SECTION 330.417. Groundwater Monitoring at Type IV Landfills

(a) The requirements in this section apply to Type IV landfills, as defined in §330.5(a)(2) of this title (relating to Classification of Municipal Solid Waste Facilities), except as provided in §330.5(b) of this title, and in subsection (b) of this section.

(b) At the discretion of the executive director, the owner or operator of a Type IV landfill may be required to install groundwater monitoring systems and to monitor on a regular basis the quality of groundwater at the point of compliance.

(1) The factors to be considered by the executive director in determining the need for groundwater monitoring shall include: relationship of the facility to drinking water intakes (both surface and subsurface); hydrogeology of the shallow water-bearing zones in the facility area; use of shallow groundwater in the facility area; type of waste being or to be taken; types of liner; likelihood of leakage of contaminants from the facility; and protection of human health and the environment.

(2) A groundwater monitoring system shall be installed in accordance with §330.403 of this title (relating to Groundwater Monitoring Systems) except for the point of compliance monitoring well spacing requirement of §330.403(a)(2) of this title.

(3) Groundwater sampling and analysis requirements shall be in accordance with §330.405(a) - (d) of this title (relating to Groundwater Sampling and Analysis Requirements).

(4) Each monitoring well or other sampling point shall be sampled and analyzed annually, or on some other schedule but not less frequently than annually as determined by the executive director, for the following constituents: chloride, iron, manganese, cadmium, zinc, total dissolved solids, specific conductance (field and laboratory measurements), pH (field and laboratory measurements), and non-purgeable organic compounds.

(5) Not later than 60 days after each sampling event, the owner or operator shall determine whether the landfill has released contaminants to the uppermost aquifer. The owner or operator shall provide an annual detection monitoring report within 60 days after the facility's annual groundwater monitoring event that includes the following information determined since the previously submitted report:

(A) the results of all monitoring, testing, and analytical work obtained or prepared in accordance with the requirements of this permit, including a summary of background groundwater quality values, groundwater monitoring analyses, any statistical calculations, graphs, and drawings;

(B) the groundwater flow rate and direction in the uppermost aquifer. The groundwater flow rate and direction of groundwater flow shall be established using the data collected during the preceding calendar year's sampling events from the monitoring wells of the Detection Monitoring Program. The owner or operator shall also include in the report all documentation used to determine the groundwater flow rate and direction of groundwater flow;

(C) a contour map of piezometric water levels in the uppermost aquifer based at a minimum upon concurrent measurement in all monitoring wells. All data or documentation used to establish the contour map should be included in the report;

(D) recommendation for any changes; and

(E) any other items requested by the executive director.

(6) The executive director may require additional sampling, analyses of additional constituents, installation of additional monitoring wells or other sampling points, and/or other hydrogeological investigations if the facility appears to be contaminating the uppermost aquifer.

(7) If the owner or operator finds the facility to have contaminated or be contaminating the uppermost aquifer, the executive director may order corrective action appropriate to protect human health and the environment up to and including that in §§330.411, 330.413, and 330.415 of this title (relating to Assessment of Corrective Measures; Selection of Remedy; and Implementation of the Corrective Action Program).

Source Note: The provisions of this §330.417 adopted to be effective March 27, 2006, 31 TexReg 2502