You are here:
Rendering hydrologic ecosystem services from urban soils: a combined field and simulation study
Citation:
Shuster, W., J. Jian, A. Bhaskar, D. Herrmann, A. Parolari, L. Schifman, AND R. Stewart. Rendering hydrologic ecosystem services from urban soils: a combined field and simulation study. Am. Geophysical Union, Washington DC,DC, December 10 - 14, 2018.
Impact/Purpose:
The process of urbanization alters soil properties under pervious surfaces (e.g., right-of-way, parks, lawns, vacant land), yet the subsequent effects on hydrologic ecosystem services such as runoff regulationare not known. If we are to make good progress in supporting the Clean Water Act and generally adjust urban ecosystems to become more infiltrative without causing unwanted side-effects, then we must then address these challenges with field-based studies that support verified models and their calibration.
Description:
The process of urbanization alters soil properties under pervious surfaces (e.g., right-of-way, parks, lawns, vacant land), yet the subsequent effects on hydrologic ecosystem services such as runoff regulation and supporting plant health are not known. Drawing on a unique urban soil taxonomic and hydrologic dataset collected in 12 cities – with each city representing a major soil order – we determined how urbanization processes altered the sequence and hydraulic properties of soil horizons (compared to pre-urbanized reference soil pedons). We then modeled the hydrologic implications of these shifts in soil properties using an unsaturated zone code (HYDRUS-1D). Simulations for each city were forced with correspondent hourly, 20-year rainfall record; evapotranspiration losses were derived from the same land-surface model. Model output included time series of cumulative surface runoff, pressure head, and soil moisture content at the depth interval of the rooting zone. The data were then transformed to frequency distributions, which revealed how urbanization affected the ability of soils to render regulating (i.e., runoff) and supporting (i.e., rooting zone soil moisture content) services. Each city had a representative response envelope that characterized differences between pre-urban reference condition and the recent past. A narrower envelope indicated more homogeneous response, and more homogenous soil hydrologic conditions, for each service offered. Looking across cities, urban soils had generated more surface runoff than reference soils. Urban soil profiles also experienced wider variations in water content, with increases in the duration of both saturated and droughty conditions compared to reference profiles. These results contribute to our understanding to what extent passive green infrastructures may feasibly and economically contribute, for example, to mitigation of urban flooding and overall improve wastewater collection system functions.