Sites with parameter concentrations that have equaled or exceeded drinking water standard(s) (DWS), including location and parameter(s) are shown in Table 3.7-7A. Impaired lakes and streams with site type, name, length of impaired stream reach, area of impaired lake, designated use standard and parameter(s) exceeded is shown in Table 3.7-7B. Figure 3.7-9 shows the location of exceedences and impairment keyed to Table 3.7-7. Not all parameters were measured at all sites; selective sampling for particular constituents is common. A description of water quality data sources and methods is found in Volume 1, Appendix A.
Well, Mine or Spring sites that have equaled or exceeded drinking water standards (DWS)
- Refer to Table 3.7-7A.
Thirty-seven sites have parameter concentrations that have equaled or exceeded DWS.
The most frequently equaled or exceeded parameter was arsenic.
Other parameters commonly equaled or exceeded in the sites measured in this basin were nitrate, total dissolved solids, mercury, cadmium and radionuclides.
Lakes and Streams with impaired waters
- Refer to Table 3.7-7B.
- Water quality standards were exceeded in one 15 mile reach of the Gila River.
- The parameter exceeded in this reach was selenium.
- This reach is part of the ADEQ water quality improvement effort called the Total Maximum Daily Load (TMDL) program. The draft TMDL report is underway.
Click for Table 3.7-7 Water Quality in the
Duncan Valley Basin
Click for Figure 3.7-9 Duncan Valley Basin
Water Quality Conditions