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Tuesday, Mar 28, 2017

Successful Environmental Site Assessments pave the way for delivering successful infrastructure projects

Environmental Site Assessment

An Environmental Site Assessment is a process which typically has up to four well-defined steps, although most projects do not progress through all four steps.  The process begins with a qualitative assessment of the likelihood that a site is contaminated, and of the nature of the potential contamination (Phase 1); to obtaining and testing samples of soil and water, and possibly soil vapour for contamination (Phase 2); to fully delineating and describing contamination and developing a remediation plan (Phase 3); and finally, to remediating the contamination (Phase 4). 

Provincial and federal contaminated site regulations govern the various steps of the assessment process.  Knowledge of the relevant regulations, and of the jurisdictional differences across Canada, is required to deliver effective assessments. Associated has completed all phases of the Environmental Site Assessment process for a wide variety of infrastructure projects across Western Canada.  Our current projects include roads and highways in British Columbia, Alberta, and Saskatchewan, as well as the Valley Line for the City of Edmonton, and pipelines for Metro Vancouver. 

Many infrastructure projects in developed urban areas are adjacent to, or bisect, industrial or commercial properties with some history of contamination related to historic waste management practices or incidental, continuous, or repetitive chemical releases, such as fuels or shop waste streams. Although qualitative, a Phase 1 Environmental Site Assessment provides valuable input near the beginning of an infrastructure development project because it casts a wide net and considers all potential forms of contamination (such as hydrocarbons, heavy metals, and salt). 

The key objective of a Phase 1 assessment is to identify and assess all areas of potential environmental concern, such as properties, buildings, and infrastructure, that could contaminate the soil, vapour, and groundwater underlying the project footprint.  Finally, a Phase 1 report provides a recommendation on whether any follow-up Phase 2 sampling of soil, groundwater, or soil vapour is required; and on the optimal methods of obtaining soil samples (e.g. using a drill rig, hydro vac, backhoe or excavator, or manually using a hand auger or shovel). We also advise whether the quantitative sampling and testing can be ‘piggy-backed’ on the geotechnical investigation, which typically occurs prior to construction, thereby saving costs. 

Information derived from a Phase 2 assessment provides more quantitative information upon which to develop an understanding of the environmental status of the site, and of the contamination that may be encountered during a project’s construction phase.  These assessments pave the way for successful project delivery, helping owners with planning and financing, and providing baseline information and knowledge of the potential environmental liabilities associated with a project site. This information helps owners plan and prepare for potential construction constraints, costs, and the time needed to manage issues related to contamination.

To be successful at the Phase 1 stage, the project team must recognize business practices that may contribute to site contamination, and be able to identify surface clues that suggest subsurface contamination.  Our experts are trained in these issues, and understand the pathways to human and environmental receptors, and how contaminants travel to points of exposure. 

Finally, contaminant migration can be influenced by climate change. For example, increases in the rate of contaminant movement can occur during floods or intense storms. Pathway distances from contaminant sources to aquatic receptors can change over time as river banks erode, and high winds can cause contaminated dust particles to migrate to neighbouring sites. Melting permafrost in northern Canada may change patterns and rates of vertical or lateral movement of contaminants.  An awareness of the potential implications of a changing climate for contaminant migration can influence our conclusions during the assessment process.

Our contaminated sites experts bring experience, intuition, and judgment to bear on Phase 1 assessments, to first consider a wide range of potential sources of contamination, then zero in on potential problem areas. Good judgments made at this stage provide the foundation for a wise allocation of funding and effort during subsequent assessment stages. A successful Environmental Site Assessment identifies and reduces project risks, and increases the likelihood of successful project delivery.