10.4122/1.1000000475
Hassan, Ahmed
Ahmed
Hassan
ahmed.hassan@dri.edu
Botros, Farag
Farag
Botros
farag.botros@dri.edu
Hassan, Ahmed
Ahmed
Hassan
ahmed.hassan@dri.edu
Assessment of Hydraulic Conductivity Upscaling Techniques and Associated Uncertainty
XVI International Conference on Computational Methods in Water Resources
2006
2006
The use of numerical models for studying subsurface flow and transport has become
common practice in hydrology over the last three decades. However, hydraulic
parameters introduced to these models are still of a major concern. Data are usually
collected at a scale much smaller than that used in numerical models but by using
geostatistical techniques, available measurements can be used to stochastically
populate the entire domain of the studied area. Models built based on these
geostatistical techniques should be on the same scale as the supporting measurements
which lead to models with very large number of cells. Dealing with these numerical
models stochastically is beyond the capabilities of current computational resources.
Upscaling is the process of transforming the detailed description of hydraulic
parameters in a grid constructed at measurement scale (fine grid) to a coarser grid
with less detailed description (coarse grid) for the purpose of numerical subsurface
modeling. The fact that the coarse grid hydraulic conductivity should have a value
between the harmonic mean and arithmetic mean of the fine grid conductivities inside
this coarse grid cell led researchers to use the power average technique for the
upscaling process with exponent varying from -1.0 to 1.0. The objective of this study
is to develop a technique for assessing the uncertainty in upscaling flow and
transport parameters and the impact of this uncertainty on prediction uncertainty of
models relying on upscaled parameter values. This technique is tested using
log-normal distribution of hydraulic conductivity with small variance and exponential
covariance, results were found to match with analytical solution.