City of Taunton, MA Illicit Discharge Detection & Elimination Program NPDES Small MS4 General Permit June 2019 IDDE PROGRAM Illicit Discharge Detection & Elimination Program City of Taunton, MA NPDES Small MS4 General Permit IDDE PROGRAM Prepared by: BETA GROUP, INC. Prepared for: City of Taunton June 2019 Illicit Discharge Detection & Elimination Program IDDE Program City of Taunton, MA TABLE OF CONTENTS 1.0 Objective ........................................................................................................................................... 1 2.0 Definitions ......................................................................................................................................... 2 3.0 Work Completed to Date ................................................................................................................... 3 4.0 Legal Authority and Statement of IDDE Responsibilities ..................................................................... 4 5.0 Receiving Waters and Impairments.................................................................................................... 4 6.0 Prohibitions and Required Actions ..................................................................................................... 7 7.0 Allowable Non-Stormwater Discharges .............................................................................................. 7 8.0 Sanitary Sewer Overflows (SSOs) ....................................................................................................... 8 9.0 Stormwater System Mapping ............................................................................................................. 9 9.1 Phase I Mapping....................................................................................................................... 9 9.2 Phase II Mapping...................................................................................................................... 9 10.0 Outfall and Interconnection Inventory ........................................................................................... 10 11.0 Initial Ranking of Outfalls and Interconnections ............................................................................. 10 12.0 Dry Weather Outfall and Interconnection Screening and Sampling ................................................ 11 12.1 Weather Conditions ................................................................................................................... 11 12.2 General Procedure for Dry Weather Outfall Screening/Sampling ............................................... 12 12.2 Interpreting Results ................................................................................................................... 12 13.0 Total Nitrogen and Total Phosphorus Source Identification Report ................................................ 13 14.0 Follow-up Ranking of Outfalls and Interconnections ...................................................................... 14 15.0 Catchment Investigations............................................................................................................... 14 15.1 System vulnerability Identification ............................................................................................. 14 15.2 Dry weather Key Junction Manhole Inspections ......................................................................... 15 15.3 Wet Weather Investigation ........................................................................................................ 16 16.0 Identification/Confirmation of Illicit Source.................................................................................... 16 17.0 Illicit discharge removal ................................................................................................................. 17 18.0 Ongoing Screening ......................................................................................................................... 17 19.0 Training ......................................................................................................................................... 17 20.0 Citizen Call in Reports .................................................................................................................... 18 21.0 Indicators of IDDE Program Progress and Reporting ....................................................................... 18 i Illicit Discharge Detection & Elimination Program IDDE Program City of Taunton, MA LIST OF TABLES Table 1-1 IDDE Program Implementation Timeline Table 5-1 City of Taunton Waterbodies and Impairments Table 11-1 Initial Outfall Ranking Results LIST OF APPENDICES Appendix A: Stormwater Outfall Map Appendix B: Outfall & Interconnection Inventory and Priority Ranking Appendix C: IDDE Composite Ranking Map and Sampling Locations Map Appendix D: Screening/Sampling Standard Operating Procedures and Forms Appendix E: IDDE Employee Training Record ii 1.0 OBJECTIVE Taunton has developed this Illicit Discharge Detection and Elimination (IDDE) program to systematically find and eliminate potential sources of non-stormwater discharges to its municipal separate storm sewer system and implement procedures to prevent future discharges. This IDDE Plan has been developed to address Minimum Control Measure 3 requirements of the United States Environmental Protection Agency’s (USEPA’s) 2016 National Pollutant Discharge Elimination System (NPDES) General Permit for Stormwater Discharges from Small Municipal Separate Storm Sewer Systems (MS4) in Massachusetts, hereafter referred to as the “2016 Massachusetts MS4 Permit” or “MS4 Permit.” The required timeline for implementing the IDDE program is shown in Table 1-1 starting from the effective 2018 date of the NPDES Small MS4 General Permit Number [MAR041164]. Table 1-1 IDDE Program Implementation Timeline Completion Date from Effective Date of MS4 permit IDDE Program Requirements 7 10 1 Year 1.5 Years 2 Years 3 Years 4 Years Years Years Written IDDE Program Plan Complete SSO Inventory Complete Written Catchment Investigation Procedure Complete Phase I Mapping Complete Phase II Mapping (updates & added details) IDDE Regulatory Mechanism or By- law (if not already in place) Complete Dry Weather Outfall Screening Follow-up Ranking of Outfalls and Interconnections Nitrogen and Phosphorus Source Identification Report (Annual Report) Catchment Investigations – Problem Outfalls Catchment Investigations – as needed based on screening and sampling results On-going Screening and Composite Annually Sampling Training Annually To note, the City of Taunton finalized and implemented a Stormwater Management Ordinance in July 2014. 1 2.0 DEFINITIONS The following definitions are provided for terms used in this IDDE Plan. A catchment is the area that drains to an individual outfall or interconnection. Dry weather is when no more than 0.1 inches of rainfall has fallen in a 24-hour period and when significant snow melt has/is occurred. A sanitary sewer overflow (SSO) is a discharge of untreated sanitary wastewater from a municipal sanitary sewer. An illicit discharge is any discharge to a municipal separate storm sewer that is not composed entirely of stormwater, except discharges pursuant to a NPDES permit (other than the NPDES permit for discharges from the municipal separate storm sewer) and discharges resulting from firefighting activities. Illicit discharges may take a variety of forms. Illicit discharges may enter the drainage system through direct or indirect connections. Direct connections may be relatively obvious, such as cross-connections of sewer services to the storm drain system. Indirect illicit discharges may be more difficult to detect or address, such as failing septic systems that discharge untreated sewage to a ditch within the MS4, or a sump pump that discharges contaminated water on an intermittent basis. Some illicit discharges are intentional, such as dumping pollutants). Some illicit discharges are related to the unsuitability of original infrastructure to the modern regulatory environment. Elimination of some discharges may require substantial costs and efforts, such as funding and designing a project to reconnect sanitary sewer laterals. Others, such as improving self-policing of dog waste management, can be accomplished by outreach in conjunction with the minimal additional cost of dog waste bins and the municipal commitment to disposal of collected materials on a regular basis. Regardless of the intention, when not addressed, illicit discharges can contribute high levels of pollutants, such as heavy metals, toxics, oil, grease, solvents, nutrients, and pathogens to surface waters. Interconnection means the point (excluding sheet flow over impervious surfaces) where the permittee’s MS4 discharges to another MS4 or other storm sewer system, through which the discharge is conveyed to waters of the United States or to another storm sewer system and eventually to a water of the United States. Junction Manhole is a manhole or structure with two or more inlets accepting flow from two or more drainage alignments. For the purposes of this report, manholes with inlets solely from individual catch basins are not considered junction manholes. Key junction is a manhole or structure that can represent one or more junction manholes without compromising adequate implementation of the IDDE program. The MATRIX is the Outfall/Interconnection Data and Priority Ranking table MS4 is a municipal separate storm sewer system The MS4 Permit is the