Simulation of Water Use Dynamics by Salix Bush in a Semiarid Shallow Groundwater Area of the Chinese Erdos Plateau

Water

Jinting Huang³  Yangxiao Zhou²  Rongze Hou¹  Jochen Wenninger² 

[1] Faculty of Engineering and Information Technology, Griffith University, 404 Musgrave Road, Coopers Plains QLD 4018, Australia;UNESCO-IHE Institute for Water Education, Department of Water Science and Engineering, P.O. Box 3015, Delft 2601 DA, The Netherlands;;Department of Hydrogeology and Environmental Geology, Xi’an Institute of Geology and Mineral Resources, No. 438, Youyidong Road, Xi’an 710054, China

关键词: shallow groundwater table;    heat transport;    liquid water and water vapor fluxes;    Salix bush;    HYDRUS-1D;    semi-arid;   

DOI  :  10.3390/w7126671

来源: mdpi

【 摘 要 】

This study analyzed the water use of the Salix psammophila bush in a semi-arid area in northwest China using a Hydrus-1D model. The model incorporated the effect of thermally driven water flow coupling liquid water, water vapor and heat transport. The model was calibrated and validated using hourly field measurements of soil water content and temperature at different depths for a growing season of 154 days. Furthermore, another Hydrus-1D model was established to simulate environments with decreased heat, rainfall or temperature and an increased leaf area index using calibrated and validated parameters. Our results show that upward and downward thermally driven water vapor fluxes account for 0.11% and 0.28%, respectively, of the corresponding direction of total water flux during the bush’s growing season. Although the vapor flux is very small, simulations incorporating heat flow revealed alterations in the temperature and pressure head gradients over the root zone, especially during dry periods. Consequently, the cumulative contributions of groundwater to evapotranspiration (ETg) with heat flow and without heat flow were 26.9% and 40.6%, respectively, during the simulation period. Therefore, the cumulative contribution of groundwater to ETg is overestimated when heat flow is excluded. Thus, we recommended that heat transport be incorporated when evaluating ETg in arid and semi-arid areas.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.