Leaching of Contaminants to Groundwater - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 791

Fig. 18.2 Capillary rise H of
water in a cylindrical tube of
radius R with a contact
angle γ

Fig. 18.3 Capillary rise of
water in a set of cylindrical
tubes of various radii

by an equivalent bundle of capillaries with identical water retention properties as
the real soil. Such an approach with capillary tubes and a water reservoir can be
used to evaluate the water content distribution in a soil above the groundwater table
at equilibrium. The experimental curve that describes this relationship between the
water content versus the height above the water table is called here the water reten-
tion curve . Many other names may be found in the literature, including pore water
characteristic curve, capillary pressure-saturation relationship, and pF curve. The
retention curve historically was often given in terms of pF, which is defined as the
negative logarithm of the absolute value of the pressure head in cm. The water reten-
tion curve provides information on how tightly water is held in pores and how much
work would need to be exerted to extract it from the different pores. The water