Semi-arid cities such as Tucson, Arizona are implementing solutions that capture rainwater as it falls and flows through the streets as stormwater, approaches that are collectively captured in the term green infrastructure. In the City of Tucson, green infrastructure is implemented in a decentralized manner throughout the streets of neighborhoods to reduce flooding impacts, support local plant life, and address urban heat island impacts. Taking advantage of the City of Tucson, Arizona as a living laboratory, this observational study evaluates the cumulative impact of green infrastructure installation in neighborhood streets on stormwater runoff response under varying rainfall regimes and seasonality. This observational study is strongly focused on the development and analysis of high-resolution empirical runoff datasets derived on scales typically underrepresented in data-limited semi-arid urban environments. This study discusses methods and analyses undertaken in order to understand urban hydrologic functioning at the urban subwatershed scale by comparing runoff ratios, runoff volumes, and peak discharge derived for paired events in nested watersheds in two urban neighborhoods in Tucson, Arizona. These runoff characteristics are compared across paired runoff events, and are summarized across rainfall regimes, seasonal distribution of rainfall, green infrastructure implementation levels, and land cover characteristics. Results will be analyzed to assess the emerging hydrological influence of green infrastructure networks in small urban streams, given heterogeneity in installation and performance. Results will also be used to describe influential metrics with regards to landscape composition, a continuing conundrum, which can be used in future semi-arid urban hydrological studies.
1School of Natural Resources and the Environment, The University of Arizona