City of Boulder/USGS Water Quality Monitoring
Boulder Creek Watershed
Boulder Creek Water Quality Index

WQI at Boulder Creek at 61st St. for October, 2000

Grade C For October, 2000, the WQI rating at Boulder Creek at 61st St. (BC-61) was Medium (C) due to a WQI value of 64.2. The chart below details the WQI calulations at this site. See the detailed explanation of the WQI method for more information.

6-parameter Test result unit Q-value weight factor total
BC-61 10/2000          
DO 145 % sat 50 0.17 8.5
Fecal Coliform 130 #/100 mL 42 0.16 6.72
pH 9.25 std units 40 0.11 4.4
Total Phosphate 0.039 mg/L PO4-P 97 0.10 9.7
Nitrates <0.1 mg/L NO3 97 0.10 9.7
Turbidity 2.3 NTU 90 0.08 7.2
totals (factors, total)       0.72 46.22
adjusted WQI         64.2

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.

WQI at Upstream Station: Boulder Creek at 30th St.

WQI at Downstream Station: Boulder Creek at 107th St

WQI at for June, 2000 at this station

Return to WQI map for October, 2000
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Last Page Update - Tuesday December 27, 2005