Volunteer science data show degraded water quality disproportionately burdens areas of high poverty

Abstract

Anthropogenic activity degrades stream water quality, especially in urban areas. Quantified connections between pollution sources, degree of water quality degradation, and the disproportionate impact of degradation on underserved communities are not yet fully explored. Here, the anthropogenic effects on water quality and the heterogeneous distribution of degraded streams were examined in the urban watershed of the Rouge River in metropolitan Detroit, Michigan. We used benthic macroinvertebrate data collected by volunteer scientists and aggregated into a Stream Quality Index (SQI) to define long-term water quality patterns. Spatial dependence of the data was assessed with spatial stream network models incorporating socio-economic and environmental predictors. The best model included poverty as an explanatory variable with a negative relationship with stream quality. SQI predictions under true watershed conditions revealed a 1% decrease in SQI with 1% increase in poverty. This work demonstrated the benefits of volunteer science and spatial modeling methods for urban stream modeling. Our finding of inequitably distributed water quality impairment in urban streams underscores the importance of focused restoration in economically oppressed urban areas.