East Orange Planned Community Areas 2 and 3 and Golf Course Vol. 2 Surface Water Quality Prepared for The Irvine Community Development Company Prepared by GeoSyntec Consultants Oakland, California Portland, Oregon May 02, 2005October 1, 2004 Prepared by The Irvine Company for Consideration by the City of Orange DRAFT Table of Contents 1 Introduction................................................................................................................... 1 2 Environmental Setting.................................................................................................. 2 2.1 Physical Setting............................................................................................................... 2 2.2 Project Area Vegetation, Soils and Land Uses ............................................................... 2 2.2.1 Historical Land Uses Within the Irvine Lake Watershed ....................................... 3 2.3 Receiving Waters and Natural Drainages....................................................................... 5 2.3.1 Receiving Waters and Beneficial Uses................................................................... 5 2.3.2 Natural Drainages................................................................................................... 7 2.4 Existing Receiving Water Quality .................................................................................. 8 2.4.1 Santiago Creek Reach 3.......................................................................................... 9 2.4.2 Irvine Lake............................................................................................................ 10 3 Regulatory SettinG..................................................................................................... 12 3.1 Clean Water Act............................................................................................................ 12 3.2 MS4 Permit ................................................................................................................... 13 3.2.1 Receiving Water Limitations ................................................................................ 13 3.2.2 Technology-based Standards................................................................................ 14 3.2.3 Local Implementation Plan................................................................................... 16 3.3 NPDES Construction General Permit........................................................................... 18 3.4 General Waste Discharge Requirements for Non-Stormwater Discharges Associated with Construction........................................................................................................ 19 3.5 Basin Plan..................................................................................................................... 19 3.6 California Toxics Rule.................................................................................................. 19 4 Pollutants of Concern and Significance Criteria......................................................... 20 4.1 List of Pollutants of Concern ........................................................................................ 20 4.2 Other Pollutants............................................................................................................ 22 4.3 Hydrologic Conditions of Concern............................................................................... 23 4.4 Significance Criteria..................................................................................................... 24 4.5 Thresholds for Significance .......................................................................................... 24 5 Project Design Features .............................................................................................. 26 5.1 Site Design BMPs......................................................................................................... 26 5.2 Source Controls............................................................................................................. 28 5.3 Treatment Control BMPs.............................................................................................. 30 5.4 Golf Course PDFs......................................................................................................... 34 5.5 Hydrologic Impacts Control PDF ................................................................................. 36 6 Water Quality Modeling Approach ............................................................................ 37 6.1 Model Description........................................................................................................ 37 6.2 Pollutants Modeled....................................................................................................... 39 6.3 Pollutants Addressed Without Modeling...................................................................... 39 7 Water Quality Impact Assessment.............................................................................. 40 7.1 Impact Assessment for Modeled Pollutants of Concern............................................... 40 7.1.1 Storm Water Runoff Volumes .............................................................................. 41 7.1.2 Total Suspended Solids......................................................................................... 42 7.1.3 Nutrients................................................................................................................ 44 ii Prepared by The Irvine Company for Consideration by the City of Orange DRAFT 7.1.4 Copper, Lead, & Zinc ........................................................................................... 47 7.2 Impact Assessment for Pollutants Addressed Without Modeling ................................ 51 7.2.1 Turbidity ............................................................................................................... 51 7.2.2 Pathogens .............................................................................................................. 52 7.2.3 Hydrocarbons........................................................................................................ 54 7.2.4 Pesticides............................................................................................................... 56 7.2.5 Trash and Debris................................................................................................... 57 7.2.6 Oxygen Demanding Compounds.......................................................................... 57 7.2.7 Summary for Pollutants of Concern ..................................................................... 58 7.3 MS4 Permit Requirements for New Development as Defined in the DAMP .............. 59 7.4 Dry Weather Impacts .................................................................................................... 64 7.4.1 Dry Weather Flow Quantity.................................................................................. 64 7.4.2 Dry Weather Flow Quality.................................................................................... 65 7.5 Construction-Related Impacts....................................................................................... 66 7.6 Other Considerations.................................................................................................... 69 7.6.1 Operation and Maintenance.................................................................................. 69 7.6.2 Monitoring ............................................................................................................ 69 7.6.3 Vector Control...................................................................................................... 70 7.6.4 Pollutant Bioaccumulation.................................................................................... 73 7.6.5 Impacts to Irvine Lake as a Water Supply and Drinking Water Source............... 74 7.7 Hydrologic Impact Analysis......................................................................................... 76 7.7.1 Oak Canyon Drainages ......................................................................................... 76 7.7.2 Golf Course Spurs................................................................................................. 77 7.8 Cumulative Impact Analysis......................................................................................... 77 8 Approach for Developing Project-Specific WQMP ................................................... 78 9 Conclusions................................................................................................................. 79 10 References................................................................................................................... 81 List of Tables Table 2-1: Project Land Uses and Areas........................................................................................ 3 Table 2-2: Existing Land Uses Within and/or Near the Project ..................................................... 4 Table 2-3. Beneficial Uses of Irvine Lake...................................................................................... 6 Table 2-4: Water Quality Data Provided by Orange County Environmental Management Agency in Santiago Creek, Reach 3..................................................................................................... 9 Table 2-5: Pathogen Data Collected by the Serrano Water District Upstream of Irvine Lake.... 10 Table 2-6: Water