Washington Administrative Code
Title 173 - Ecology, Department of (See also Titles 197, 317, 372, and 508)
Chapter 173-304 - Minimum functional standards for solid waste handling
Section 173-304-490 - Groundwater monitoring requirements
Universal Citation: WA Admin Code 173-304-490
Current through Register Vol. 24-06, March 15, 2024
(1) Applicability. These requirements apply to owners and operators of landfills, piles, landspreading disposal facilities, and surface impoundments that are required to perform groundwater monitoring under WAC 173-304-400.
(2) Groundwater monitoring requirements.
(a) The groundwater monitoring system must
consist of at least one background or upgradient well and three down gradient
wells, installed at appropriate locations and depths to yield groundwater
samples from the upper most aquifer and all hydraulically connected aquifers
below the active portion of the facility.
(i)
Represent the quality of background water that has not been affected by leakage
from the active area; and
(ii)
Represent the quality of groundwater passing the point of compliance.
Additional wells may be required by the jurisdictional health department in
complicated hydrogeological settings or to define the extent of contamination
detected.
(b) All
monitoring wells must be cased in a manner that maintains the integrity of the
monitoring well bore hole. This casing must allow collection of representative
groundwater samples. Wells must be constructed in such a manner as to prevent
contamination of the samples, the sampled strata, and between aquifers and
water bearing strata and in accordance with chapter 173-160 WAC, Minimum
standards for construction and maintenance of water wells.
(c) The groundwater monitoring program must
include at a minimum, procedures and techniques for:
(i) Decontamination of drilling and sampling
equipment;
(ii) Sample
collection;
(iii) Sample
preservation and shipment;
(iv)
Analytical procedures and quality assurance;
(v) Chain of custody control; and
(vi) Procedures to ensure employee health and
safety during well installation and monitoring.
(d) Sample constituents.
(i) All facilities shall test for the
following parameters:
(A)
Temperature;
(B)
Conductivity;
(C) pH;
(D) Chloride;
(E) Nitrate, nitrite, and ammonia as
nitrogen;
(F) Sulfate;
(G) Dissolved iron;
(H) Dissolved zinc and manganese;
(I) Chemical oxygen demand;
(J) Total organic carbon; and
(K) Total coliform.
(ii) The jurisdictional health department in
consultation with the department may specify additional or fewer constituents
depending upon the nature of the waste; and
(iii) Test methods used to detect the
parameters of (d)(i) of this subsection shall be EPA Publication Number SW-846,
Test Methods for Evaluating Solid Waste - Physical/Chemical
Methods except for total coliform which shall use the latest edition
of Standard Methods for the Examination of Water and
Wastewater.
(e)
The groundwater monitoring program must include a determination of the
groundwater surface elevation each time groundwater is sampled.
(f) The owner or operator shall use a
statistical procedure for determining whether a significant change over
background has occurred. The jurisdictional health department will approve such
a procedure with the guidance of the department.
(g) The owner or operator must determine
groundwater quality at each monitoring well at the compliance point at least
quarterly during the life of an active area (including the closure period) and
the post-closure care period. The owner or operator must express the
groundwater quality at each monitoring well in a form necessary for the
determination of statistically significant increases.
(h) The owner or operator must determine and
report the groundwater flow rate and direction in the uppermost aquifer at
least annually.
(i) If the owner or
operator determines that there is a statistically significant increase for
parameters or constituents at any monitoring well at the compliance point, the
owner or operator must:
(i) Notify the
jurisdictional health department of this finding in writing within seven days
of receipt of the sampling data. The notification must indicate what parameters
or constituents have shown statistically significant increases;
(ii) Immediately resample the groundwater in
all monitoring wells and determine the concentration of all constituents listed
in the definition of contamination in WAC
173-304-100 including additional
constituents identified in the permit and whether there is a statistically
significant increase such that the groundwater performance standard has been
exceeded, and notify the jurisdictional health department within fourteen days
of receipt of the sampling data.
(j) The jurisdictional health department may
require corrective action programs including facility closure if the
performance standard of WAC
173-304-460(2)(a)
is exceeded and, in addition, may revoke any
permit and require reapplication under WAC
173-304-600.
(3) Corrective action program. An owner or operator required to establish a corrective action program under this section must, at a minimum with the approval of the jurisdictional health officer:
(a) Implement a corrective action program
that reduces contamination and if possible prevents constituents from exceeding
their respective concentration limits at the compliance point by removing the
constituents, treating them in place, or other remedial measures;
(b) Begin corrective action according to a
written schedule after the groundwater performance standard is
exceeded;
(c) Terminate corrective
action measures once the concentrations of constituents are reduced to levels
below the limits under WAC
173-304-460(2)(a).
Statutory Authority: Chapter 43.21A RCW. 85-22-013 (Order 85-18), § 173-304-490, filed 10/28/85.
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