Washington Administrative Code
Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508)
Chapter 173-351 - Criteria for municipal solid waste landfills
Section 173-351-410 - Groundwater sampling and analysis requirements
Current through Register Vol. 24-06, March 15, 2024
(1) The groundwater monitoring program must include consistent sampling and analysis procedures that are designed to ensure monitoring results that provide an accurate representation of groundwater quality at the background and downgradient wells installed in compliance with WAC 173-351-400 and with this section. The owner or operator must submit the sampling and analysis program documentation as a part of the permit application in accordance with WAC 173-351-730(1)(b)(iii). The program must include procedures and techniques for:
(2) The groundwater monitoring program must include sampling and analytical methods that are appropriate for groundwater sampling and that accurately measure hazardous constituents and other monitoring parameters in groundwater samples or reflect an acceptable practical quantitation limit (PQL). Groundwater samples must not be field-filtered prior to laboratory analysis except for geochemical indicator parameters used for cation-anion balance evaluations in WAC 173-351-430(5). All analyses must be sent to an accredited laboratory in accordance with chapter 173-50 WAC, Accreditation of environmental laboratories.
(3) Groundwater elevations must be measured in each well immediately prior to purging, each time groundwater is sampled. The owner or operator must determine the rate and direction of groundwater flow each time groundwater is sampled. Groundwater elevations in wells which monitor the same MSWLF unit must be measured within a period of time short enough to avoid any groundwater fluctuations which could preclude the accurate determination of groundwater flow rate and direction. All groundwater elevations must be determined:
(4) The owner or operator must establish background groundwater quality in hydraulically placed upgradient or background well(s) for each of the monitoring parameters or constituents required in the particular groundwater monitoring program that applies to the MSWLF unit, as determined under WAC 173-351-430, 173-351-440, or 173-351-450. Background groundwater quality may be established at wells that are not located hydraulically upgradient from the MSWLF unit if it meets the requirements of WAC 173-351-400 through 173-351-490.
(5) The number of samples collected to establish water quality data must be consistent with the appropriate statistical procedures determined pursuant to WAC 173-351-420. The sampling procedures must be those specified under WAC 173-351-430 for detection monitoring, WAC 173-351-440 for assessment monitoring, and WAC 173-351-440(7) for remedial action.
Statutory Authority: RCW 70.95.020(3), 70.95.060(1), and 70.95.260(1), (6). 12-23-009 (Order 07-15), § 173-351-410, filed 11/8/12, effective 12/9/12. Statutory Authority: Chapter 70.95 RCW and 40 CFR 258. 93-22-016, § 173-351-410, filed 10/26/93, effective 11/26/93.