A PRELIMINARY ASSESSMENT OF WATER QUALITY AT THE RAINWATER-HARVESTING BASIN LEVEL IN AN URBAN SEMI-ARID ENVIRONMENT

Abstract

One of the anticipated benefits of green infrastructure is the capture in curb-cut basins of stormwater runoff that has accumulated urban contaminants as it runs over asphalt and pavement. These contaminants may include motor oil, pathogens, and sediments. The desert tolerant vegetation and soils within these residential rainwater-harvesting basins are expected to improve water quality by capturing these contaminants that would have otherwise flowed into local washes and recharged into the groundwater. This project reports on a preliminary comparative study of stormwater runoff quality in two Tucson washes (High School Wash and Bronx Wash) that receive runoff from neighborhoods containing rainwater-harvesting basins. The primary goal of this research project was to design a water-sampling device and protocol that accounts for variability in basins’ soil composition, successfully filters debris and soil, and collects enough sample size for water quality analysis. The secondary research goal was to conduct a preliminary comparative assessment at the neighborhood wash scales to quantify the effects of green infrastructure basins in urban areas.