City of Boulder/USGS Water Quality Monitoring
Water Quality Index for April, 2002 at
Boulder Creek Above Coal Creek

Grade D For April, 2002 the WQI rating at Boulder Creek Above Coal Creek (BC-aCC) was Bad (D) due to a WQI value of 44.62. 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 215.00 50.00 0.17 8.50
Fecal Coliform #/100 mL 50.00 49.77 0.16 7.96
pH pH 9.21 43.61 0.11 4.80
Total Phosphate mg PO4/L 1.37 30.00 0.10 3.00
Nitrates mg NO3/L 5.00 33.98 0.10 3.40
Turbidity NTU 8.50 77.38 0.08 6.19
Total Solids mg/l 526.00 20.00 0.07 1.40
Totals (factors, total) 0.79 35.25
Adjusted WQI 44.62

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 107th St

WQI at Downstream Station: Boulder Creek Below Coal Creek

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 - Saturday December 24, 2005