City of Boulder/USGS Water Quality Monitoring
Water Quality Index for August, 2006 at
North Boulder Creek at Boulder Falls

Grade B For August, 2006 the WQI rating at North Boulder Creek at Boulder Falls (NBC-FALLS) was Good (B) due to a WQI value of 84.49. 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 0.00 99.00 0.17 16.83
Fecal Coliform #/100 mL 50.00 49.77 0.16 7.96
pH pH 7.34 93.28 0.11 10.26
Total Phosphate mg PO4/L 0.04 97.26 0.10 9.73
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 1.44 93.93 0.08 7.51
Total Solids mg/l 38.00 85.81 0.07 6.01
Totals (factors, total) 0.69 58.30
Adjusted WQI 84.49

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: North Boulder Creek diversion to Lakewood

WQI at Downstream Station: Boulder Creek at Orodell

WQI for July at this station

WQI for September at this station

Return to WQI map for August


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Last Page Update - Thursday March 01, 2007