MultiSector Influences on Urban Water Supply Across the United States

Abstract:

In the United States, and globally, the public has opposed and often defeated proposed investments in water reuse facilities for augmenting drinking water supplies. Opposition to water reuse stems partly from the notion that source water is pristine, not to be contaminated or degraded by human activity. The reality is that many cities throughout the United States draw water from highly complex watershed systems, wherein the activities of agriculture, resource extraction, power generation, and human development interact with and degrade source water. Previous research has shown that knowledge of these activities and their influence on source water can shift public attitudes on water reuse—highlighting a key role for science to provide this information. In this work we combine spatial polygons of United States urban drinking water supply catchments with geospatial layers detailing the presence of human activity—namely croplands, power plants, economic sectors, and human settlements. These data are used to characterize and cluster more than 200 United States cities according to concentrations of degraded flow reaching their municipal water supply intakes. Results highlight an enormous variety in watershed complexity—ranging from cities relying on pristine source water, to cases where almost all of the flow reaching drinking water intakes during dry months is discharge from upstream wastewater treatment facilities. We rank cities according to the level of upstream impact on water, and demonstrate how geographical factors explain many of differences in watershed complexity across the country.

In the United States, and globally, the public has opposed and often defeated proposed investments in water reuse facilities for augmenting drinking water supplies. Opposition to water reuse stems partly from the notion that source water is pristine, not to be contaminated or degraded by human activity. The reality is that many cities throughout the United States draw water from highly complex watershed systems, wherein the activities of agriculture, resource extraction, power generation, and human development interact with and degrade source water. Previous research has shown that knowledge of these activities and their influence on source water can shift public attitudes on water reuse—highlighting a key role for science to provide this information. In this work we combine spatial polygons of United States urban drinking water supply catchments with geospatial layers detailing the presence of human activity—namely croplands, power plants, economic sectors, and human settlements. These data are used to characterize and cluster more than 200 United States cities according to concentrations of degraded flow reaching their municipal water supply intakes. Results highlight an enormous variety in watershed complexity—ranging from cities relying on pristine source water, to cases where almost all of the flow reaching drinking water intakes during dry months is discharge from upstream wastewater treatment facilities. We rank cities according to the level of upstream impact on water, and demonstrate how geographical factors explain many of differences in watershed complexity across the country.