Geochemical Models of Water-Quality Changes During Aquifer Storage Recovery (ASR) Cycle Tests, Phase 1: Geochemical Models Using Existing Data

摘要

Geochemical models were developed using existing water-quality data sets from three permitted, potable-water Aquifer Storage Recovery (ASR) systems in south Florida. All three systems store and recover water in different permeable zones of the upper Floridan Aquifer System (FAS). At the Olga ASR system, water is stored in the Suwannee Limestone; at the North Reservoir ASR system, water is stored in the Arcadia Formation of the lower Hawthorn Group. Both sites are located in Lee County, along the southwest Gulf Coast of Florida. At the Eastern Hillsboro ASR system, water is stored in the basal Hawthorn unit; this system is located in Palm Beach County near the southeastern Atlantic Coast of Florida. The objectives of this study are to use geochemical modeling methods to simulate (1) mixing between native water of the upper FAS and recharge water during cycle testing; (2) geochemical reactions that occur during the storage phase of cycle tests in different lithologies; and (3) controls on arsenic transport and fate during ASR cycle testing. Existing cycle test data sets were developed for permitting purposes, not research; therefore, concentrations of some major dissolved constituents are estimated. Quantitative uncertainty that resulted from the use of incomplete water-quality datasets is defined for these geochemical models.