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

Abstract

Abstract: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.

Modelling the effects of land cover and climate change on soil water partitioning in a boreal headwater catchment

“…h 50 represents the water head at which the water extraction rate is reduced by 50%; p determines the f(h) curve shape. These two parameters vary for vegetation and soils (Gribb et al, 2009;Huang et al, 2015).…”

Modelling Projected Changes in Soil Water Budget in Coastal Kenya under Different Long-Term Climate Change Scenarios

“…This was based on the analysis of actual and future (modelled) regional climate data, projected changes in climate, statistical weather realizations and the solution of Richards equation as implemented in the HYDRUS-1D model. Several studies have already carried out in similar Arid and Semi-Arid Lands (ASALs)/dry regions using the HYDRUS-1D model similar to large parts of the study area [60][61][62]. Considerations were stressed on the three soil types covering the largest area along the Kenyan coast and the adjacent hinterlands as well as the sandy soils of the Lamu sand dunes.…”

Water Resources Assessment and Management in Drylands

“…Huang et al [5], in their paper entitled "Simulation of water use dynamics by Salix bush in a semi-arid shallow groundwater area of the Chinese Erdos Plateau", evaluate the impacts of using this plant to develop shelterbelts and to return farmland to forest. They used the Hydrus-1D model to evaluate the contributions of groundwater and the plant to evapotranspiration (ET).…”