Putting the “LID” on Water Pollution New Water Quality Requirements for Land Use County of Orange Mary Anne Skorpanich Richard Boon

Overview 1.Introduction 2.Key Terms 3.Regulatory Framework 4.WQMP Process 5.Schedule 6.Questions

Urban Runoff Effects There are four interrelated but separable effects of land-use changes on the hydrology of an area: changes in peak flow characteristics, changes in total runoff, changes in quality of water, and changes in the hydrologic amenities. --Luna Leopold, 1968

Low Impact Development: LID The low-impact development “functional landscape” emulates the predevelopment temporary storage (detention) and infiltration (retention) functions of the site. This functional landscape is designed to mimic the predevelopment hydrologic conditions through runoff volume control, peak runoff rate control, flow frequency/duration control, and water quality control. --Low Impact Development Hydrologic Analysis, The Prince George’s County DER, p.11

Water Quality Management Plan A project submittal that describes the Best Management Practices that will be implemented and maintained throughout the life of a project. Conceptual and/or Preliminary WQMPs Final Project WQMPs

Municipal Stormwater Permits Require County, OCFCD and cities to: Effectively prohibit non-stormwater discharges into the municipal drainage system Implement controls on stormwater pollution to the maximum extent practicable Prescribes a management program Drainage Area Management Plan Section Land Development Renewed in 1990, 1996, 2002, 2009

2009 Stormwater Permits: Land Development Santa Ana RegionSan Diego Region LID: On- or off-site 85th percentile storm volume capture for LID and water quality LID: On-site 85th percentile storm volume capture for LID and water quality Hydromodification: 2 year storm volume capture for discharges to susceptible channels Hydromodification: (0.1)2 year-10 year storm volume hydrograph matching

Land Development Program Revamp 2003 Stormwater Permits Priority Projects must treat the design storm runoff volume 2009 Stormwater Permits Priority Projects must retain the design storm runoff volume using LID and/or participate in alternative compliance mechanisms Priority Projects must address hydromodification

Consultation Process Permittee Advisory Group, PAG Technical Advisory Group, TAG Building industry representatives, OCBC Engineering, geotechnical, and landscape architecture professional associations Water and wastewater agencies OC Coastkeeper, Natural Resources Defense Council Federal and state regulators Meetings held October

Priority Projects (I) New development projects that create 10,000 ft 2 or more of impervious surface Automotive repair shops Restaurants where the land area of development is 5,000 ft 2 or more, including parking area Hillside developments of 5,000 ft 2 or more Parking lots of 5,000 ft 2 or more

Priority Projects (II) Impervious surface of 2,500 ft 2 or more located within, directly adjacent to, or discharging directly into receiving waters within Environmentally Sensitive Areas Streets, roads, highways, and freeways All significant redevelopment projects: the addition or replacement of 5,000 ft 2 or more of impervious surface on an already developed site Retail Gasoline Outlets

WQMP Process, North Orange County

LID Hierarchy 1.On-site Infiltration 2.On-site Evapotranspiration 3.On-site Harvest and Reuse 4.On-site Bio-treatment 5.Off-site LID 6.In-lieu fee

Developing a Project WQMP

Infiltration

Evapotranspiration, Harvest & Use, Bio-Treatment

Regional Retention

Resources

Schedule Submit Proposed Model WQMP and Technical Guidance Document to Santa Ana Regional Board (March 22, 2011) Board Approval of Model WQMP (April 22, 2011) Model WQMP implementation (August, 2011) Submit Updated Model WQMP (SUSMP) to San Diego Regional Board (December, 2011)

Questions office: hour hotline: SPILL