A webinar will be held to present results of research conducted throughout the past several years to investigate the efficacy of real time optical sensors for predicting the level of sewage contamination in surface water. The U.S. Geological Survey and the University of Wisconsin-Milwaukee have collaborated on research to provide an efficient means to assess sewage contamination levels resulting from imperfect sewage conveyance infrastructure.

This research has focused on three different spatial scales that can be used to serve different watershed management objectives. The research has included study of large watersheds for overall assessment of sewage contamination levels on a large scale, medium sized watersheds for prioritizing areas of a watershed with the greatest sewage contributions, and small watersheds at the storm-sewer level to attempt to track contamination back to the source. At all scales, the study design included sampling of surface waters for analysis of human-associated bacteria as a confident measure of sewage contamination along with concurrent analysis of optical properties of water (fluorescence and absorbance). A relationship between sewage contamination (human-associated bacteria) with optical properties of water would allow for development of a sensor system to predict sewage contamination in real time. Such a relationship would allow for more rigorous assessment of presence, variability, magnitude, and loading contributions of sewage that is currently possible.

The webinar will provide an overview of the challenges associated with detecting sewage contamination in environmental waters, general contamination levels detected in different geographic, seasonal, and hydrologic situations, and the relationships found between human-associated bacteria and optical properties of water, and the strengths and weaknesses of these relationships in the three different spatial scales.


  • Sandra L. McLellan, PhD, Great Lakes Water Institute, School of Freshwater Sciences, University of Wisconsin-Milwaukee
  • Steven R. Corsi (moderator), Research Hydrologist, Upper Midwest Water Science Center, U.S. Geological Survey

There will be 1.5 Professional Development Hours (PDHs) offered for this webcast. Please check with your state accreditation agency to determine if you qualify. The PDH instructions will be sent to all attendees 24 hours after the webcast has ended.

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