SECTION 252:616-5-4. Monitoring

  The DEQ may require groundwater monitoring for wastewater contaminants when there is a potential for groundwater contamination. This section describes the criteria for monitoring when required by the DEQ.

(1)   Groundwater flow direction. Determine the hydrologic gradient or groundwater flow direction with at least three wells spaced in a triangular pattern, an appropriate distance apart. Hydrologic connections to surface water bodies may also be used to estimate the direction of groundwater flow.

(2)   Wells. Install at least one well or borehole upgradient and at least two wells or boreholes downgradient. Install a sufficient number of wells or boreholes to insure prompt and reliable detection of wastewater. The total depth of each well or borehole and the screened interval of each well shall be subject to prior DEQ approval. Design, install and plug all wells and boreholes according to the OWRB rules, OAC 785:35.

(3)   Monitoring plan. Submit a detailed monitoring plan to the DEQ before constructing or installing any wells or boreholes. Do not install them until the plan is approved. Notify the DEQ five days before installing or plugging any wells or boreholes so that a DEQ representative may observe the work. The monitoring plan must:

(A)   Describe the purpose and scope of the monitoring system;

(B)   Locate all wells and boreholes on a map, and provide the rationale used to determine the locations. The monitoring system may include existing wells and boreholes if they are properly located and constructed; and

(C)   Describe all sampling and analysis methods, including the sample type (such as liquid, sludge, composite or grab) and the purpose of each sample type (e.g., waste stratification, waste composition, extent of contamination); the location and depth of each type of sample, and the frequency of sampling; the type of equipment used for each type of sample (e.g., hand-held, truck mounted drilling rig; split-spoon or auger); the EPA-approved analytical method number (see 40 CFR Part 136) for each type of sample and parameter analyzed; and the laboratory name and certification number and evidence that the parameters analyzed are included in the laboratory certification.

(4)   Split samples. When requested by the DEQ, provide five days prior notice to the DEQ of the next sampling schedule so that a DEQ representative may be present to collect split samples and observe sampling methods.

(5)   Additional land application monitoring criteria.

(A)   Parameters. Sample and analyze the soil, surface water and/or groundwater (site-specific monitoring) of a land application site for the same parameters for which the wastewater or sludge is tested.

(B)   Form 2-L. Include the information required in form 2-L.

(C)   Well data. Include the number, total depth, depth of completion, and screened intervals of monitoring wells proposed for or existing on a land application site, including well logs or drillers logs, if available, and the elevation of each well as surveyed, the depth to static water level and the date the level was measured.

[Source: Added at 17 Ok Reg 1925, eff 6-12-00]