Speaker: Kylie Boenisch-Oakes, EVEN PhD Candidate, Masters group

Topic: ReSource Tracker: An Open-Source Approach to Tracking Treated Wastewater Effluent in Streams with Applications to Environmental Justice

Abstarct: Treated wastewater effluent increasingly shapes both surface water quantity and quality, yet screening tools that quantify its prevalence (occurrence of effluent in a stream) and severity (percent contribution of effluent to a stream) and support equity-focused decisions remain limited. This work presents ReSource Tracker, an open-source geospatial model and interactive web tool that estimates monthly percent wastewater (%WW) in Colorado streams by combining National Hydrography Dataset Plus High Resolution (NHDPlus HR) river networks, United States Geological Survey (USGS) stream gages, and facility-level effluent flows. Wastewater discharges were accumulated and paired with either gage-based or NHDPlus-based data for streamflow to compute %WW for every stream and month. Model outputs were validated through field measurements including parameters like dissolved organic carbon, conductivity, and nutrients. There was good agreement with model estimates to field data in both magnitude and seasonality. By linking %WW to census tracts and Climate and Economic Justice Screening Tool (CEJST) indicators, the model also quantified how wastewater prevalence and severity vary with rurality, poverty, race/ethnicity, and other environmental burdens. ReSource Tracker provides a transparent, scalable method that can be employed by utilities, regulators, or researchers to support environmental-justice focused decision-making regarding wastewater-impacted surface waters.