R 299.9506 Hydrogeological reports; content.

Rule 506. (1) A hydrogeological report must include all the following information: (a) A summary of the groundwater monitoring data obtained during the interim status period pursuant to the provisions of 40 CFR part 265, subpart F, where applicable, and a summary of other groundwater monitoring data collected pursuant to state or federal law. (b) Identification of the uppermost aquifer and aquifers hydraulically interconnected to the uppermost aquifer beneath the facility property, including groundwater flow direction and rate, and the basis for the identification. (c) Identification of any aquifer utilized by public and private wells within 2,000 feet of the proposed site. (d) Identification of all other aquifers evidenced by available well or boring logs. (e) The delineation of all the following on the topographic map required pursuant to the provisions of 40 CFR 270.14(b)(19): (i) The waste management area and other treatment or storage areas. (ii) The property boundary. (iii) The proposed point of compliance, as defined pursuant to the provisions of 40 CFR 264.95. (iv) The proposed location of groundwater monitoring wells as required pursuant to the provisions of 40 CFR 264.97. (v) To the extent possible, the information required pursuant to the provisions of subdivision (b) of this subrule. (f) On the topographic map required pursuant to the provisions of 40 CFR 270.13(l), identification of all domestic, municipal, industrial, oil, and gas wells and soil borings within 1 mile of the site in all directions for which copies of logs are available. (g) A description of any plume of contamination that has entered the groundwater from a hazardous waste management unit or other regulated activity at the site at the time that the application was submitted that does both of the following: (i) Delineates the extent of the plume on the topographic map required pursuant to the provisions of 40 CFR 270.14(b)(19). (ii) For landfills, surface impoundments, land treatment units, and waste piles, identifies the concentration of each constituent listed in the provisions of 40 CFR part 261, appendix VIII, throughout the plume or identifies the maximum concentrations of each constituent in the plume. (2) A hydrogeological report must include detailed plans and an engineering report describing the proposed groundwater monitoring program to be implemented to meet the requirements of R 299.9612 or a justification for a waiver pursuant to the provisions of subrule (7) of this rule. The engineering report must include all the following information for this purpose: (a) Soil boring logs and the results of soil sampling from the borings that are sufficient to adequately define soil and groundwater conditions at the site. All the following procedures must be utilized in collecting the data: (i) Not less than 5 soil borings must be made for the first 5 acres of the site, and 3 borings must be made for each additional 5 acres or portion thereof. A lesser number of borings may be made for nonactive portions of the site, such as buffer zones, and by supplementing boring information with geophysical testing, such as resistivity surveys. Soil borings must be located in a grid pattern so that there is a minimum of 1 boring in each major geomorphic feature, such as ridges, lowlands, and drainage swales, and all borings must extend not less than 30 feet below proposed grade or the anticipated bottom elevation of any installed or constructed liner. (ii) At each boring, soil samples must be collected from each soil layer or change in lithology. Two of the 5 soil borings that are required by the provisions of paragraph (i) of this subdivision must be evaluated and logged using continuous sampling methods, such as continuous tube sampling, coring, or continuously driven split spoons. For sites that are larger than 5 acres, 1 of each of the 3 additional soil borings that are required by the provisions of paragraph (i) of this subdivision must be evaluated and logged using continuous sampling methods. Samples that are collected from each soil layer or change in lithology must be tested for all the following: (A) Particle size distribution by both sieve and hydrometer. (B) Atterburg limits according to ASTM standard D4318-10, which is adopted by reference in R 299.11001. (C) Classification pursuant to the unified soil classification system, according to ASTM standard D2487-11, which is adopted by reference in R 299.11001. (iii) Each soil layer at a site must be evaluated for both of the following: (A) Moisture content, according to ASTM standards D6913-04 and D7928-16, which are adopted by reference in R 299.11001. (B) Permeability with water by the triaxial cell method as described in the EPA document entitled "Soil Properties, Classification, and Hydraulic Conductivity Testing," which is adopted by reference in R 299.11008; constant head method, according to ASTM standard D2434-68, which is adopted by reference in R 299.11001; approved in-situ field method; or other method approved by the director. All soil samples collected for determination of permeability must be collected by standard undisturbed soil sampling techniques, such as a 3-inch diameter Shelby tube or large diameter split spoon. (iv) Boring logs must include all the following: (A) Soil and rock descriptions. (B) Method of sampling. (C) Sample depth. (D) Date of boring. (E) Water level measurements. (F) Soil test data. (G) Boring location. (H) Standard penetration number by ASTM standard D1586-11, which is adopted by reference in R 299.11001. (v) All soil borings that are not converted to observation wells pursuant to the provisions of subdivision (b) of this subrule must be carefully backfilled, plugged, and recorded in accordance with the provisions of the well installation and well decommissioning procedures in ASTM standards D5092-04 and D5299-14, or a plan approved by the director. (vi) All elevations must be corrected to USGS datum. (b) Static water level measurements from observation wells and, where appropriate, well clusters that are located at the sites of soil borings and are constructed in accordance with the provisions of R 299.9612. Measurements must be accurate to the nearest 0.01 foot, corrected to USGS datum, and shall be taken from not less than 3 observation wells and 1 well cluster for the first 5 acres of the facility or portion thereof and 1 observation well for each additional 10 acres or portion thereof. Landfills, surface impoundments, waste piles, and land treatment facilities must have not less than 3 well clusters established as part of the monitor well system and not less than 1 cluster well for each 20 acres of the proposed site. All observation wells must be constructed and abandoned in accordance with the well installation and well decommissioning procedures in ASTM standards D5092-04 and D5299-14, or a plan approved by the director. (c) A water level contour map based on stabilized water level readings and using values contoured on an interval of not more than 1 foot. (d) If more than 2 well clusters have been constructed, then groundwater flow net diagrams illustrating horizontal and vertical flow directions of groundwater. (e) The location and depth of all observation wells and evidence that these observation wells are located effectively to detect hazardous constituents from the facility, based on all the following: (i) Groundwater flow direction. (ii) Velocity. (iii) Horizontal and vertical gradients. (iv) Thickness of the saturated and unsaturated zones. (v) The dispersion properties of hazardous waste constituents, such as the following: (A) Specific gravity. (B) Solubility. (C) Chemical reactivity within the formation. (D) Characteristics of decomposition products. (f) At each soil boring that is to be completed as an observation well during or following the hydrogeologic investigation, the lithology of that soil boring must be continuously sampled, logged, and classified pursuant to the unified soil classification system in accordance with ASTM standard D248711, which is adopted by reference in R 299.11001, from an elevation of 10 feet above the expected screened interval to the base of the borehole. Continuous sampling tubes, coring devices, or continuously collected split spoon samples may be used to satisfy this requirement. The director may allow the substitution of alternate information for this requirement or waive this requirement based on available information, site-specific hydrogeologic conditions, and available technology. (3) If the presence of hazardous constituents has not been detected in the groundwater at the time of license application, then the owner or operator shall submit sufficient information, supporting data, and analysis to establish a detection monitoring program that complies with the requirements of R 299.9612 and the provisions of 40 CFR 264.98. The submission must include all the following: (a) A proposed list of primary and secondary monitoring parameters and proposed monitoring frequencies for these parameters. (b) A proposed groundwater monitoring system. (c) Background values for each proposed primary and secondary monitoring parameter or procedures to calculate the values. (d) A description of proposed sampling, analysis, and statistical comparison procedures to be utilized in evaluating groundwater monitoring data. (e) Procedures for preventing cross-contamination in wells during activities such as well installation, purging, or sampling. (f) Evidence that sampling procedures and well construction materials are compatible with proposed monitoring parameters. (4) If the presence of hazardous constituents has been detected in the groundwater at the point of compliance at the time of license application, the owner or operator shall submit sufficient information, supporting data, and analysis to establish a compliance monitoring program that complies with the requirements of R 299.9612 and the provisions of 40 CFR 264.99. The submission must include all the following: (a) A description of the wastes previously handled at the facility. (b) A characterization of the contaminated groundwater, including concentrations of hazardous constituents. (c) A list of hazardous constituents for which compliance monitoring will be undertaken in accordance with the provisions of R 299.9612 and 40 CFR 264.97 and 264.99. (d) Proposed concentration limits for each hazardous constituent that do not exceed the background level of that constituent in the groundwater or a concentration limit that is not less stringent than allowed pursuant to the provisions of RCRA. (e) Detailed plans and an engineering report describing the proposed groundwater monitoring system in accordance with the requirements of 40 CFR 264.97. (f) A description of proposed sampling, analysis, and statistical comparison procedures to be utilized in evaluating groundwater monitoring data. (5) If hazardous constituents have been measured in the groundwater that exceed the concentration limits established pursuant to the provisions of 40 CFR 264.94(a)(2), Table l, or if groundwater monitoring conducted at the time of the license application indicates the presence of hazardous constituents from the facility in groundwater over background concentrations, then the owner or operator shall submit sufficient information, supporting data, and analyses to establish a corrective action program that complies with the requirements of R 299.9612 and the provisions of R 299.9629. To demonstrate compliance with the provisions of R 299.9612 and R 299.9629, the owner or operator shall address, at a minimum, all the following items: (a) A characterization of the contaminated groundwater, including concentrations of hazardous constituents. (b) The concentration limit for each hazardous constituent found in the groundwater, which must not exceed the background level of that constituent found in the groundwater at the time that limit is specified in the operating license. (c) Detailed plans and an engineering report describing the corrective action to be taken. (d) A description of how the groundwater monitoring program will demonstrate the adequacy of the corrective action. (6) For landfills, surface impoundments, waste piles, and land treatment units, a hydrogeological report must include all the following additional information that is necessary to determine site suitability and facility design: (a) For each boring made pursuant to the provisions of subrule (2) of this rule, all the following tests at intervals of not more than 5 feet or change in geologic formation: (i) Particle size distribution by both sieve and hydrometer. (ii) Atterburg limits according to ASTM standard D4318-10, which is adopted by reference in R 299.11001. (iii) Classification pursuant to the unified soil classification system according to ASTM standard D2487-11, which is adopted by reference in R 299.11001. (b) For each boring mad pursuant to the provisions of subrule (2) of this rule, the following tests at intervals of not more than 10 feet: (i) Permeability, by any of the following methods: (A) The triaxial cell method, as described in the EPA document entitled "Soil Properties, Classification and Hydraulic Conductivity Testing," which is adopted by reference in R 299.11008. (B) The constant head method, according to ASTM standard D2434-68, which is adopted by reference in R 299.11001. (C) An in-situ field method approved by the director. (D) Other methods approved by the director. (ii) Moisture content, according to ASTM standards D6913-04 and D7928-16, which are adopted by reference in R 299.11001. (c) Soil boring logs and the results of soil sampling from the borings that are sufficient to adequately define bedrock conditions at the site. (d) Additional information for determining the geotechnical characteristics of each soil layer at the site, such as any of the following: (i) Shear strength. (ii) Insitu density. (iii) Specific gravity. (iv) Stress deformation. (v) Shrinkage limit. (vi) Clay mineralogy. (vii) Information on the presence of cracks, fissures, and other voids that may increase the effective permeability of the soil. (e) A series of geologic cross sections or fence diagrams referenced to a site map and illustrating all the following: (i) Existing topography. (ii) Soil borings. (iii) Soil classification. (iv) Stratigraphy and other properties. (v) Bedrock. (vi) Wells. (vii) Stabilized water level readings and proposed site grades. (f) Water budget calculations under present site conditions, future active operations, and, for disposal facilities, the postclosure period. The calculations must consider all the following factors: (i) Precipitation. (ii) Evaporation. (iii) Runoff. (iv) Infiltration. (v) Evapotranspiration. (vi) Groundwater flow velocities and volume. (vii) Soil moisture holding capacity. (viii) For disposal facilities, the capacity of proposed waste types to hold moisture. (7) The director may waive or substitute alternate information for the information specified in subrule (2) or (6) of this rule based on site-specific considerations and available technology. (8) The provisions of 40 CFR 264.94(a)(2), table 1, 264.95, 264.97, 264.98, 270.13(l), and 270.14(b)(19) and part 265, subpart F, are adopted by reference in R 299.11003. Editor's Note: An obvious error in R 299.9506 was corrected at the request of the promulgating agency, pursuant to Section 56 of 1969 PA 306, as amended by 2000 PA 262, MCL 24.256. The rule containing the error was published in Michigan Register, 2025 MR 8. The memorandum requesting the correction was published in Michigan Register, 2025 MR 13.