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Abstract In arid and semiarid regions of northwest China, there are abundant shallow coal reserves throughout the region, yet during the mining process, the shallow water resources available are typically depleted due to the formation of fractures in the shallow subsurface. Water-preserved mining is the only option for coal mining in arid regions of northwest China. Based on the geological and hydrogeological conditions of the study area, this paper investigates the basic conditions and mechanisms of goaf water storage. A time series model for goaf water storage is proposed, along with a method for estimating the quantity of goaf water storage. Finally, hydrochemical characteristics of mine water and water quality characteristics after purification in the study area were analyzed. As indicated by the analysis results, after simple purification, the goaf water can meet industrial, ecological and agricultural water consumption standards. In the end, combined with current monitoring results of goaf water pressure and the status of goaf water utilization in the study area, this paper describes the quantity and the effect of utilizing goaf water storage. Goaf water storage can effectively alleviate the scarcity of local production and domestic water, and provides the most effective approach of large-scale water-preserved mining of shallow coal seams in the arid regions of northwest China. [ABSTRACT FROM AUTHOR]

The Soil and Water Assessment Tool (SWAT) model is diffusely applied to areas with uniform precipitation distribution and gentle slopes. However, the SWAT has apparent defects in the process of ecohydrological simulation in mid-high latitudes and arid regions. This model can merely be used in agricultural catchments with gentle slopes and uniform rainfall, and the simulation is not suitable for high-altitude alpine catchment. To this point, this paper makes appropriate improvements to the runoff module, and specifically corrects the key sensitive parameters. The global sensitivity and performance assessment of the model's parameters were carried out before and after the improvement using the monthly data of runoff and evaporation from 1990 to 2018 in the Kaidu River basin in northwestern China. It is indicated that the Modified SWAT simulates the performance of monthly runoff and evapotranspiration better than the original SWAT, which overestimates the runoff volume throughout hydrological changes in different periods. Compared with the monthly water production under different land use/cover conditions, the highest water production was found in forest and grassland. By modifying the SWAT algorithm, the structural non-determinacy of the Modified SWAT is significantly reduced, and the adaptability of the model is improved. Thus, the Modified SWAT shows a better simulation performance in arid areas with considerable terrain variation and scarce rainfall data. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding spatiotemporal urbanization is one of the key questions related to sustainable urbanization in the drylands of northern China (DNC). However, urban expansion in the DNC has not been quantified and assessed effectively due to a lack of reliable data and methods. In this paper, we investigate urban expansion in the DNC at multiple scales, ranging from the whole region to four dryland subtypes, and six urban agglomerations in the DNC from 1992 to 2015. We also simulate urban expansion in the DNC from 2015 to 2050 by coupling the scenario framework of the Shared Socioeconomic Pathways (SSPs) with the Land Use Scenario Dynamics-urban (LUSD-urban) model. Despite of the uncertainty in the research, our findings provide useful insight into the past and the future urban expansion in the DNC. The results indicate that the urban land in the DNC expanded rapidly from 4110 km 2 in 1992 to 20,969 km 2 in 2015. Furthermore, the urban land in the DNC will continue to expand from 20,969 km 2 to 22,987–36,622 km 2 by 2040, with an annual growth of 80.72–403.48 km 2 under all SSPs. Thus, it is suggested that effective measures are urgently needed to facilitate sustainable urban development in the DNC. [ABSTRACT FROM AUTHOR]

The determination of spatiotemporal variation in ecosystem service value and its drivers is fundamental to ecosystem service management and decision-making. This paper selects a typical oasis irrigation district in the arid regions of northwest China as the research object. Using the benefit transfer method to evaluate the ecosystem service value variation caused by land use and land cover change and characteristics of its spatial distribution based on multi-temporal land use and land cover data sets (1977, 1987, 1997, 2007, 2017). Meanwhile, the contributions of factors driving ecosystem service value and their interactions were explored using geographical detector. The results showed the following: 1) The land use and land cover structure was stable from 1977 to 2017, and the overall ecosystem service value increased slightly. The services provided by the oasis ecosystem dominated the fluctuations in ecosystem service value throughout the study region. 2) Ecosystem service value exhibited a strong positive spatial autocorrelation. The high values were concentrated in the oasis area in the north of the study area, while the low values mainly appeared in the desert ecosystem. 3) The land use degree and human activity intensity index of human factors are the main factors leading to the differentiation of ecosystem service value. Synergized interactions among human activities, changes in landscape patterns, and natural factors produced the spatial differentiation in ecosystem service value of the study region. The results suggest that in future decision-making for ecosystem management, the direction of human activities within the ecological environment should be controlled. Improve the diversity of patches, reduce the degree of landscape fragmentation, improve the ecosystem service function of LULC, optimize the allocation of ecological landscape resources. [ABSTRACT FROM AUTHOR]

As the rapid development of economy, hydropower, as a kind of cleaner energy, is bringing in huge economic benefits, leading to the appearance of a great many of hydropower plants. Decades after the hydropower plants operation, series of quite serious ecological problems were brought in due to the changes in the natural flow. To restore the river ecosystem, this paper is making efforts on seeking series of operation schemes to balance the socio-economic and ecology benefits. Therefore, a simulation (Model-I) and an optimization (Model-II) operation model are established to provide a feasibility and a reasonable scheme for the multi-objective long-term and mid-term hydropower plant operation. To resolve the complex model, large-system coordinated decomposition method and an idea that efficiently narrows down the search space are used. The Irtysh River basin in China is selected as the study area to apply the model and make a trade-off to balance the water supply for socio-economics and ecology. The results show that the average annual power generation of hydropower plant group in Model-I is 2.5% more than that in Model-Ⅱ, both more than that of practical operation. In Model-I the water supply in dry year is far less than the minimum need (50%), but the Model-II provided a reasonable solution that the water supply in dry year is close to the median need (80%). Besides, the water supply for ecology in Model-II is obviously increased compared with Model-I, and the ratio increases from 56% to 86%, at the same time, the ratios to socio-economics are from 92% to 98%. Specially, the ratio of agricultural irrigation increases from 84% to 94%. In a word, the scheme meets the water requirements for socio-economics and ecology under considering the hydropower plants benefits, providing a scientific theoretical basis for water resource management. [ABSTRACT FROM AUTHOR]

Optimization of the urban landscape composition and configuration through initiative planning is important to sustainable development of the drylands of northern China (DNC). Taking the agro-pastoral transitional zone of northern China (APTZNC) as an example, this paper developed an approach of sustainable urban landscape planning (SULP) under the stress of climate change in the DNC. First, we quantify the amount of water resources under the future climate change impacts (CCI). Then, we adjust the urban land area based on water resources carrying capacity constraints. Finally, we use the LUSD-urban (Land Use Scenario Dynamics-urban) model to adjust the configuration of the urban landscape to avoid occupying important natural habitats and corridors, prime croplands, and floodplains. We find that the SULP can effectively mitigate the comprehensive effects of regional urban landscape dynamics on water resources, food security, ecological security, and flood risks. By performing the SULP, prime croplands, floodplains, and important natural habitats and corridors occupied by urban land will decrease by 2,187 km2, 750 km2, and 130 km2, respectively, during the period of 2015–2050 in the APTZNC. We also find that the proposed approach can effectively manage the impacts of climate change on water resource capacity and reduce water stress of the entire APTZNC and its sub-regions. Thus, the proposed SULP approach and the experiences from the case study in the APTZNC are helpful for guiding urban landscape planning to achieve sustainable development of cities in the DNC and even in the drylands around the world. • Sustainable urban landscape planning under the stress of climate change was performed. • Urban land area was adjusted based on water resources carrying capacity constraints. • Urban landscape configuration was adjusted to avoid occupying important areas. • The planning can mitigate the comprehensive effects of urban landscape dynamics. • Addressing the climate change impacts should be incorporated into urban landscape planning. [ABSTRACT FROM AUTHOR]