Tyson Wash | Site Hydrogeology

Subsurface soils at the site consist of two main units. Interbedded layers of well-cemented gravel, sand, silt, and clay exist from approximately ground surface to 70 feet bgs. Below 70 feet the soils consist of silty clay to clay, with the estimated clay percentage ranging from 50 percent to nearly 100 percent.

The groundwater system in the vicinity of Quartzsite consists of a shallow and a deep aquifer.  The shallow aquifer exists from approximately 45 to 70 feet bgs. The depth to groundwater in the deep aquifer is encountered at approximately 400-500 feet bgs. The shallow aquifer beneath the site has been impacted by PCE and TCE contamination.

The depth to the shallow groundwater aquifer beneath the site ranges from approximately 41 to 55 feet bgs. In March 2002 the direction of groundwater was to the north/northeast. In September 2003, the direction of groundwater was to the north. The Town of Quartzsite is currently providing water and sewer to the residents within the site. Due to the residents receiving the Town of Quartzsite water, their private well use has declined. The decline in use of the water in the shallow aquifer may be the reason the direction of groundwater flow is towards the north/northwest along Tyson Wash.