Stormwater Pollution Prevention Plan - Phoenix Sky Harbor ...

Non-mining MSGP 2010 General Permit
6.2.3.2 Impaired Waters Monitoring Schedule.
Discharges to impaired waters without an approved TMDL.
Beginning in the first wet season following the permittee’s discharge authorization, the
permittee shall monitor twice per wet season at each outfall discharging stormwater to an
impaired water without an approved TMDL. Once the four (4) samples have been collected, if
the pollutant for which the water is impaired is not detected above applicable water quality
standards, the permittee may discontinue further monitoring for that pollutant, under this
section. The permittee shall keep records of this finding with the SWPPP. If the pollutant for
which the water is impaired is found in the discharge above applicable water quality
standards for any of the samples collected in the first year of sampling, the permittee shall
continue monitoring twice during each wet season.
Further, this monitoring requirement does not apply after one year if the pollutant for which
the waterbody is impaired is not detected above natural background levels in the discharge,
and the permittee documents, as required in Part 5.4, that this pollutant is not expected to be
present above natural background levels in the discharge.
If the pollutant for which the water is impaired is not present and not expected to be present
in the facility’s discharge, or it is present but it has been determined that the presence is
caused solely by natural background sources, the permittee shall include a notification to this
effect in the first monitoring report, after which annual monitoring may be discontinued. To
support this determination, the following documentation must be submitted with the first
monitoring report and kept with the SWPPP records:
An explanation of why the presence of the pollutant causing the impairment in your
discharge is not related to the activities at the facility; and
Data and/or studies that tie the presence of the pollutant causing the impairment in the
discharge to natural background sources in the watershed.
Discharges to impaired waters with an ADEQ approved TMDL.
For stormwater discharges assigned a WLA in an approved TMDL, the facility shall monitor
for the pollutant for which the TMDL was written. Beginning in the first wet season following
the facility’s date of discharge authorization, the permittee shall monitor twice per wet season
at each outfall discharging stormwater to the impaired water with an approved TMDL.
ADEQ’s authorization to discharge will include specifications on any additional pollutant(s) to
monitor.
If the pollutant for which the water is impaired is not detected above the applicable WLA in
the TMDL after the four samples have been collected, the permittee may discontinue further
monitoring, under this section. The permittee shall keep records of this finding onsite with the
SWPPP.
If the pollutant for which the water is impaired is found above the applicable WLA in the
TMDL in the discharge for any of the samples collected in the first year of sampling, the
permittee shall continue monitoring twice during each wet season. Attainment of the WLA for
SSC will be based on the median of four samples collected from four different measureable
storm events.
6.2.4 Additional Monitoring Required by ADEQ.
ADEQ may notify the permittee, in writing, of additional discharge monitoring required to ensure
protection of receiving water quality in cases where there is evidence that a pollutant is being discharged
that is not being monitored for by the permittee and that the pollutant may be causing or contributing to
exceedances of a water quality standard. Any such notice will provide an explanation of the reasons for
the monitoring, locations, and parameters to be monitored, frequency and period of monitoring, sample
types, and reporting requirements.
Stormwater Discharges Associated with Industrial Activity 30