Evaluating alternatives for groundwater quality management in Green Valley-Sahuarita, Arizona

Abstract

This study develops several water quality management alternatives in the area based upon a two-dimensional steady volume Discrete State Compartment (DSC) model, historical land use-water quality relationships, and compatibility with current local, regional, state and federal regulations. Simulations result in recommendations suggesting changes in several land use activities. Modeling in mining areas suggest pumping two times the tailing pond recharge from interceptor wells at Duval mine to prevent downgradient public supply well contamination. Interceptor and industrial well pumpage schemes at Anamax, Cyprus Pima, and ASARCO are also suggested. Retirement of irrigated farm land will result in an overall improvement in groundwater quality based upon historical data and modeling scenarios. Effluent reuse and Central Arizona Project water appear to not have an adverse effect upon groundwater quality based on simulations. Future suggested studies include sampling groundwater for pesticides from farming and organic by-products in the copper flotation process, extending future modeling periods, and performing sensitivity analyses on input parameters.