Simulation of Ground-Water Flow and Potential Land Subsidence, Avra Valley, Arizona

摘要

In 1983, the U.S. Geological Survey, in cooperation with the City of Tucson, began an investigation to evaluate the potential for aquifer-system compaction, land subsidence, and earth fissures in Avra Valley (Anderson, 1989; Cuff and Anderson, 1987). The study was divided into three phases, a detailed hydrogeologic investigation (Anderson, 1989), a stress-strain analysis of extensometer data (Hanson, 1987; 1989), and the development of an areal-subsidence model. The report documents the procedures used to develop a numerical simulation of ground-water flow and subsidence of the study area. The simulation was calibrated through 1977, with an additional transient simulation through 1984, and was used to evaluate the potential for water-level decline and land subsidence from 1985 through 2024. The year 2025 was designated by the Arizona Ground-Water Management Act of 1980 (State of Arizona, 1980) as the time by which pumpage and recharge must be brought into balance.