City of Boulder/USGS Water Quality Monitoring
Water Quality Index for May, 2005 at
Boulder Creek above Dry Creek

Grade B For May, 2005 the WQI rating at Boulder Creek above Dry Creek (BC-aDC) was Good (B) due to a WQI value of 74.60. 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 92.90 95.43 0.17 16.22
Fecal Coliform #/100 mL 80.00 44.37 0.16 7.10
pH pH 7.44 93.77 0.11 10.31
Total Phosphate mg PO4/L 0.34 75.48 0.10 7.55
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 14.90 65.41 0.08 5.23
Total Solids mg/l 187.00 72.26 0.07 5.06
Totals (factors, total) 0.69 51.48
Adjusted WQI 74.60

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 75th St

WQI at Downstream Station: Boulder Creek at 95th St

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