Horton equation

Horton equation

Horton’s equation is the most common relationship for describing infiltration capacity in a soil. It describes the decrease in capacity as more water is absorbed by the soil, and has the form:

f = fc + (f0 - fc)・e-kt

where f is the infiltration capacity (mm/h) at time t,

f0 and fc are the initial and final constant rates of infiltration (mm/h)>>

k is a shape factor (fixed at a value of 2/h in ILSAX)

t is the time from the start of rainfall (h).





The soil type specified in DRAINS determines values for f0 and fc.

Horton models are discussed in Chapter 3 of Book 5 of ARR 2019, in Section 3.5.3.4.


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