Section 329IAC10-24-4. Hydrogeologic study

   (a) An application for restricted waste site Type I or Type II or nonmunicipal solid waste landfill must be accompanied by a proposal for the installation of monitoring devices, upgradient and downgradient from the landfill with respect to ground water flow direction. The proposal must consist of a hydrogeologic study that provides the information specified in subsection (b). The commissioner may modify the requirements for the proposal dependent on site characteristics. The proposal must be certified by a registered professional engineer or licensed professional geologist, either of whom shall have education or professional experience in hydrogeology or hydrology.

  (b) The proposal must provide the following information by means of maps, diagrams, and narrative:

(1) Summary of regional and site-specific geologic information obtained from recent or previous soil borings, coal borings, area ground water monitoring well logs, and published reports.

(2) Water table and potentiometric surface maps of the proposed site, including ground water flow directions as follows:

(A) Such maps must be prepared from data from cased holes or piezometers capable of measuring hydraulic head at a maximum screen interval of five (5) feet. This limitation on the maximum length of the screened interval must not apply to those piezometers used to determine a water table surface. At least:

(i) three (3) such devices must be necessary for fill areas less than twenty (20) acres;

(ii) four (4) such devices for fill areas between twenty (20) and fifty (50) acres;

(iii) five (5) such devices for fill areas between fifty (50) and ninety (90) acres; and

(iv) six (6) such devices for fill areas greater than ninety (90) acres.

The required devices must be evenly distributed over the site. In addition, vertical hydraulic gradients must be measured, at a minimum, of two (2) separate points at the site. Additional nested piezometers or ground water monitoring wells may be required by the commissioner to adequately determine vertical components. When more than one (1) aquifer is present within the specified boring depths required in section 3(1)(C) of this rule, individual water table and potentiometric maps may be required.

(B) Monthly water level measurements over a period of at least six (6) months, along with water table and potentiometric surface maps constructed from each measurement event, must be submitted to the commissioner prior to operation of the facility.

(C) The proposal must discuss the evidence and potential of significant components of vertical ground water flow. If there are significant components of vertical flow, cross-sectional representations of equipotential lines and ground water flow direction must be provided that adequately represent the flow beneath the site.

(3) Identification of aquifers below the proposed site to the depth required by section 3(1)(C) of this rule, including the following information:

(A) Aquifer thickness or thicknesses.

(B) Lithology.

(C) Estimated hydraulic conductivity and effective porosity.

(D) Presence of low permeability units above or below.

(E) Whether the aquifers are confined or unconfined.

In addition, a general identification and description must be provided for aquifers known to exist from the geologic literature and area ground water monitoring well logs.

(4) Known or projected information on hydraulic connections of ground water to surface water and hydraulic connections between different aquifers at site.

(5) Information on the current and proposed use of ground water in the area, including any available information on existing quality of ground water in the aquifer or aquifers.

(6) Diagrammatic representation of proposed ground water monitoring well design and construction, including any available information on existing quality of ground water in the aquifer or aquifers.

(7) Proposed ground water monitoring well locations, including length and elevation of screened intervals.

  (c) The commissioner may require that pumping tests or similar hydraulic tests be performed to provide a more accurate determination of aquifer characteristics where necessary to determine the adequacy of site or monitoring system design. (Solid Waste Management Division; 329 IAC 10-24-4; filed Mar 14, 1996, 5:00 p.m.: 19 IR 1890; readopted filed Jan 10, 2001, 3:25 p.m.: 24 IR 1535; filed Feb 9, 2004, 4:51 p.m.: 27 IR 1861, eff Apr 1, 2004; readopted filed May 14, 2007, 1:53 p.m.: 20070523-IR-329070138BFA; readopted filed Jul 29, 2013, 9:20 a.m.: 20130828-IR-329130179BFA)