Eddleston groundwater and soil moisture monitoring

This report describes work undertaken to continue monitoring at two experimental sites on the Eddleston Water, a tributary of the River Tweed. These experimental sites were set up as part of the wider Eddleston Water Project, which aims to reduce the impact of flooding in and downstream of the village of Eddleston. For a full description of the project, including how and why the monitoring network was established, please see Spray et al. (2016). The first experimental site is part of Darnhall Mains Farm, adjacent to the village of Eddleston (Ó Dochartaigh et al. 2019). It is approximately 0.2 km2 (approximately 400 m by 500 m) and covers most of the width of the Eddleston Water floodplain on both sides of the river (Figure 1). The site is farmland predominately comprising mixed livestock farming on improved grassland, but part of the floodplain has been fenced off, which has allowed trees to be planted and vegetation to recover. The monitoring at this site comprises eight boreholes in which groundwater level is recorded. The data are stored with the National Geoscience Data Centre (https://www.bgs.ac.uk/geological-data/national-geoscience-data-centre/, ID 128585). A key objective of the experimental site is to improve understanding of the role of groundwater in floodplain environments and during flooding. In particular, we want to understand the role of antecedent conditions in controlling the ability of the floodplain to act as a buffer between hillslope and river. The second experimental site is the Cringletie hillslope observatory (Figure 1, Peskett et al. 2020). The site is approximately 2500 m2 (approximately 50 m by 50 m) and comprises two transects parallel to the slope: one through a narrow forest strip and one on improved grassland used for mixed livestock farming (see Peskett et al. 2020). The installed monitoring equipment comprises soil moisture sensors, rain gauges and piezometers fitted with pressure transducers. The site was set up by Dr Leo Peskett as part of his PhD and was handed over to the BGS in 2020. The aim of the experimental site is to determine whether forest strips planted perpendicular to a hillslope can reduce surface runoff during flood events. In 2020, the BGS received funding from the Scottish Government to check the monitoring equipment; download all data and reset the loggers; replace broken equipment; and collate, process and quality check the data. In 2020/21, fieldwork was affected by the Covid-19 restrictions with colleagues travelling separately to the sites and maintaining social distancing, among other precautions