There is nothing more galling to those interested in rivers than witnessing a serious pollution. These occur through negligence, bad luck or, more commonly, a lack of investment in infrastructure and maintenance.
Both rivers have suffered from serious industrial pollution events over the years. In 1994, for example, the Wye was badly affected by an accidental discharge of 20 tons of sugar at Hereford and the following year, by a huge, inadvertent chemical release into the river Elan.
The Usk once suffered from such poor water quality in the estuary that fish could only migrate in high flows. Thankfully, improvements were made at Newport steelworks and to other discharges.
But the two rivers flow through farmland for most of their lengths and have also been affected by serious agricultural pollution. This has taken the form of both what is called “spot” or “point source” pollution (where a pollution event is traceable to one source) and “diffuse pollution”.
Diffuse pollution is a more general malaise which affects the water quality of a river or a whole catchment but is not necessarily traceable to a single point.
It is often more serious because it is harder to detect and prevent, and punctuated with more significant incidents. In fact, those responsible are often unaware that they are causing a problem as the impact of their activity alone does not cause any significant damage. Combined, however, it has a disastrous impact on fish and all other wildlife.
When the Foundation first started we found that sheep dip was having an extremely negative effect on the rivers. Nowadays, diffuse pollution from agriculture comes mostly in the form of phosphates and pesticides, usually attached to soil particles.
However, point source events can also occur from agriculture that can be catastrophic for rivers and fish. Slurry entering the river is quite often the cause, stripping the water of oxygen, suffocating the fish and other aquatic creatures. This has been most noticeable in Wales, which lacks the regulatory controls that exist in England.
The notorious pollution event on the Teifi in 2016 is an example of this but we are not immune in the Wye and Usk catchments.
The river Llynfi, an upper Wye tributary, recently suffered a major fish kill of trout, grayling, juvenile salmon and other species. Meanwhile, a major slurry spill-related disaster on the Honddu (Monnow tributary) was narrowly avoided by quick intervention from Natural Resources Wales.
Some organisations take valuable retrospective action against polluters (statutory authority prosecutions and civil action by Fish Legal, for example). The Foundation’s work, however, is geared more to prevent pollution entering the rivers in the first instance.
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