No Flow? No Problem! Drivers of flow and long-term change in non-perennial streams

Sam Zipper collage

March 17, 2021

No Flow? No Problem! Drivers of flow and long-term change in non-perennial streams

Sam ZipperAssistant Scientist, Kansas Geological Survey, University of Kansas, Lawrence, KS

Join us for the live stream March 17, 11:45am EST, or view later:


Non-perennial streams and rivers account for over 50% of global river network length, but are poorly understood relative to their perennial counterparts. This lack of understanding of the hydrology of non-perennial streams has led to substantial uncertainty in how they should be managed and governed. This talk synthesizes work at scales ranging from an individual reach to a cross-continental analysis to explore the drivers of flow in non-perennial streams, with a particular focus on feedbacks between non-perennial streams and groundwater resources. Using a mixture of continental-scale data synthesis, machine learning approaches, numerical models, and detailed field investigations, we find that the flow regimes of non-perennial have changed significantly through time, and that climate and human actions interact to control flow regimes at scales from the reach to the continent. 


Sam Zipper is an assistant scientist at the Kansas Geological Survey (KGS), a research and service unit at the University of Kansas. Originally from the Seattle area, he did his undergrad degree in Geology from Pomona College and a Ph.D. in Freshwater & Marine Science from the University of Wisconsin-Madison. After spending a few years in Canada, he joined KGS in August 2019 specializing in hydrogeology and ecohydrology of anthropogenic landscapes. For more information, please see his website at

Seminar postcard