[2021 AR] Alluvial

2021 Report

Alluvial Water Quality


Alluvial (groundwater) contributes approximately 10% of the total annual yearly inflow to the Reservoir. Phosphorus concentrations in groundwater are higher than the average of all surface water inflows, and similar to Cherry Creek.

Long-term concentrations of total phosphorus in the alluvial inflow (MW-9) to Cherry Creek Reservoir are more consistent than surface water inflows (CC-10). Note that the alluvial groundwater concentrations typically hover around the 200 µg/L background phosphorus level in the streams. In WY 2021, the median TP concentration of the alluvial inflow was 306 μg/L, which was used to update the historical median to 237μg/L.

The historical pH at this site appears to be relatively stable over time. The historical conductivity values at MW-9 suggest a slightly increasing trend over time.

Why does Alluvial Water Quality Matter?

Groundwater travels more slowly than surface water to the reservoir. CCBWQA samples groundwater to investigate the contribution and timing of past and current pollutant loads that originate underground.


Nutrient Concentrations: Alluvial and Surface Water Comparisons

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.

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