Estimating evapotranspiration and groundwater flow from water-table fluctuations for a general wetland scenario

Ecohydrology
By: , and 

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Abstract

The use of diurnal water-table fluctuation methods to calculate evapotranspiration (ET) and groundwater flow is of increasing interest in ecohydrological studies. Most studies of this type, however, have been located in riparian wetlands of semi-arid regions where groundwater levels are consistently below topographic surface elevations and precipitation events are infrequent. Current methodologies preclude application to a wider variety of wetland systems. In this study, we extended a method for estimating sub-daily ET and groundwater flow rates from water-level fluctuations to fit highly dynamic, non-riparian wetland scenarios. Modifications included (1) varying the specific yield to account for periodic flooded conditions and (2) relating empirically derived ET to estimated potential ET for days when precipitation events masked the diurnal signal. To demonstrate the utility of this method, we estimated ET and groundwater fluxes over two growing seasons (2006–2007) in 15 wetlands within a ridge-and-swale wetland complex of the Laurentian Great Lakes under flooded and non-flooded conditions. Mean daily ET rates for the sites ranged from 4.0 mm d−1 to 6.6 mm d−1. Shallow groundwater discharge rates resulting from evaporative demand ranged from 2.5 mm d−1 to 4.3 mm d−1. This study helps to expand our understanding of the evapotranspirative demand of plants under various hydrologic and climate conditions.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Estimating evapotranspiration and groundwater flow from water-table fluctuations for a general wetland scenario
Series title Ecohydrology
DOI 10.1002/eco.1356
Volume 7
Issue 2
Year Published 2015
Language English
Publisher Wiley-Blackwell
Publisher location Chilchester, UK
Contributing office(s) Great Lakes Science Center
Description 13 p.
First page 378
Last page 390
Country United States
State Michigan
Online Only (Y/N) N
Additional Online Files (Y/N) N