City of Boulder/USGS Water Quality Monitoring
Water Quality Index for September, 2002 at
Boulder Creek at Orodell

Grade B For September, 2002 the WQI rating at Boulder Creek at Orodell (BC-ORO) was Good (B) due to a WQI value of 74.86. 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 83.00 87.64 0.17 14.90
Fecal Coliform #/100 mL 490.00 23.85 0.16 3.82
pH pH 7.39 93.61 0.11 10.30
Total Phosphate mg PO4/L 0.04 97.26 0.10 9.73
Nitrates mg NO3/L 0.50 93.69 0.10 9.37
Turbidity NTU 15.00 65.41 0.08 5.23
Total Solids mg/l 96.00 82.90 0.07 5.80
Totals (factors, total) 0.79 59.14
Adjusted WQI 74.86

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 at Boulder Falls

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

WQI for August at this station

WQI for October at this station

Return to WQI map for September


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Last Page Update - Saturday December 24, 2005