In their comment, Labolle and Clausnitzer [this issue] review assumptions implicit in the water-content-based form of the Richards' equation and comment on the relevant literature. To illustrate the pitfalls of omitting a clear presentation of the restrictions associated with the use of this form of the Richards equation, they call attention to Russo [1991] as a case where it appears that this form of the Richards equation has been misapplied. They did not provide, however, any sort of analysis that might quantify the implications of this misapplication. Here I will concentrate on the criticism raised in the comment regarding Russo [1991] only.
In their comment, Labolle and Clausnitzer [this issue] review assumptions implicit in the water-content-based form of the Richards' equation and comment on the relevant literature. To illustrate the pitfalls of omitting a clear presentation of the restrictions associated with the use of this form of the Richards equation, they call attention to Russo [1991] as a case where it appears that this form of the Richards equation has been misapplied. They did not provide, however, any sort of analysis that might quantify the implications of this misapplication. Here I will concentrate on the criticism raised in the comment regarding Russo [1991] only.