Question

compare Horton's Model, Philip's Model, Kostiakov Model, and Green-Ampt Model in the measurement of infiltration using Hydrograph Analysis. Give one sample problem of each model and how it is being applied.

Answer 1

HORTON'S INFilTRATION MODEL

It indicates that if the rainfall supply exceeds the infiltration capacity, infiltration tends to decrease in an exponential manner. Although simple in form, difficulties in determining useful values for /0 and k restrict the use of this equation.

problem- The rainfall rate at 20 minutes i = 8 cm/h exceeds the corresponding infiltration capacity f_op = 6.15 cm /h. Therefore, the actual infiltration rate equals the infiltration capacity, and the decay of infiltration capacity follows Horton's equation with an initial infiltration capacity equal to f_op and starting at time t_* = 20 min

Philip's infiltration model was used to fit the simulated results of the dominant influencing factors. For the same soil, the sorptivity (s) is a power function relationship with film hole diameter, while the steady infiltration rate (a) is a power function relationship with film hole diameter and water depth

Kostiakov's model was then applied to the measured field data to obtain the soil infiltration parameters. The parameters were then used to predict the equations that described the cumulative infiltration of these soils. Simulated data were compared to the field data to see if the two have a close agreement.

Green and Ampt (1911) directly applied Darcy's law and proposed an approximately physical model for water infiltration from a ponded surface into a deep homogeneous soil with a uniform initial water content. ... When the rainfall rate is greater than the soil infiltration rate capacity, the soil surface will be ponded.