: “Since 2005 we have very much been a pioneer in sustainable catchment management with things like woodland management, watercourse protection and now through the work of safeguard zones the company is expanding its approach into non-owned areas in the south.”

She said the approach is driven by drinking water safeguard zones – which are determined by the Environment Agency in abstraction areas with pollution risks. Raw water quality has deteriorated and become harder to treat because of activities on land so the company is targeting its activities in safeguard zones to improve water quality around reservoirs, groundwater and rivers.

The surface water safeguard zones are designated to address problems with discolouration – caused by peat, algae eutrophication algal blooms, pesticides run-off. For groundwater, problems include nitrates, pathogens, solvents.

The company relies heavily on landowner engagement and Moore says they are increasingly on board with embracing cover crops. “When we started in 2018 we had a nine tonne nitrogen reduction target, now it’s 15 tonnes, which shows how willing farmers are to adopt the schemes.”

She explains it’s about “finding the sweet spot” between what the company needs to achieve and what farmers want to do, which has meant adapting to find best solutions both economically and ecologically.

While we usually think of catchment areas as adjacent to rivers, Moore explains everything that drains and filtrates into aquifers has its own catchment – and challenges.

“A lot of the issues we have are from diffused pollutions – lots of small pollution sources that on their own would have a negligible, but together have a significant, effect.” These include fertilisers, pesticides, industrial waste, waste from mining operations, nitrates from stables, caravan parks and septic tanks where the catchment is not connected to mains sewerage.

“Every catchment is very different, so we developed different tools, schemes and advice, there’s no one-size fits all,” Moore says adding that specific risks need to be assessed in each area.

In the past water companies would rely on water treatment but the holistic approach at catchment level aims to prevent pollutants at source.

“We capture potential risks from land use types and assess these risks to ensure how effective our water treatment is. The whole purpose is about addressing challenges at catchment scale out in the landscape rather than relying solely on water treatment.”

Preventing pollutants from entering the waterways makes economic and ecological sense, says Moore but explains quantifying the cost benefits is tricky because each area is so varied.

Moore discussed some of the solutions identified across the company’s southern region:

Cover crops

The company works with landowners and offers incentives for farmers to grow cover crops after the harvest in autumn and winter when fields are fallow. Through auctions, farmers bid to sow specific crops funded by UU to stop nitrates leeching from bare fields through the soil zone into groundwater.

Moore says cover crops are a really effective way to mitigate nutrient loss, minimise soil erosion and improve soil structure when the fields are fallow.

Incentives favour crops that capture more nitrogen and farmers are paid relative to the amount of time crops are in the ground.

Agronomy tool

The company utilises a nitrogen management tool from CF Fertilisers, which is based on the science of soil management and crop production to advise farmers on the nutrients required based on the soil type on their land. Precise information based on soil sampling throughout the growing season is given to farmers to show all the nitrogen available throughout the cycle of a crop and studying the effects of using fewer nutrients on the yield. Moore says the project, now entering its second year, is targeted at arable and maize growers.

Biomass – Miscanthus

This ornamental grass is seen in gardens up and down the country but a sterile hybrid of the hardy perennial is now being trialled by UU to cover bare fields in groundwater catchment areas.

The miscanthus has very low agrochemical requirement and can be harvested and sold as biomass, for animal bedding and even for bioplastics. Moore says this hits the sweet spot between what farmers want and what is needed in the catchment.

Willow and poplar

Another biomass crop is being grown in the northern region with short rotation willow crops added to flood-prone pastureland in Cumbria. These can stabilise and re-profile riverbanks after flood damage.

Further south, in Cheshire UU is reaching out to landowners to grow willow and poplar, which can both be used as biomass crops. Moore said these “energy crops” can promote net zero emissions, improve water quality, provide natural flood management benefits, boost biodiversity as well as being profitable.

As with the miscanthus trial, the goal is to improve raw water quality at source, reduce the pressure on treatment processes, and bring wider benefits to nature at the same time.