Groundwater monitoring for evaluating the pasture carrying capacity and its vulnerability in arid and semi-arid regions: A case study of urban and mining areas in Mongolia

Abstract

Arid and semi-arid regions cover 41% of the global land area and 2 billion people, 90% of which belong to developing countries, live there. Variation in precipitation due to climate change brings big large influences on ground and underground water resources, and especially it is predicted that arid and semi-arid regions are getting drier. Therefore, it is imperative to clarify impacts to environmental vulnerability caused by the variation of water cycle (VWC) due to climate change and consider options for its adaption. Mongolia is a typical country where environmental vulnerability is getting worse by VWC. Our previous studies revealed that the increase of evapotranspiration and permafrost degradation by global warming deteriorate the pasture carrying capacity (PCC) in semi-arid regions in Mongolia. In this manner, VWC is a key component of PCC, but VWC depends on not only climate change but also human activities. Recent mine development and urbanization, as well as growth of livestock, increase groundwater use, but their influences have not been clarified. To explore the influence of urbanization and mining, we have started groundwater monitoring of urban areas in semi-arid regions (Northern Mongolia) and mining areas in arid regions (Southern Mongolia) since May 2018. After investigating hundreds of wells in those areas, and finally selected 11 wells in urban areas and 7 wells in mining areas for groundwater monitoring. 22 Onset HOBO U20 Water Level Loggers (Forestry Suppliers, Inc.), including 5 Loggers for atmospheric correction, and a Water Flow Rate Sensor (Keyence Inc.) are working for measuring groundwater usage. Meanwhile, with data analyses of groundwater level at 875 wells from 2015 to 2017 measured by the local basin authority, it was found that the groundwater level of mining area had a tendency of decreasing widely comparing with that of non-mining area.