Characterization of DOC in "Accidental" Urban Wetlands in Phoenix, AZ

Accidental wetlands have been created on the bed of the Salt River and are fed by storm-water outfalls discharging at various sections of the Phoenix Metropolitan Area. Water discharges from these outfalls throughout the year, during both dry conditions (base flow) and during rain events (storm flow). In this study, DOC content and composition was studied during these two flow conditions, in the outfalls and along the wetland flow path. The importance of DOC lies in its role in transporting carbon via water movement, between different parts of a landscape, and therefore between pools in the ecosystem. Urbanization has influenced content and composition of DOC entering the accidental urban wetland via outfalls as they represent watersheds from different areas in Phoenix. First, DOC load exhibited higher quantities during stormflow compared to baseflow conditions. Second, DOC load and fluorescence analysis outcomes concluded the outfalls are different from each other. The inputs of water on the north side of the channel represent City of Phoenix watersheds were similar to each other and had high DOC load. The northern outfalls are both different in load and composition from the outfall pipe on the southern bank of the wetland as it represents South Mountain watershed. Fluorescence analysis results also concluded compositional changes occurred along the wetland flow path during both stormflow and baseflow conditions. In this study, it was explored how urbanization and the associated changes in hydrology and geomorphology have affected a desert wetland's carbon content.