Effects of anisotropy on the capture zone of a partially penetrating well

Dimensional analysis is used to show the effects of aquifer anisotropy on capture zone geometry for a partially penetrating well that is screened from the top of a confined aquifer. Dimensionless similarity criteria are identified which allow an extension of results for advective transport modeling from isotropic conditions to anisotropic ones. Using published results of modeling capture zones in isotropic aquifers, it is shown that anisotropy is important in determining the size and shape of the capture zone under two conditions:(1) the pumping rate is small compared to the scaled regional flow velocity, and (2) the well has a low degree of penetration. Examples are used to show that disregard of even modest aquifer anisotropy can significantly affect estimates of capture zone.