North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 13 - SOLID WASTE MANAGEMENT › Subchapter B - SOLID WASTE MANAGEMENT › Section .0500 - DISPOSAL SITES › Section 13B .0538 - GEOLOGIC AND HYDROGEOLOGIC INVESTIGATIONS FOR C&DLF FACILITIES

Current through Register Vol. 39, No. 2, July 15, 2024
(a) Site Hydrogeologic Report. In accordance
				  with Rule .0536(c)(3) of this Section, a permit applicant shall conduct a
				  hydrogeologic investigation and prepare a report. An investigation shall assess
				  the geologic and hydrogeologic characteristics of the parcel on which the
				  C&DLF unit is proposed to be constructed (hereinafter "site") to determine
				  the suitability of the site for solid waste management activities, which areas
				  of the site are most suitable for C&DLF units, and the general groundwater
				  flow paths and rates for the uppermost aquifer. The report shall provide an
				  understanding of the relationship of the site groundwater flow regime to local
				  and regional hydrogeologic features with special emphasis on the relationship
				  of C&DLF units to groundwater receptors such as drinking water wells and to
				  groundwater discharge features. Additionally, the scope of the investigation
				  shall include the general geologic information necessary to address compliance
				  with the location restrictions described in Rule .0536(c)(4) through (c)(10) of
				  this Section. The site hydrogeologic report shall provide the following
				  information:
(1) A report on the geology and
				  hydrogeology of the regional and local study areas as defined in Rule
				  .1618(c)(1) and (2) of this Subchapter based on research of available
				  literature for the area. This information is to be used in planning the field
				  investigation. For sites located in piedmont or mountain regions, this report
				  shall include an evaluation of structurally controlled features identified on a
				  topographic map of the area.
(2) A
				  report on field observations of the site that includes information on the
				  following:
(A) topographic setting, springs,
				  streams, drainage features, existing or abandoned wells, rock outcrops
				  including trends in strike and dip, and other features that may affect site
				  suitability or the ability to effectively monitor the site; and
(B) groundwater discharge features. For a
				  proposed site where the owner or operator does not control the property from
				  any landfill unit boundary to the controlling, downgradient, groundwater
				  discharge features additional borings, geophysical surveys, or other
				  hydrogeological investigations shall be required to characterize the nature and
				  extent of groundwater flow; and
(C)
				  the hydrogeological properties of the bedrock, if the water table of the
				  uppermost aquifer is in the bedrock. For the purpose of this Rule, "bedrock"
				  means material below auger refusal.
(3) Borings for which the numbers, locations,
				  and depths provide an understanding of the subsurface conditions and
				  groundwater flow regime of the uppermost aquifer at the site. The number and
				  depths of borings required shall depend on the hydrogeologic characteristics of
				  the site. There shall be no less than an average of one boring for each 10
				  acres of the proposed landfill facility. All borings intersecting the water
				  table shall be converted to piezometers or monitoring wells in accordance with
				  15A NCAC
				  02C .0108. Boring logs, field logs and notes,
				  and well construction records for all onsite borings, wells, and piezometers
				  shall be placed in the operating record, and shall also be provided to the
				  Division upon request. Field logs and notes shall be legible; and may be
				  typewritten.
(4) A testing program
				  for the borings that describes the frequency, distribution, and type of samples
				  taken and the methods of analysis, such as ASTM Standards provided at
https://www.astm.org
, used to obtain
				  the following information:
(A) standard
				  penetration - resistance using a method such as ASTM D 1586;
(B) particle size analysis using a method
				  such as ASTM D 6913;
(C) soil
				  classification: Unified Soil Classification System using a method such as ASTM
				  D 2487;
(D) formation descriptions;
				  and
(E) saturated hydraulic
				  conductivity, porosity, and effective porosity for each lithologic unit of the
				  uppermost aquifer including the vadose zone.
(5) In addition to borings, other
				  investigation techniques may be used to obtain an understanding of the
				  subsurface conditions at the site, including geophysical well logs, surface
				  geophysical surveys, and tracer studies.
(6) Stratigraphic cross-sections identifying
				  hydrogeologic and lithologic units, and stabilized water table
				  elevations.
(7) Water table
				  information, including:
(A) tabulations of
				  water table elevations measured at the time of boring, 24 hours, and stabilized
				  readings for all borings, measured within a period of time short enough to
				  avoid temporal variations in groundwater flow which could preclude accurate
				  determination of groundwater flow direction and rate;
(B) tabulations of stabilized water table
				  elevations over time to develop an understanding of seasonal fluctuations in
				  the water table;
(C) an estimation
				  of the long-term seasonal high groundwater table based on stabilized water
				  table readings, hydrographs of wells in the area, precipitation and other
				  meteorological data, streamflow measurements from the site frequent enough to
				  demonstrate infiltration and runoff characteristics, and any other information
				  available; and
(D) a discussion of
				  any natural or man-made activities that have the potential for causing water
				  table fluctuations, including tidal variations, river stage changes, flood pool
				  changes of reservoirs, high volume production wells, and injection
				  wells.
(8) The
				  horizontal and vertical dimensions of groundwater flow including flow
				  directions, rates, and gradients.
(9) Groundwater contour map(s) to show the
				  occurrence and direction of groundwater flow in the uppermost aquifer and any
				  other aquifers identified in the hydrogeologic investigation. The groundwater
				  contours shall be superimposed on a topographic map. The location of all
				  borings and rock cores and the water table elevations or potentiometric data at
				  each location used to generate the groundwater contours shall be shown on the
				  groundwater contour map(s).
(10) A
				  topographic map of the site locating soil borings with accurate horizontal and
				  vertical control, which are tied to a permanent onsite benchmark.
(11) Information for public potable wells and
				  public water supply surface water intakes within the site characterization
				  study area in accordance with Rule .0536(c)(1) of this Section, including:
(A) available information and records for
				  well construction, number and location served by wells, and production rates
				  for public potable water wells; and
(B) available information for all surface
				  water intakes, including location, use, and production rate.
(12) Identification of other
				  geologic and hydrologic considerations including slopes, streams, springs,
				  gullies, trenches, solution features, karst terranes, sinkholes, dikes, sills,
				  faults, mines, groundwater discharge features, and groundwater recharge and
				  discharge areas.
(13) A report
				  summarizing the geological and hydrogeological evaluation of the site that
				  includes the following:
(A) a description of
				  the relationship between the uppermost aquifer of the site to local and
				  regional geologic and hydrogeologic features;
(B) a discussion of the groundwater flow
				  regime of the site focusing on the relationship of C&DLF units to
				  groundwater receptors and to groundwater discharge features;
(C) a discussion of the overall suitability
				  of the proposed site for solid waste management activities and which areas of
				  the site are most suitable for C&DLF units; and
(D) a discussion of the groundwater flow
				  regime of the uppermost aquifer at the site and the ability to monitor the
				  C&DLF units to ensure early detection of any release of monitored
				  constituents to the uppermost aquifer.