Impact of multiple uncertainties on gravimetric variations across randomly heterogeneous aquifers during pumping
AffiliationDepartment of Hydrology and Atmospheric Sciences, University of Arizona
KeywordsGlobal sensitivity analysis
Variably saturated flow
MetadataShow full item record
CitationMaina, F. Z., Guadagnini, A., & Riva, M. (2021). Impact of multiple uncertainties on gravimetric variations across randomly heterogeneous aquifers during pumping. Advances in Water Resources, 154.
JournalAdvances in Water Resources
Rights© 2021 Elsevier Ltd. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe evaluate the relative importance of the uncertainty related to parameters characterizing partially saturated groundwater flow on head and gravity changes associated with pumping tests taking place in homogeneous and heterogeneous porous media. We frame our study in a Global Sensitivity Analysis setting and assess the way imperfect knowledge of such parameters influences the probability distribution (pdf) of head and gravimetric variations recorded during well operation. We rely on a set of detailed computational analyses and conceptualize uncertain model parameters as random quantities. Randomly heterogeneous domains are treated by considering main geostatistical descriptors (i.e., variance and correlation scale) of three-dimensional spatial distributions of system properties as affected by uncertainty. We quantify the effects of the latter on the resulting pdf of (ensemble) mean and variance of head and gravity changes through a numerical Monte Carlo approach. While all uncertain parameters are influential to gravity changes in both homogeneous and randomly heterogeneous scenarios, consistent with the integral nature of gravity observations, our study enables us to quantify their relative importance. Values of Ensemble mean and variance of head and gravity changes associated with randomly heterogeneous fields are generally more influenced by the variance rather than by the correlation scale of the spatially heterogeneous parameters considered. Uncertainty in the correlation scale is more influential to the shape, and hence on extreme values, of the probability distribution of these moments.
Note24 month embargo; available online 12 June 2021
VersionFinal accepted manuscript