City of Boulder/USGS Water Quality Monitoring
Water Quality Index for June, 2006 at
North Boulder Creek diversion to Lakewood

Grade A For June, 2006 the WQI rating at North Boulder Creek diversion to Lakewood (NBC-Lw) was Excellent (A) due to a WQI value of 94.34. 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 100.64 98.68 0.17 16.77
Fecal Coliform #/100 mL Data Unavailable
pH pH 7.42 93.77 0.11 10.31
Total Phosphate mg PO4/L 0.02 98.23 0.10 9.82
Nitrates mg NO3/L 0.00 100.00 0.10 10.00
Turbidity NTU 4.62 85.57 0.08 6.85
Total Solids mg/l 5.50 81.13 0.07 5.68
Totals (factors, total) 0.63 59.44
Adjusted WQI 94.34

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 May at this station

WQI for July at this station

Return to WQI map for June


Thank You! BASIN was a community project which benefitted from over 1000 hours of public volunteer time. BASIN was highlighted by the US EPA in a national case study in its 2001 handbook Delivering Timely Environmental Information to Your Community. Thank you to all volunteers, and especially to the late Jim Waterman, BASIN Project Coordinator!

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Last Page Update - Thursday March 01, 2007