9 was used to estimate the mean equivalent diameter of the pipe (D, m) as a function of
pressure head at the pipe inlet ([H.sub.o], m) for known flow rates, contained within the interval of the experimental flow rates, and fitting a power-law relation of D as a function of [H.sub.0], for 5 [less than or equal to] [H.sub.0] [less than or equal to] 10 m.
[K.sub.r] (h) is the relative hydraulic conductivity and it is a function of the
pressure head which makes the Richards equation highly nonlinear.
As the matric potential is less than zero, the soil energy state was better expressed by the
pressure head (the negative value of the metric potential) to give a more readily interpreted illustration of the SWCC.
(2016b), the highly negative
pressure head used at the beginning of the experiment restricted its use to soil samples that had good contact between the nylon mesh of the sorptivimeter and the corresponding mesh located at the bottom of the soil cylinder (e.g.
A trapezoidal labyrinth long-path emitter with a minimal differential operating
pressure head of [DELTA][h.sub.min] = 500 cm was used; then
The idea of the system design also includes emitter discharge variations due to change in
pressure head, which depends upon variability in manufacturing, change in temperature of water and choking in flow.
For example, the water retention curve, which defines the relationship between soil water content (6) and soil water
pressure head (h), is an important physical property of soil material.