Comparisons to Regional Reference Condition

Sometimes an upstream control is difficult to locate. One such example is an effluent dependent stream where there is no native flow upstream of a discharge. Under such circumstances, comparisons are often made to similar streams or lakes in the same region, based on the assumption that biological populations in the same ecological region should be similar to each other. This approach is often used as a screening-tool to assess the condition of a stream near a client’s activities (discharge, plant siting, etc.). If the local conditions are different from a regional reference condition, additional studies may be warranted.

GEI helps clients by identifying upstream control, developing biological population assumptions, and conducting stream condition assessments, as well as reviewing of appropriate regulatory concerns.