How can you tell if a river in the UK is healthy?

To Graham Lawton

When it comes to British river conditions, looks can be deceiving. I recently spent some time by the River Fal in South West England. The Faru River looks beautiful and pristine, but it is far from it. Much of it is in the Cornwall Area of ​​Outstanding Natural Beauty, and the river is home to Fal oysters, a Protected Food of Origin. However, the river has been called ‘the most polluted river in England’.

last year, independence The newspaper analyzed the Environment Agency (EA) data on sewage runoff in the UK and found the Fal River to be the dirtiest river in the country. In 2021, raw sewage from more than one of the 103 storms that have flowed into the river he has spent nearly 7500 hours, or more than 10 months.

Shocking as it may seem, such an event is a built-in feature of the region’s wastewater treatment system. Not uncommon in these areas, it occurs after heavy rainfall into his century-old drains in Cornwall. This is a composite system that mixes sewage (brown water) and domestic wastewater (miscellaneous wastewater) with rainwater and sends it to a treatment plant.

“It’s outdated,” says Tessa Wardley of The Rivers Trust, a conservation charity based in Carrington, Cornwall. She said, “It hasn’t been updated or upgraded. Sewage goes out of the house through pipes and into pipes that also go into street drains.”

After the storm, this deluge of rainwater and sewage can overwhelm water treatment plants, causing dirty water to flow back into homes and businesses. Southwest Water, the local water company, is allowed to open emergency overflow he pipes and drain excess water directly into the phall. “This is a big problem,” he says Wardley.

Therefore, one way to gauge the health of local rivers is to look at whether the sewage system is combined with or separated from stormwater runoff. In general, urban areas combine sewage and stormwater, while rural areas separate them. But as the Cornwall system shows, this is only a rule of thumb.

Alternatively, EA publishes a detailed annual data set of UK storms. Other countries in the UK have similar resources. It takes a little digging, but the information is detailed. Overflow near my accommodation in Cornwall His pipes run from the Mylarbridge wastewater treatment plant into the River Fal, and in 2021 he will have drained 179 times, a total that will take him 145.8 hours. got it.

Note, however, that this is far from comprehensive data as not all overflow sites were monitored. Only 67 of the 103 people released to Far collect data.

There are other gaps in the record. The data only recorded the number of drains and their duration, not the amount of water into which the sewage was injected. To the naked eye, Fal is clearly not flooded with sewage. independenceThe story sparked outrage in nearby communities. Claims that Fal is the most polluted in England are “absolute bullshit”, Martin Raiti, who runs an oyster fishery at Sailors His Creek Shellfish in Flushing Village, told a local paper. packet.

Lawrence Coldrick of the West Country Rivers Trust said the story was ‘disappointing’. ) is suffering from the longest period of outflow,” he said. packetThe monitoring the water company does “shows only the frequency and length of the runoff, not the amount, importantly,” he said. In other words, the Fal is the most frequently polluted river in England, but not necessarily the most polluted.

status update

To better understand the condition of UK rivers, you can check the ecological and chemical conditions. All national surface water bodies are assessed according to the criteria set out in the European Union’s Water Framework Directive, and classifications are published by the EA in England and the corresponding EAs in Scotland, Wales and Northern Ireland.

These assessments show that we can almost guarantee that no river in the UK is in the best ecological condition and is polluted with chemicals.

There are five categories of ecosystem health, ranging from good to bad. According to figures released by the Joint Nature Conservation Commission, which advises the UK government and devolved administrations, none of the rivers of England, Wales and Northern Ireland are in the top category, while Scottish rivers Only 8% show that they reach this standard.

For chemical pollution, rivers are classified as benign or unfavorable based on permissible concentrations of 52 priority substances. According to these estimates, all rivers in England are in decline.

“It’s becoming clear that the river chemistry is actually very bad,” says Wardley. The list of pollutants and their sources is huge. These include pesticides, fertilizers, “forever chemicals” such as perfluoroalkyl and polyfluoroalkyl substances (PFAS), industrial wastewater, microplastics, microfibers, pharmaceuticals flushed down the toilet, thinners, and cooking oils. It sucks up drains, detergents, car wax, and more.

However, without chemical test kits, there aren’t many obvious signs of these contaminants. But everywhere in the world there are visual cues that are good indicators of river conditions in a more general sense.

“The appearance of a river can be seen in terms of its physical properties,” says Stephen Addy of CREW, the Scottish Center for Water Expertise at the James Hutton Institute in Aberdeen. “Straight? Canalized? Deep? Not connected to a floodplain? These are all unnatural attributes.”

Natural attributes are easy to spot, says Michael Ekleman of the UK Center for Ecology and Hydrology in Wallingford. “Natural rivers have complex shapes, meanders, etc., and a wide variety of habitats. You can see and hear better, everything you get from a healthy river that you don’t get if you go to an unhealthy one.

When it comes to water quality, you can’t tell just by looking at the water itself. “Rivers are often quite muddy and people think, ‘I wouldn’t jump in there,’ but most of the time it’s just sediment,” he says. “They collect their colors from geology, so they’re not necessarily polluted, but you’ll only know when you start looking at the flora and fauna.”

A small seed is a good starting point. “When it comes to water quality, problems such as very high algae cover can occur, and in extreme cases, even dangerous algal blooms,” he says.

flagship species

The perfect payoff, Wardley says, is the presence of so-called sewage fungi, slimy-looking, brown masses of mold that thrive in nutrient-contaminated water. “If you see it covering stones or river water, you can be sure there is a problem with the water quality.”

Larger flora and fauna are good indicators of river health. The presence of fish is a good sign, as is lush green vegetation along the waterways and banks. There are also some healthier “flagships” such as otters, freshwater pearl mussels and birds called dippers. “They depend on a good supply of river macroinvertebrates, which are indicators of good water quality,” he says. As for raw sewage, we all know it when we see it.

“It can be very difficult to tell just by looking at the river,” says Wardley. “But there are signs that everyone can see. And smell.”

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