Accurately identifying and predicting droughts can provide local managers with a basis for decision-making. The Xinyang region is prone to droughts and floods, which have a large impact on local agriculture and socio-economics. This paper employs precipitation data from the Xinyang region to provide a scientific basis for drought and flood control measures in this region. The data are first treated with standardized precipitation indices (SPIs) on three-month, six-month, and nine-month time scales. Subsequently, a Morlet wavelet analysis is performed for each of the three time scales analyzed for the SPI. The results show multiple time scales of drought and flood disasters in the Xinyang region. The cycles of drought and flood disasters in the Xinyang region show different fluctuations on different SPI scales. The SPI time series reflect a strong fluctuation period of 17a for drought and flood disasters in the Xinyang region. An analysis of the variance of the wavelet coefficients showed that the first main cycle of drought and flood disasters in the Xinyang region is 7a, and the second and third sub-cycles are 4a and 13a, respectively. We conclude that floods are more frequent than droughts in Xinyang and are more likely to occur from 2017 to 2021, with a subsequent shift to droughts. Local managers should put drought prevention measures in place to deal with droughts after 2021.

The Ebinur Lake Basin is an ecologically sensitive area in the arid region of northwest China. In recent years, the ecological environment in the basin has continued to deteriorate, and the ecosystem function has been seriously degraded. However, among the functions of the ecosystem in the Ebinur Lake Basin, the water production function is considered to be the core upholding the ecological equilibrium and security of the basin. Water production can reflect the environmental service function, which is essential for the economic vitality and ecological well-being of the basin. The factors that impact water yield are diverse; moreover, of these, climate change and land use conversion are particularly significant. Therefore, understanding how these changes affect water yield will help to formulate proper water management strategies in the basin. Using the InVEST model, this study examined how the water yield evolved and was distributed across the Ebinur Lake Basin between 2000 and 2020 while considering both the temporal and spatial dimensions. Using this foundation, the scenario analysis approach was utilized to explore the impact of climate change and land use conversion on water yield by controlling the variables, and the response of the water yield to climate and land use change was discussed. It was concluded that water yield was on an upward trend from 2000 to 2010, was on a downward trend from 2010 to 2020, and declined from 2000 to 2020 as a whole. Regarding the water yield distribution, higher-water-producing areas were found predominantly in the northwest and southeast and along the higher-altitude rim of the basin. Among the various land categories, the primary types were grassland and unused land, both of which equally and substantially contributed to the water yield, contributing over 85% to the overall water yield. The response of the water yield varied significantly among various land use types when their areas changed, and the land conversion over this period contributed to a slight decline in water yield across the basin. The influence of climate change on water yield in the Ebinur Lake Basin during the study period surpassed that of land use by a wide margin, constituting more than 86% of the total impact. This study can provide relevant information for relevant policies and decisions on the optimal allocation of land use in the Ebinur Lake Basin and can provide scientific development for the comprehensive evaluation of water resources and sustainable development of the basin.

It is important to clarify the suitable ratio of well–canal combined irrigation and the suitable range for ecological groundwater depth for the ecological stability of the arid zone. The MODFLOW model was used to reconstruct long-term groundwater depth by analyzing the response relationship between vegetation cover and groundwater depth in the Weigan River irrigation district. The suitable range for ecological groundwater depth was obtained, and based on this range, the suitable well–canal combined irrigation ratio in the research area was further simulated. The results show the following: (1) The average annual depth of groundwater in 82.9% of the study area increased from 2012 to 2021, and the average annual depth of groundwater increased by 1.03 m in 2021 compared to 2012. The average depth of the groundwater in the upstream area increased the most, with an increase of 1.96 m. (2) The vegetation cover in the study area from 2012 to 2021 increased in general, with an increase of 0.0461 over the 10-year period, but it fluctuated between years. (3) The depth of the groundwater in the study area suitable for the growth of vegetation in the irrigation area ranged from 3 to 5 m, and the value of NDVI within this range concentrated near 0.564–0.731, which represents a good state of vegetation growth. (4) The ratio of combined well and canal irrigation in the study area from 2012 to 2014 surged from 0.13 in 2012 to 0.48 in 2014, and the irrational harvesting and replenishment relationship led to a rapid increase in the depth of buried groundwater. A suitable well–canal combined irrigation ratio of 0.396 in the study area was obtained. This study is beneficial for maintaining the sustainable development and utilization of water resources and ecological stability in the Weigan River irrigation district.