Helen Dahlke

Helen Dahlke

Position Title
Assistant Professor

Land, Air and Water Resources


Dahlke, an assistant professor in the Department of Land, Air and Water Resources, specializes in physical hydrology. Dahlke completed her Ph.D. at Cornell University in environmental engineering, and was a postdoctoral researcher at Stockholm University in Sweden before joining the CA&ES faculty in 2013.

Research interests:

Hydrology, water resources, climate change, surface water–groundwater interactions, pollutant transport, environmental tracers, isotope hydrology, environmental geophysics, glacier and snow hydrology. 

Brief overview:

The water resources of California are vulnerable to climate variability and changes in water availability. Reduced snowpack, alterations in river flows, and increasing water demand have an impact on water supply and on biogeochemical cycling—the natural flow of essential chemical elements such as nitrogen, phosphorus, salt, and carbon within the physical and biological environment.

My main research goal is to improve understanding of the processes and mechanisms that control how water and geochemicals move through the landscape. I study water and biogeochemical cycles through field and laboratory experiments, statistical analyses, and numerical modeling. I am particularly interested in identifying feedbacks and thresholds in the hydrology and biogeochemistry of systems such as the Sierra Nevada or the agricultural landscape of the Central Valley.

This research will advance our ability to predict floods, droughts, and other extremes and to support planning and resource-management decisions for more sustainable use of our natural resources. 


Current projects:

  • Estimation of the feasibility, risks, and costs of using agricultural lands to actively recharge California’s groundwater aquifers at times when excess surface water is available  
  • Monitoring of ecosystem change in the Sierra Nevada using stable water isotopes and environmental DNA (eDNA) traces
  • Test of synthetic DNA tracers for the investigation of flow pathways in various hydrological systems