In November 2021, the Environment Act became law and, with it, the promise of ambitious targets that would turn the tide on nature’s decline. Early last year, new regulations set out the detail of targets on water[i], waste, woodland and other topics that all contribute to the overarching and ambitious ‘apex’ goal, of seeing declines in species abundance halted by 2030.

For our watery habitats, the targets are intended to tackle the key pressures against which there has been stubbornly little progress to date. Nutrient pollution is a key factor that blights the freshwater environment, not just in England but around the globe. Although there are downsides to having targets on specific, potentially siloed topics, the logic of seeking to drive action on THE greatest pressure faced by our rivers, lakes and coastal waters is understandable. In freshwaters, phosphate is the pollutant causing the greatest number of failures against ecological standards. It’s a reason that more than half of England’s rivers, and three quarters of lakes, are assessed as not being in good health.[ii]

Of particular concern is the impact of phosphate pollution upon England’s chalk streams. Globally rare and extremely rich in wildlife, to say that the ‘jewels in the crown’ of our freshwater environment have lost their sparkle is an understatement of epic proportions. Blighted by nutrient pollution, chemicals, abstraction, man-made alterations  and invasive species, endless campaigns and practical efforts have to date failed to stem their decline, let alone ensure their recovery. The problems they face are vast, and conservationists and (most) campaigners acknowledge that it won’t be fast, easy or cheap to change this.

However, we must take every opportunity to try – and the Environment Act water targets should present just that opportunity. One of these targets will see water companies work to reduce phosphorus from treated wastewater by 80% by 2038, relative to a 2020 baseline. There is an interim target of 50% by January 2028.

These are big numbers, that could bring big nature benefits. Imagine if the target drove action at all treatment works on chalk stream waterbodies that currently fail phosphate targets...

It would make sense that, to achieve the greatest improvements for chalk stream ecology, the works on failing stretches of river would be targeted. But of course, things are rarely that straightforward. Whilst the ecological benefits might be greatest, there are several reasons why upgrades may unfortunately end up being directed elsewhere.

Economies of scale

Equivalent pollution reductions can be achieved with far greater ease at a large works collecting the sewage from ten thousand people, than by updating 10 separate works each serving a community of a thousand. In terms of meeting targets, companies might sensibly opt for the single job over the multiple. This keeps down costs; important because the improvements are ultimately paid for by customers. But such an approach accounts only for economy, not for ecology.

Bigger works tend not to be located in the tributaries or upper reaches of chalk streams, but often serve the larger urban populations at the river’s downstream end. Upgrades there may benefit only a few kilometres of chalkstream at best, before the river spills out into the sea (where it is nitrate, rather than phosphate, which has the more significant impact). By contrast, improving discharges in small headwater streams can make a big difference to the sensitive ecology; every kilogram of phosphate removed in a headwater stream could see a meaningful fall in in-river concentrations, whilst the same load removed in downstream reaches may have a negligible effect given the far, far larger flow volumes available to dilute pollution.

Yet as far as we know, there is no guidance that tells companies to prioritise based on the effect that cleaner discharges will have on in-river concentrations, on the sensitivity of the receiving waters, or on the length of river downstream that will benefit from any improvements.

Phosphate-counting

Drainage and wastewater management plans recently developed by water companies exist so that sewerage systems can, from here on, be managed in a more strategic way. One of their objectives is to ensure that discharge permits, which set water quality standards for the effluent coming from treatment works, are adhered to. As these permits are intended to protect the environment, it might seem that the plans could act as the framework for prioritising upgrades, focussing on those works where permits are, or are at risk of, being breached.

But again, it’s not as simple as one might hope. A reasonable proportion of works – for Southern Water for example it’s about a fifth - do not have permits with numeric limits. Called ‘descriptive permits’, there is no driver to monitor phosphate discharges, let alone reduce them. Typically, these works are the smaller works, so exactly those that may be located in a chalk stream’s sensitive headwater reaches.   

Ofwat (the Water Industry regulator) has established an industry performance metric to further encourage companies to reduce phosphate pollution. The metric enables the inclusion of treatment works even if they don’t have a phosphorus licence limit, by assuming a 2020 baseline concentration of 5mg/l against which any improvements would be counted. The industry target may therefore incentivise companies to take action at these smaller works. But it’s unclear whether such improvements would also be countable towards the UK Government’s Environment Act target, which companies also need to meet. If not, companies are unlikely to prioritise these works if, by upgrading elsewhere, they can hit two targets with one stone.

No to nature?

Another problem with seeking to upgrade smaller treatment works is that they often have a very small footprint, with little spare space available to add new facets to the treatment process; extra treatment tanks, settlement tanks or filters. Where upgrades aren’t affordable, or simply aren’t possible, the opportunity for improvement seems to falter. At these sites, the scope to utilise nature-based solutions could offer alternative hope. Treatment wetlands are wildlife-rich sites that use natural processes to further strip pollutants from treated wastewater before it is discharged. A treatment wetland installed at the downstream discharge point could ‘polish’ or help ‘clean’ the effluent. Whilst, arguably, it may not deliver the higher standards that traditional treatment could secure, this argument against a wetland only holds true if there’s any prospect of traditional treatment actually being put in place. If it’s never going to be approved due to cost, then surely some improvement, via a wetland, is better than none? Another alternative is a catchment solution. Where you can’t improve the treatment works, make equivalent improvements across the catchment instead, such as by supporting farmers to reduce pollution from excess fertiliser, slurry spreading or soil runoff. At the moment, none of these options would count towards the target.

Of course there’s nothing preventing companies from doing these things anyway, in line with biodiversity commitments and corporate pledges to act in the public good - assuming of course the expenditure is approved – and in the current climate where every extra penny on customers bills will be pored over, elective spend seems pretty unlikely.   

So where does this leave our chalk streams?

Currently we risk seeing (not insignificant) expenditure to achieve pollution reductions that look good on paper but that are of limited ecological benefit. Chalk streams could end up with little investment; perhaps only upgrades to works low down the catchment where it’s most cost-effective to achieve phosphate reductions – whether the river needs it or not. In the small streams and brooks of the upper reaches, there are multiple factors that dissuade taking action. Process and price trump pragmatism and benefit to biodiversity. Or so it appears right now. But maybe, there is the opportunity for guidance to emerge that has thought about all of this and which steers companies to deliver pollution reductions which don’t just meet a target.

We want to see such guidance directing companies to deliver upgrades where they have meaningful ecological benefit to chalk streams, removing phosphate where it is causing the greatest harm to nature, and ensuring the recovery of our long-suffering chalk streams.