City of Boulder/USGS Water Quality Monitoring
Water Quality Index for April, 2005 at
North Boulder Creek diversion to Lakewood

Grade A For April, 2005 the WQI rating at North Boulder Creek diversion to Lakewood (NBC-Lw) was Excellent (A) due to a WQI value of 94.06. 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 100.00 98.51 0.17 16.75
Fecal Coliform #/100 mL Data Unavailable
pH pH 7.23 92.13 0.11 10.13
Total Phosphate mg PO4/L 0.02 98.23 0.10 9.82
Nitrates mg NO3/L 0.02 98.54 0.10 9.85
Turbidity NTU 3.82 88.03 0.08 7.04
Total Solids mg/l 4.50 80.81 0.07 5.66
Totals (factors, total) 0.63 59.26
Adjusted WQI 94.06

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: Middle Boulder Creek Above North Boulder Creek Confluence

WQI at Downstream Station: North Boulder Creek at Boulder Falls

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