Page 131 - California Stormwater Workshop Handouts

Industrial General Permit Fact Sheet

method of assuring that: (1) BMPs are effective in reducing or preventing
pollutants in storm water discharge in compliance with BAT/BCT, and (2) the
discharge is not causing or contributing to an exceedance of a water quality
standards. The stakeholders state that visual observations are not effective in
measuring pollutant concentrations nor is it effective in determining the presence
of colorless and/or odorless pollutants. The stakeholders state that qualitative
monitoring (and the use of indicator parameters) will not provide results useful for
calculating pollutant loading nor will it accurately characterize the discharge.

Stakeholders in favor of requiring only visual observations state that sampling
and analysis is unnecessary because (1) the previous permit did not include
NELs so the usefulness of sampling and analysis data is limited, (2) a significant
majority of Dischargers should be able to develop appropriate BMPs without
sampling and analysis data, (3) most pollutant sources and pollutants can be
detected and mitigated through visual observations, (4) the costs associated with
quantitative monitoring are excessive and disproportionate to any benefits, (5)
U.S. EPA’s storm water regulations do not require sampling, (6) The 2008 MSGP
relies heavily on visual observations and requires only a limited number of
specific industries to conduct sampling and analysis, and (7) the majority of
Dischargers are small businesses and do not have sufficient training or
understanding to perform accurate sampling and analysis.

Stakeholders in favor of requiring both visual observations and a cost-effective
qualitative monitoring program state that (1) both are within the means and
understanding of most Dischargers, and (2) monitoring results are useful for
evaluating a Discharger’s compliance without unnecessarily increasing the
burden on the Discharger and without subjecting Dischargers to non-technical
enforcement actions.

The State Water Board finds that it is feasible for the majority of Dischargers to
develop appropriate BMPs without having to perform large amounts of
quantitative monitoring, which can be very costly. In the absence of
implementing NELs, the State Water Board has determined that the infeasibility
and costs associated with developing quantitative monitoring programs at each
of thousands industrial facilities currently permitted would outweigh the limited
benefits. The primary difficulty associated with requiring intensive quantitative
monitoring lies with the cost and the difficulty of accurately sampling industrial
storm water discharges.

Stakeholders that support quantitative monitoring believe the data is necessary
to determine pollutant loading, concentration, or contribution to water quality
violations. In order to derive data necessary to support those goals, however,
the data must be of high quality, meaning it must be accurate, precise and have
an intact chain of custody. Many industrial facilities do not have well-defined
storm water conveyance systems for sample collection. Storm water frequently
discharges from multiple locations through sheet flow into nearby streets and
adjoining properties. Sample collection from a portion of the sheet flow is an
inexact measurement since not all of the flow is sampled. Requiring every
Discharger to construct well-defined storm water conveyances may cost

Order 2014-0057-DWQ 47