| (A) a laboratory report of soil characteristics determined from at least one sample from each soil layer or stratum that will form the bottom and side of the proposed excavation and from those that are less than 30 feet below the lowest elevation of the proposed excavation. Additional tests shall be performed, as necessary, to provide a typical profile of soil stratification within the site. No laboratory work need be performed on highly permeable soil layers such as sand or gravel. The samples shall be tested by a competent independent third-party soils laboratory; (B) permeability tests performed according to one of the following standards on undisturbed soil samples. Permeability tests shall be performed using tap water or .05 Normal solution of calcium sulfate (CaSO 4 ), and not distilled water, as the permeant. Those undisturbed samples that represent the sidewall of any proposed cell, pit, or excavation shall be tested for the coefficient of permeability on the sample's in-situ horizontal axis; all others shall be tested on the in-situ vertical axis. All test results shall indicate the type of tests used and the orientation of each tested sample. All calculations for the final coefficient of permeability tests result for each sample tested shall be included in the report: (i) constant head with back pressure per Appendix VII of Corps of Engineers Manual EM1110-2-1906, "Laboratory Soils Testing;" American Society for Testing and Materials (ASTM) D5084 "Saturated Porous Materials Using a Flexible Wall Permeameter"; (ii) falling head per Appendix VII of Corps of Engineers Manual EM1110-2-1906, "Laboratory Soils Testing"; (iii) sieve analysis for the 200, and less than 200 fraction per ASTM D1140; (iv) Atterberg limits per ASTM D4318; and (v) moisture content per ASTM D2216; (C) the depth at which groundwater was encountered and records of after-equilibrium measurements in all borings. The cross-sections prepared in response to paragraph (4)(G) of this subsection must be annotated to note the level at which groundwater was first encountered and the level of groundwater after equilibrium is reached or just prior to plugging, whichever is later. This water-level information must also be presented on all borings required by paragraph (4) of this subsection and presented in a table format in the report; (D) records of water-level measurements in monitoring wells. Historic water-level measurements made during any previous groundwater monitoring shall be presented in a table for each well; (E) a tabulation of all relevant groundwater monitoring data from wells on site or on adjacent MSW landfill unit(s); and (F) identification of the uppermost aquifer and any lower aquifers that are hydraulically connected to it beneath the facility, including groundwater flow direction and rate, and the basis for such identification (i.e., the information obtained from hydrogeologic investigations of the facility area); (6) for owners and operators seeking an arid exemption for their landfill unit designs, a groundwater certification process must be used for meeting the provisions for groundwater certification of the arid exemption, as described in §330.5(b) of this title: (A) locate and plot the facility accurately on a topographic map (7.5-minute or 15-minute United States Geological Survey quadrangle). Draw a line to enclose all of the area within one mile of the facility boundary; (B) visit the facility and locate by physical inspection water wells and springs in the facility area. Determine the locations and plot them on the topographic map: (i) if no wells or springs exist within the facility area, refer to subparagraph (I) of this paragraph. Otherwise, refer to clause (ii) of this subparagraph; and (ii) determine from appropriate records (for example, water-well drillers, pump installers, city records, underground water conservation district, Texas Water Development Board, Texas Commission on Environmental Quality, United States Geological Survey, etc.) which of the wells are completed in the shallowest aquifer. If no wells are completed in the shallowest aquifer or if the shallowest aquifer is more than 150 feet below the land surface at the facility, refer to subparagraph (I) of this paragraph. Otherwise, refer to subparagraph (C) of this paragraph; (C) determine the groundwater gradient of the shallowest aquifer in the vicinity of the facility. This can be done by measuring stabilized water levels in wells completed in the shallowest aquifer in the facility area (from subparagraph (B)(ii) of this paragraph) or from previous hydrogeologic studies using contemporaneous stabilized water-level measurements. Care should be taken to measure water levels when nearby high-volume wells, such as irrigation wells, have not been pumped for a long enough period to allow the water level to stabilize. Where no data exist or cannot be determined, the regional gradient can be used; (D) from springs and from the wells completed in the shallowest aquifer, select the two wells/springs downgradient of and nearest to the facility based on the findings from subparagraph (C) of this paragraph. Select a well/spring upgradient or lateral to the facility, where groundwater quality is not likely to have been affected by landfill activities and preferably not by other human activities such as oil and gas operations, feedlots, sewage treatment plants, septic systems, etc; (E) sample the three selected wells/springs determined by subparagraphs (C) and (D) of this paragraph in accordance with accepted practices, such as described in technical guidance from the executive director. The owner or operator shall have the samples analyzed by a qualified laboratory for the following parameters: (i) chloride; (ii) nitrate (as N); (iii) sulfate; (iv) total dissolved solids; (v) specific conductance; (vi) pH; (vii) chromium; (viii) non-purgeable organic carbon; and (ix) volatile organic compounds listed in §330.419 of this title (relating to Constituents for Detection Monitoring); (F) if permission cannot be obtained to sample one or more of the three selected wells/springs, select one or more alternate wells/springs, within the plotted area. If fewer than three wells/springs are available, sample those that are available; (G) if permission cannot be obtained to sample any appropriately located wells/springs, submit written documentation of the facts to the executive director. If the executive director confirms that permission cannot be obtained for sampling, the well(s) may be eliminated from consideration; (H) compile the data from subparagraphs (A) - (F) of this paragraph in a report that includes: (i) a map showing all known wells, springs, facility boundaries, sampling points, etc.; (ii) a map showing the groundwater gradient and data points; (iii) chemical analyses, showing analytical methods used; (iv) logs and construction information for the sampled wells and description and flow rate for sampled springs; (v) text describing methods of investigation, such as sampling and water-level measurements; and (vi) conclusions with respect to presence or lack of evidence of groundwater contamination by the facility; (I) where no wells or springs are present in the facility area or the shallowest water level is more than 150 feet below land surface at the facility, submit a brief report describing the facility (with a map of the area) and the method(s) of determining the lack of appropriate sampling points or depth to the shallowest aquifer. Confirmed absence of sampling points will be deemed to be "no evidence of groundwater contamination"; (J) the report shall be signed and sealed by the qualified groundwater scientist who reviewed the data and reached the conclusions; (K) if there is no evidence of groundwater contamination by the landfill, the qualified groundwater scientist who reviewed the data and reached the conclusions shall sign and seal a statement in the following format: "I (we) have reviewed the groundwater data described in a report submitted with this certification and have found no evidence that the __________ municipal solid waste landfill located at ___________ has contaminated groundwater in the uppermost aquifer"; and (L) the executive director may accept information and data, other than described in this paragraph, as showing that there is no evidence of groundwater contamination by the landfill, if the information and data are deemed to be adequate for such a determination. Cont'd... |
