Alterations to groundwater chemistry due to modern water transfer for irrigation over decades
Alterations to groundwater chemistry due to modern water transfer for irrigation over decades
复制标题
几十年来现代灌溉输水导致地下水化学变化
DOI：
10.1016/j.scitotenv.2020.137170
复制
发表时间：
2020-05-15
影响因子：
9.8
通讯作者：
Gao, Yanyan
中科院分区：
文献类型：
--
作者：
Jia, Hui;Qian, Hui;Gao, Yanyan
After a long-term surface irrigation in the southern edge of the Chinese Loess Plateau, the local groundwater is diluted to some extent, which differs from most of the other surface irrigation systems. Identifying the origin of groundwater salinity and determining the implications of irrigation can provide insights into the sustainable development of irrigation systems. In this study, a comprehensive investigation of groundwater, river water, canal water, and irrigation system was conducted. Our results suggest that the irrigation activities produce significant influence on the hydrochemistry of both river and groundwater. In the north-eastern part of the study area, hydrochemistry types are mainly HCO3-Na and HCO3 center dot SO4-Na types which is recharged by the river replenished by water transfer for irrigation. In the south-western part, groundwater is mainly HCO3-Na center dot Mg type which largely directly receives canal water recharge. The correlation between the irrigation water volume and the salinity variation confirms that mixing with fresh irrigation water which was derived from the reservoirs and the canals, during the irrigation period, dilutes the local groundwater. The natural hydrogeochemical processes of the loess aquifer suggest that the water-rock interactions and cation exchange process supply the excessive Na+ and other solutes to the groundwater, resulting HCO3-Na type water with high salinity. Additionally, the slow Groundwater flow and poor hydrologic cycle between the groundwater and the scarce rainfall promote natural salts accumulation. The delta O-18 and delta D values indicate that modern rainfall may only account for small part of recharge to groundwater. In contrast, the irrigation water, as well as the canal and the reservoir seepage, contribute to a large proportion of groundwater recharge. The finding is beneficial for the policy-makers for the future water management schemes, in large surface irrigation systems, in order to achieve sustainable development goal. (C) 2020 Elsevier B.V. All rights reserved.
