Darcy's Hydraulic Conductivity Given Infiltration Capacity From Green-Ampt Equation Calculator

Green-Ampt Equation:

\[ K = \frac{f_p}{1 + \frac{\eta \cdot S_c}{F_p}} \]

Infiltration Capacity at Any Time t (fp):

cm/h

Porosity (η):

Capillary Suction at Wetting Front (Sc):

Cumulative Infiltration Capacity (Fp):

cm/h

Darcy's Hydraulic Conductivity (K):

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1. What is the Green-Ampt Equation?

The Green-Ampt equation is a simplified model for estimating infiltration into soils. It provides a physically-based approach to predict the rate at which water enters the soil surface, taking into account soil properties and initial moisture conditions.

2. How Does the Calculator Work?

The calculator uses the Green-Ampt equation:

\[ K = \frac{f_p}{1 + \frac{\eta \cdot S_c}{F_p}} \]

Where:

\( K \) — Darcy's Hydraulic Conductivity (cm/h)
\( f_p \) — Infiltration Capacity at Any Time t (cm/h)
\( \eta \) — Porosity (dimensionless)
\( S_c \) — Capillary Suction at Wetting Front
\( F_p \) — Cumulative Infiltration Capacity (cm/h)

Explanation: The equation calculates the hydraulic conductivity based on the current infiltration rate and soil properties including porosity and capillary suction.

3. Importance of Darcy's Hydraulic Conductivity

Details: Darcy's Hydraulic Conductivity is a fundamental property that measures a soil's ability to transmit water. It is crucial for understanding groundwater flow, designing drainage systems, and predicting water movement in agricultural and environmental applications.

4. Using the Calculator

Tips: Enter all values with appropriate units. Infiltration capacity and cumulative infiltration capacity should be in cm/h. Porosity is a dimensionless value between 0 and 1. All input values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of Darcy's Hydraulic Conductivity values?
A: Hydraulic conductivity varies widely depending on soil type, from less than 0.01 cm/h for clay to over 100 cm/h for gravel.

Q2: How does porosity affect hydraulic conductivity?
A: Generally, higher porosity leads to higher hydraulic conductivity, but the relationship also depends on pore size distribution and connectivity.

Q3: What factors influence capillary suction at the wetting front?
A: Capillary suction is influenced by soil texture, with finer soils typically having higher capillary suction values due to smaller pore sizes.

Q4: When is the Green-Ampt model most applicable?
A: The Green-Ampt model works best for uniform soils with clearly defined wetting fronts and under constant rainfall or ponding conditions.

Q5: What are the limitations of the Green-Ampt equation?
A: The model assumes homogeneous soil properties, sharp wetting fronts, and may not accurately represent complex field conditions with soil layering or preferential flow paths.