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Grad student talk - Using hydrochemical tracers to understand streamflow generation in Boulder Creek

Thursday, March 17, 2016, 12:30PM - 1:30PM


Qinghuan Zhang


SEEC room S225

The upper Boulder Creek Watershed is located in a mountainous area, and the hydrology is dominated by snowmelt runoff. Hydrochemical tracers, such as basic ions and stable water isotopes, serve as helpful tools in investigating source water contributions to streamflow. The hydrochemical tracers are analyzed in the upper Boulder Creek Watershed at Orodell. In general, soil water contributes the highest fraction, whereas groundwater contributes least. This implies that lateral subsurface flow is important when moving downstream.

During summer months, groundwater contribution to stream flow is more important at higher elevation of the Middle Boulder Creek main stem, such as at Nederland. It is uncertain whether this is a general trend on an annual basis, and needs further study. It is different from the headwater catchments in which groundwater contributions become more important with decreasing elevation.

Streamflow at the Boulder Creek Watershed at Orodell is not just an aggregation of runoff responses from the main stem. The study of streamflow sources and flow paths has significance in understanding the resilience of streamflow to climate change and natural disturbances.