In recent years, a large-scale afforestation campaign has been implemented in Inner Mongolia, China, to control desertification and soil erosion. However, the water consumption associated with large-scale afforestation significantly impacts the water resources in Inner Mongolia, resulting in a major ecological risk. This study aimed to evaluate the ecological risk of water resources caused by afforestation in the region. In this study, using land cover data, normalized difference vegetation index (NDVI) data, and meteorological data, we performed trend analysis and used the water balance equation and water security index (WSI) to analyze the ecological risks of water resources caused by afforestation in Inner Mongolia from 2000 to 2020. The results show that (1) the afforestation area in Inner Mongolia was 5.37 × 10⁴ km² in 2000–2020; (2) afforestation in arid and semi-arid areas led to a reduction in water resources; (3) afforestation reduced water resources in the study area by 62 million cubic meters (MCM) per year; and (4) ~76% of afforestation regions faced ecological risks related to water resources. This study provides scientific suggestions for the sustainable development of regional water resources and afforestation.

In the context of climate change, it is essential for sustainable development to assess the risks associated with climate change and human-induced vegetation degradation. The Hunshandake Sandy Land provides a variety of ecosystem services and is a substantial ecological security barrier in the Beijing–Tianjin–Hebei area of China. This study used the Normalized Difference Vegetation Index (NDVI) to analyze the spatiotemporal variation trend in vegetation in the Dabusennur Watershed using linear trend analysis and the GeoDetector model to identify the main drivers of vegetation change in the watershed. Finally, the study assessed the risk of ecological degradation in the vegetation of the watershed. The results show that the NDVI in the study area has had a fluctuating trend in the last 22 years, and the change has been small. Precipitation and groundwater depth are the key factors affecting vegetation change. The NDVI reaches its maximum value when the groundwater depth is at 2.75 m. The vegetation ecology of the basin is relatively fragile, mainly with medium risk and large risk. To cope with the ecological risk of vegetation degradation caused by climate change, appropriate water use strategies should be formulated to ensure ecological water use. The present study’s outcomes provide the basis for developing ecological engineering solutions in the arid and semi-arid parts of northern China.

The study of the temporal evolution of chloride ions in groundwater is important for identifying whether their sources are due to anthropogenic pollution or natural factors. Groundwater in the northern part of Dalat Banner, Ordos City, has high chloride ion content and exhibits strong temporal variability. To identify the source of chloride ions and reveal their evolution mechanisms, the fast Fourier transform (FFT) was used to determine the trend and cycle of chloride ion evolution, and the groundwater dynamics field combined with multivariate statistical analysis was used to identify the source of chloride ion pollution. Calculations show that the background value of chloride ions in groundwater in the study area is 195.17 mg/L, reaching a maximum of 459 mg/L under the influence of rainfall. The fluctuation of chloride ion concentration is mainly related to the total rainfall in the study area over 165 days, and a single rainfall of more than 15 mm affects the concentration of chloride ions in groundwater. The results of this study show that the background values of chloride ions are mainly influenced by the groundwater dynamical field, and the temporal volatility is mainly influenced by atmospheric rainfall.