The line graph provides statistical information about the proportion of river water that is chemically good enough in four distinct countries in the UK over a twelve-year period, starting from 1990.
It is evident that Wales and Northern Ireland had the highest quality of river water throughout the survey. Additionally, except for Wales, the others’ water quality rate experienced an upward trend.
In 1990, over a fifth of Scotland’s river water was assessed to be in good condition, which is roughly twice lower than that of England. The data set of England then peaked in the next six years, while the figure for the amount of good quality river water in Scotland rose slightly by nearly 10% and maintained at nearly one-third until 1996. Afterwards, the water quality rate in England witnessed a plunge, before bouncing back to approximately 50% in 2002. Regarding the figure for Scotland, after a proliferation, it reached about 60% in the beginning of the twenty-first century, and had decreased by 20% by 2002.
During the period from 1990 to 1998, the data for Wales and Northern Ireland stayed relatively consistent, with none of them accounted for less than 85%. However, the data set of Wales’ river water quality then declined moderately and reached a low of 80% in the end of the survey. Meanwhile, the rate of well qualified water in Northern Ireland surpassed that of Wales in 2000, and leveled off in the next two years.