The line graph illustrates the percentage of water in UK rivers that was classified as containing good chemical quality from 1990 to 2002.
Overall, Wales and Northern Ireland had the highest percentage compared to the others rivers. In addition, both showed a stable growth, but in the end both of them showed two opposite trajectories. While a decrease was reported in the former, the latter showed a rise. In contrast, England and Scotland exhibited several changes in the trend, remaining them in low level in comparison to the other rivers. Nevertheless, at first both’s trend was predictable.
Initially, Wales and Northern Ireland showed comparable percentage of having good chemical quality at approximately 96 and 84 percents, respectively. Both showed a slight increase until the year 1998. Afterward, both showed opposite trends. Afterward, the former underwent a downward trend, whereas the latter experienced an upward trend. However, Northern Ireland, after reaching peak (at around 99 percent), began going down.
On the other hand, England and Scotland displayed more changes in tendency compared to Wales and Northern Ireland. Initiating in 1990, difference between percentages in England and Scotland was significant at roughly 45 and 21 percents, in the same order. Both showed similar patterns of tendency until 1992. It is worth noting that Scotland underwent a plateau until 1996, before a surge continuing until 2000. Ultimately, it the plummeted. Meanwhile, England proceed its growth before soaring in 1994. Afterward, in 1996 the percentage plummeted, allowing to be overtaken by Scotland. Finally, the percentage increased.