The U.S. Geological Survey Arizona Water Science Center in cooperation with Tucson Water has monitored water-level and aquifer compaction at several wells in Avra Valley and Tucson Basin since about 1980. The purpose of the data collection is to document compaction of the aquifer system in response to stresses induced by water-level change, provide control for satellite-based observations of land subsidence, and develop long-term records that can be used to better understand the local aquifers including improved estimates of aquifer properties of hydraulic conductivity and storage. Each well is equipped with a borehole extensometer that measures compaction between the land surface and the bottom of the extensometer, and a pressure transducer that measures water levels. Monitoring since 2016 has produced hourly records at 12 extensometer wells.
Continuous record from the extensometer network has provided valuable documentation for aquifer-system responses including water-level rise in Avra Valley associated with recharge of Central Arizona Project (CAP) water, and in the Tucson Central Well Field associated with reduced groundwater withdrawal. Additionally, continuous compaction records show land-surface elevation increase associated with rise in water level. The majority of the network sites show that land-surface compaction continues to occur owing to maximum stresses associated with previous water-level decline. Continued operation of the network is needed to document the lag-time required for eventual cessation of aquifer compaction to allow a better understanding of the response of the aquifer systems in the Active Management Area (AMA) to evolving water-management scenarios.
Groundwater-storage change and land-surface elevation change in Tucson Basin and Avra Valley, south-central Arizona--2003-2016
Land Subsidence and Aquifer-System Compaction in the Tucson Active Management Area, South-Central Arizona, 1987-2005
Aquifer compaction and ground-water levels in south-central Arizona
Aquifer-system compaction, Tucson Basin and Avra Valley, Arizona
The U.S. Geological Survey Arizona Water Science Center in cooperation with Tucson Water has monitored water-level and aquifer compaction at several wells in Avra Valley and Tucson Basin since about 1980. The purpose of the data collection is to document compaction of the aquifer system in response to stresses induced by water-level change, provide control for satellite-based observations of land subsidence, and develop long-term records that can be used to better understand the local aquifers including improved estimates of aquifer properties of hydraulic conductivity and storage. Each well is equipped with a borehole extensometer that measures compaction between the land surface and the bottom of the extensometer, and a pressure transducer that measures water levels. Monitoring since 2016 has produced hourly records at 12 extensometer wells.
Continuous record from the extensometer network has provided valuable documentation for aquifer-system responses including water-level rise in Avra Valley associated with recharge of Central Arizona Project (CAP) water, and in the Tucson Central Well Field associated with reduced groundwater withdrawal. Additionally, continuous compaction records show land-surface elevation increase associated with rise in water level. The majority of the network sites show that land-surface compaction continues to occur owing to maximum stresses associated with previous water-level decline. Continued operation of the network is needed to document the lag-time required for eventual cessation of aquifer compaction to allow a better understanding of the response of the aquifer systems in the Active Management Area (AMA) to evolving water-management scenarios.