Abstract
In recent years, the amount of water diverted from the Yellow River has been decreasing year by year, which is the biggest problem for the development and utilization of water resources in Yinchuan Oasis (YCO). Through the implementation of the Agricultural Water-saving Transformation Project (AWSTP), water resource shortage in the YCO has been alleviated greatly, and ecological degradation problems, such as soil salinization, have also been effectively addressed. However, how the shallow groundwater in YCO has changed after the AWSTP remains unclear. This paper, based on a lot of statistical data and measured data, and by using statistical and geostatistical methods, reveals the evolution of shallow groundwater in YCO in the past 18 years (2000–2017), since the implementation of the AWSTP and its driving factors, from two aspects: groundwater dynamics and groundwater quality. The results show that compared with the initial stage of AWSTP, the amount of water diverted from the Yellow River for the YCO reduced by 36%, and accordingly, the average groundwater depth in the irrigation period increased from 0.98 m to 2.01 m, representing an increase of 1.03 m, and an average annual increase of 6cm. Moreover, the depth increase in the irrigation period is higher than that in the non-irrigation period, and that in the Northern Irrigation Area (NIA) is higher than that in the Southern Irrigation Area (SIA). Furthermore, the groundwater storage is decreasing at a rate of 855.6 × 104 m3·a−1, and the cumulative storage has reduced by nearly 1.54 × 108 m3, indicating that it is in a long-term negative equilibrium. In terms of temporal and spatial distribution of total dissolved solids (TDS) in groundwater, the TDS in SIA and NIA decreased from 1.41 g·L−1 and 1.84 g·L−1 to 1.15 g·L−1 and 1.77 g·L−1, respectively. The saline water area with a TDS above 5 g·L−1 and the freshwater area with a TDS below 1 g·L−1 decreased by 16.6 km2 and 334.4 km2, respectively, while the brackish water area with a TDS of 1~3 g·L−1 increased by 492 km2. The spatial and temporal distribution heterogeneity of TDS in groundwater is reduced and is in a slight desalinized trend overall. However, the groundwater in some areas, such as the Xingqing District, Jinfeng District, Xixia District, Yongning County, Helan County and Huinong District of Yinchuan Oasis, is at risk of further salinization. Due to the agricultural water-saving caused by the reduction of water amount diverted from the Yellow River, the groundwater recharge in YCO was reduced by 36.3%, which, together with measures such as drainage, groundwater exploitation, and industrial restructuring, drives the groundwater circulation in the YCO to a new equilibrium. This study can help us to understand the influencing process and mechanism of agricultural water-saving on groundwater systems in YCO and provide reference for efficient use and optimal allocation and management of agricultural water resources.
Highlights
Water resource plays an important role in human’s life and social development, and is the biggest challenge to ecological security and economic development [1]
K =1 where, ∆Wi is the variation of groundwater storage in the ith year in Yinchuan Oasis; k = 1, 2, with 1 for the Northern Irrigation Area (NIA) and 2 for the Southern Irrigation Area (SIA); i is the year, which is from 2000~2017; μ is the specific yield of phreatic aquifer in YCO, which is usually 0.039–0.051 according to the calculation results of the hydrogeological department, with 0.051 for SIA and 0.039 for NIA ; ∆Hik is the average variation of the water table at the end of the ith year in SIA or NIA; Fk is the area of NIA or SIA
The research above shows that the groundwater depth in Yinchuan Oasis, no matter in Southern or NIA, is deepening and the accumulative groundwater storage is decreasing after water-saving transformation
Summary
Water resource plays an important role in human’s life and social development, and is the biggest challenge to ecological security and economic development [1]. Water-saving irrigation, as a method to relieve the water use conflict between humans and nature, has been popularized in arid regions around the world [4,5]. It plays a very important strategic role in ensuring water security, food security, ecological security, and sustainable development of agriculture [6]. For the impact of agricultural water-saving on groundwater, studies on groundwater levels and evaporation variation account for a relatively large proportion [20,21,22,23,24,25,26,27]. Xu and his colleagues studied the impact of water-saving on groundwater levels in Hetao Irrigation District using the lumped groundwater balance model
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Environmental Research and Public Health
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
