Understanding A CSM – Finding Data Gaps

When preparing a Record of Site Condition under O.Reg. 153/04, the investigative team must create a conceptual site model, or a CSM. The CSM clearly articulates the project team’s (including Qualified Person, project engineers, field scientists, and others) understanding of the site’s environmental system framework, impacts and associated potential risks.

One aspect of the CSM is to identify all the major and minor gaps in data. In other words, the team needs to point out the things they don’t know and create a plan in order to fill in the missing information.

What are data gaps?

According to the US EPA, there are three types of data gaps:

Quality: If the quality of existing data does not meet current standards, there is a gap in the quality of data. For example, pre-2011 environmental site assessment reports were written under previous allowable concentration limits for contaminants, since O.Reg. 153/04 was amended in July 2011. Another instance of this would be if samples were collected using outdated methods that are no longer accurate, or if the methods of data collection are unknown.

Location: There is a location-based gap in data if previously unsampled locations exist on the property. This may mean that one or more areas of the properties requires horizontal or vertical delineation to define the extent of an area of contamination. This could mean that the concentrations of contaminants in soil or groundwater are unknown at the surface of the soil or by wells that supply drinking water. Location data gaps are also important to consider when designing remedial systems, as the geologic and hydrogeologic properties of the site must be defined clearly.

Objective: An objective data gap exists when previously unforeseen issues are encountered which alter the information needed on the site. For instance, if samples weren’t analysed for a particular contaminant of concern which is now part of applicable regulations or has been raised as a possible issue, it would be necessary to fill that data gap before proceeding. Or, if a new treatment or risk management approach is being considered, new information related to these objectives may be required.

Filling Data Gaps

The approach to filling data gaps will depend on the complexity of the site and the amount of information that will be required to complete missing sections of the CSM.

To begin, perform an evaluation, moving systematically through the available data. This evaluation will work towards the site’s specific goals, with the overall objective of creating a draft CSM with all data gaps highlighted.

Next, depending on the significance of the data gaps, the investigative team could move into a full scale environmental site assessment. This is warranted when there is a very large gap in the information available for the site. If this is not the case, targeted investigations to supplement available data may be more appropriate.

We’ll be blogging soon about using the US EPA’s Triad approach to fill data gaps in a fast and efficient way.