Is the discharge of “contaminated” groundwater into surface water likely to be “insignificant?
In some cases, overseeing agencies are likely to be able to conclude that a release from groundwater into surface water will be “insignificant” – and therefore “under control” – based on the levels of contaminants in the groundwater, without consideration of the volume or flow of the surface water body. As a rule of thumb, we have found that, if the groundwater concentrations for all constituents are less than 10 times the appropriate surface water quality criteria for both human health and aquatic life, the current groundwater discharge should be “insignificant” for environmental indicator purposes. In this case, the regulator would conclude that the groundwater environmental indicator had been met (at least with respect to the discharge to surface water).
