Urban water storage capacity inferred from observed evapotranspiration recession
- 1Hydrology and Quantitative Water Management Group, Wageningen University, Wageningen, The Netherlands. (harro.jongen@wur.nl)
- 2Meteorology and Air Quality Group, Wageningen University, Wageningen, The Netherlands.
- 3School of Agriculture and Environment, University of Western Australia, Crawley, Australia.
- 4Department of Meteorology and Climatology, Faculty of Geographical Sciences, University of Lodz, Lodz, Poland.
- 5Department of Atmospheric Sciences, Yonsei University, Seoul, South Korea.
- 6Korean Environment Institute, Sejong, South Korea.
- 7Wageningen Environmental Research, Wageningen University, Wageningen, The Netherlands.
- 8Institute for Atmospheric and Earth System Research / Physics, University of Helsinki, Helsinki, Finland.
- 9Helsinki Institute of Sustainability Science, University of Helsinki, Helsinki, Finland.
- 10Chair of Climatology, Technische Universität Berlin, Berlin, Germany.
- 11Department of Geography, National University of Singapore, Singapore.
- 12Royal Netherlands Meteorological Institute (KNMI), De Bilt, The Netherlands.
- 13Department of Meteorology, University of Reading, Reading, United Kingdom.
- 14Independent Research Scientist, Singapore, Singapore.
The amount and dynamics of urban water storage play an important role in mitigating urban flooding and heat. Assessment of the capacity of cities to store water remains challenging due to the extreme heterogeneity of the urban surface. Evapotranspiration (ET) recession after rainfall events during the period without precipitation, over which the amount of stored water gradually decreases, can provide insight on the water storage capacity of urban surfaces. Assuming ET is the only outgoing flux, the water storage capacity can be estimated based on the timescale and intercept of its recession. In this paper, we test the proposed approach to estimate the water storage capacity at neighborhood scale with latent heat flux data collected by eddy covariance flux towers in eleven contrasting urban sites with different local climate zones, vegetation cover and characteristics and background climates (Amsterdam, Arnhem, Basel, Berlin, Helsinki, Łódź, Melbourne, Mexico City, Seoul, Singapore, Vancouver). Water storage capacities ranging between 1 and 12 mm were found. These values correspond to e-folding timescales lasting from 2 to 10 days, which translate to half-lives of 1.5 to 7 days. We find ET at the start of a drydown to be positively related to vegetation fraction, and long timescales and large storage capacities to be associated with higher vegetation fractions. According to our results, urban water storage capacity is at least one order of magnitude smaller than the known water storage capacity in natural forests and grassland.
How to cite: Jongen, H., Steeneveld, G.-J., Beringer, J., Fortuniak, K., Hong, J., Hong, J.-W., Jacobs, C., Järvi, L., Meier, F., Roth, M., Theeuwes, N., Velasco, E., and Teuling, R.: Urban water storage capacity inferred from observed evapotranspiration recession, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2765, https://doi.org/10.5194/egusphere-egu21-2765, 2021.
