Starting in the 1980s the city began recharge experiments, with pilot projects along the Santa Cruz River opposite the Roger Road Wastewater Treatment Plant. Recharge involves adding water to the aquifer. Monitoring determined the rate recharge was occurring and detected changes in water quality. The city subsequently developed other recharge projects. The project with the largest anticipated full-scale capacity is the Central Avra Valley Storage and Recovery Project.

In the 1960s, the city experimented with a series of ponds for wastewater treatment using effluent from Roger Road. Then Tucson Water Director Frank Brooks used to boast of the high quality of the water by eating fish caught in those ponds. The last of the ponds was eliminated in the 1980s in response to fears that water leaching out of the ponds to groundwater was being contaminated by old landfill material. In 1998, the city opened its first constructed wetland to the public — the Sweetwater Wetland near the Roger Road Treatment Plant.

OTHER WATER QUALITY PROBLEMS

Treatment of sewage has been the major water quality challenge for many years, but by no means the only one. During World War II Tucson became a center of airplane construction and maintenance. Several plants located near the Tucson Airport regularly used solvents to degrease aircraft parts. Solvents were not known then to be a health hazard, and the waste products were often evaporated in unlined ponds or allowed to run into washes. A few employees expressed concern at the time, but it was not until the 1970s that people on the south side of town noticed the occurrence of an unusually high incidence of certain illnesses. The Arizona Department of Health and the EPA began studies to determine the cause. As a result of these studies and legal action, officials came to believe that trichloroethylene (TCE) had reached the groundwater and was probably creating health problems such as lupus and birth deformities. A citizen group, Tucsonans for a Clean Environment (TCE), formed on the so uthside to ensure that the problem was taken resolved to the benefit of the residents.

Since most of the manufacturing companies had long since left town, Hughes Aircraft (now Raytheon), the Tucson Airport Authority, the U.S. Air Force and the City of Tucson shared the burden of cleaning up the contaminated water. The city shut down three production wells and brought water from other wells to area customers. Hughes and the city installed a clean-up facility, under EPA oversight. What to do with the water after the TCE was removed became a major concern. The issue was later addressed as part of the anti-CAP initiative or Proposition 200. This passed and became the Water Consumer Protection Act. Tucson voters stated that water from polluted sources could not be used in the city system, even if federal Safe Drinking Water standards were met.

ADEQ has identified a number of other water quality problems in the Tucson area, including 17 groundwater contamination sites. The sources of contamination include historic landfills, manufacturing plants, mining and agricultural activities, aircraft waste disposal, and gas station and dry cleaning operations. In some cases the contamination exceeds federal Safe Drinking Water standards, and groundwater from the affected areas cannot be used for drinking unless treated to meet those standards. (See Chapter 6).