Stormwater Permit Renewal Update

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~' :~"~'~1 the program shall provide for opportunities such as off site mitigation (banking) or J a payment in lieu program. Hydromodification and Stormwater Retrofits Assessment Stormwater retrofits help improve water quality by providing stormwafer treatment in locations where practices pceviously didn't exist or were ineffective. Hydromodification assessments will help define stormwater flow and volume-related 'impacts to local receiving streams and propose management objectives and pertormance criteria designed to minimize those impacts. Permit language that requires these assessments will compliment the water quality and quantity performance standards discussed above and will give DEQ some of the information necessary to provide program oversight and continue the development of pertormance standards in future permit iterations (fourth generation). Anticipated Permit Language Permittees will be required to conduct a hydromodification assessment no later than the third year of the permit and a retrofit assessment no later than the fourth year of the permit. . With respect to the Hydromodification assessment, the permittees will be required to use a systematic approach to: ^ Assess watersheds within the MS4 for stream hydromodification impacts. ^ Prioritize hydromodification control strategies. • Prioritize hydromodification control areas. ^ Develop appropriate management objectives and pertormance criteria. ~r~ ~~, With respect to the Stormwater Retrofit Assessment, the permittees will be required to use a systematic approach to: • Define retrofitting objectives • Identify potential retrofit locations • Define the preferred treatment options • C~eate a retrofit project priority list ~ Water Qualitv Monitorinq The current MS4 permits (except Salem and Eugene) include specific, prescriptive monitoring requirements,as well as objective-oriented, narrative monitoring requirements. The monitoring requirements were "brought in" to the permit from the permittees Stormwater Management Plans. (SWMP) and are simply a reflection of the monitoring commitments made by the permittees in 2004/2005. The permittees current monitoring programs are diverse, with different parameters being analyzed and varying levels of effort. The current monitoring requirements are inflexible due to the fact that they become °fixed" when they are included in Schedule B of the MS4 permits. For the next round of permits DEQ is focusing on simplifying and clarifying the monitoring requirements and structuring the requirements in a way that allows for adaptive management during the permit cycle: Monitoring-related permit conditions will include specific "core" instream and MS4 monitoring requirements. Permittees' SWMPs will build on the basic permit requirements by describing how the permittees will implement and adaptively manage a monitoring program that achieves the narratiVe monitoring requirements contained in the permit. In January, 2008, DEQ outlined the proposed monitoring strategy4 for the permittees and asked °"DEQ T'houghts on Monitoring" PowerPoint presentation. Presented at the 1/10/08 ACWA Stormwater Renewal Subcommittee Meeting. 3