Two-Dimensional Probabilistic Infiltration Analysis in a Hillslope Using First-Order Moment Approach

Area of Science:

• Hydrogeology
• Geophysics
• Environmental Science

Background:

• Spatial variability in saturated hydraulic conductivity (K_s) significantly impacts hillslope hydrology.
• Understanding pore-water pressure dynamics is crucial for predicting water flow and stability in unsaturated and saturated zones.

Purpose of the Study:

• To introduce a first-order moment analysis method for evaluating pore-water pressure variability.
• To investigate the influence of K_s variance, spatial anisotropy, and infiltration flux on pore-water pressure uncertainty.

Main Methods:

• Employed a first-order moment analysis approach.
• Analyzed the impact of variance of the natural logarithm of K_s (ln K_s), spatial structure anisotropy of ln K_s, and normalized vertical infiltration flux (q).

Main Results:

• Pore-water pressure variability differs between unsaturated and saturated regions.
• In unsaturated zones, higher K_s variance, greater anisotropy, and lower infiltration flux increase pressure head variability.
• In saturated zones, higher K_s variance, lower anisotropy, or higher infiltration flux increase pressure head variability.

Conclusions:

• The variance of ln K_s has the most significant impact on pressure head variance, especially in saturated zones.
• These findings offer critical insights into how soil heterogeneity affects hillslope hydrology and flow field uncertainty.