Groundwater turbidity above the drinking water limit is a common problem in groundwater supply boreholes that abstract from fractured aquifer systems, such as the Chalk in South East England.
Academic Lead - Professor Stefan Krause
Turbidity spikes can result from fast groundwater recharge through fractures during storm events or in response to subsurface disturbance related to groundwork engineering in the vicinity of groundwater abstraction infrastructure. If turbidity exceeds a threshold value water abstraction must be stopped, potentially putting the constant provision of potable water at risk and also causing significant costs to the water companies.
In this project, the Active Distributed Temperature Sensing fibre-optic technology (ADTS) is used for detecting the (often sudden) onset of water turbidity spikes in groundwater abstraction boreholes. ADTS allows for continuous monitoring of temperature along the borehole at a high spatial and temporal resolution.
From an analysis of the heating and cooling phases it is possible to detect temperature anomalies corresponding to fractures in the aquifer that can be linked to independent measurements of turbidity. This will allow for a better understanding of the causes of the turbidity spikes and provide very useful information to the water companies who can then implement actions to minimize or resolve turbidity problems.
This project is funded by the UK Natural Environment Research Council (NERC Reference: NE/R014752/1) and is in collaboration with the British Geological Survey and with Affinity Water Ltd.