Spatiotemporal patterns of water table fluctuations and evapotranspiration induced by riparian vegetation in a semiarid area

Authors

Weifeng Yue, Beijing Normal University
Tiejun Wang, University of Nebraska-Lincoln
Trenton E. Franz, University of Nebraska-LincolnFollow
Xunhong Chen, University of Nebraska-Lincoln

Document Type

Article

Date of this Version

2016

Citation

Yue, W., T. Wang, T. E. Franz, and X. Chen (2016), Spatiotemporal patterns of water table fluctuations and evapotranspiration induced by riparian vegetation in a semiarid area, Water Resour. Res., 52, 1948–1960, doi:10.1002/2015WR017546.

Comments

Copyright 2016. American Geophysical Union. All Rights Reserved.

Abstract

Groundwater evapotranspiration (ET_g) links various ecohydrological processes and is an important component in regional water budgets. In this study, an extensive monitoring network was established in a semiarid riparian area to investigate various controls on the spatiotemporal pattern of water table fluctuations (WTFs) and ET_g induced by riparian vegetation. Along a vegetation gradient (~1200 m), diurnal WTFs were observed during a growing season in areas covered by woody species (Populus sect. Aigeiros and Juniperus virginiana) and wet slough vegetation (Panicum virgatum and Bromus inermis) with deeper root systems; whereas, no diurnal WTFs were found in the middle section with shallower-rooted grasses (Poa pratensis and Carex sp.). The occurrence of diurnal WTFs was related to temperature-controlled plant phenology at seasonal scales and to radiation at subdaily scales. Daily ET_g in the mid-growing season was calculated using the White method. The results revealed that depth to water table (DTWT) was the dominant control on ETg, followed by potential evapotranspiration (ET_p). By combining the effects of DTWT and ET_p, it was found that at shallower depths, ET_g was more responsive to changes in ET_p, due to the closer linkage of land surface processes with shallower groundwater. Finally, exponential relationships between ET_g/ET_p and DTWT were obtained at the study site, although those relationships varied considerably across the sites. This study demonstrates the complex interactions of WTFs and ET_g with surrounding environmental variables and provides further insight into modeling ETg over different time scales and riparian vegetation.