[2018 AR] Chlorophyll-a

2018 Report


The reservoir chlorophyll α growing season (July through September) concentration was 20.2 μg/L, exceeding the 18 μg/L growing season standard. The seasonal mean concentration is measured in the upper three meters of the water column (photic zone), with an allowable exceedance frequency of once in five years. The reservoir has exceeded the chlorophyll α standard in four of the last five years, and eight of the last ten years.

Why Sample for Chlorophyll-a?

The Authority is tasked with improving, protecting, and preserving water quality for beneficial uses. The Authority samples for chlorophyll α because it can tell us about the amount of algae in the reservoir, and high levels of algae may impact the reservoir's beneficial uses.

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Seasonal Mean Concentrations of Chlorophyll-a Measured in Cherry Creek Reservoir

info_outlineEach point on the graph represents a seasonal mean value for samples collected in July, August, and September of that year. The red line represents the chlorophyll a standard for the reservoir. Hover over a point to view the specific value for the corresponding year.

Cherry Creek Reservoir Cholorophyll-a Drilldown

info_outlineEach point on this graph represents a sampling event. The different point colors represent different locations. To learn more about a specific data point, hover over it with your mouse.

Hey! This page is interactive.

  • Hover over a point to view the specific value for the corresponding year.
  • For the Cherry Creek Reservoir Cholorophyll-a Drilldown graph you can change the start and end dates to look at different time periods.
  • Select a season from the dropdown to see results from either summer or annual sampling.