City of Boulder/USGS Water Quality Monitoring
Water Quality Index for May, 2007 at
Boulder Creek at 107th St

Grade B For May, 2007 the WQI rating at Boulder Creek at 107th St (BC-107) was Good (B) due to a WQI value of 77.74. 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 100.30 98.51 0.17 16.75
Fecal Coliform #/100 mL Data Unavailable
pH pH 7.75 91.97 0.11 10.12
Total Phosphate mg PO4/L 0.83 42.42 0.10 4.24
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 8.51 77.38 0.08 6.19
Total Solids mg/l 315.00 55.81 0.07 3.91
Totals (factors, total) 0.53 41.20
Adjusted WQI 77.74

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 95th St

WQI at Downstream Station: Boulder Creek Above 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 - Tuesday June 12, 2007