HYDRO31270

• Permit No: M1980244
• IBM Index Class Name: Hydrology
• Doc Date: 6/3/1994
• Doc Name: RATIONALE FOR PUBLIC NOTICE
• Media Type: D
• Archive: No

• art I
Page if of 19
Permit No. CO-0042562
B. MONITORING REQUIREMENTS
4. Chronic WET Testing - Outfalls 001 and 002 (continued)
(d) Automatic Compliance Schedule Upon Failure of Test
If a routine chronic WET test is failed, regardless of whether the limit
is in effect, the following automatic compliance schedule shall apply.
As part of this the permittee shall either:
(i) proceed to conduct the PTI/TIE investigation as described in Part
I.B.4,e, or
(11) conduct accelerated testing using the single species found to be
more sensitive.
If accelerated testing is being performed, the permittee shall provide
written notification of the results within 14 calendar days of
completion of the "Pattern of Tozicity"/"No Tozicity" demonstration.
Testing will be at least once every two weeks for up to five tests
until; 1) two consecutive tests fail or three of five tests fail, in
which case a pattern of toxicity has been demonstrated or 2) two
consecutive tests pass or three of five tests pass, in which case no
pattern of toxicity has been found. If no pattern of toxicity is found
the toxicity episode is considered to be ended and routine testing is to
resume. If a pattern of toxicity is found, a PTI/TIE investigation is
to be performed. If a pattern of toxicity is not demonstrated but a
significant level of erratic toxicity is found, the Division may require
an increased frequency of routine monitoring or some other modified
approach.
(e) PTI TIE
The results of the PTI/TIE investigation are to be received by the
Division within 120 days of the demonstration of chronic WET in the
routine test, as defined above, or if accelerated testing is performed.
the date the pattern of toxicity is demonstrated. A status report is to
be provided to the Division at the 30. 60 and 90 day points of the
PTI/TIE investigation. The Division may extend the time frame for
investigation where reasonable justification exists. A request for an
extension must be made in writing and received prior to the 120 day
deadline. Such request must include a justification and supporting data
for such an extension.
The permittee may use the time for investigation to conduct a PTI or
move directly into the TIE. A PTI consists of a brief search for
possible sources of WET, which might reveal causes of such toxicity and
appropriate corrective actions more simply and cost effectively than a
formal TIE. If the PTI alloys resolution of the WET incident, the TIE
need not necessarily be conducted. If, however, WET is not identified
or resolved during the PTI, the TIE must be conducted within the allowed
120 day time frame.
amended effective