What Does MS4 Mean to You? A study of sewer and storm drain cross contamination Presented by Bryn Evans

What will we talk about?  A little about surface water quality regulations  What a sewer agency is doing about them The goal:  A look at future regulations  Start thinking of how MS4 might affect sewer agencies…

Cuyahoga River 1969

POTWs Industry Construction Phase I MS4s Phase II MS4s Industrial Point Sources Stormwater CWA amended (1987)

Gutters/inlets Outfalls Pipes Channels

Monitoring, Program Development Monitoring, Pilots, Program Enhancement Monitoring, Pilots, Enhancement, Implementation

 Watershed-based  Numerical goal compliance point  Bacteria is a priority pollutant

Priority Water Quality Conditions Sources Goals, Strategies, Schedules Monitoring and Assessment Adaptive Management Process  Source assessment  MS4 discharge-focused  Implementation strategies

 City of Santa Barbara Studies Bacteria in storm drain Human-specific Sewer exfiltration shown to be source (Sercu et al. 2011, ES&T)

 Evaluate small sub-watershed area  Identify potential areas of: Exfiltration –and – Infiltration  Determine frequency  Prioritize potential next step implementation

 Each phase narrows search Ph I – “Desktop” Portion (GIS, rec dwgs, CCTV) Ph II – Field Investigation (CCTV Storm Drains) Ph III – Field Testing (dye, soil, sampling) Ph IV – Pipe Repair/replacement

 Contributing Factors Pipe crossings Vertical separation Sewer pipe condition Storm drain Material/Size Soil type

Watershed Study Area Sewer Pipe Legend

 Investigate : Closed Pipe –And – Open Channels Open Channel Storm Drain Closed Channel Storm Drain Sewer Pipe Legend

Sewer Crossing Storm Drain  GIS functions  Combine sewer data to storm drain and soil data

 107 (21%) sewer pipes selected for further study  GIS/data accuracy key

 Compiled GIS data into categories  Missing Data  Use record drawings

 5 Categories, 12 sub categories  Weighted scoring

 Recent CCTV available for all mains  Identify defects relative to exfiltration

 Based on scoring matrix  Narrow search down 19 of 507 (4%) sewer pipes above storm drain 12 of 19 (2%) also cross storm drain 6 of 12 (1%) also have defect 2 of 6 (0.3%) also in sandy soil  highest rating

 Water Quality Improvement Plans required for municipalities  Bacteria is an MS4 issue Sewer exfiltration may be a source  Process available to implement cost-effective pilot study  Allows prioritization of potential sites for next step implementation

 Understand applicable MS4 water quality issues  Communicate with stormwater department/ municipal agencies  Evaluate “potential sites” for exfiltration issues  Leverage resources within/outside agency

Bryn Evans, CPSWQ Dudek