Question

The term "Infiltrability" is coined by

• A. Robert E. Horton
• B. Daniel Hillel
• C. J.R. Philip
• D. Green, W. H., and G. A. Ampt

Hint:

Remember:
- Horton $\rightarrow$ Infiltration Capacity (empirical model).
- Green-Ampt $\rightarrow$ Wetting Front Infiltration (approximate physical model).
- J.R. Philip $\rightarrow$ Infiltrability (and Sorptivity, rigorous physical model).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Infiltration is the physical process of water entering the soil through its surface.
Historically, researchers used different terms to describe the rate and capacity of this process.

Step 3: Detailed Explanation:
Let us review the historical development of infiltration terms:
1. Robert E. Horton:
Horton developed the classic "infiltration equation" ($f(t) = f_c + (f_0 - f_c)e^{-\beta t}$) and introduced the term "infiltration capacity."
However, the term "capacity" is technically incorrect because it implies a static volume (like a bucket), whereas infiltration is a dynamic rate of flux.
Thus, Option (A) is incorrect.
2. Green and Ampt:
In 1911, Green and Ampt developed the first physical, simplified model to estimate infiltration based on Darcy's Law and wetting front suction.
They did not introduce the specific term "infiltrability."
Thus, Option (D) is incorrect.
3. J. R. Philip:
In 1957, the Australian soil physicist John Robert Philip proposed a physical theory of infiltration.
He introduced the term "infiltrability" (or soil water infiltrability) to replace "infiltration capacity."
He defined infiltrability as the maximum rate at which a given soil can absorb water through its surface under specific conditions.
Using the term "infiltrability" (similar to "permeability" or "conductivity") clarifies that it represents a dynamic physical property of the soil.

Step 4: Final Answer:
The term "Infiltrability" was coined by the soil physicist J. R. Philip.
Therefore, the correct option is (C).