Lecture 27: Jacob Method

In this lecture, the Jacob method is introduced as a simplified approach to the Theis equation for analyzing groundwater flow. Jacob recognized that for small values of the parameter u, the Theis equation could be approximated by ignoring higher-order terms, leading to simpler expressions for drawdown. The method uses semi-logarithmic plots of drawdown against time to determine aquifer transmissivity and storage coefficient, with equations derived from this simplified form. This approach is particularly useful when steady-state or steady-shape conditions are established near the pumping well, though it is less effective for large distances or unconfined aquifers due to the slower development of steady conditions. Jacob's method provides reliable results under these conditions but should not be used where hydraulic boundaries influence the flow before these conditions are met.