Estimating falling rate evaporation from finite soil columns.

Area of Science:

• Geo-environmental Engineering
• Soil Science
• Water Resource Management

Background:

• Evaporation estimation is critical for agriculture and geo-environmental applications, particularly in soil covers for mining and landfills.
• Accurate evaporation prediction aids in the initial design stages of engineered soil covers, enhancing environmental protection.
• Understanding water movement in unsaturated soils is fundamental to predicting evaporation dynamics.

Purpose of the Study:

• To evaluate an analytical equation for estimating falling rate evaporation from finite soil columns.
• To compare the equation's predictions with experimental data and finite element modeling.
• To demonstrate the utility of an analytical approach for practical soil evaporation estimation.

Main Methods:

• Utilized Gardner and Hillel's equation involving soil moisture diffusivity for evaporation calculation.
• Modeled evaporation from coarse and fine sand columns using the finite element model SoilCover.
• Compared analytical solutions and numerical model results against experimental evaporation data.

Main Results:

• The analytical equation demonstrated reasonable agreement with experimental data for falling rate evaporation from sand columns.
• The finite element model SoilCover also showed good correlation with experimental results.
• The findings support the use of the analytical solution for estimating evaporation from finite soil columns.

Conclusions:

• The analytical solution provides a viable method for estimating falling rate evaporation from finite columns of coarse and fine sand.
• This approach can simplify the estimation of actual soil evaporation, benefiting the design of engineered covers.
• Key data requirements include soil-water characteristic curves, hydraulic conductivity-suction functions, and initial water content.