Soil - Covered Surveys
Studies have shown that the majority of damage to geomembrane liners occur during placement of earthen materials on the liner. Damages such as rock punctures and large machinery traffic are the main causes of these penetrations to the liner. The soil-covered survey method can be used to locate any leaks that may have occurred during these circumstances. This is conducted on the operation layer prior to placement of layers thereafter. A survey grid system throughout the entire cell will be constructed using string lines, paint lines and/or flag lines. Pre-wetting the operation layer and isolating the cell perimeter will increase leak detection sensitivity and may be required to conduct the survey. Potential measurements will be collected via a custom-made soil probe and by a portable data acquisition system. The data will be downloaded to a portable computer or tablet and a custom-made software graphical plot interpretation will be generated. After careful analysis of suspect leak signals, manual measurements will be performed to further investigate the leaks. The soil-covered survey cannot be performed when soil temperatures are below freezing.