Early on 5th December, an unusually high water flow saturated with kaolin-like material was seen above Quick Bridge on the River Piall in Cornwood Parish.
Weir on tributary from Headon China clay works to Quick Bridge on River Piall 10.15h 05 Dec 22 (Julia Bertram)
Drawing upon volunteers contributing to the Westcountry Rivers Trust’s Citizen Science Investigation of water quality, co-ordinated by Yealm Estuary to Moor (YEM), the source was soon identified as being from the direction of Headon China clay works. Relevant measurements and photographs taken downstream from the junction with River Piall established that the River Yealm water was discoloured along its entire length for as long as 6 hours.
River Yealm at Popple’s Bridge 0950h 05 Dec 22 (Neil Tugwell)
Kaolin-like deposits of more than 15 cm deep have been found along the river’s banks and bed, including evidence of flows more than 60 cm deep on or next to Public Footpath 25 adjoining Broomage Waste workings.
Kaolin-like deposits at Piall Bridge 1430h 05 Dec 22 and reported to the Environment Agency by Julia Bertram
Map of footpaths (in red) neighbouring Broomage Waste (Cornwood PC)
Heavy deposits on bed of River Yealm close to Lotherton Bridge, more than 5 miles below the source of pollution 07 Dec 22 (Chris Westwood)
Further pollution was observed in the River Piall early in the morning (whilst still dark) on 08 December 2022 and persisted for as long as 6 hours.
It is understood that fisheries specialists have assessed the impact on fish and fish habitat. There can be no doubt that the high concentrations of suspended matter would, at the very least, have disorientated fish, amphibians and invertebrates. In addition, the smothering of their gills and skin would have affected their ability to absorb oxygen.
This week’s event will continue to have a significant ecological impact, given that the pollutant has also settled, smothering our river banks and bed. Nobody can know how long it will take to disperse but inevitably, there will be damage to both the ecology and amenity value of our environment. The river bed was covered with kaolin-like material for many miles downstream, depriving plant and animal life of both light and oxygen. Breeding grounds for trout and salmon depend upon the small spaces between the stones and gravel to lay eggs for protection, but the spaces will now be clogged, perhaps for years, with inevitable loss of this year’s eggs, normally laid by salmon from November to January.
Historical records establish that pollution from clay workings into the Rivers Piall and Yealm have occurred repeatedly many times over the past 50 years, the previous one of most recent note on 16 November 2020. On that occasion the Environment Agency (EA) categorised the river turning white then as a 'serious incident' indicating that rainfall had caused contaminated run-off to escape the containment area of a quarry-related operation. The EA added ‘while the discolouration was intense, it was short-lived and washed through the system quickly’. Apparently, action was taken to stop any further quarry discharge and no prosecution was made.
When the cause of this event will be disclosed by the EA is uncertain, as they may argue that any such disclosure might compromise effective prosecution of the guilty party, and thus not be in the public interest. Prosecution might certainly be the only effective means to help stop this happening yet again. A significant associated fine could also help, especially if the proceeds from such a fine, or an agreed alternative contribution, can be used to help restore the biodiversity and ecology of our river.
Further to this article, a full report has been drafted on behalf of River Yealm Water Quality Group, comprised of nominated representatives from each of the riparian parish councils that border our river (Brixton, Yealmpton, Newton & Noss, Sparkwell and Cornwood), to help with any representations those councils may make to the Environment Agency.