Water Quality Conditions in the Little Colorado River Plateau Basin

Wells, springs and mine sites with parameter concentrations that have equaled or exceeding drinking water standard(s), including location and parameter(s) are shown in Table 2.1-7A.  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 2.2-7B. Figure 2.1-10 shows the location of water quality occurrences keyed to Table 2.1-7. A description of water quality data sources and methods can be found in Volume 1, Appendix A. Information on contamination sites in the basin is in Section 2.0.6 Water Supply - Contamination Sites.

Wells, Springs and Mine Sites

  • 237 wells, springs and mine sites have parameter concentrations that have equaled or exceeded drinking water standards.
  • North of Highway 264, the parameters most frequently exceeded in the sites measured were thallium and radionuclides in both wells and springs
  • Between Highway 264 and Interstate 40, the parameter most frequently exceeded in the sites measured was arsenic.  There is a notable arsenic cluster in the vicinity of the Hopi communities of Polacca, Kykotsmovi and Keams Canyon.
  • South of Interstate 40 the parameters most frequently exceeded in the sites measured were arsenic and cadmium.
  • For the entire basin, the most frequently exceeded constituents measured, in order of greatest occurrence were arsenic, radionuclides, thallium, lead and TDS.

Lakes and Streams

  • Water quality standards were equaled or exceeded in eight lakes, where mercury was the most common contaminant.
  • Water quality standards were equaled or exceed in two reaches of Nutrioso Creek and six reaches of the Little Colorado River with turbidity the most common contaminant.
  • At this time, 12 of the 16 sites are part of the ADEQ water quality improvement effort called the Total Maximum Daily Load (TMDL) Program. These include sites b, c, f, and h-p in Table 2.1-7B.  
  • Final TMDL reports have been completed for The Little Colorado River (Nutrioso Creek to Camero Wash), Little Colorado River (Water Canyon Creek to Nutrioso Creek),  Rainbow Lake and Nutrioso Creek from its headwaters to the Little Colorado River where Clean Water Act 319 projects are ongoing.

Effluent Dependent Reaches

  • See Figure 2.1-10
  • There is one effluent dependent reach, the Rio de Flag, at Flagstaff.  Effluent is discharged to the Rio de Flag from the Rio de Flag and Wildcat Hill wastewater treatment plants.

 

Table 2.1-7 Water Quality

Click for Table 2.1-7 Water Quality Exceedences in the

Little Colorado River Plateau Basin

Figure 2.1-10 Water Quality

Click for Figure 2.1-10 Little Colorado River Plateau Basin

Water Quality Conditions

 

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