There is high confidence that potential impacts due to unconventional gas resource development can be mitigated for all pathways of ‘potential concern’. However, the knowledge base is generally limited for the threshold of material change and for some cause-and-effect relationships. Confidence in the assessment will be improved as knowledge of these relationships and thresholds is established.
In the causal network, each link evaluation is based on the best available data and knowledge. However, in some cases the knowledge base may be limited for (i) the cause-and-effect relationship, (ii) the threshold of material change, or (iii) the mitigation strategies and whether they are available and effective. Each link evaluation is assigned a confidence score of ‘low’, ‘medium’ or ‘high’ (Table 3). Where the knowledge base is limited, this is reflected in the causal network as uncertainty. Where there is insufficient knowledge to support a robust threshold of material change, links are generally evaluated as material by applying the precautionary principle.
TABLE 3 Confidence assessment of links in the causal network
Are we confident that the link is possible? a
Are we confident that the link is or is not material? b
Are we confident the link can or cannot be mitigated?
c
Confidence
Yes
Yes / Not applicable
Yes / Not applicable
High
Yes
Yes
No
Medium
Yes
No
Yes
Medium
No
Yes
Yes
Medium
Yes
No
No / Not applicable
Low
No
Yes
No / Not applicable
Low
No
No
Yes
Low
No
No / Not applicable
No / Not applicable
Low
a based on publication(s) with local system relevance or self-evident
b based on publication(s) with local system relevance
c based on publication(s) with local system relevance or publicly documented in approval conditions or proponent protocols
Confidence statements for each link (
Table 3
) are combined into confidence statements for pathways (Table 4). Confidence in the cause-and-effect relationship and thresholds of material change is generally low, reflecting that the knowledge base on hydrological and ecological functioning at the local scale is emerging. However, there is high confidence that regulation and management procedures can mitigate potential impacts (see mitigation strategy in Table 4).
TABLE 4 Number of causal pathways with high or low confidence in cause-and-effect relationship, threshold of material change and mitigation strategies
Level of concern
Cause-and-effect relationship (number of causal pathways)
Threshold of material change (number of causal pathways)
Mitigation strategy (number of causal pathways)
Level of confidence
Low
High
Low
High
Low
High
Very low concern
326
247
529
44
0
573
Low concern
856
242
1,098
0
0
1,098
Potential concern
247
160
401
6
0
407
Potentially high concern
0
0
0
0
0
0
Data: Geological and Bioregional Assessment Program (2021g)
