Countywide Model Countywide Model SUSMPSUSMP

July 17, 2008July 17, 2008

TopicsTopics

SUSMP TimelineSUSMP Timeline

GoalsGoals

Approach to ComplianceApproach to Compliance NPDES Permit RequirementsNPDES Permit Requirements Model SUSMP FeaturesModel SUSMP Features

Model SUSMP TimelineModel SUSMP Timeline12/0612/06 Bay Area presentations to Hydromodification Work GroupBay Area presentations to Hydromodification Work Group

5/075/07 Consultant team selectedConsultant team selected

10/0710/07 Discussed Proposed SUSMP Approach with Discussed Proposed SUSMP Approach with Hydromodification Work GroupHydromodification Work Group

11/0711/07 Prepared interim updates to Model SUSMPPrepared interim updates to Model SUSMP

2/082/08 Presented SUSMP Approach to TAC and Water BoardPresented SUSMP Approach to TAC and Water Board

3/083/08 Presented SUSMP Approach to Development CommunityPresented SUSMP Approach to Development Community

4/084/08 Received task order to prepare the SUSMPReceived task order to prepare the SUSMP

5/085/08 Discussed detailed outline and principal issues with Discussed detailed outline and principal issues with Hydromodification Work GroupHydromodification Work Group

6/086/08 Drafts dated June 12 and June 26Drafts dated June 12 and June 26

7/087/08 July 16 draft and July 24 submittalJuly 16 draft and July 24 submittal

Goals for SUSMPGoals for SUSMP

Make it easier for applicants to Make it easier for applicants to prepare submittalsprepare submittals

Make it easier for municipal staff Make it easier for municipal staff to review submittals for complianceto review submittals for compliance

Promote consistent and fair Promote consistent and fair implementation countywideimplementation countywide

Integrate LID, treatment, and hydrograph Integrate LID, treatment, and hydrograph modification management requirementsmodification management requirements

SUSMP Compliance ApproachSUSMP Compliance Approach

Comply with new requirements:Comply with new requirements: Low Impact DevelopmentLow Impact Development TreatmentTreatment Hydromodification managementHydromodification management

Provide options and flexibilityProvide options and flexibility MunicipalitiesMunicipalities DevelopersDevelopers

Create option to use integrated design approach Create option to use integrated design approach Promote consistent and complete presentation Promote consistent and complete presentation of design information and calculationsof design information and calculations

Low Impact Development Low Impact Development D.1.d.(4)D.1.d.(4)

NPDES Permit:NPDES Permit: Use LID site design principlesUse LID site design principles Drain a portion of impervious areas to pervious areasDrain a portion of impervious areas to pervious areas Use permeable surfacesUse permeable surfaces

Model SUSMP—LID Design GuideModel SUSMP—LID Design Guide Guidance for applying site design principles and Guidance for applying site design principles and

using pervious pavementsusing pervious pavements Divide the site into Drainage Management AreasDivide the site into Drainage Management Areas Identify surface cover for each DMAIdentify surface cover for each DMA Account for drainage from each DMAAccount for drainage from each DMA Design criteria for LID features and facilitiesDesign criteria for LID features and facilities Design recommendations learned from experienceDesign recommendations learned from experience

Treatment Controls Treatment Controls D.1.d.(6)D.1.d.(6)

NPDES PermitNPDES Permit Infiltrate, filter, or treat flow from all developed Infiltrate, filter, or treat flow from all developed

portions of the projectportions of the project Select more effective controls including bioretentionSelect more effective controls including bioretention Correctly size and design to achieve MEPCorrectly size and design to achieve MEP

Model SUSMPModel SUSMP LID Design Guide ensures integrated LID design LID Design Guide ensures integrated LID design

meets treatment criteriameets treatment criteria SUSMP specifies selection and design criteria if SUSMP specifies selection and design criteria if

applicant chooses not to use the integrated approach applicant chooses not to use the integrated approach

Hydromodification Hydromodification (D.1.d.10)(D.1.d.10)

NPDES Permit:NPDES Permit: Apply criteria so runoff rates, durations, and Apply criteria so runoff rates, durations, and

velocities are controlled (all projects)velocities are controlled (all projects) Interim criteria for projects 50 acres and upInterim criteria for projects 50 acres and up To be superseded by HMP To be superseded by HMP (D.1.g.)(D.1.g.)

Model SUSMPModel SUSMP Integrated LID design controls runoff ratesIntegrated LID design controls runoff rates Facility designs will be updated for HMPFacility designs will be updated for HMP Option to perform continuous simulationOption to perform continuous simulation

Source Controls Source Controls (D.1.d.(5))(D.1.d.(5))

NPDES Permit:NPDES Permit: Implement source control BMPs to minimize Implement source control BMPs to minimize

pollutants of concernpollutants of concern

Model SUSMP:Model SUSMP: Appendix lists sources to be controlled and Appendix lists sources to be controlled and

specifies the control measures to be usedspecifies the control measures to be used

Implementation Process Implementation Process (D.1.d.(9))(D.1.d.(9))

NPDES Permit:NPDES Permit: Each Copermittee shall implement a processEach Copermittee shall implement a process Identify measures necessary for implementationIdentify measures necessary for implementation

Model SUSMP:Model SUSMP: Acknowledges each municipality will apply Acknowledges each municipality will apply

their own requirementstheir own requirements Provides a general model for preparing Provides a general model for preparing

project submittalsproject submittals Facilitates countywide consistency and Facilitates countywide consistency and

streamlined reviewsstreamlined reviews

Pollutants of Concern Pollutants of Concern (D.1.d.(3))(D.1.d.(3))

NPDES PermitNPDES Permit Local SUSMPs shall include a procedure to identify Local SUSMPs shall include a procedure to identify

Pollutants of ConcernPollutants of Concern

Model SUSMPModel SUSMP Pragmatic approachPragmatic approach Identify Pollutants of Concern countywideIdentify Pollutants of Concern countywide Specify practicable and effective Specify practicable and effective

source controls and treatment controlssource controls and treatment controls Allow for rare circumstances when controls should be Allow for rare circumstances when controls should be

tailored to land use or watershedtailored to land use or watershed

SummarySummary

Pro-active approach to compliance with Pro-active approach to compliance with new NPDES Permit requirementsnew NPDES Permit requirementsFlexibility for municipalities and developersFlexibility for municipalities and developersDetailed support for an integrated design Detailed support for an integrated design option applicable to most developmentsoption applicable to most developmentsPromotes consistency and streamlined Promotes consistency and streamlined preparation and review of submittalspreparation and review of submittalsIncorporates design knowledge and Incorporates design knowledge and lessons learned from LID implementationlessons learned from LID implementation