Combining Water Resources, Socioenvironmental, and Psychological Factors in Assessing Willingness to Conserve Groundwater in the Vietnamese Mekong Delta

Using the Global Land Surface Satellite (GLASS) leaf area index (LAI), the actual evapotranspiration (ETa) and available water resources in the Mekong River Basin were estimated with the Remote Sensing-Based Vegetation Interface Processes Model (VIP-RS). The relative contributions of climate variables and vegetation greening to ETa were estimated with numerical experiments. The results show that the average ETa in the entire basin increased at a rate of 1.16 mm year−2 from 1980 to 2012 (36.7% of the area met the 95% significance level). Vegetation greening contributed 54.1% of the annual ETa trend, slightly higher than that of climate change. The contributions of air temperature, precipitation and the LAI were positive, whereas contributions of solar radiation and vapor pressure were negative. The effects of water supply and energy availability were equivalent on the variation of ETa throughout most of the basin, except the upper reach and downstream Mekong Delta. In the upper reach, climate warming played a critical role in the ETa variability, while the warming effect was offset by reduced solar radiation in the Mekong Delta (an energy-limited region). For the entire basin, the available water resources showed an increasing trend due to intensified precipitation; however, in downstream areas, additional pressure on available water resources is exerted due to cropland expansion with enhanced agricultural water consumption. The results provide scientific basis for practices of integrated catchment management and water resources allocation.

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Responses of groundwater to precipitation variability and ENSO in the Vietnamese Mekong Delta

Hydrology Research ◽

10.2166/nh.2021.024 ◽

2021 ◽

Author(s):

Phong V. V. Le ◽

Hai V. Pham ◽

Luyen K. Bui ◽

Anh N. Tran ◽

Chien V. Pham ◽

...

Keyword(s):

Water Resources ◽

Climate Variability ◽

Time Scales ◽

Groundwater Level ◽

Southern Oscillation ◽

Mekong Delta ◽

Precipitation Variability ◽

Annual Precipitation ◽

Aquifer Recharge ◽

Deep Aquifers

Abstract Groundwater is a critical component of water resources and has become the primary water supply for agricultural and domestic uses in the Vietnamese Mekong Delta (VMD). Widespread groundwater level declines have occurred in the VMD over recent decades, reflecting that extraction rates exceed aquifer recharge in the region. However, the impacts of climate variability on groundwater system dynamics in the VMD remain poorly understood. Here, we explore recent changes in groundwater levels in shallow and deep aquifers from observed wells in the VMD and investigate their relations to the annual precipitation variability and El Niño–Southern Oscillation (ENSO). We show that groundwater level responds to changes in annual precipitation at time scales of approximately 1 year. Moreover, shallow (deep) groundwater in the VMD appears to correlate with the ENSO over intra-annual (inter-annual) time scales. Our findings reveal a critical linkage between groundwater level changes and climate variability, suggesting the need to develop an understanding of the impacts of climate variability across time scales on water resources in the VMD.

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Assessment of Water Resources and Salinity Intrusion in the Mekong Delta

Water International ◽

10.1080/02508060108686889 ◽

2001 ◽

Vol 26 (1) ◽

pp. 86-95 ◽

Cited By ~ 7

Author(s):

Nguyen Huu-Thoi ◽

Ashim Das Gupta

Keyword(s):

Water Resources ◽

Mekong Delta ◽

Salinity Intrusion

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A Subregional Model of System Dynamics Research on Surface Water Resource Assessment for Paddy Rice Production under Climate Change in the Vietnamese Mekong Delta

Climate ◽

10.3390/cli8030041 ◽

2020 ◽

Vol 8 (3) ◽

pp. 41

Author(s):

Tuu Nguyen Thanh ◽

Van Pham Dang Tri ◽

Seungdo Kim ◽

Thuy Nguyen Phuong ◽

Thuy Lam Mong ◽

...

Keyword(s):

Climate Change ◽

Water Resources ◽

System Dynamics ◽

Sea Level ◽

Water Consumption ◽

Human Activities ◽

Environmental Changes ◽

Mekong Delta ◽

Coastal Areas ◽

Dry Season

Effective water management plays an important role in socioeconomic development in the Vietnamese Mekong Delta (VMD). The impacts of climate change and human activities (that is, domestic consumption and industrial and agricultural activities) vary in different subregions of the delta. In order to provide intersectoral data for determining the significantly impacted subregions of the VMD, the present study simulated interactions between local climatic patterns, human activities, and water resources using a system dynamics modeling (SDM) approach with each subregion as an agent of the developed model. The average rainfall and temperature of 121 subregions in the VMD were collected during 1982–2012, and the future changes of climate by provinces were based on the Representative Concentration Pathways (RCP) scenarios (RCP4.5 and RCP8.5) by the end of 21st century. The assessment was based on the levels of impact of various factors, including (1) water consumption, (2) differences between evapotranspiration and rainfall, and (3) spatial distribution of salinity intrusion over the delta scale. In the coastal areas, as well as the central and upstream areas, water resources were projected to be affected by environmental changes, whereas the former, characterized by the lack of surface freshwater, would be affected at a greater scale during the dry season. Besides, the sea level rise would lead to an increase in negative impacts in the eastern coastal areas, suggesting that water-saving techniques should be applied not only for agriculture, but also for industry and domestic water consumption during the dry season. In addition, the south subregions (that is, the western subregions of the Hau River except for An Giang) were likely to be flooded due to the simulated high rainfall and seasonal rises of sea level during the wet season. Therefore, the alternative forms of settlement and livelihood should be considered toward balance management with changing delta dynamics.

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