The document provides an update on water quality studies being conducted to develop a Long Term Control Plan for combined sewer overflows (CSOs) as required by a consent decree. Flow monitoring and water quality sampling have been completed, and hydraulic and water quality models are being developed and calibrated to assess CSO impacts and evaluate control alternatives. Key accomplishments include characterizing system flows, monitoring water quality during rain events, and developing preliminary hydraulic models of the sewer system. Upcoming steps involve further refining the models and using them to identify long term CSO control options.

1. Water Quality Update Presented to CPAC January 12, 2003

2. Objectives of Presentation How tasks fit together to support the Long Term Control Plan What has been accomplished

3. Tools to Understand CSO Impacts Flow Characterization System Characterization and Flow Metering Hydraulic Sewer Model Water Quality Study Water Quality Model Long Term Control Plan

4. Consent Decree Requirements All study efforts required by consent decree CD included specific items each study must include Study work plans were approved April 7, 2003 Reports for Flow Characterization and Water Quality Study are due in April 2004. Long Term Control Plan Report due October 2005.

5. System Characterization

6. Flow Metering

7. Hydraulic Sewer Modeling

8. Water Quality Study

9. Water Quality Model

10. Long Term Control Plan

11. How Monitoring/ Models Are Used in Long Term Control Planning Monitoring Shows current conditions Helps identify unusual operating conditions Provide data to make sure models make sense Models Fill in the gaps where we can’t monitor Predicts what will happen with different rainfall conditions Allows evaluation of changes to the system

12. 2003 Flow Metering Locations

13. 2003 Flow Metering Program Meter Installation Meters Installed May through August Site Visits – Site Check/Data Download weekly

14. Metering Locations – data set

15. Data Set 1999 City-wide Flow Monitoring Study – 48 meters SCADA data – 47 data collection locations 2003 Data – 36 metering locations Point Place - __ metering locations Overall – 130+ metering locations with consistent data analysis techniques

16. 2003 Metering Period Rain Events Several Rain Events Greater than One Inch 88% 1.07 May 31, 2003 91% 3.57 September 1, 2003 73% 2.66 August 3, 2003 97% 1.58 July 7, 2003 97% 1.36 June 11, 2003 42% 2.01 May 9, 2003 Percentage of Meters Recording Data Amount of Rain (inches) Date of Wet Weather Event

17. Sanitary Area Flow Contributions Percent Capture – 1999 and 2003

18. Sanitary Area Flow Contributions Peaking Factor – 1999 and 2003

19. Sanitary Area Flow Contributions Separated portions of the sewer system will contribute significant flow in wet weather. There are a number of very wet areas of the system where flow reduction work is encouraged The sanitary flow rates during wet weather are important to consider in evaluating CSO control alternatives and the overall impact on the plant

20. Combined Area Flow Contributions Combined Area Flow (Hydrologic) Response This is a critical parameter for modeling. Values fall within typical ranges 73% of Combined Area Monitored

21. Estimated Capture Rates 2003

22. Combined Flow Summary Data collected to calibrate model Ability of flow to be delivered to the interceptor varies significantly by regulator Variability in frequency of discharge Overloading of interceptor system

23. Windermere Pump Station 9/1/03 Response

26. System Hydraulics - observations The system backs up during wet weather events The majority of the back up seems to start at the WWTP Because of the backups, flow reverses direction in the sewers. More overflow to the waterways also occurs.

27. System Hydraulics - consequences Once the WWTP can process more flow System backup should be reduced Less CSO discharge to the waterways Less risk of basement backup

28. Water Quality Study Instream (CSO Area) Dry weather sampling (2 events) Wet weather sampling (2 events) Upstream Boundary (Watershed) Dry/wet, 17 weekly sampling events Intensive DO Monitoring Two 2-week periods

29. 2003 Sampling Locations

30. Wet Weather Event Monitoring May 1, 2003: Fast-moving spring storm (shown) 0.6” at Toledo Express CSO duration ~ 2 hours September 1, 2003 Slower-moving late summer storm 2.6” at Toledo Express CSO duration ~ 14 hours

31. WW Monitoring Results - Bacteria Ottawa River: WW1 – low concentrations, dominated by upstream WW2 – high upstream + significant in-stream contribution Decreased concentrations downstream due to Maumee Bay mixing Primary Contact Recreational Standard Primary Contact Recreational Standard

32. WW Monitoring Results – Dissolved Oxygen Maumee River WW1 – Aeration elevates DO WW2 – CSOs also reduce downstream DO

33. Consent Decree Requirements – Hydraulic Sewer Model Workplan, approved April 7, 2003 Develop sewer model to predict: Flows Hydraulic grade lines and capacities CSO frequencies and volumes Use in conjunction with WQ model to support Long Term Control Plan

34. Hydraulic Model Coverage

35. Status of Hydraulic Model East Side model is operational Calibrated to 2003 metering data Calibration is preliminary, pending: West Side and 10-Mile Creek calibrations - consistency Runs with complete model - reasonableness West Side calibration not far behind 10-Mile Creek to be calibrated in December

36. East Side Hydraulic Submodel

37. Calibration to 2003 Metering Data Also important to accurately estimate flows to interceptor (example: Eastside Interceptor)

38. Consent Decree Requirements – WQ Model Workplan, approved April 7, 2003 Model shall be capable of: Accurately modeling WQ in the 3 streams Under wide range of conditions Assessing impacts of CSOs on WQ Assessing changes in CSO impact due to Long Term Control measures under evaluation

39. Summary Flow Characterization Study - close to completion Water Quality Study - on schedule Hydraulic Model - on schedule about ready to use Water Quality Model – will build off of hydraulic model Long Term Control Plan – will use the models as tools to develop alternatives

40. Next Steps Long Term Control Plan – begin evaluation of alternatives Gather input from stakeholders and the general public