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Stormwater C.3 Guidebook. 6 th Edition. CCCWP Management Committee February 15, 2012. Topics. Brief Guidebook History Key Changes from 5 th Edition Ongoing Issues Recommended Action. Guidebook History. 6 th Edition. Special Projects Table 4-14 on Page 60
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Stormwater C.3 Guidebook 6th Edition CCCWP Management CommitteeFebruary 15, 2012
Topics • Brief Guidebook History • Key Changes from 5th Edition • Ongoing Issues • Recommended Action
6th Edition • Special Projects • Table 4-14 on Page 60 • Narrative Analysis of Feasibility of LID on Special Projects (Instructions are in Guidebook but need to reference these instructions in template) • Technical Criteria for non-LID Facilities (in preparation; to be posted to website)
6th Edition • Harvesting and Reuse • Feasibility Screening Procedure on Page 40-42 • Background on Page 17 • Underdrain discharge located at top of gravel layer unless infiltration must be prevented
6th Edition • Soils, Plants, and Irrigation • Updated Appendix B • Incorporates MRP “Attachment L”
Template • Follows organization and content of guidance in Chapter 3 • Annotated with explanations and prompts • Prompts Harvesting and Use Feasibility Calculations • Prompt for feasibility narrative to be added • Supports presentation of sizing calculations in Chapter 4 • Substitute for, or check, results of IMP Sizing Calculator • Includes a project data summary to facilitate compilation of reports
Ongoing Issues • Hydrograph Modification Management • Report and proposal due April 2013 • Present model verification monitoring results demonstrating that the IMPs are sufficiently overdesigned and perform to meet the 0.1Q2 low flow design criteria; or • Present study results of Contra Costa County streams geology and other factors that support the low flow design criteria of 0.2Q2 as the limiting HMP design low flow; or • Propose redesigns of the IMPs to meet the low flow design criteria of 0.1Q2 to be implemented during the next permit term. • Awaiting news on Prop. 84 grant application • Data will also be relevant re: infiltrationand evapotranspiration requirements
Ongoing Issues • Feasibility/Infeasibility of Infiltration, Evapotranspiration, and Harvesting/Reuse • Response to Water Board staff comments on BASMAA submittal is pending BASMAA Board approval • Report on implementation experience is due December 1, 2013 • Documenting harvesting/reuse projects is important
Recommendations • Approve the Stormwater C.3 Guidebook6th Edition and direct staff to publish it and the template on the Program website. • Direct staff to prepare and publish a new 2-page “Stormwater C.3 Update” summarizing policy changes
Provision C.3 Reporting Annual and “Special Projects” CCCWP Management CommitteeFebruary 15, 2012
Special Projects Reporting • Narrative discussion of onsite LID feasibility • Infiltration, evapotranspiration, harvesting/reuse per Stormwater C.3 Guidebook 6th Edition • Description of site and DMAs • Need for pavement where proposed • Why any landscaped areas can’t be bioretention • Narrative discussion of offsite LID feasibility • Owner owns land in same watershed? • In-lieu program exists? • Technical Criteria for Non-LID Facilities • Reference an existing certification program, or • Prepare our own minimum design criteria?