Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0009 - Solid Waste Management
Chapter 4 - CONSTRUCTION AND DEMOLITION LANDFILL REGULATIONS
Section 4-8 - Monitoring Standards
Universal Citation: WY Code of Rules 4-8
Current through September 21, 2024
(a) Collection and management of samples: Groundwater, soil core, vadose zone, and decomposition gas samples shall be collected and managed in accordance with Department guidance or equivalent methods approved by the Administrator.
(b) Groundwater monitoring:
(i) Groundwater monitoring systems:
(A) A groundwater system must be installed
that consists of a sufficient number of wells to monitor water from the
uppermost aquifer that may be affected by leakage from the facility or unit.
The system must be capable of monitoring the quality of background groundwater
and groundwater passing the relevant point of compliance established by the
Administrator that shall be within 150 meters (492 feet) of the waste
management unit boundary on land owned by the owner of the landfill. Well
locations must be approved by the Administrator.
(B) The Administrator may approve a
groundwater monitoring system designed to monitor groundwater from the
facility, in lieu of individual waste disposal units, if the system is
determined to be capable of adequately detecting groundwater pollution. In
approving a facility-wide groundwater monitoring system, the Administrator
shall consider:
(I) Number, spacing, and
orientation of the individual waste units.
(II) Hydrologic setting.
(III) Site history and design.
(IV) Type of waste accepted at the individual
waste units.
(C) The
design of the groundwater monitoring system must be based on site-specific
hydrogeologic conditions including information on aquifer thickness, aquifer
properties, groundwater flow direction and rate (including seasonal
variations), and on geologic information on the soils, any aquitards,
aquicludes, or confining formations, at the site. The design of the system must
be approved by the Administrator.
(ii) Groundwater sampling and analysis shall
meet the requirements of Chapter 2, Section
9(b)(i)(C)(I) through
(IV).
(iii) Statistical evaluations of groundwater
data shall meet the requirements of Chapter 2, Section
9(b)(i)(C)(V) through
(VII).
(iv) Detection monitoring: The owner or
operator shall institute a detection monitoring program by sampling each well
at least semiannually, and testing each sample for the constituents specified
in Chapter 2, Appendix C, unless the Administrator approves an alternate
sampling frequency.
(A) The owner or operator
must determine whether or not there is a statistically significant increase
over background values as follows:
(I) The
owner or operator must compare the groundwater quality of each parameter or
constituent at each monitoring well using the approved statistical method;
and
(II) Within thirty (30) days
after completing sampling and analysis, unless an alternate time frame is
approved by the administrator, the owner or operator must determine whether
there has been a statistically significant increase over background at each
monitoring well.
(B) If
there is a statistically significant increase over background for one or more
constituents in any well the operator must:
(I) Notify the Administrator in a written
report with supporting documentation and place a copy of the report in the
facility operating record within fourteen (14) days.
(II) The owner or operator may be required to
initiate an assessment monitoring program unless within ninety (90) days or an
alternate time frame approved by the Administrator, the owner or operator
demonstrates to the Administrator in writing that the statistically significant
increase over background is not due to the solid waste disposal facility or
unit, but that the difference is due to another source of pollution, error in
sampling, analysis or statistical evaluation, or natural variation in
groundwater quality. The owner or operator shall prepare a report documenting
this demonstration, and following approval by the Administrator, place the
report in the operating record for the facility. If the demonstration is
approved, the owner or operator shall continue detection monitoring.
(III) If a successful demonstration is not
made:
(1.) The owner or operator shall request
that the Administrator classify groundwater according to Wyoming Water Quality
Rules and Regulations and establish groundwater protection standards.
(v)
Assessment monitoring:
(A) If there is a
statistically significant increase over background for one or more Appendix C
constituent(s) in any well, the Administrator may require the operator to
analyze groundwater samples for the constituents found in Chapter 2, Appendix A
or B. Some or all of these constituents may be added to the detection and/or
assessment monitoring program for the facility.
(B) After groundwater protection standards
have been established, within thirty (30) days after completing sampling and
analysis, unless an alternate time frame is approved by the Administrator, the
owner or operator shall determine if there has been a statistically significant
increase over a groundwater protection standard for each applicable constituent
in each downgradient well specified by the Administrator using a statistical
method approved by the Administrator.
(C) If one or more constituents are detected
at statistically significant levels above the groundwater protection standard
at a relevant point of compliance established by the Administrator that is no
more than 150 meters (492 feet) from the waste management unit boundary on land
owned by the owner of the landfill, the owner or operator shall notify the
Administrator within fourteen (14) days of the constituents detected above the
groundwater protection standard in a written report with supporting
documentation.
(I) Unless the owner or
operator demonstrates that the statistically significant increase was caused by
another source, resulted from an error in sampling, analysis, or statistical
evaluation, or from natural variation in groundwater quality, the Administrator
may require the owner or operator to characterize the nature and extent of the
release, conduct an assessment of corrective measures, and institute corrective
action remedies approved by the Administrator.
Disclaimer: These regulations may not be the most recent version. Wyoming may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google
Privacy Policy and
Terms of Service apply.
