The NRFA have published additional trend pages for each of the 146 stations in the UK Benchmark Network (UKBN2).
The analysis of trends in river flow is important as increased flooding and water scarcity are among the UK’s most important climate change risks. However, the detection of a climate-based trends is complicated by the effect of human disturbance on river flow regimes. To resolve this, the NRFA has designated a benchmark network of ‘near natural’ catchments since 2003, most recently updated in 2017 to the 146 stations in the UKBN2 network.
Each trends page (e.g. http://nrfa.ceh.ac.uk/data/station/trends/2002) contains:
- The benchmark suitability score for the use of the data in the three flow regime segments (low, medium and high)
- A plot of flow regime indicators with an assessment of trend magnitude and direction, with any changepoints marked
Trends are analysed using the Mann-Kendall (MK) test, with the MK statistic – a positive (negative) value indicates an increasing (decreasing) trend. Change points are determined using the Pettitt test and shown by a vertical line. More information on the trend analysis methodology is available in Harrigan et al. (2018).