Page 195 - California Stormwater Workshop Handouts

ATTACHMENT G

REQUIREMENTS FOR DISCHARGERS WHO HAVE BEEN GRANTED AN
OCEAN PLAN EXCEPTION FOR DISCHARGES TO ASBS

Special Protections Section E.6. Flowchart to Determine
Compliance with Natural Water Quality

Compare receiving water post-storm sample concentration to
the 85% threshold of reference sample concentrations

Is post-storm Compliance with natural
concentration > water quality

85% threshold? Compliance with natural water quality

no

yes

Compare receiving water post-storm to pre-storm sample
concentration

Is post storm Receiving W ater sample similar to local
receiving water background - No Action
sample > pre-
no
storm
concentration?

yes

Resample receiving water pre- and post-storm (during the next
feasible storm event) and analyze per Water Board approval

Is post storm re- Compliance with natural water quality
sample(s)
concentration
>85% threshold? no

yes Receiving Water sample similar to local
background - No Action
Is post storm
receiving water no
sample > pre-

storm
concentration?

yes

Exceedance of natural water quality*

* When an exceedance of natural water quality occurs, the Discharger must comply with Section D. Note, when sampling
data is available, end-of-pipe effluent concentrations will be considered by the Water Boards in making this determination.

Order 2014-0057-DWQ 14