New York City Department of Combined Sewer Overflow Environmental Protection Long Term Control Plan for Capital Project No. WP-169 Alley Creek and Little Neck Bay Long Term Control Plan II November 2013 TABLE OF CONTENTS CSO Long Term Control Plan II Long Term Control Plan Alley Creek and Little Neck Bay TABLE OF CONTENTS EXECUTIVE SUMMARY ........................................................................................................................ ES-1 1.0 INTRODUCTION ............................................................................................................ 1-1 1.1 Goal Statement ................................................................................................................ 1-1 1.2 Regulatory Requirements (Federal, State, Local) ........................................................... 1-2 1.3 LTCP Planning Approach ................................................................................................ 1-3 2.0 WATERSHED/WATERBODY CHARACTERISTICS .................................................... 2-1 2.1 Watershed Characteristics ............................................................................................... 2-1 2.2 Waterbody Characteristics ............................................................................................. 2-33 3.0 CSO BEST MANAGEMENT PRACTICES .................................................................... 3-1 3.1 Collection System Maintenance and Inspection Program ............................................... 3-2 3.2 Maximizing Use of Collection System for Storage ........................................................... 3-3 3.3 Maximizing Wet Weather Flow to WWTPs ...................................................................... 3-3 3.4 Wet Weather Operating Plan ........................................................................................... 3-3 3.5 Prohibition of Dry Weather Overflows .............................................................................. 3-4 3.6 Industrial Pretreatment Program ...................................................................................... 3-4 3.7 Control of Floatable and Settleable Solids ....................................................................... 3-4 3.8 Combined Sewer Replacement ....................................................................................... 3-5 3.9 Combined Sewer Extension ............................................................................................. 3-5 3.10 Sewer Connection and Extension Prohibitions ................................................................ 3-5 3.11 Septage and Hauled Waste ............................................................................................. 3-5 3.12 Control of Runoff .............................................................................................................. 3-6 3.13 Public Notification ............................................................................................................. 3-6 3.14 Characterization and Monitoring ...................................................................................... 3-6 3.15 CSO BMP Report Summaries ......................................................................................... 3-6 4.0 GREY INFRASTRUCTURE ........................................................................................... 4-1 4.1 Status of Grey Infrastructure Projects Recommended in Facility Plans .......................... 4-1 4.2 Other Water Quality Improvement Measures Recommended in Facility Plans (dredging, floatables, aeration) ........................................................................................ 4-1 4.3 Post-Construction Monitoring ........................................................................................... 4-2 5.0 GREEN INFRASTRUCTURE ........................................................................................ 5-1 5.1 NYC Green Infrastructure Plan (GI Plan)......................................................................... 5-1 5.2 Citywide Coordination and Implementation ..................................................................... 5-1 5.3 Completed Green Infrastructure Projects to Reduce CSOs (Citywide and Watershed-Specific) ......................................................................................................... 5-3 5.4 Future Green Infrastructure in the Watershed ................................................................. 5-8 6.0 BASELINE CONDITIONS AND PERFORMANCE GAP ............................................... 6-1 6.1 Define Baseline Conditions .............................................................................................. 6-1 6.2 Baseline Conditions - Projected CSO Volumes and Loadings after the Facility Plan and GI Plan ...................................................................................................................... 6-4 6.3 Performance Gap ........................................................................................................... 6-12 i of vi CSO Long Term Control Plan II Long Term Control Plan Alley Creek and Little Neck Bay 7.0 PUBLIC PARTICIPATION AND AGENCY COORDINATION ....................................... 7-1 7.1 Local Stakeholder Team ............................................................................................................... 7-1 7.2 Summaries of Stakeholder Meetings ............................................................................... 7-2 7.3 Coordination with Highest Attainable Use ....................................................................... 7-4 7.4 Internet Accessible Information Outreach and Inquiries .................................................. 7-4 8.0 EVALUATION OF ALTERNATIVES ............................................................................. 8-1 8.1 Considerations for LTCP Alternatives under the Federal CSO Policy ............................. 8-1 8.2 Matrix of Potential CSO Reduction Alternatives to Close Performance Gap from Baseline ........................................................................................................................... 8-7 8.3 CSO Reductions and Water Quality Impact of Retained Alternatives ........................... 8-23 8.4 Cost Estimates for Retained Alternatives ...................................................................... 8-31 8.5 Cost-Attainment Curves for Retained Alternatives ........................................................ 8-34 8.6 Use Attainability Analysis (UAA) .................................................................................... 8-42 8.7 Water Quality Goals ....................................................................................................... 8-44 8.8 Recommended LTCP Elements to Meet Water Quality Goals ...................................... 8-45 9.0 LONG TERM CSO CONTROL PLAN IMPLEMENTATION .......................................... 9-1 9.1 Adaptive Management (Phased Implementation) ............................................................ 9-1 9.2 Implementation Schedule ................................................................................................ 9-3 9.3 Operation Plan/O&M ........................................................................................................ 9-3 9.4 Projected Water Quality Improvements ........................................................................... 9-4 9.5 Post Construction Monitoring Plan and Program Reassessment .................................... 9-4 9.6 Consistency with Federal CSO Policy ............................................................................. 9-4 9.7 Compliance with WQ Goals ............................................................................................. 9-4 10.0 REFERENCES ............................................................................................................. 10-1 11.0 GLOSSARY ................................................................................................................. 11-1 APPENDICES Appendix A: Long Term Control Plan (LTCP) Alley Creek Kickoff Meeting - Summary of Meeting and Public Comments Received Appendix B: Long Term Control Plan (LTCP) Alley Creek Public Meeting #2 - Summary of Meeting and Public Comments Received Appendix C: Summary of Public Comments Received via Email and DEP Responses Appendix D: Alley Creek Use Attainability Analysis Appendix E: SPDES Variance LIST OF TABLES Table ES-1. Alley Creek and Little Neck Bay Alternatives Summary .................................................... ES-2 Table ES-2. Alley Creek and Little Neck Bay Alternatives Summary .................................................. ES-13 Table 1-1. 2012 DEC 303(d) Impaired Waters Listed and Delisted (with Source of Impairment) ......... 1-2 Table 2-1. Land Use within the Alley Creek and Little Neck Bay Drainage Area .................................. 2-4 Table 2-2. Comparison of Rainfall Years for Collection System Modeling .......................................... 2-11 Table 2-3. Tallman Island WWTP Drainage Area(1): Acreage Per Sewer Category ............................ 2-13 Table 2-4. Tallman Island WWTP Drainage Area: Acreage By Outfall/Regulator ............................... 2-13 Table 2-5. Sanitary and Stormwater Discharge Concentrations, Tallman Island WWTP .................... 2-22 Table 2-6. Stormwater Discharge Concentrations, Nassau County .................................................... 2-23