Understanding wastewater effluent impacts on the Clear Creek watershed

Visible changes to the water quality of Clear Creek are seen below several point sources located in Golden, CO, introduce wastewater discharge into the aquatic environment. There are several regulations within the United States that set up parameters for the amount of discharge and the type of effluent allowed to be released into a freshwater system, but fluctuations in water quality can still occur. This study was designed to provide a comprehensive comparison between water quality above and below these point sources, specifically a brewery with several prior NPDES permit violations in Golden, Colorado. Testing was conducted at two sites below the point sources and one site above with sampling dates occurring in the July, September, October, and November of 2014. Analysis confirmed the change between test sites cc-1 compared to cc-2 and cc-3 in water quality with drastic differences in several analyte concentrations. Results showed elevated temperatures, higher alkalinity and specific conductance measurements, higher concentrations of chloride, phosphorus, nitrate, nitrite, orthophosphate, total organic carbon, and E. coli downstream. Analyte concentrations also showed a correlation between stream flow with average concentrations being the lowest during the July sampling date when stream flow was the highest. Many of these analytes are directly dependent on each other, so any changes in concentration typically resulted in changes of other analyte concentrations within Clear Creek. E. coli concentrations increased downstream where nutrient concentrations were elevated and temperatures were higher. The October sampling date in particular showed the largest concentrations with the greatest increase between cc-1 and cc-2 for several of the analytes measured. The exact reason for the greater increase in analyte concentrations cannot be confirmed, but reduced flow beyond the point sources or an increase in point source discharge could very well be what caused the differences. All of these changes can pose serious risks to both environmental and human health, and should be addressed by making continual improvements to the treatment process for each point source.