Question

Q4. The parameters for the Horton's equation are f,-3.6 mm/hr, fc- 0.8 mm/hr and k- 4.1 hr1. Determine the infiltration rates after 0, 10 min, 1 hr, 1.5 hr and 2 hr and the cumulative infiltration after 2 hours.

Answer 1

Horton's equation is given by:

$f=f_c+(f_o-f_c)e^{-k_ht}$

fe 0.8mm/hr

fo- 3.6mm/hr

kh = 4.1hr-1

For

f = 0.8 + (3.6-0.8)e-4, 1-0

f3.6mm/hr

For  $t=10min =\frac{1}{6}hr$

f-0.8 + (3.6-0.8)є_4.1x

f = 2.214mm/hr

For

t = 1hr

f 0.8 + (3.6-0.8)є_4.1x1

846mmlh

For

t 1.5/27.

4.1x1.5 f 0.8 + (3.6-0.8)є_

f = 0806mm /hr

For $t=2hr$

f = 0.8 + (3.6-0.8)e-41x2

f = 0801mm/hr