The line graph illustrates the proportion of river in rivers of UK that was categorised as high-quality chemical water over a 12-year period, from 1990 to 2002.
Overall, during the period, rivers in Wales and Scotland showed a steady pattern until 1998, over the few next years, they showed changes, the river in Scotland had a small rise in chemical quality while the river in Wales experienced a modest decline. The rivers in Northern Ireland and England had turbulent trends. In particular,Northern Ireland exhibited dramatic trends. The highest-quality chemical water was observed in rivers of Wales and Scotland.
Wales and Scotland remained stable until 1998 (97% and 95% respectively). Then Wales’ chemical quality gradually decreased to about 88% by 2002 while Scotland showed a slight increase to 98%.
Northern Ireland had a small decline over the next two years to 87% in 1992, however, it sharply increased in following years to 96% by 1994. Then it decreased dramatically again(82%). During following 8 years, Northern Ireland’s high-quality chemical increased and reached 98%. While England had an almost stable pattern until 1998, when it was at 84%, then It increased drastically to 90% over the next two years by 2000. England showed a steady pattern over the following two years, reaching 84% by 2002.