The purpose of the survey was to assist in the investigation of potential leachate migration pathways via fractured bedrock, as part of ongoing environmental monitoring and remediation efforts.
The main goal was to characterize subsurface conditions in and around five newly drilled boreholes, specifically focusing on:
• Identifying fracture zones and assessing their orientation and continuity
• Detecting possible leachate pathways through fractured groundwater zones
• Measuring in-situ physical parameters such as formation temperature and conductivity
• Providing high-resolution data to support hydrogeological modelling and risk assessment
RGS deployed a combination of high-resolution geophysical logging tools during three site visits. The suite of tools included:
• High Resolution Optical Televiewer (Hi-OPTV)®: Delivered high-resolution, oriented images of the borehole walls, enabling precise identification and characterization of fractures, bedding planes, and other structural features.
• High Resolution Acoustic Televiewer (HRAT)®: Provided complementary acoustic images in less clear borehole environments, particularly helpful in identifying fractures in fluid-filled or clouded boreholes.
• Temperature Conductivity: Recorded natural temperature and conductivity profiles to indicate possible zones of groundwater inflow and leachate presence.
• 3-Arm Caliper: Measured variations in borehole diameter to identify zones of potential fracturing or lithological changes.
The data delivered by RGS enabled Arcadis to map the orientation and extent of subsurface fractures with precision and detect any anomalies in groundwater temperature and conductivity, suggesting potential leachate migration. This assisted Arcadis in improving the conceptual hydrogeological models of the landfill site and supported future decision-making on monitoring strategies and remediation planning.
RGS’s high-resolution geophysical logging played a crucial role in characterizing the subsurface conditions at the Ty Llwyd landfill site. The work not only contributed vital information to the Arcadis investigation into leachate risks but also highlighted the value of advanced borehole logging in environmental site assessments.
