Page 127 - California Stormwater Workshop Handouts

Industrial General Permit Fact Sheet

a. Whether BMPs addressing pollutants in industrial storm water discharges and
authorized NSWDs are effective for compliance with the effluent and receiving
water limitations of this General Permit,

b. The presence of pollutants in industrial storm water discharges and authorized
NSWDs (and their sources) that may trigger the implementation of additional
BMPs and/or SWPPP revisions; and,

c. The effectiveness of BMPs in reducing or preventing pollutants in industrial
storm water discharges and authorized NSWDs.

Effluent sampling and analysis information may be useful to Dischargers when
evaluating the need for improved BMPs. The monitoring requirements in this
General Permit recognize the 2008 MSGP approach to visual observations as an
effective monitoring method for evaluating the effectiveness of BMPs at most
facilities. Section 6.2 of the 2008 MSGP limits its monitoring sampling requirements
to certain industrial categories. Similar to the previous permit, this General Permit
requires all Dischargers to sample unless they have obtained NEC coverage or
have an inactive mining operation(s) certified as allowed under this General Permit
Section XIII.

This General Permit defines a Qualifying Storm Event (QSE) to provide clarity to
Dischargers of when sampling is required. The previous permit (Section B.5.a)
specified that sampling was required within the first hour of discharge, however, this
General Permit requires Dischargers to sample within four hours of the start of
Discharge. Many Dischargers were not able to get samples of their discharge
locations within one (1) hour under the previous permit so this general permit has
expanded the timeframe allowed to provide enough time to sample all discharge
locations. The previous permit required three working dry days before sampling and
this General Permit defines this period as 48 hours, this timeframe was decreased
to provide more opportunities for Dischargers to obtain samples. This General
Permit does not specify a volume for sampling due to the complexity of using rain
gauges and the limited access of rain gauge station data.

Dischargers are only required to obtain samples required during scheduled facility
operating hours and when sampling conditions are safe in accordance with Section
XI.C.6.a.ii of this General Permit. If a storm event occurs during unscheduled
facility operating hours (e.g. during the weekend or night) and during the 12 hours
preceding the scheduled facility operating hours, the Dischargers is still responsible
for obtaining samples at discharge locations that are still producing a discharge at
the start of facility operations. Under the previous permit, many Dischargers were
unable to obtain samples due to rainfall beginning at night.

The State Water Board recognizes that it may not be feasible for all facilities to
obtain four QSEs in a reporting year because there may not be enough qualifying
storm events to do so. Therefore, a Discharger that is unable to collect and analyze
storm water samples from two QSEs in each half of a reporting year due to a lack of
QSEs is not in violation of Section XI.B.2. Dischargers that miss four QSEs during

Order 2014-0057-DWQ 43