Pioneering Leak Detection Surveys
Willowstick UK – The Challenge of Leak Detection
Pin-pointing the exact location of a seepage pathway has challenged geophysicists and engineers for decades. Many leak detection techniques are commonly deployed within the industry however many of these have proven to be inaccurate, costly, time-consuming and often overestimate the severity of the problem area. If we can track leakage, we can target remediation before problems become out of control at a reduced cost.
Seepage of groundwater or contaminants through containment structures such as dams, mine tailings, oil and gas chambers, or bedrock pose extensive problems to both industry and the environment. Geotechnical techniques are pivotal when tracking groundwater seepage and to facilitate targeted and cost-effective remediation.
Internal erosion derived from seepage can significantly reduce the integrity of a structure, increasing its likelihood of failure. This is significant when it can be considered that 78% of Dam failures in the UK are due to internal erosion (DEFRA 2002). In addition, the discharge of contaminants and chemicals into the environment can result in detrimental ecological implications.
Where Willowstick UK come in…
Willowstick UK is proud to be globally spearheading groundbreaking, non-intrusive leak detection technology. We use a geophysical survey technique which provides an accurate, non-intrusive and cost effective solution to leak detection. The overall approach to the fieldwork involves energising the groundwater of interest with an AC electrical current with a specific signature frequency between the paired electrodes. As the electrical current follows through preferential flow paths in the study area between the electrodes i.e. seepage paths, it generates a magnetic field. This is measured by sensitive coils in the surveying equipment.
The surveying equipment consists of a GPS system mounted to a specialist surface instrument which measures the magnetic field response of an induced electric current. Electrodes are placed in an opposing configuration about the pre-determined a survey area. These magnetic field measurements are then recorded on a portable computer system empowered with Arc GIS. Readings are taken along lines in a grid pattern (typically 10x10m) to provide sufficient coverage to adequately delineate the groundwater characteristics of interest. This technology provides an accurate and highly reliable interpretation of both the location and orientation of subsurface flow paths. The magnetic field data collected is modelled using unique software to provide the client with detailed 3D representation of the area of concern), facilitating targeted remediation at a reduced cost.