PhD project outline: Evaluating the impact of woodland management and drinking water abstraction on groundwater fed wetlands
Sustainable supply of drinking water is an increasing concern, and demand needs to be balanced against other unintentional environmental impacts. Groundwater aquifers that feed lowland wetlands are a commonly used source of relatively clean drinking water for water companies. However, continued abstraction can cause drops in local groundwater depths, with damaging consequences for the health of the ecosystem. These ecosystems are extremely valuable due to their high biodiversity and ability to store carbon.
Greywell Fen in the Loddon catchment, between the villages Greywell and North Warnborough in North Hampshire, is a particularly important site as it is a rare chalk lowland fen environment, supporting an abnormally high invertebrate and plant diversity. Consequently, it is classified as a Site of Special Scientific Interest (SSSI). South East Water have been abstracting groundwater from the chalk aquifer beneath Greywell Fen since the 1900s, but have agreed to cease abstraction due to concerns of declining ecological health from drying of the fen. Instead they will abstract water from the River Thames, about 30 miles away. Tree encroachment is also a problem at the site, primarily owing to changing management. Trees have an influence on the environment as a result of their high water and increased shading which can further reduce groundwater levels and encourage conditions that prevent critical fen species from flourishing.
This project aims to evaluate the effects of the groundwater abstraction and the management of tree encroachment (cut back and grazing) on the water levels and health of the fen. Wider environmental impacts of transferring supply to the River Thames compared to continuing at Greywell will also be considered.
Elaine Halliday joined the University of Reading in September 2019 to work on her PhD on ‘Evaluating the impact of woodland management and drinking water abstraction on groundwater fed wetlands’, supervised by Joanna Clark, Anne Verhoef, David Macdonald (British Geological Survey), Debbie Wilkinson (South East Water). This PhD is funded by NERC Scenario Doctoral Training Programme, South East Water and British Geological Survey. She completed an MSc in Environmental Science and Management at University of York in 2018, with her research project on pharmaceutical contamination introduced through use of treated wastewater as irrigation. Using a series of source-pathway-receptor routes, human and environmental exposure and risk was modelled and quantified for current Israeli irrigation practices and possible future UK practices. This involved collaboration with the Hebrew University of Jerusalem where she presented her findings at a conference the following year. She also has an integrated Master’s in Chemistry with a year in Industry at the University of York.
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