Evaluation of Solute Export of Biogeochemically Active Species in Neighborhood-Scale Semi-Arid Nested Catchments

Abstract:

Interventions in the form of green infrastructure have been increasing in semi-arid cities such as Tucson, Arizona (Elder & Gerlak, 2019). The development of observational information assessing the combined influence of the green infrastructure network on the neighborhood scale can be used to address policy-relevant questions regarding green infrastructure design and implementation goals in the region. However, the data limited nature of semi-arid urban areas hinders the ability of scientists to assess hydrologic response and shifts in water quality and solute transport resulting from green infrastructure implementation as a function of frequency and magnitude of wetting events.

This study investigates the influence of neighborhood-scale green infrastructure networks upon water quality and solute transport in a semi-arid urban nested catchment in Tucson, Arizona. In particular, this study is focused on differences in concentration and load export of biogeochemically active species within nested urban watersheds between an upstream “control” location and a downstream location that drains the control watershed and an area of elevated green infrastructure implementation. Results will be analyzed to assess the emerging influence of green infrastructure networks on solute transport in small urban streams, given heterogeneity in basin installation and performance. Initial results indicate heterogeneity of solute transport across rainfall regimes. Linear regressions developed between upstream (control) and downstream locations indicate potential solute retention for the conservative chloride tracer, as well as nitrate, nitrite, phosphate, and sulfate.