URBAN STORMWATER HARVESTING: IMPLICATIONS AND STRATEGIES FOR DETENTION BASIN SOILS

Abstract

As the Southwest continues to be impacted by increasing drought stress under changing climate conditions, innovative water-harvesting strategies will become a necessary dimension of sustainable water use. The University of Arizona campus has been incorporating waterharvesting regimes within its urban landscape for over 20 years. This project explores the physical and geochemical consequences for the surface soils exposed to high volumes of stormwater discharge and contaminants found in urban runoff. Soil samples were collected from four different basin sites across the UA campus. These samples were analyzed and compared using x-ray diffraction, x-ray fluorescence, particle size analysis, and various basic chemical analyses. The samples were found to vary significantly by their relative type (basin vs. control) based on pH, LOI, and several geochemical datasets. Soils were most often significantly different relative to their specific site for geochemical and mineralogical data. Data suggest that basin properties are most dependent on the age of the basin and the type of runoff received. Observations also suggest the necessity for soil amendment to improve water and soil quality at these sites. The application of biochar at the surface of these basins has been studied for the improvement of local water collection basins.