Horizontal anisotropy of the principal ground-water flow zone in the Salinas alluvial fan, Puerto Rico

Well drawdown data from an anisotropic aquifer in the Salinas alluvial fan were collected and analyzed with a computer program called TENSOR2D. The program uses ordinary and weighted least-squares optimization procedures to solve the system of simultaneous equations needed to define the theoretical transmissivity ellipse. Prediction of drawdown data was made by coupling the anisotropy ellipse with the Hantush modified leaky-confined or Theis model. Drawdown data predicted by using the theoretical directional diffusivity obtained with the weighted least-squared fit gave a more accurate representation of the actual drawdown data than when using the test-data directional diffusivity. -from Author