The Influence of Climatic, Watershed, and Water-use Changes on Extreme Low Streamflows in the United States

Science Center Objects

Extreme low streamflows impact water availability for human systems and ecosystems. Numerous researchers have analyzed trends in low streamflows in the U.S. There is no known published work, however, on historical trends over time in the most extreme low streamflows—the flows with the largest impacts on human systems and ecosystems. The current study attempts to fill this gap. The wealth of historical U.S. Geological Survey streamflow, watershed, and water-use data across the country provides a great opportunity to better understand this critical issue.

 

Our Research: We aim to provide better understanding of the effect of historical climatic changes, human watershed changes (such as urbanization and reservoir storage), and water-use changes on extreme low flows in the United States.

Why this Research is Important: Hydrologic drought in the United States can have severe impacts on agriculture, municipal water supply, and ecosystems. It is important to know whether extreme low flows have been changing over time and why, to better inform future drought flows.

Ipswich River in Reading, Massachusetts at low water level

Ipswich River at extreme low streamflow in Reading, Massachusetts during September, 2005. 

(Credit: David Armstrong, USGS. Public domain.)

Objective(s):

  1. Hydrologic drought in the United States can have severe impacts on agriculture, municipal water supply, and ecosystems. It is important to know whether extreme low flows have been changing over time and why, to better inform future drought flows.
     
  2. Identify the climatic influences and direct human influences on extreme low streamflows in the United States by examining trends and variability in extreme low streamflows for both least-disturbed and disturbed basins across the country.

  3. Investigate the influence of winter and spring groundwater recharge on summer low streamflows.

Methods: Research continues with project collaborators to select the best statistical methods for each project objective.