The line graph illustrates the percentages of river water meeting good chemical quality standards, in four countries in the UK, from 1990 to 2002.
Overall, rivers in the Nothern Ireland and Wales consistently had the cleanest water. Additionally, with the exception of Wales, all the regions showed the improvements in their water quality over the period shown.
With regards to the two leading nations, in 1990, roughly 96% of rivers in Wales were classified as having good chemical levels, noticeably higher than Nothern Ireland’s 83%. In the following years, water’s river cleanliness remained relatively stable until 1998, before declining sharply to 80% by 2002. In contrast, Nothern Ireland’s river quality gradually improved, with its purity rising to nearly 100% in 2000, and then slightly falling to around 96% in 2002, having surpassed Wales in 1999.
Regarding the remaining countries, in 1990, Scotland’s rivers were of the lowest quality in terms of chemical composition, with only 20% of river water there up to par, less than half of England’s 45%. Subsequently, the latter’s rivers quality rose sharply to a peak of 70% in 1996, and then dramatically fell back to a low of 30%, followed by a significant recovery to 50% by 2002. Similarly, the percentage of river cleanliness rose steadily to 30% in 1992, and then reaching a peak of 60% in 2000, before declining to 40% in 2002.