The applicant shall perform laboratory and field
investigations to define the physical characteristics of the proposed
landfill's location. At a minimum these investigations shall include the
following specified requirements unless an alternative geotechnical
investigation program under s.
NR
512.085 specifically addressing these requirements, or
a portion thereof, was accepted in writing by the department before the
geotechnical investigation program for the feasibility report was initiated.
Should the applicant identify minor discrepancies between the following
specified requirements and the content of the feasibility report prior to its
submittal to the department, the applicant may choose to identify those minor
discrepancies in a separate letter to the department, including an explanation
for them, and either propose a time table for providing that information or
justify why it is not necessary to submit that specific information and request
the necessary exemptions. The department shall respond to a letter in writing
either accepting the explanation and requested approach or indicating that the
discrepancies need to be addressed prior to issuing feasibility
completeness.
(1) BORINGS. As
specified in Table 1, borings sufficient to define sub-surface conditions shall
be drilled both inside and outside the proposed limits of filling.
(a) At a minimum, borings shall be drilled in
10 separate locations for the first 5 or less acres of the proposed fill area.
Two borings shall be drilled for each additional 5 or less acres of proposed
fill area. The borings shall be located on a grid pattern. All borings shall be
located in or within 300 feet of the proposed limits of filling.
(b) Borings shall extend a minimum of 25 feet
below the anticipated sub-base grade. If the boring is located outside the
proposed limits of filling, the applicable sub-base grade is the elevation of
the bottom of the proposed base liner nearest to the borehole.
(c) If regional information suggests that
bedrock is within 50 feet of the lowest elevation of the proposed sub-base
grades, one boring shall be extended at least 5 feet into bedrock. Every
attempt shall be made to locate this boring outside the proposed limits of
filling. Bedrock drilling shall be performed in accordance with ch. NR 141 and
s.
NR 507.05.
Note: Bedrock is defined in s.
NR
500.03(18).
(d) Samples shall be collected and retained
and boring logs shall be prepared in accordance with ss.
NR 507.05
and
507.14.
(e) Borings not converted to wells shall be
abandoned in accordance with ss.
NR
507.08 and
141.25.
(2) WELLS. As specified in Table 1, wells
sufficient to define the hydrogeologic and groundwater quality conditions shall
be installed. At a minimum, this includes:
(a) Installing observation wells to
adequately define the water table surface and horizontal hydraulic gradients.
At a minimum, 5 water table observation wells shall be installed for the first
5 or less acres of disposal area and one additional observation well for each
additional 5 or less acres of disposal area. The observation wells shall be
constructed so that the water table intersects the well screens at all times
during the year.
(b) A piezometer
shall be installed adjacent to a water table observation well at 2 separate
locations to create well nests for the first 5 or less acres of disposal area.
One additional piezometer for each additional 10 or less acres of disposal area
shall be installed to create additional well nests. For every 20 acres of
disposal area at least one well nest shall be placed within the proposed limits
of filling.
(c) For proposed limits
of filling located in a fine-grained soil environment, each well nest required
in par. (b) shall consist of 3 wells: a water table observation well, a
piezometer installed at or just below the proposed subbase grades and a deeper
piezometer installed at least 15 feet below the bottom of the upper
piezometer's well screen.
(d) All
wells shall be located no more than 300 feet from the proposed limits of
filling and at least half of the wells shall be located no more than 150 feet
from the proposed limits of filling.
(e) All wells shall be designed, installed,
developed, documented and sampled in accordance with ch. NR 141 and ss.
NR
507.06,
507.07,
507.14 and
507.17. Alternative methods of well
design and installation which achieve comparable results shall be approved by
the department prior to well construction.
Note: Fine-grained soil environment is defined
in s.
NR
500.03(86).
Table 1
|
Coarse-Grained Soil
Environments
|
|
Piezometers
|
Water Table Observation Wells
|
Borings
|
Area
|
|
2
|
5
|
10
|
First 5 or less acres
|
|
-
|
1
|
2
|
Each additional 5 or less acres
|
|
1
|
-
|
-
|
Each additional 10 or less acres
|
|
Fine-Grained Soil Environments
|
|
Piezometers
|
Water Table Observation Wells
|
Borings
|
Area
|
|
4
|
5
|
10
|
First 5 or less acres
|
|
-
|
1
|
2
|
Each additional 5 or less acres
|
|
2
|
-
|
-
|
Each additional 10 or less acres
|
(3) FIELD DIRECTION. A professional geologist
or qualified technician who is directly supervised by a professional geologist
shall observe and direct the drilling of all borings and the installation,
development and abandonment of all wells. A professional geologist or qualified
technician who is directly supervised by a professional geologist shall also
conduct all in-field hydraulic conductivity tests and visually describe and
classify all of the geologic samples.
(4) LABORATORY AND FIELD ANALYSIS. Laboratory
and field analyses shall be conducted to identify the specific geologic,
hydrogeologic and groundwater quality conditions at the proposed facility as
outlined below:
(a) For each major soil unit
encountered, at least 5 representative samples shall be analyzed for grain size
distribution using mechanical and hydrometer methods and Atterberg limits as
appropriate for the particular type of material. Each representative sample
shall be classified according to the unified soil classification system.
Note: Major soil unit is defined in s.
NR
500.03(138).
(b) Laboratory hydraulic conductivity tests
shall be conducted on at least 2 representative samples from each major
fine-grained soil unit. Tests shall be run on undisturbed samples when
conditions allow.
(c) The
department may require that other tests be conducted as appropriate for the
particular type of material.
(d) An
in-field test shall be conducted on each well to determine the in-situ
hydraulic conductivity. The test shall be of long enough duration and include a
sufficient amount of data to provide a representative estimate of the actual
hydraulic conductivity.
(e) After
each well has been properly developed, successive water level measurements
shall be taken until stabilized readings are obtained. Stabilized water level
measurements shall be obtained on a monthly basis for a minimum of 6 months
prior to submittal of the feasibility report. After this period, quarterly
water level measurements shall be obtained for at least 4 quarters.
(f) Stabilized water level measurements shall
be obtained on a monthly basis for a minimum of 6 months prior to submittal of
the feasibility report from surface water bodies including streams, lakes,
ponds, drainage ditches and wetlands located within 1,000 feet of the proposed
limits of filling. After this period, quarterly water level monitoring shall be
performed for at least 4 quarters.
(g) At least 4 rounds of baseline groundwater
monitoring shall be performed on all observation wells and piezometers located
outside the proposed limits of filling which were installed to evaluate the
proposed property in accordance with s.
NR
507.18 and submitted along with the feasibility
report.
(h) The department may
require other work such as groundwater modeling, pump tests, geophysical
investigations, isopach maps or a fence diagram to assess the hydrogeologic
conditions at the proposed facility.
(5) SAMPLE RETENTION. All soil and bedrock
samples collected from the proposed property shall be retained in accordance
with s.
NR
507.05.
(6) ADDITIONAL REQUIREMENTS FOR LANDFILLS
WITH EXTENDED COLLECTION LINES.
(a) Landfills
shall meet the requirements of pars. (b) and (c) where they will accept
municipal solid waste and contain leachate collection lines that exceed 1,200
feet from the end of each cleanout to the toe of the opposite slope. Where the
requirements of this subsection differ from other requirements of this chapter,
these requirements shall take precedence.
(b) A minimum of one boring in the area of
each proposed cell shall be drilled to physically characterize subbase
conditions for landfill foundation assessment of stability and settlement.
Borings shall be extended to a minimum of 50 feet below proposed subbase grades
or to competent bedrock, whichever is shallower. Borings shall include standard
penetration testing. Samples shall be taken at each significant soil layer. A
minimum of one sample from each fine grained layer and from each soft or
compressible coarse grained layer shall be subjected to geotechnical testing to
define parameters used in assessments of stability and settlement of the
liner.
(c) Consolidation testing
data shall be included with the data summarized by major soil unit in the table
required by s.
NR 512.10(2)
(d).
