EGU23-8426, updated on 13 Mar 2023
https://doi.org/10.5194/egusphere-egu23-8426
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Effect of Rainfall Fractal Behaviour on that of Recharge and Groundwater Levels

Abrar Habib1, Athanasios Paschalis2, Adrian P. Butler2, Christian Onof2, John P. Bloomfield3, and James P. R. Sorensen3
Abrar Habib et al.
  • 1University of Bahrain, Civil Engineering Department, Bahrain (abr.habib@gmail.com)
  • 2Imperial College London, Department of Civil and Environmental Engineering, London, SW7 2AZ, UK
  • 3British Geological Survey, Maclean Building, Crowmarsh Gifford, Wallingford, Oxon, OX10

Using a physically based recharge-groundwater flow model, a multiplicative random cascade rainfall model and robust detrended fluctuation analysis (r-DFA), the effect of the fractal behaviour of rainfall on recharge and groundwater levels is investigated. The study site selected for this work is in Wallingford, United Kingdom, where groundwater levels in a shallow riparian aquifer and meteorological data of high temporal resolution are monitored.

The rainfall model is calibrated to the observed rainfall and used to simulate 40 synthetic rainfall series exhibiting different scaling behaviour (with r-DFA scaling exponents between 0.6 and 1.05). The scaling behaviour of the rainfall series are then objectively quantified using r-DFA. The synthetic rainfall is used as forcing to run the recharge-groundwater flow model which is calibrated to the observed groundwater levels.

It is found that small changes in the fractal behaviour of rainfall has a significant effect on the fractal behaviour of recharge and this in turn results in a small change in the fractal behaviour of groundwater levels. The significant effect on the fractal behaviour of drainage is attributed to the extended recharge periods which correspond to more frequent rain events in rainfall with higher scaling exponents. This effect is more subdued in groundwater level fluctuations due to attenuation of the recharge signal as it percolates through the unsaturated zone.

How to cite: Habib, A., Paschalis, A., Butler, A. P., Onof, C., Bloomfield, J. P., and Sorensen, J. P. R.: Effect of Rainfall Fractal Behaviour on that of Recharge and Groundwater Levels, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8426, https://doi.org/10.5194/egusphere-egu23-8426, 2023.