Remedial Action Plan - Rochford Field - Newhall Remediation Project

5. LONG-TERM GROUNDWATER MONITORING PLAN
GWPC and SWPC will be addressed through natural dilution and attenuation monitoring or
demonstration of point of compliance monitoring (i.e., monitoring of groundwater at down gradient
locations prior to groundwater discharge to surface water).
At a minimum, groundwater monitoring will include four quarterly, followed by three annual
groundwater monitoring events. The first planned quarterly monitoring event will take place
approximately two to three months after earthwork activities have been completed. Additionally, one
round of groundwater monitoring will be conducted prior to the start of the remedial construction.
The monitoring well network will include six existing monitoring wells (RF-HA108-MW, RF-HA108-
MWD, RF-HA207-MW, RF-HA123-MW, RF-HA115-MW and RF-HA110-MW) and one new
monitoring well (RF-HA301-MW), shown on Figure 2B. The wells will be protected and extended (2
ft) during EC construction. During each monitoring event, groundwater will be sampled using lowflow
purging and sampling methodology. The samples will be analyzed for constituents that are
consistent with those previously detected in soil and groundwater and include the following:
VOCs via USEPA Method 8260B;
PAHs via USEPA Method 8270C;
ETPH via Connecticut DEP methods;
13 Priority Pollutant Metals (totals, unfiltered) via USEPA Method 200.7/200.8.
The monitoring results will be tabulated and compared against the GWPC, SWPC and RVC.
Following completion of four years of monitoring, the data will be evaluated with regard to the
requirement and frequency of any additional monitoring and to evaluate compliance with GWPC,
SWPC and RVC. We will submit our recommendations for future groundwater monitoring to
CTDEEP for review and approval.
Once CTDEEP determines that groundwater compliance at the site has been achieved, the wells will be
abandoned in-place by filling the wells with cement grout.
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