Sites with parameter concentrations that have equaled or exceeded drinking water standard(s) (DWS), including location and parameter(s) are shown in Table 4.2-7A.  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 4.2-7B.  Figure 4.2-9 shows the location of exceedences and impairment keyed to Table 4.2-7.  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 4.2-7A.
• Sixty sites have parameter concentrations that have equaled or exceeded DWS. 
• Frequently equaled or exceeded parameters include fluoride and arsenic
• Other parameters equaled or exceeded in the sites measured in this basin were cadmium, copper, lead, nitrates, total dissolved solids and radionuclides.

Lake and Streams with Impaired Waters

• Refer to Table 4.2-7B.

• Water quality standards were exceeded in two reaches of Boulder Creek, one reach of Burro Creek, Alamo Lake and Coors Lake.

• The mercury drinking water standard was exceeded in every impaired stream or lake. Other parameters exceeded in Alamo Lake include ammonia and pH levels.  Arsenic, copper and zinc were exceeded in Boulder Creek.

• Boulder Creek and Alamo Lake are part of the ADEQ water quality improvement effort called the Total Maximum Daily Load (TMDL) program.  The final TMDL report has been completed for Boulder Creek and an implementation plan is underway.  Modeling is complete for Alamo Lake and ADEQ is drafting the TMDL document.

• Burro Creek and Coors Lake are not part of the TMDL program at this time.

Click to view Table 4.2-7 Water Quality Exceedences in the Bill Williams Basin