Application of mass-balance method to evaluate recharge rate patterns in a Quaternary aquifer in northern Mexico

Abstract

This study deals with the application of mass-balance method to evaluate spatial changes in recharge-discharge rates patterns. MODFLOW was used to generate two finite-difference steady-state groundwater models for an alluvial aquifer at the Lagunera Region in northern Mexico. Additionally, a spreadsheet program was developed to generate recharge-discharge patterns distribution corresponding to 2002 and 2014 years. Inverse numerical modeling was used to calibrate the steady-state groundwater models applying a universal parameter estimation code. A root-mean square error between observed and simulated heads was used as statistical control to evaluate model calibration. Results show that recharge values are predominant at surrounding areas whereas discharge values are dominant at central zones coinciding with agricultural areas. Furthermore, alternative-hypothesis from sign test suggests that a change has occurred in recharge patterns distribution for the studied period.