#36 Run-off or dive in?

Stood on the warm stonework of the quay at Claverton Weir, I registered the familiar anxiety that preludes diving into a UK river/lake, or the sea: is it safe?

7977825840_dc55a03c9a_o-2Warley weir – photo by Tom Edgington at: https://flic.kr/p/d9YrFo

It was a halcyon day. The sun throbbed, cows browsed the opposite meadow, another train would soon chunter past. I had already sidled along the plant-strewn weir and was now poised to plunge deep into the water. I was not alone, as well as my partner and our children, the quay was packed with excitable youths replete with scant swim-wear and sunglasses. I reached for my son’s hand, he joined his with my daughter, then my partner, her son and his friend. We leapt off…

The surface of the Avon erupted in multiple explosions, screams, limbs and laughter. It was utterly euphoric. For several hours, we dived and swam, immersing ourselves, our permeable skin and vulnerable mucous membranes in the dark river. Five out of six of us spent the next few days either vomiting or stricken with diarrhoea.

The Environment Agency provides a useful online map of local water quality. Looking at the closest sample site (the confluence of Wellow Brook and the River Avon), the data suggests that the water quality here was grade A between 1993 and 2009.


The term Grade A water could be seen as misleading. Saturated with man-made pollutants, it is by no means pure. Levels of nitrates and phosphates in the river are also measured in the E.A. sample, and were rated consistently at level 5 between 2004 and 2009. Level 1 is described as a very low level of pollution, level 6 is the very worst.

The Wild Swimming Quick Guide to Water Quality explains that Grade A and B water is fine to swim in and that high levels of nitrates and phosphates are not dangerous to human health, but surely the effect of these contaminants on the occasional swimming human is only of elementary concern? High levels of these chemicals cause water to become eutrophic- rich in nutrients that support plants, which flourish, then decompose, depleting oxygen levels and killing animal life.

The local water authority, Wessex Water, have encouraged farmers to reduce their use of pesticides and fertlisers. This is part of a wider strategy by the Environment Agency which incentivises farmers to sign up to an Environmental Stewardship Scheme. The E.A. has published a map of NVZs (Nitrogen Vulnerable Zones) so that farmers are aware of the potential damage chemical run-off can have to local watercourses. Natural England is the government’s environmental advisory body and is responsible for payments to farmers based on a sliding-scale of how environmentally accountable they are. Their website shows a typical payment in 2013 to a lowland farm with 100 (qualifying) hectares as £3000. Clearly, encouraging farmers to regulate their use of dangerous chemicals is a good idea, the quantity of pollutants in our waters has decreased hugely over recent years. The problem is that improvements to water quality have plateaued. Despite the efforts of the governmental bodies, the levels of agricultural pollution in our rivers remain unacceptably high. However important the environment might be, farmers have crops to maximise, supermarkets to stock and bills to pay.

Run-off is not the only pollutant in our waters. Sewage is also regularly dumped into rivers courtesy of an out-moded system of combined sewer overflows (CSOs). Whenever there is an extended period of wet weather, many of our rivers (and therefore coastlines) have raw, untreated sewage spewed into them. Referring to work already done by Wessex Water in 2003 to over 100 CSOs around Bath, a spokesperson for ongoing projects said,

“River water quality is not the primary issue, the Avon is a large, healthy river. Water quality is hardly compromised by the discharge of sewer waters. This scheme is primarily about aesthetics.”

The aesthetics alluded to are, presumably, faecal waste, tampons, condoms and toilet paper. The logic here seems to be that water dilutes things- the bigger the river, the smaller the problem of waste becomes.

Of course, natural waste produced by animals living in or alongside a river is also an important factor. E. Coli and cryptosporidium are rife in freshwater, each causing a variety of health problems, both non-serious and life-threatening. The Swim Healthy leaflet from Public Health England is clear and straightforward,

“Open water is not considered to be of bathing quality as it can contain sewage, livestock contamination, and pollution from farming or industry.”

Rats also like to swim in rivers. Whenever one mentions wild swimming, the apocryphal threat of Weil’s disease surfaces. In fact, out of the variety of dangers lurking in our waters, leptospirosis is the one we are least likely to encounter. The NHS website cites 44 cases in 2011, none of which were lethal.

The small stretch of the Avon that I like to swim in only serves as an example. The following graph is taken from a highly critical EU: Water Framework Directive Implementation Report 2012, and indicates the state of UK rivers back then:

The gradual revival in bathing beyond the municipal pool may well have been reinvigorated by Roger Deakin’s brilliant travelogue, Wild Swimming. Since its publication in 1999, there has been a steady flow of books on this theme and the phrase wild swimming has entered common parlance. The activity itself, like tattoos and graffiti, has entered the mainstream; there is no shortage of hearty folk lining up to take the plunge. At Claverton Weir, what was once a local secret now clamours with people. It is a spectacular meander set, amphitheatre-like, amid a deep, forested valley. When I visit, however many people fill the cow meadow, the landscape itself exerts a strong sense of permanence, as well as beauty: we did not make this, it does not exist to serve our fleeting purpose.

This year, I brought shears to clip back the thriving nettles and invasive Himalayan balsam that overhang the top of the weir, growing almost hydroponically in the fertiliser-rich river . Freshwater mussel shells glimmer in the shallows below, evidence that the Avon remains a viable habitat, despite its impurity. A family of swans glide into the scene, there are dragonflies. Immense willows and alder hiss in the breeze. I stand again on the brink, poised, tremulous. Having reviewed the data for this piece of paradise, it will no longer be the prospect of mind-numbing cold that fills me with dread, or uncertainty of what lies beneath, but rather knowledge, sharp stark statistics, of what I’m sharing the water with.