DRAINAGE OF CLAY OVERLYING ARTESIAN AQUIFER .2. TECHNICAL ANALYSIS

Subsurface drains in clay soil overlying a shallow artesian aquifer intercept water from the aquifer and the deep percolation from the root zone. Flow down the backfilled drain-line trench is significant immediately after irrigation. The zone of influence of such drains is very limited, and only a small percentage of deep percolation is intercepted by the drains. A mathematical model is constructed to simulate these different sources of flows contributing to total drain flow. The model was calibrated with field data described in the companion paper, and results from the model were used to develop empirical equations quantifying the contribution of flows from different sources to total drain flows.