City of Boulder/USGS Water Quality Monitoring
Water Quality Index for April, 2007 at
Boulder Creek at 95th St

Grade C For April, 2007 the WQI rating at Boulder Creek at 95th St (BC-95) was Medium (C) due to a WQI value of 54.71. 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 72.40 75.47 0.17 12.83
Fecal Coliform #/100 mL 330.00 27.19 0.16 4.35
pH pH 8.01 86.56 0.11 9.52
Total Phosphate mg PO4/L 1.55 27.58 0.10 2.76
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 12.70 69.02 0.08 5.52
Total Solids mg/l 438.00 39.52 0.07 2.77
Totals (factors, total) 0.69 37.75
Adjusted WQI 54.71

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 above Dry Creek

WQI at Downstream Station: Boulder Creek at 107th St

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 - Tuesday June 12, 2007