Episodic pollutions Is there anything as galling to those interested in rivers than seeing major pollution? These occur through negligence, bad luck or, more commonly, a lack of investment in infrastructure and maintenance. In addition to phosphate and pesticides entering rivers from many sources (diffuse pollution), single events can occur from agriculture (point source pollutions) 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 (such as Nitrogen Vulnerable Zones [NVZs]) that exist in England. The notorious pollution event on the Teifi in 2016 is an example of this (photo right) 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. This is shown in the title image of this page.