City of Omaha Combined Sewer Overflow Annual Report NPDES Permit No. NE0133680 October 1, 2010 through September 30, 2011 Table of Contents I. Introduction ............................................................................................................................................. 3 II. Executive Summary ................................................................................................................................ 3 A. Nine Minimum Controls (NMC) ............................................................................................ 4 B. LTCP Documentation .............................................................................................................. 4 C. Compliance Schedule ............................................................................................................... 4 D. CSO Outfall Monitoring .......................................................................................................... 5 E. In-stream Monitoring ............................................................................................................... 5 F. Other Information .................................................................................................................... 5 III. Nine Minimum Controls ....................................................................................................................... 6 A. Proper Operation and Maintenance (O & M) ....................................................................... 6 B. Maximize Use of the Collection System for Storage ............................................................ 6 C. Review and Modification of Pretreatment Programs .......................................................... 7 D. Maximization of Flow to the POTWs for Treatment ........................................................... 8 E. Prohibition of CSOs during Dry Weather ............................................................................. 9 F. Control of Solid and Floatable Materials in CSOs ............................................................. 12 G. Pollution Prevention .............................................................................................................. 12 H. Public Notification .................................................................................................................. 13 I. Monitoring to Characterize CSO Impacts and the Efficacy of CSO Controls ................ 13 IV. LTCP Documentation ........................................................................................................................... 16 A. Characterization and Modeling of the CSO System .......................................................... 16 B. Public Participation Plan ....................................................................................................... 17 C. Consideration of Sensitive Areas ......................................................................................... 17 D. Evaluation of Alternatives..................................................................................................... 18 E. Cost/Performance Considerations ...................................................................................... 18 F. Operational Plan ..................................................................................................................... 18 G. Maximizing Treatment at the Existing POTW Treatment Facilities ................................ 18 H. Implementation Schedule...................................................................................................... 19 I. Post-Construction Compliance Monitoring Program ....................................................... 20 V. Compliance Schedule ........................................................................................................................... 22 A. Project Implementation ......................................................................................................... 22 B. LTCP Overall .......................................................................................................................... 26 VI. CSO Outfall Monitoring Data ............................................................................................................. 29 A. Missouri River Wastewater Treatment Plant (MRWWTP) - Outfall 102 ........................ 30 B. CSO Discharge Monitoring at Select Outfalls .................................................................... 30 VII. In-Stream Monitoring Data ......................................................................................................... 32 VIII. Other Information ........................................................................................................................ 35 A. Missouri River Flood ............................................................................................................. 35 B. Reduction in the Number of Overflow Events ................................................................... 37 C. Reduction in the Number of CSO Outfalls ......................................................................... 38 D. Receiving Water Quality ....................................................................................................... 38 E. City of Omaha RNC Program ............................................................................................... 40 F. Rate Information ..................................................................................................................... 41 G. Material Management ............................................................................................................ 42 Attachment 1 – SOP Reporting of Dry Weather Sewer Overflows and Bypasses ......................................... 43 Attachment 2 – Dry Weather Overflow Media Releases .................................................................................. 44 Attachment 3 – Public Participation Report ....................................................................................................... 45 Attachment 4 – LTCP Project Progress Reports ................................................................................................. 46 Attachment 5 – LTCP Project Change Documentation ..................................................................................... 47 List of Figures Figure 1: Total Projects Graph ................................................................................................................ 27 Figure 2: CSO Monitoring ....................................................................................................................... 29 Figure 3: In-Stream Monitoring ............................................................................................................. 32 Figure 4: TSS Values Compared Over Time ......................................................................................... 39 Figure 5: E.coli Values Compared Over Time...................................................................................... 39 Figure 6: E.coli Reduction over LTCP implementation ...................................................................... 40 Figure 7: Average Residential Sewer Fee Increase .............................................................................. 41 List of Tables Table 1- NPP Industries in CSS ................................................................................................................ 8 Table 2 - Dry Weather CSOs reached waters of the State .................................................................. 10 Table 3 - Dry Weather CSOs that were contained ............................................................................... 11 Table 4 - Wet Weather CSO Occurrences ............................................................................................. 14 Table 5 - Flow Monitoring Program ...................................................................................................... 17 Table 6 - Phase I Major Projects of the LTCP ....................................................................................... 23 Table 7 - Phase 2 Major Projects of the LTCP ....................................................................................... 24 Table 8 - Phase 3 Major Projects of the LTCP ....................................................................................... 24 Table 9 - Phase 1 and 2 Sewer Separation Projects .............................................................................. 25 Table 10 - Phase 3 and 4 Sewer Separation Projects ............................................................................ 26 Table 11 - Phase Milestones .................................................................................................................... 27 Table 12 - CSO 102 Monitoring Summary ............................................................................................ 30 Table 13 - CSO Monitoring ..................................................................................................................... 31 Table 14 - In-Stream Monitoring Results .............................................................................................. 34 - 2 - ___________________________________________________________________________________________________________________________ I. Introduction A National Pollutant Discharge Elimination System (NPDES) Permit (NE0133680) for City of Omaha Combined Sewer Overflows