City of Boulder/USGS Water Quality Monitoring
Water Quality Index for April, 2006 at
Boulder Creek at Orodell

Grade B For April, 2006 the WQI rating at Boulder Creek at Orodell (BC-ORO) was Good (B) due to a WQI value of 81.13. 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 77.70 82.12 0.17 13.96
Fecal Coliform #/100 mL 20.00 61.54 0.16 9.85
pH pH 7.18 91.15 0.11 10.03
Total Phosphate mg PO4/L 0.03 98.23 0.10 9.82
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 7.65 79.51 0.08 6.36
Total Solids mg/l 30.00 85.16 0.07 5.96
Totals (factors, total) 0.69 55.98
Adjusted WQI 81.13

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 March at this station

WQI for May at this station

Return to WQI map for April


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Last Page Update - Thursday March 01, 2007