Investigating the Spatio-Temporal Variation of Soil Moisture and Agricultural Drought towards Supporting Water Resources Management in the Red River Basin of Vietnam

Nguyen Duc Luong,Thi Hieu Bui,Nguyen Hoang Hiep

doi:10.3390/su13094926

Abstract

The increasing serious droughts recently might have significant impacts on socioeconomic development in the Red River basin (RRB). This study applied the variable infiltration capacity (VIC) model to investigate spatio-temporal dynamics of soil moisture in the northeast, northwest, and Red River Delta (RRD) regions of the RRB part belongs to territory of Vietnam. The soil moisture dataset simulated for 10 years (2005–2014) was utilized to establish the soil moisture anomaly percentage index (SMAPI) for assessing intensity of agricultural drought. Soil moisture appeared to co-vary with precipitation, air temperature, evapotranspiration, and various features of land cover, topography, and soil type in three regions of the RRB. SMAPI analysis revealed that more areas in the northeast experienced severe droughts compared to those in other regions, especially in the dry season and transitional months. Meanwhile, the northwest mainly suffered from mild drought and a slightly wet condition during the dry season. Different from that, the RRD mainly had moderately to very wet conditions throughout the year. The areas of both agricultural and forested lands associated with severe drought in the dry season were larger than those in the wet season. Generally, VIC-based soil moisture approach offered a feasible solution for improving soil moisture and agricultural drought monitoring capabilities at the regional scale.

Highlights

Published: 28 April 2021The Red River basin (RRB) is one of the largest river basins in the world and the second largest river basin in Vietnam, which crosses three countries including China, Laos, and Vietnam
The areas that suffered from the mild drought (D1) and severe drought (D3) for these two types of agricultural and pasture land in the dry season (4.31% of total area) were 1.28 times larger than those in the wet season (3.38% of total area)
The variable infiltration capacity (VIC) macroscale hydrological model was applied for simulation of the daily soil moisture at a grid resolution of 0.1◦ × 0.1◦ during the 10-year period of 2005–2014 for the northeast, northwest, and River Delta (RRD) regions of the RRB part belongs to the territory of Vietnam

Summary

Introduction

Published: 28 April 2021The Red River basin (RRB) is one of the largest river basins in the world and the second largest river basin in Vietnam, which crosses three countries including China, Laos, and Vietnam. The RRB has a tropical monsoon climate with distinct dry and wet seasons. Droughts occur frequently in the RRB, especially during the dry season in which many areas of the RRB suffer serious water shortage that significantly affects economic activities (i.e., domestic water supply and irrigation water). In the dry season of 2005, the water level in the Red River decreased to the lowest level for the last 100 years. Under the context of the increasing impact of climate change in recent years, especially during the dry season, the increased average temperature has led to greater evaporation. The frequent and serious droughts in the RRB have unfavorable impacts on agriculture, ecosystem, hydrology, and socioeconomic development.

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