Ground water resources.
Ground water resources.
(1) Testing and sampling for injury to ground water resources shall be performed using methodologies described in the Assessment Plan.
(2) Chemical analyses performed to meet the requirements of the Injury Determination phase for ground water resources shall be conducted in accordance with methods that are generally accepted or have been scientifically verified and documented.
(3)
(i) The term “water sample” shall denote a volume of water collected and preserved to represent the bulk water and any dissolved or suspended materials or microorganisms occurring in the ground water resource.
(ii) The source of ground water samples may be from natural springs, in seeps, or from wells constructed according to generally accepted methods.
(4) Sampling of ground water or of geologic materials through which the ground water migrates shall be conducted according to generally accepted methods.
(5) Measurement of the geohydrologic properties of the resource shall be conducted according to generally accepted practice.
(6) Description of lithologies, minerals, cements, or other sedimentary characteristics of the ground water resource should follow generally accepted methods.
(7) Interpretation of the geohydrological setting, including identifying geologic layers comprising aquifers and any confining units, shall be based on geohydrologic and geologic literature and generally accepted practice.
(8)
(i) Interpretation of ground-water flow systems or estimation of transport of oil or hazardous substances in ground water through the use of models shall be based on geohydrologic literature and current practice.
(ii) The applicability of models used during the assessment should be demonstrated, including citation or description of the following.
(A) Physical, chemical, and biological processes simulated by the model;
(B) Mathematical or statistical methods used in the model; and
(C) Model computer code (if any), test cases proving the code works, and any alteration of previously documented code made to adapt the model to the assessment area.
(iii) The validity of models used during the assessment should be established, including a description of the following:
(A) Model boundary conditions and stresses simulated;
(B) How the model approximates the geohydrological framework of the assessment area;
(C) Grid size and geometry;
(D) Sources of geohydrological, chemical, and biological data used in the model;
(E) Lists or maps of data used to describe initial conditions;
(F) Time increments or time periods modeled;
(G) Comparison of predicted fluxes of water and solutes with measured fluxes;
(H) Calibration-verification procedures and results; and
(I) Type and results of sensitivity analyses made.