Water Content Dependence of Solute Reaction Parameters

The water content dependence of degradation coefficients is implemented using a modified equation of Walker [1974]:

where μr is the values of a particular coefficient (rate constant) at the reference water content θr, μ is the value of this coefficient at the actual water content θ, and B is a solute dependent parameter (usually 0.7). The reference water content, θr, which may be different for different soil layers, is calculated from the reference pressure head, hr, which is considered to be constant for a particular compound. The solute dependent exponent, B, and the reference pressure head, hr, are entered in the Water Content Dependent Solute Reaction Parameters dialog window.