Stormwater Pollution Prevention Plan - Phoenix Sky Harbor ...

Non-mining MSGP 2010 General Permit
to Part 7 for additional reporting and recordkeeping requirements.
6.1 Analytical Monitoring Procedures
6.1.1 Analytical Monitoring Locations
6.1.1.1 Monitored Outfalls
Applicable monitoring requirements apply to each outfall authorized by this permit. If the facility
has two or more outfalls believed to discharge substantially identical stormwater and/or allowable nonstormwater,
based on the similarities of the general industrial activities and control measures, exposed
materials that may significantly contribute pollutants to stormwater, and runoff coefficients of their
drainage areas, the permittee may monitor the discharge at just one of the outfalls and report that the
results also apply to the substantially identical outfall(s). The allowance for monitoring only one of the
substantially identical outfalls is not applicable to any outfalls with numeric effluent limitations set forth in
Part 2.2.1. The permittee is required to monitor each outfall covered by a numeric effluent limitation as
identified in Part 6.2.2.
6.1.1.2 Commingled Discharges.
If discharges authorized by this permit commingle with discharges not authorized under this
permit, any required sampling of the authorized discharges must be performed at a point before they mix
with other unauthorized discharges to the extent practicable.
6.1.1.3 Monitoring for Allowable Non-Stormwater Discharges
Unless otherwise specified by ADEQ, permittees are required to monitor allowable nonstormwater
discharges (as delineated in Part 1.1.3) only when they are commingled with stormwater
discharges associated with industrial activity.
6.1.2 Monitoring Events
6.1.2.1 Monitoring Periods.
Monitoring requirements in this permit begin within 90 calendar days of receiving the
Department’s authorization to discharge. The required monitoring events may be distributed during
seasons when precipitation occurs, or when snowmelt results in a measurable discharge from the site.
Wet seasons, for the purposes of analytical monitoring, apply statewide and are defined as
follows:
Summer wet season: June 1 – October 31
Winter wet season: November 1 – May 31
The term ‘wet season’ includes areas of the state where freezing conditions exist that prevent
runoff from occurring for extended periods. In areas where freezing conditions exist, the required
monitoring and sample collection may be distributed during seasons when precipitation runoff, either as
melting snow or rain mixed with melting snow, occurs.
6.1.2.2 Measurable Storm Events.
All required monitoring must be performed on a storm event that results in a discharge from the
facility (“measurable storm event”) that follows the preceding measurable storm event by at least 72 hours
(3 calendar days). The 72 hour (3 day) storm interval does not apply if the permittee is able to document
that less than a 72 hour interval is representative for local storm events during the sampling period. In the
case of snowmelt, the monitoring must be performed at a time when a measurable discharge occurs at
the site.
For each monitoring event, except snowmelt monitoring, the permittee shall identify the person
performing the monitoring, the date and estimated duration (in hours) of the rainfall event, estimated
rainfall total (in inches) for that rainfall event, and time (in days) since the previous measurable storm
Stormwater Discharges Associated with Industrial Activity 24