Lotowater was retained by Dillon Consulting Limited (Dillon) to provide specialized services in down-hole data collection to assist in diagnosing a groundwater issue related to the solvent TCA. The two impacted wells were located on an industrial site in Northern Ontario, near Sudbury. The client remains anonymous due to the sensitive nature of the work.
The wells were constructed in granite bedrock up to 100 m deep, with a very thin overburden layer. The objective of the testing was to locate water producing features and determine flow patterns in the wells, in an attempt to delineate the zones containing contaminants.
The first phase of the project involved video inspection, geophysical logging and flow profiling of the wells. The detailed video surveys were essential in visually identifying fractures and possible water producing zones. Lotowater performed acoustic televiewer and caliper logs which were necessary to evaluate the integrity of the well casings and to provide reliable physical down-hole data of the wells. Finally, a flow distribution profile was completed to help characterize flow patterns in the wells and to determine the location of the water producing features. This information was used to select isolation points for a series of packer tests, which comprised the second phase of the project.
The objective of the packer testing was to quantify the water production and to measure the concentration of contaminant in three separate zones in the well. Packer testing involved the installation of a packer system to hydraulically isolate each zone, followed by purging of each zone prior to the collection of water samples for in-depth water quality analysis.
This information helped Dillon identify the various water producing zones and correlate the geology across the site, which in turn helped to determine the necessary course of action for resolving this groundwater issue.
Due to the potential risk of accidental release of contaminants into the environment, Lotowater took extreme precaution to ensure that all discharge waters were contained. A spill response plan and emergency decontamination procedures were in place prior to the initiation of any field work.