.Groundwater Professional Bulletin Board

MONITORING PLAN CLARIFICATION

We have received questions regarding the removal of monitoring wells from the accepted Tier 2 SCR monitoring plan. When all monitoring wells (e.g., S, T & G wells) for a receptor meet exit monitoring criteria, the monitoring wells utilized for that specific receptor may be removed from the monitoring plan if they are not being used to monitor additional receptors.

The current software (Tier 2 v2.51) handles this situation by placing monitoring wells in the "NFA" category located at the bottom of the monitoring plan. The NFA category is receptor specific, meaning a monitoring well located in the category may not have met exit monitoring criteria for a different receptor(s). Accordingly, a monitoring well may be listed in both the active monitoring plan section and the NFA section. If such is the case, the monitoring well should be sampled until it meets exit monitoring criteria for all receptors for which it is being monitored.

As always, we recommend you rely on the accepted Tier 2 SCR monitoring plan and the current version of the software to indicate which monitoring wells to sample for annual monitoring.

Questions regarding this posting may be directed to Brian Jergenson at (515)242-6490 or brian.jergenson@dnr.state.ia.us.