Use of Groundwater and Surface Water Fluctuations to Estimate Evapotranspiration

Wednesday, February 24, 2016: 10:05 a.m.
Paul Davis , EnviroLogic Inc., Durango, CO
Sergey Pozdniakov , Faculty of Geology, Dept. of Hydrogeology, Moscow, Russia
James Syme , RAND Corporation, Santa Monica, CA

An important component of groundwater resource management is the knowledge of water removed from the system by evapotranspiration. In this study, estimates of evapotranspiration in northwest New Mexico were derived from fluctuations of groundwater levels in piezometers and from fluctuation in streamflow. Fourier analysis was used to separate and quantify the daily fluctuations caused by evapotranspiration from other potential causes of diurnal fluctuations. For surface water, the resulting fluctuations were directly integrated to yield estimates of daily evapotranspiration. For groundwater, the resulting fluctuations were combined with a one-dimensional groundwater flow model to yield daily estimates of evapotranspiration. Analysis of the daily evapotranspiration estimates over time revealed a systematic change in evapotranspiration throughout the year.

Paul Davis, EnviroLogic Inc., Durango, CO
Paul Davis is a consulting geohydrologist who owns EnviroLogic Inc located in Durango, Colorado. He graduated from the University of New Mexico with a degree in geology and New Mexico Institute of Mining and Technology with a degree in hydrology. Prior to starting EnviroLogic Inc., Mr. Davis worked at the US Geological Survey’s Water Resources Division in Albuquerque as well as at Sandia National Laboratories. Mr. Davis is currently a member of the United Kingdom’s Committee on Radioactive Waste Management and a consultant to the International Atomic Energy Agency.

Sergey Pozdniakov, Faculty of Geology, Dept. of Hydrogeology, Moscow, Russia
Sergey Pozdniakov is a member of the Faculty of Geology and Chair of the Department of Hydrogeology at Moscow State University in Russia.

James Syme, RAND Corporation, Santa Monica, CA
James Syme worked for Envirologic Inc from 2009 to 2012. While there, he worked developing methodologies for estimating ET from stream records and treating stable isotope mass balance mixing models with uncertainty in addition to providing support for hydrologic analysis and groundwater modeling. He holds a BS in pure mathematics and a BA in political science from the University of New Mexico and an MS in Applied Mathematics from the University of Colorado Denver. James is currently a research assistant at RAND Corporation in Santa Monica, CA, where much of his work focuses on planning for climate change under uncertainty.