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| DOI：10.13522/j.cnki.ggps.2025306 |
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| Spatiotemporal dynamics of groundwater depth in the Dengkouyangshui Irrigation District, Inner Mongolia |
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Meng Xin, Zheng Hexiang, Wang Wanning, Li Xianyue, Ma Ruidong
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1. Institute of Water resources Science of Pasturing Area of the Ministry of Water Resources, Hohhot 010020, China;
2. Inner Mongolia Agricultural University, Hohhot 010018, China;
3. Inner Autonomous Region Huanghe Dengkou Irrigation District Management Center, Baotou 014030, China
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| Abstract: |
| 【Objective】Most arid and semi-arid regions depend heavily on groundwater to support agricultural production, making an understanding of groundwater dynamics and their driving factors essential for sustainable water-resource management. This study analyzed the spatiotemporal variation in groundwater depth and its major influencing factors in the Dengkou Irrigation District, Inner Mongolia, China.【Method】The analysis was based on groundwater and related hydroclimatic and irrigation data collected from 2018 to 2024. The Mann-Kendall trend test and spatial interpolation methods were used to characterize temporal trends and spatial patterns of groundwater depth, respectively, and to examine their relationships with irrigation water diversion, precipitation, and hydrogeological conditions.【Result】①From 2018 to 2024, groundwater depth ranged from 1.7 to 2.8 m and exhibited an annual increasing trend of approximately 0.2 m. Seasonally, surface water diverted from the Yellow River for spring and autumn irrigation accounted for approximately 15% and 40% of the annual irrigation water supply, respectively, and was associated with decreases in groundwater depth of 17% and 14%, respectively. Approximately 70% of annual precipitation occurred during rainy season, contributing to groundwater recharge and a shallower groundwater depth. ②Groundwater depth in all three irrigation sub-districts showed an increasing trend from 2018 to 2024, but the temporal patterns differed because of differences in Yellow River water diversion and hydrogeological conditions. The Main Canal Irrigation District experienced the largest increase in Yellow River water diversion, the deepest groundwater levels, and the fastest increase in groundwater depths. The Minsheng Canal Irrigation District showed a significant synchronous increase in water diversion and groundwater depth, together with relatively shallow groundwater and the steepest increasing trend in groundwater depth. The extensive distribution of water-rich zones contributed to pronounced fluctuations in groundwater depth. The Yuejin Canal Irrigation District was the only sub-district where Yellow River water diversion decreased; it had the shallowest groundwater depth and relatively stable groundwater dynamics. Its moderate groundwater abundance, slower runoff, and declining water diversion were associated with weaker groundwater recovery and smaller fluctuations in groundwater depth. ③Spatially, groundwater depth generally increased from the east to the west. Groundwater depth in the Main Canal Irrigation District ranged from 4.5 to 6.5 m, whereas that in the Minsheng and Yuejin Canal Irrigation Districts ranged from 1 to 3 m. Across all three sub-districts, groundwater was deeper in the west and shallower in the east, reflecting spatial differences in hydrogeological conditions and groundwater recharge and discharge processes.【Conclusion】From 2018 to 2024, groundwater depth in the Dengkou Irrigation District exhibited an overall increasing trend with considerable temporal fluctuations and was greater in the west than in the east. Groundwater dynamics were jointly influenced by precipitation, irrigation practices, Yellow River water diversion, and hydrogeological conditions. These findings provide a basis for improving integrated groundwater and irrigation-water management in the Dengkou Irrigation District and other arid irrigation regions. |
| Key words: groundwater level dynamics change Mann-Kendall trend test Dengkou Irrigation Region |
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