Page 91 - California Stormwater Workshop Handouts

Industrial General Permit Fact Sheet

c. NAL exceedances are solely attributable to pollutants from natural background
sources.

Information supporting the above demonstrations must be included in QISP-
prepared Level 2 ERA Technical Reports.

7. CWA section 303(d) Impairment

This General Permit requires a Discharger to monitor additional parameters if the
discharge(s) from its facility contributes pollutants to receiving waters that are listed
as impaired for those pollutants (CWA section 303(d) listings). This General Permit
lists the receiving waters that are 303(d) listed as impaired for pollutants that are
likely to be associated with industrial storm water in Appendix 3. For example, if a
Discharger discharges to a water body that is listed as impaired for copper, and the
discharge(s) from its facility has the potential sources of copper, the Discharger must
add copper to the list of parameters to monitor in its storm water discharge.

8. Design Storm Standards for Treatment Control BMPs

This General Permit includes design storm standards for Dischargers implementing
treatment control BMPs. The design storm standards include both volume- and
flow-based criteria. Dischargers are not required to retrofit existing treatment control
BMPs unless required to meet the technology-based effluent limitations and
receiving water limitations in this General Permit.

9. Qualifying Storm Event (QSE)

This General Permit defines a QSE as a precipitation event that:
a. Produces a discharge for at least one drainage area; and,

b. Is preceded by 48 hours with no discharge from any drainage area.

The definition above differs from the definition in the previous permit, resulting in an
increase number of QSEs eligible for sample collection. Therefore, most
Dischargers will be able to collect the required number of samples, regardless of
their facility location.

10. Sampling Protocols

This General Permit requires Dischargers to collect samples during scheduled
facility operating hours from each drainage location within four hours of: (1) the start
of the discharge from a QSE occurring during scheduled facility operating hours, or
(2) the start of scheduled facility operating hours if the QSE occurred in the previous
twelve (12) hours. The benefits of this sampling protocol: (a) allows a more
reasonable amount of time to collect samples, (b) increases the likelihood for
samples collected at discharge locations to be representative of the drainage area
discharge characteristics, (c) increases the number of QSEs eligible for sample
collection, and, (d) reduces the likelihood of Dischargers collecting samples with
short-term concentration spikes.

Order 2014-0057-DWQ 7