Page 14 - California Stormwater Workshop Handouts

Industrial General Permit Order

cause or contribute to an exceedance of applicable water quality standards.
Water quality standards apply to the quality of the receiving water, not the
quality of the industrial storm water discharge. Therefore, compliance with
the receiving water limitations generally cannot be determined solely by the
effluent water quality characteristics. If any Discharger’s storm water
discharge causes or contributes to an exceedance of a water quality
standard, that Discharger must implement additional BMPs or other control
measures in order to attain compliance with the receiving water limitation.
Compliance with water quality standards may, in some cases, require
Dischargers to implement controls that are more protective than controls
implemented solely to comply with the technology-based requirements in this
General Permit.

F. Total Maximum Daily Loads (TMDLs)

38. TMDLs relate to the maximum amount of a pollutant that a water body can
receive and still attain water quality standards. A TMDL is defined as the sum
of the allowable loads of a single pollutant from all contributing point sources
(the waste load allocations) and non-point sources (load allocations), plus the
contribution from background sources. (40 C.F.R. § 130.2(i).) Discharges
addressed by this General Permit are considered to be point source
discharges, and therefore must comply with effluent limitations that are
“consistent with the assumptions and requirements of any available waste
load allocation for the discharge prepared by the state and approved by U.S.
EPA pursuant to 40 Code of Federal Regulations section 130.7. (40 C.F.R. §
122.44 (d)(1)(vii).) In addition, Water Code section 13263, subdivision (a),
requires that waste discharge requirements implement any relevant water
quality control plans. Many TMDLs contained in water quality control plans
include implementation requirements in addition to waste load allocations.
Attachment E of this General Permit lists the watersheds with U.S. EPA-
approved and U.S. EPA-established TMDLs that include requirements,
including waste load allocations, for Dischargers covered by this General
Permit.

39. The State Water Board recognizes that it is appropriate to develop TMDL-
specific permit requirements derived from each TMDL’s waste load allocation
and implementation requirements, in order to provide clarity to Dischargers
regarding their responsibilities for compliance with applicable TMDLs. The
development of TMDL-specific permit requirements is subject to public
noticing requirements and a corresponding public comment period. Due to
the number and variety of Dischargers subject to a wide range of TMDLs,
development of TMDL-specific permit requirements for each TMDL listed in
Attachment E will severely delay the reissuance of this General Permit.
Because most of the TMDLs were established by the Regional Water Boards,
and because some of the waste load allocations and/or implementation
requirements may be shared by multiple Dischargers, the development of
TMDL-specific permit requirements is best coordinated at the Regional Water
Board level.

Order 2014-0057-DWQ 6