9VAC25-91-190. GCS well monitoring.
A. All GCS wells required by 9VAC25-91-170 A 13 a in the ODCP requirements shall be monitored as follows:
1. Monthly gauging of GCS groundwater monitoring wells.
a. Measure and record static water levels monthly.
b. Reference all water-level measurements, including total well-depth measurements, from an established and documented point on the top of the well casing.
c. Measurements shall be correlated with mean sea level datum and measured to the nearest 0.01 foot.
2. Quarterly groundwater and vapor monitoring.
a. Quarterly vapor monitoring of all GCS wells identified in the ODCP-GCS shall be conducted prior to collecting quarterly groundwater samples.
b. Quarterly vapor monitoring consists of collecting one monitoring well headspace measurement.
c. Quarterly groundwater sampling (visual inspection) of all wells identified in the ODCP-GCS shall be conducted.
(1) Measure for free product on top of the groundwater.
(2) Collect groundwater samples for visual inspection.
d. Tabulate vapor measurements and quarterly visual groundwater monitoring results for each well sampled.
3. Annual groundwater monitoring for laboratory analysis.
a. Annual groundwater sampling of all wells identified in the ODCP groundwater characterization study (GCS) shall be conducted.
b. Annual groundwater monitoring consists of collecting groundwater samples for laboratory analysis.
c. Groundwater samples shall be collected and analyzed for BTEX and TPH for each well.
B. The GCS groundwater well monitoring should not be confused with the monitoring of groundwater wells utilized to satisfy 9VAC25-91-170 A 18 (i.e., leak detection wells).
Derived from Virginia Register Volume 14, Issue 18, eff. June 24, 1998.