City of Boulder/USGS Water Quality Monitoring
Water Quality Index for July, 2002 at
Boulder Creek at 61st St.

Grade B For July, 2002 the WQI rating at Boulder Creek at 61st St. (BC-61) was Good (B) due to a WQI value of 74.69. The chart below details the WQI calulations at this site. See the detailed explanation of the WQI method for more information.


Parameter Unit Parameter Value Q-value Weight Factor Total
DO% % sat 135.50 81.96 0.17 13.93
Fecal Coliform #/100 mL 170.00 35.78 0.16 5.72
pH pH 8.51 69.18 0.11 7.61
Total Phosphate mg PO4/L 0.02 98.23 0.10 9.82
Nitrates mg NO3/L 0.10 97.90 0.10 9.79
Turbidity NTU 4.90 84.92 0.08 6.79
Total Solids mg/l 155.00 76.13 0.07 5.33
Totals (factors, total) 0.79 59.00
Adjusted WQI 74.69

The WQI is computed by converting measured Water Quality Parameters to "Q-Values" using charts developed by the National Sanitation Foundation (NSF) water quality scientists. The Q-Values are then multiplied by a weighting factor based on the importance of that water quality parameter. These values are totaled and then divided by the sum of the weight factors.

WQI at Upstream Station: Boulder Creek at Eben G. Fine Park

WQI at Downstream Station: Boulder Creek above WW Plant

WQI for June at this station

WQI for August at this station

Return to WQI map for July


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Last Page Update - Saturday December 24, 2005