7 Del. Admin. Code § 1302-265-F-265.90

Current through Reigster Vol. 28, No. 6, December 1, 2024

Section 1302-265-F-265.90 - Applicability

(a) The owner or operator of a surface impoundment, landfill, or land treatment facility which is used to manage hazardous waste must implement a groundwater monitoring program capable of determining the facility's impact on the quality of ground water in at least the uppermost aquifer underlying the facility, except as § 265.1 and paragraph (d) of this section provide otherwise.

(b) Except as paragraphs (d) and (e) of this section provide otherwise, the owner or operator must install, operate, and maintain a groundwater monitoring system which meets the requirements of § 265.91, and must comply with §§ 265.92-265.94. This groundwater monitoring program must be carried out during the active life of the facility, and for disposal facilities, during the post-closure care period as well. In case of a surface impoundment used for storage/treatment of hazardous waste, groundwater monitoring after the active life of the facility, may be required if deemed necessary by the Secretary.

(c) By June 30, 1983, the owner or operator of a surface impoundment, landfill or land treatment facility which is used to manage hazardous waste must submit to the Department a hydrogeologic report, except as paragraph (d) of this section provides otherwise. The report must be certified by a "qualified engineer" or "qualified geologist". (See § 260.10 for definitions of "qualified engineer" and "qualified geologist"). This report shall include at a minimum the following:

(1) A definition of the geology of the site and surrounding area. This shall include:

(i) A description of the various lithologic units including grain size distribution, shape and color to a depth which includes at least the uppermost confined aquifer underlying the site; and

(ii) Isopach and structure contour maps and cross-sections showing these various lithostratigraphic units.

(2) A description of the groundwater movement in at least the water table and uppermost confined aquifers underlying the site and the surrounding area including:

(i) The rate and direction of flow, both horizontally and vertically; and

(ii) A potentiometric surface map and cross-section of each aquifer.

(iii) A map showing the difference in hydraulic head between the water table and uppermost confined aquifers.

(3) A description of the hydrologic characteristics of the lithostratigraphic units to a depth which includes at least the uppermost confined aquifers underlying the site and the surrounding area such as, but not limited to, hydraulic conductivity, porosity, aquifer thickness, transmissivity, and storage coefficient;

(4) A description of the chemical quality of the groundwater of at least the water table and uppermost confined aquifers underlying the site and surrounding area to include the parameters specified in § 265.92 (b)(1), (b)(2), (b)(3) and any other parameters specified by the Department depending on the composition of the waste; a description of the chemical quality of nearby surface water may be required if deemed necessary by the Department;

(5) A prediction of the potential movement of any contaminants that may enter the groundwater underlying the site and the surrounding area including the rate, extent and direction, both horizontal and vertical migration and the potential impact on groundwater and if applicable on surface water.

(6) An estimate of the amount of leachate which may be generated at the site. This shall be done by using methods described in the following publications: "Hydrologic Simulation on Solid Waste Disposal Sites", U.S. Environmental Protection Agency, Office of Water and Waste Management, SW-868, September 1980; or the "Use of the Water Balance Method for Predicting Leachate Generation from Solid Waste Disposal Sites", U.S. Environmental Protection Agency, Office of Solid Waste Management Program, SW-168, October, 1975; or an equivalent method approved by the EPA.

(7) A description of the existing groundwater and, if applicable, surface water monitoring program used to detect and determine and contaminant migration at the site and surrounding area.

(8) A proposal for further monitoring including additional monitoring wells and if applicable surface water monitoring stations, parameters for analysis and monitoring schedule.

(d) All or part of the groundwater monitoring requirements of this section may be waived if the owner or operator can demonstrate that there is a low potential for migration of hazardous waste or hazardous waste constituents from the facility via the uppermost aquifer to water supply wells (domestic, industrial or agricultural) or to surface water. This demonstration must be in writing, and must be kept at the facility by the effective date of these amendments and also must be submitted to the Department for approval within fifteen days of the effective date of these amendments. This demonstration must be certified by a "qualified engineer" or "qualified geologist" except in defining the geology and geologic materials in (d)(1)(ii) and (d)(2)(i) which must be certified by a "qualified geologist". Where a demonstration under this section was prepared prior to the effective date of these amendments and was not certified in accordance with the above revised requirements, the owner or operator shall submit a demonstration which complies with these additional certification requirements within ninety (90) days of the effective date of these amendments. This demonstration must establish the following:

(1) The potential for migration of hazardous waste or hazardous waste constituents from the facility to the uppermost aquifer, by an evaluation of:

(i) A water balance of precipitation, evapotranspiration, run-off, and infiltration; and

(ii) Unsaturated zone characteristics (i.e., geology and geologic materials, physical properties, and depth to ground water); and

(2) The potential for hazardous waste or hazardous waste constituents which enter the uppermost aquifer to migrate to a water supply well or surface water, by an evaluation of:

(i) Saturated zone characteristics (i.e., geology and geologic materials, physical properties, and rate of ground water flow); and

(ii) The proximity of the facility to water supply wells or surface water.

(e) If an owner or operator assumes (or knows) that groundwater monitoring of indicator parameters in accordance with § 265.91 and § 265.92 would show statistically significant increases (or decreases in the case of pH) when evaluated under § 265.93 (b), he may install, operate, and maintain an alternate groundwater monitoring system (other than the one described in § 265.91 and § 265.92). If the owner or operator decides to use an alternate groundwater monitoring system he must:

(1) By the effective date of these amendments, submit to the Secretary a specific plan, certified by a "qualified engineer" or "qualified geologist" which satisfies the requirements of § 265.93 (d)(3) for an alternate groundwater monitoring system. This plan is to be placed in the facility's operating record and maintained until closure of the facility.

(2) No later than the effective date of these amendments, initiate the determinations specified in § 265.93 (d)(4).

(3) Prepare and submit a written report in accordance with § 265.93 (d)(5) and place in the facility's operating record until closure of the facility.

(4) Continue to make the determination specified in § 265.93 (d)(4) on a quarterly basis until final closure of the facility; and

(5) Comply with the recordkeeping and reporting requirements in § 265.94 (b).

(f) The Secretary may replace all or part of the requirements of this subpart applying to a regulated unit (as defined in § 122.90), with alternative requirements developed for groundwater monitoring set out in an approved closure or post-closure plan or in an enforceable document (as defined in § 122.1 (c)(7)), where the Secretary determines that:

(1) A regulated unit is situated among solid waste management units (or areas of concern), a release has occurred, and both the regulated unit and one or more solid waste management unit(s) (or areas of concern) are likely to have contributed to the release; and

(2) It is not necessary to apply the requirements of this subpart because the alternative requirements will protect human health and the environment. The alternative standards for the regulated unit must meet the requirements of § 264.101 (a).

(Amended August 23, 1999)

7 Del. Admin. Code § 1302-265-F-265.90

22 DE Reg. 678 (2/1/2019) (Final)