Narragansett Bay Commission CSO Phase I
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Narragansett Bay Commission Evaluation of CSO Phase I Project: Water Quality Outcomes Prepared by the Staff of the Division of Planning, Policy & Regulation April 21, 2016 Narragansett Bay Commission Mission Statement: To maintain a leadership role in the protection and enhancement of water quality in Narragansett Bay and its tributaries by providing safe and reliable wastewater collection and treatment services to its customers at a reasonable cost. Page left blank intentionally ACKNOWLEDGEMENTS This report was written by Pamela J. Reitsma, Christine Comeau, Catherine Oliver and Eliza Moore, NBC Environmental Scientists, who also performed the extensive data analysis needed to complete this report. This report was produced for Thomas Brueckner, Engineering Manager. The report was also edited and the project completed under the general direction of Thomas P. Uva, Planning, Policy & Regulation Director. John E. Motta, Environmental Monitoring & Data Analysis (EMDA) Manager, is acknowledged for his guidance and assistance in preparing this report and James Kelly, EMDA Assistant Manager is acknowledged for writing sections of this report and preparing GIS graphics, as well as for his assistance and support. John Zuba, Permits Manager, is recognized for his guidance and encouragement and Steve Lallo, Permits Coordinator, is acknowledged for sharing his knowledge on stormwater, as well as graphics support. Rebecca Songolo, EMDA Monitoring Field Supervisor, is recognized for aiding in preparing data sets. A special acknowledgement to the entire staff of the EMDA Section, as their hard work each and every day has allowed the NBC to successfully complete water quality sampling throughout the NBC service district: Sara Nadeau, Rebecca Songolo and Jeffrey Tortorella Monitoring Field Supervisors Joseph Caranci, Stephen DePasquale, Michael Giammarco, Michael Golenia, Fern Johnson, Amanda Kezirian, David Thacker and Kevin Wilcox Environmental Monitors Joanne Parker and Brandi-Lynn Colacone Olga Shirzadi and Ashley Petteruto EMDA Data Assistants EMDA Clerks Walter Palm, Laboratory Manager, and the entire Laboratory Staff are recognized for their exemplary quantitative and qualitative analysis of each water quality sample: Angelina Glater Assistant Laboratory Manager Edward Davies Elizabeth Teixeira Lab Sample Compliance Coordinator Senior Environmental Chemist Lauren Lessuck Nora Lough Senior Organic Chemist Biologist Janet Luu and Ryan Sullivan Kim Sandbach and Kara Taglianetti Environmental Chemists Chemists Leslie Ahlborg, William Beaudry, Kerri Houghton, Robert Noonan and Ralph Ruggiano, Jr. Laboratory Technicians Katherine Archambault Laboratory Clerk Kimberly Kirwan, Planning, Policy & Regulation Administrative Assistant, is recognized for her assistance on all aspects of report preparation and finalization. Pamela Ciolfi, Engineering Administrative Assistant, is acknowledged for her assistance in the final formatting of the original report. Terri Breeden, EMDA Data Assistant, is recognized for her thorough editing and formatting assistance. Page left blank intentionally Table of Contents List of Figures ............................................................................................................................................... vii List of Tables ................................................................................................................................................. x Executive Summary ....................................................................................................................................... 1 Chapter I – Introduction ................................................................................................................................ 5 Narragansett Bay Commission Service Area .............................................................................. 5 The NBC Collection System ....................................................................................................... 6 NBC Combined Sewer Overflow Abatement Program Overview .............................................. 7 NBC CSO Abatement Program Goals ...................................................................................... 13 Field’s Point Wastewater Treatment Facility Upgrades ........................................................... 14 Bucklin Point Wastewater Treatment Facility Upgrades .......................................................... 14 Report Overview ....................................................................................................................... 15 Chapter II – Change in Wet Weather Discharges from NBC Treatment Facilities ...................................... 17 Methods ..................................................................................................................................... 17 Results ....................................................................................................................................... 17 Field’s Point Wastewater Treatment Facility ...................................................................................... 17 Bucklin Point Wastewater Treatment Facility .................................................................................... 19 Results Summary....................................................................................................................... 21 Chapter III – Combined Sewer Overflow and Stormwater Sampling.......................................................... 23 Combined Sewer Overflow Sampling ...................................................................................... 23 Monitoring & Analytical Methods ...................................................................................................... 23 Results ................................................................................................................................................. 25 Results Summary ................................................................................................................................. 27 Stormwater Sampling ................................................................................................................ 28 Monitoring & Analytical Methods ...................................................................................................... 28 Results ................................................................................................................................................. 29 Results Summary ................................................................................................................................. 31 Chapter IV – Effect of Phase I CSO Tunnel on Pollutant Loadings .............................................................. 33 Pre-Phase I CSO Pollutant Loads.............................................................................................. 33 Post-Phase I Pollutant Loads ..................................................................................................... 33 Results Summary....................................................................................................................... 35 v Chapter V – Evaluation of Bacterial Contamination in Rivers ..................................................................... 37 Monitoring & Analytical Methods ............................................................................................ 37 Results ....................................................................................................................................... 41 Dry Weather Overflows ...................................................................................................................... 41 Urban Rivers ........................................................................................................................................ 41 Results Summary....................................................................................................................... 67 Chapter VI – Evaluation of Bacterial Contamination in the Providence and Seekonk Rivers ..................... 69 Monitoring & Analytical Methods ............................................................................................ 69 Providence River Results .......................................................................................................... 72 Providence River Fecal Coliform Results ............................................................................................. 72 Providence River Enterococci Results ................................................................................................. 82 Seekonk River Results .............................................................................................................. 87 Seekonk River Fecal Coliform Results ................................................................................................. 87 Seekonk River Enterococci Results ..................................................................................................... 94 Documented Benefits of Improved Upper Bay Water Quality ................................................. 94 Results Summary....................................................................................................................... 99 Providence River Fecal Coliform ......................................................................................................... 99 Providence River Enterococci ..........................................................................................................