Soil Water and Phreatic Evaporation in Shallow Groundwater during a Freeze–Thaw Period

Chunyan Miao,Qi Du,Junfeng Chen,Xiuqing Zheng,Yongxin Xu,Yongbo Zhang

doi:10.3390/w9060396

Chunyan Miao, Qi Du + Show 4 more

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https://doi.org/10.3390/w9060396

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Abstract

The exchange between shallow groundwater and soil water is unusually strong during freeze-thaw periods. The purpose of this study is to determine the effect of four different groundwater table depths (GTDs) and two soil textures on soil water moisture migration and phreatic evaporation during a freeze-thaw period using lysimeters. The results show that a high-moisture zone (HMZ) formed at a depth of 25–35 cm for sandy loam with a soil moisture content of 52%, while no obvious HMZ formed for fine sand when the GTD was 0.5 m. When the GTD was 2.0 m, a HMZ formed at a depth of 50–70 cm for sandy loam at the highest soil moisture content of 22%, while a HMZ formed at a depth of 60–80 cm for fine sand with a soil moisture content of 10%. The cumulative phreatic evaporation increased by a power function on freezing days during the freezing period. The total phreatic evaporation for sandy loam declined linearly with the increasing of GTD, and with the largest evaporation value of 73.6 mm for fine sand when the GTD was 1.0 m during the freeze-thaw period. The research would be significant for water resource assessment, the conversion of farmland water, and the prevention of saline land.

Highlights

The exchange between the vadow zone and shallow groundwater is an important process in a water cycle
The groundwater table depths (GTDs) was 0.5 m with sandy loam, a high-moisture zone (HMZ) formed at a depth of 25–35 cm and the maximum soil
When the GTD was 0.5 m with sandy loam, a HMZ formed at a depth of 25–35 cm and the maximum moisture content was up to 52%; no obvious HMZ formed for the fine sand

Summary

Introduction

The exchange between the vadow zone and shallow groundwater is an important process in a water cycle. Phreatic evaporation is the major form of groundwater consumption. It is one of the main water sources of regional evapotranspiration in shallow groundwater areas [1], which can result in soil salinization [2,3,4], and can affect the accuracy of water resource evaluation [5]. Many investigators in soil physics, hydrogeology, irrigation and drainage, and surface water and water source science have conducted a great deal of research on the mechanisms and laws of phreatic evaporation.

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