Assessing existing surface water supply sources in the Vietnamese Mekong delta: case study of Can Tho, Soc Trang, and Hau Giang provinces

The VMD, home to over 21 million people, is a part of the Mekong delta that covers an area of approximately 3.9 million hectares with a dense maze of canals and rivers [1]. Water plays a significant role in strategies for economic growth for the region in general and specifically for the provinces of Can Tho, Hau Giang, and Soc Trang [2]. Nonetheless, in recent years, the impacts of climate change and sea level rise are serious threats as they cause extreme phenomena such as salinity intrusion and severe droughts [3, 4]. These negative effects on water supply security in the delta creates possible threats to water supply systems. While groundwater is widely used in coastal areas, surface water is still a primary source of water in the provinces. However, the substantial extraction of groundwater for domestic use causes delta-wide subsidence that necessarily restricts excessive groundwater extraction [5, 6], therefore, the probability of switching to surface water needs to be taken into account. Rivers and canals in this region are usually considered as surface water resources for water supply systems. Nevertheless, the degradation of surface water quality due to pollution from anthropogenic activities has also limited the availability of surface water for domestic use in these provinces [7]. Assessing the water quality from the rivers and canals therefore is an important part of identifying acceptable areas for surface water supply abstraction to support water supply management. Currently, most water treatment plants in the VMD experience low capability of desalination followed by expensive construction and operation costs [8, 9]. Meanwhile, salinity is a significant criterion for the selection of water sources. Selected water sources are characterized by low frequency of salinity. Geographic Information System (GIS) software has continually demonstrated very informative spatial analyses in water monitoring research that supports water supply management. This paper aims to evaluate existing salinity and surface water quality in Can Tho, Hau Giang, and Soc Trang provinces, thereby building effective strategies and providing support to water utilities for water supply security in the context of climate change and local human activities. Assessing existing surface water supply sources in the Vietnamese Mekong delta: case study of Can Tho, Soc Trang, and Hau Giang provinces