Ala. Admin. Code r. 335-6-15-.28

Current through Register Vol. 43, No. 1, October 31, 2024

Section 335-6-15-.28 - Secondary Investigation Requirements

(1) When required in order to determine the full lateral and vertical extent and location of: soils contaminated by the release; the presence of free product; and the presence and concentrations of dissolved product contamination in the groundwater, the Department may require owners and operators to conduct a secondary investigation of the release site. This investigation must include the surrounding area possibly affected by the release if any of the following conditions exist:

(a) There is evidence that groundwater wells have been affected by the release (e.g., as found during release confirmation or previous corrective action measures);

(b) Free product is found to need recovery in compliance with Rule 335-6-15-.27;

(c) There is evidence that contaminated soils may be in contact with groundwater (e.g., as found during conduct of the initial response measures or investigations required under Rules 335-6-15-.24 through 335-6-15-.26); and

(d) The Department requests an investigation, based on the potential effects of contaminated soil or groundwater on nearby surface water and groundwater resources.

(2) The investigations required by paragraph (1) of this rule shall:

(a) Be sufficient to define the full lateral and vertical extent of soil and groundwater contamination;

(b) Determine the rate and direction of pollutant and groundwater migration through the use of piezometers and/or monitoring wells;

(c) Include results of groundwater sampling and analysis from monitoring wells at one background and a minimum of three down-gradient locations. The location of the down-gradient wells should take into consideration the direction of groundwater flow and should be placed so as to define the plume of contamination and the outer limits of the plume of contamination;

(d) Include a determination of the uppermost aquifer and an initial evaluation of the potential for hydraulic interconnection with lower aquifers. This evaluation may be made based upon the results of site soil sampling and borings and available literature data but may also require installation of wells into underlying aquifers. If this becomes necessary proper well construction techniques must be used to ensure that wells do not serve as conduits for contamination of underlying aquifers;

(e) Include analytical results for soil and groundwater samples for parameters which are appropriate to the nature of the stored substance and according to methods specified in Rule 335-6-15-.32; and

(f) Provide sufficient information for the selection and design of appropriate corrective actions.

(3) The Department may require additional sampling and analyses to be performed if it is determined that the number or location of samples, or methods used in the analysis of such samples, are not sufficient to define the full lateral and vertical extent of soil and groundwater contamination.

(4) Owners and operators must submit a plan of study sufficient to accomplish the objective of paragraphs (1) and (2) of this rule together with a schedule of implementation. The owners and operators shall make any modifications to the plan of study deemed necessary by the Department.

(5) The plan of study must contain construction details for monitoring wells. Monitoring wells must be constructed in a manner acceptable to the Department or the Department may require them to be properly closed. Except where cross-contamination of aquifers is of concern, general construction details for monitoring wells should conform to the requirements of Rule 335-6-15-.17(f)6. through 8., 10. through 14. and 20. The Department may require modification of proposed construction details.

(6) Owners and operators must submit the information collected under paragraphs (1) through (3) of this rule within the schedule submitted in paragraph (4) of this rule or in accordance with a schedule established by the Department.

(7) The secondary site investigation must be performed in accordance with accepted geologic practices by a licensed professional geologist or registered professional engineer experienced in hydrogeologic investigations.

(8) All investigation derived waste shall be handled as stated in 335-6-15-.26(9).

Ala. Admin. Code r. 335-6-15-.28

Effective April 5, 1989. Amended: Filed August 28, 2003; effective October 2, 2003. Amended: filed July 2, 2007; effective August 6, 2007.

Amended by Alabama Administrative Monthly Volume XXXVI, Issue No. 02, November 30, 2017, eff. 12/8/2017.

Amended by Alabama Administrative Monthly Volume XL, Issue No. 05, February 28, 2022, eff. 4/14/2022.

Authors: Sonja Massey, Curt Johnson, Lee Davis, Dorothy Malaier

Statutory Authority:Code of Ala. 1975, § 22-36-3.