City of Boulder/USGS Water Quality Monitoring
Water Quality Index for May, 2002 at
Boulder Creek Above Coal Creek

Grade C For May, 2002 the WQI rating at Boulder Creek Above Coal Creek (BC-aCC) was Medium (C) due to a WQI value of 64.53. 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 111.20 96.24 0.17 16.36
Fecal Coliform #/100 mL 50.00 49.77 0.16 7.96
pH pH 8.97 50.33 0.11 5.54
Total Phosphate mg PO4/L 0.55 56.13 0.10 5.61
Nitrates mg NO3/L 2.30 50.49 0.10 5.05
Turbidity NTU 9.30 75.25 0.08 6.02
Total Solids mg/l 257.00 63.39 0.07 4.44
Totals (factors, total) 0.79 50.98
Adjusted WQI 64.53

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 107th St

WQI at Downstream Station: Boulder Creek Below Coal Creek

WQI for April at this station

WQI for June at this station

Return to WQI map for May


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Last Page Update - Saturday December 24, 2005