Estimation of evapotranspiration for terrestrial phreatophytes: Case study in the Hailiutu River Watershed of Erdos Basin, China

In arid and semi-arid area, evapotranspiration (ET) is a major component of the water budget in vegetated soils and shallow groundwater systems. This paper analysis the transpiration characters of terrestrial phreatophytes base on a case study in the HaiLiutu River Watershed of Erdos Basin, China. The results shows that the net radiation is the major effect for transpiration and under deep root reach capillary height of groundwater conditions, transpiration of salix supply mainly by groundwater and the vadose zone acts as conveyor. The potential ET and ET of groundwater are estimated by Penman-Monteith equation and modified White method respectively. The comparison between Penman-Monteith and modified White method´s values shows lag characters because of the difference between the local and overall hydraulic gradients. The study results afford further scientific evidences for water budget.