City of Boulder/USGS Water Quality Monitoring
Water Quality Index for April, 2006 at
Boulder Creek above WW Plant

Grade B For April, 2006 the WQI rating at Boulder Creek above WW Plant (BC-aWWTP) was Good (B) due to a WQI value of 80.90. 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 139.40 78.71 0.17 13.38
Fecal Coliform #/100 mL Data Unavailable
pH pH 8.30 76.89 0.11 8.46
Total Phosphate mg PO4/L 0.02 98.23 0.10 9.82
Nitrates mg NO3/L Data Unavailable
Turbidity NTU 7.80 78.69 0.08 6.30
Total Solids mg/l 201.00 70.32 0.07 4.92
Totals (factors, total) 0.53 42.88
Adjusted WQI 80.90

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 61st St.

WQI at Downstream Station: Boulder Creek above Dry Creek

WQI for March at this station

WQI for May at this station

Return to WQI map for April


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