**CE 374K Hydrology Homework
#4 Spring 2004**

Problems from text

(1) 3.5.1 Evaporation by Priestley-Taylor method

(2) 3.6.3 Evaporation by several methods

(3) 4.1.2 Soil water movement

(4) Soil water parameterization.

The relationship between the suction head, ψ, the moisture content, θ, and the unsaturated hydraulic conductivity K can be described by the Van Genuchten equations:

_{}

_{}

The follow parameters were measured at site Bosque

K_{s} = 2 x 10^{-4} cm/s

θ_{r}
= 0.0450

a = 0.00497

n = 2.12901

m = 1 – (1/n)

f = 0.3782

Determine and plot the functions ψ versus θ, and K
versus θ, for the range θ_{r} <
θ < f. This corresponds, approximately, to the range
1 < ψ < 1000 cm.

(5) Text problem 4.3.3 on the Green-Ampt method