Carrying Capacity and Coupling Coordination of Water and Land Resources Systems in Arid and Semi-arid Areas: A Case Study of Yulin City, China

Quantitatively assessing the carrying capacity of water and land resources systems in arid and semi-arid areas is crucial for achieving the 2030 Sustainable Development Goals.In this work,taking Yulin City in China as a case study and employing the Criteria Importance Through Intercriteria Correlation(CRITIC)method,a modified model of coupling degree was developed to evaluate the car-rying capacity of water and land resources systems endowment and utilization,as well as their coupling coordination degree from 2013 to 2020.Our findings indicate that the water and land resources of Yulin are diminishing due to declines in agriculture,higher industrial water use,and wetland shrinkage.However,reallocating domestic water for ecological sustainability and reducing sloping farmland can mitigate this trend of decline.Temporally,as the coupling coordination between water and land resources system endowment in Yulin continuously improved,the coupling coordination between water and land resources system utilization first decreased and then in-creased with 2016 as the turning point.Spatially,the carrying capacity of water and land resources systems,the coupling coordination degree between water and land resources system endowment,and the coupling coordination degree between water and land resources system utilization in Yulin exhibited the same pattern of being higher in the six northern counties than in the six southern counties.Improving the water resources endowment is vital for the highly efficient use of water and land resources.

Optimization of water-urban-agricultural-ecological land use pattern:A case study of Guanzhong Basin in the southern Loess Plateau of Shaanxi Province,China

Extensive land use will cause many environmental problems.It is an urgent task to improve land use efficiency and optimize land use patterns.In recent years,due to the flow decrease,the Guanzhong Basin in Shaanxi Province is confronted with the problem of insufficient water resources reserve.Based on the Coupled Ground-Water and Surface-Water Flow Model(GSFLOW),this paper evaluates the response of water resources in the basin to changes in land use patterns,optimizes the land use pattern,improves the ecological and economic benefits,and the efficiency of various spatial development,providing a reference for ecological protection and high-quality development of the Yellow River Basin.The research shows that the land use pattern in the Guanzhong Basin should be further optimized.Under the condition of considering ecological and economic development,the percentage change of the optimum area of farmland,forest,grassland,water area,and urban area compared with the current land use area ratio is+2.3,+2.4,-6.1,+0.2,and+1.6,respectively.The economic and ecological value of land increases by14.1%and 3.1%,respectively,and the number of water resources can increase by 2.5%.

Study on ecological and economic effects of land and water resources allocation in Sanjiang Plain

The pattern of groundwater usage and industrial development in the Sanjiang Plain remains a concern of Chinese government. In accordance with the Water Conservancy Planning of the Sanjiang Plain, this paper presents a Sanjiang Plain resources allocation model which is established to be used in controlling water, land, ecology and economy in consideration of 50%-level and 75%-level years, planting structure adjustment, industry development by 2020, and different transit water exploitation schemes. Lingo10 global optimization has been adopted in solving the model. The results show that by 2020 the output of three industries will increase to a certain degree, the grain yields will satisfy state demand, and regional service value will decrease dramatically. Such results provide theoretical basis and practical significance for instructing the development and exploitation of the Sanjiang Plain.

Climate change, water resources and sustainable development in the arid and semi-arid lands of Central Asia in the past 30 years

The countries of Central Asia are collectively known as the five "-stans": Uzbekistan, Kyrgyzstan, Turkmenistan, Tajikistan and Kazakhstan. In recent times, the Central Asian region has been affected by the shrinkage of the Aral Sea, widespread desertification, soil salinization, biodiversity loss, frequent sand storms, and many other ecological disasters. This paper is a review article based upon the collection, identification and collation of previous studies of environmental changes and regional developments in Central Asia in the past 30 years. Most recent studies have reached a consensus that the temperature rise in Central Asia is occurring faster than the global average. This warming trend will not only result in a higher evaporation in the basin oases, but also to a significant retreat of glaciers in the mountainous areas. Water is the key to sustainable development in the arid and semi-arid regions in Central Asia. The uneven distribution, over consumption, and pollution of water resources in Central Asia have caused severe water supply problems, which have been affecting regional harmony and development for the past 30 years. The widespread and significant land use changes in the 1990 s could be used to improve our understanding of natural variability and human interaction in the region. There has been a positive trend of trans-border cooperation among the Central Asian countries in recent years. International attention has grown and research projects have been initiated to provide water and ecosystem protection in Central Asia. However, the agreements that have been reached might not be able to deliver practical action in time to prevent severe ecological disasters. Water management should be based on hydrographic borders and ministries should be able to make timely decisions without political intervention. Fully integrated management of water resources, land use and industrial development is essential in Central Asia. The ecological crisis should provide sufficient motivation to reach a consensus on unified water management throughout the region.

Problems of Sustainable Use and Management of Water and Land Resources in Uzbekistan

In this paper, the problems of rational use, protection and management of water and irrigated land resources of Uzbekistan are discussed. Uzbekistan is using more than 50% water resources of the region and therefore it’s more vulnerable to the problems of water deficiency and pollution caused by mismanagement, use of outdated technologies, and climate change impact. Utilization of water resources on main branches of economy (irrigation, industry and drinking water supply) from 2000-2009 and in some cases beyond this period was analyzed. Based on the data analyzed, the conditions of irrigated land degradation in Uzbekistan are estimated. The results of this analysis suggest several possibilities toward a sustainable use of irrigated lands: i) reduction of the groundwater table depth;ii) decrease of the level of mineralization of groundwater, and iii) improvement of ameliorative conditions of irrigated lands. The causes resulting in degradation of the irrigated lands and practical measures on the reduction of salinization of the irrigated lands are also recommended.

DEVELOPMENT STRATEGIES OF WATER AND LAND RESOURCES IN THE HEXI REGION,CHINA

Hexi region is located in the northwest arid zone in China,being both the base of industry and agriculture,and the prop of developing northwestern China on a large scale in the next century.On the basis of the study on exploitation and utilization process of water and land resources in past 40 years,and present productivity,this paper approaches the utilization trend and development potential of water and land resources;analyses the characteristics,problems and directions of resource utilization in the future;and proposes the countermeasures of rational development of water and land resources.

Study on the Sustainable Use of Land-water Resources in Shandong Province of China Based on Food Security

After the analysis of food security of Shandong Province since 1990s, based on the change of grain output and per unit grain yield, it was considered that food production of Shandong Province was generally stable; through comparing the proportion of per capita possession of grains and per unit grain yield of Shandong Province in the whole country, it revealed that they were higher than the national average level. On this basis, the relationship between land-water resources and food security had been analyzed, and it summarized that Shandong water resources were insufficient, agricultural water was not enough and water had been seriously polluted; and that cultivated area was large and the overall quality was high. Meanwhile, it had analyzed the spatial pattern of land-water resources and the loss of water and soil. Finally, suggestions for the sustainable use of land-water resources in Shandong Province based on food security had been proposed. It should enhance the construction of basic agricultural facilities and implement united dispatching of multiple water resources; strengthen the supervision of cultivated land resources and comprehensively develop reserve resources of cultivated lands; and intensify the treatment of land-water resources and prevention of the loss of water and soil in key areas.

Study on functions and rational allocation of Shule River Basin groundwater resources

Based on Investigation and Assessment on Rational Exploitation and Utilization of Groundwater Resources in Typical Areas of the Hexi Corridor, the thesis studies on groundwater and environmental problems arising from the large-scale agricultural development projects in Shule River Basin. The thesis analyzes problems in exploiting and utilizing water resources, defines the function zoning of groundwater resources in key areas and evaluates them. Finally, the thesis uses three-dimensional unsteady flow simulation and regional social and economic development plan to study on the allocation of groundwater in Shule River Basin. A proposal for rational allocation of Shule River Basin water resources has been put forward.

Interactions between water-land resources and oasis urban development at the northern slopes of the Tianshan Mountains,Xinjiang,China

Urban development in arid and semi-arid regions is largely constrained by fragile physical environ- ments. The characteristics of an urban settlement are different from those in other regions of China. This paper analyses the coupling characteristics and spatio-temporal variations for oasis urban development and water-land resources at the northern slopes of the Tianshan Mountains by principal component analysis and a coupling degree model. The result shows that the degree and change in regional use of water and land resources are different among the studied cities/counties during their development. The built-up areas of these cities/counties have changed little with increasing populations and urbanization levels, which well reflects that the urban development in arid and semi-arid regions is limited by oasis areas. Per capita amount of water supplied, however, presented a trend of slowed growth with increasing levels of urbanization. Water consumption gradually increased with urban development and the improvement of people＇s living standards, accompanied by enhanced water use efficiency. The level of urbanization can be assessed through the coupling degree between oasis urban development and the use of water and land resources. A high coupling degree represents a high level of comprehensive urban devel- opment and use of water-land resources. Alternatively, a low coupling degree denotes a low level of urban devel- opment and water-land resource use.

Coupling of water and land resources and its application in regionalization

This paper focuses on the coupling of water and land resources based on several factors related closely to either water or land resources, which have become a topical subject due to the economic expansion and their sustainable development in recent years. A case of Qihe County in Shangdong Province, China has been used to demonstrate the methodology of the coupling and its application in regionalization with the help of geographical information system (GIS) tool. Field observation and measurement of soil salt and moisture in several profiles are used to verify the results of the coupling, which gives reasonable distribution of different areas regarding to the advantages and disadvantages for sustainable agriculture.

Theory and model of water resources complex adaptive allocation system

Complex adaptive sys tem theory is a new and important embranchment of system science, which prov ides a new thought to research water resources allocation system. Based on the a nalysis of complexity and complex adaptive mechanism of water resources allocat ion system, a fire-new analysis model is presented in this paper. With t he description of dynamical mechanism of system, behavior characters of agents and the evaluation method of system status, an integrity research system is built to analyse the evolvement rule of water resources allocation system. A nd a brief research for the impact of water resources allocation in benefi cial regions of the Water Transfer from South to North China Project is conducted.

The Research of Ecology-Oriented Reasonable Deployment of Water Resources at Shuangtaizi Estuary Wetland

Shuangtaizi estuary wetland, the largest natural conservation district in China, and one of the best preserved, largest ecological lands with the most complete vegetation types in the world, is located in Panjin city, Liaoning Province. In recent years, the degradation of Shuangtaizi estuary wetland is very serious. In order to rescue lives in the wetland and protect valuable natural resources, the information system of Shuangtaizi estuary wetland was built with '3S' technology, and the minimum, optimum, and maximum eco-environmental water requirements were calculated respectively. Furthermore, for restoring the ecological functions of wetland and preventing wetland degradation, the balance between supply and demand of water resource was analyzed , and an optimal allocation scheme of water resources was proposed based on three kinds of equilibrium.

The supporting capability of Water and land resources for sustainable increase of yield in North China Plain

The potential of yield increase in the North China Plain is about 30 billion kg by ameliorating the low yield and medium low yield farmlands and 4 billion kg by reclaiming unused land. Water shortage will be the main limitation to the further increase of grain crop yield. The amount of water shortage is 8 200 million m3 at present, and will be 17 720 million m3 in 2 000. Yield increase can not be realized by using more water in the future. Other factors such as decrease of the area of cultivated land and the grain crop growing area, deterioration of environment and destruction of resources will also affect the development of grain production. Some suggestions have been proposed in the paper for attaining sustainable increase of yield in the plain.

Coordinated optimal allocation of water resources and industrial structure in the Beijing-Tianjin-Hebei regions of China

Optimizing the allocation of water resources is critical for promoting the optimization and upgrading of industrial structure and coordinated development in the Beijing-Tianjin-Hebei regions of China.Based on specific regional and water conditions,to strengthen the constraints on water resources,the“three-step”adaptive management approach of“scheme design-scheme diagnosis-scheme optimization”of water resource allocation are adopted to facilitate the coordinated optimal allocation of water resources and industrial structure in the Beijing-Tianjin-Hebei regions.First,from the level of overall industry,a water resource allocation scheme for the regions is designed by applying the master-slave hierarchical mode and a bi-level optimal model to determine the ideal amount of water resource allocation for the regions and respective industries.Second,the diagnostic criteria of spatial balance,structural matching,and coordinated development are constructed to determine the rationality of the water resource allocation scheme.Then a benefit compensation function with water market transactions is developed,to adaptively adjust the water resource allocation scheme.Finally,the optimization and upgrading of industrial structure are promoted to improve water consumption efficiency and the coordinated development of the Beijing-Tianjin-Hebei regions.The study can provide reference for the Beijing-Tianjin-Hebei regions to realize the comprehensive optimal allocation of water resources in the regions and improve the adaptability of water resources and industrial structure optimization.

Optimal allocation of land resources in the process of economic development

In this paper,the writer uses a mathematical model to analyze:a theoretical model of land resources optimal allocation with the constraint of sustainable development;equilibrium and defects of land resources allocation in a competitive market;and how effective governmental supervision can change the equilibrium in the market and promote the optimization of land resources allocation.The main points of this paper are:continuous and excessive conversions that change land resources from agricultural use to non-agricultural use in the process of economic development are economic rules;a competitive market is an important way to improve the efficiency of land resources allocation;effective governmental supervision can cover the shortage of market and promote the optimization of land resources allocation;a reasonable arrangement of land property rights can reduce the transaction costs of government management in optimizing land resources allocation;and,the targets of land resources optimal allocation are developing along with economic development.

Impact of Climate and Land-Use Changes on Water Security for Agriculture in Northern China

North China is the most important food basket of China, where the majority of wheat and corn are produced. Most crops grown in North China are irrigated, thus water security is food security. Since the 1980s, drying has been frequently observed, as shown by a reduction in precipitation, cutoff in riverflow, and shrinkage of lakes. This increase in drying cannot be explained by climate change alone. We propose that intensive land-use in this area in recent decades has had a significant impact. The objectives of the study are to develop a quantitative model of the concurrent processes of climate change and land-use in North China, and to estimate the relative contributions of each on the observed drying. We integrated relevant socioeconomic data, land-use data, and climate data in the model, and carried out a detailed multi-temporal （decade, year, day） analysis. Results showed that land-use has greatly changed since 1999. This change is mainly associated with an extremely important 1999 national policy of ＂returning farmland and grazing land to forest and grassland＂. We found an interesting interaction between climate change and land use policy on riverflow, runoff, and evapotranspiration. During 1970s and 1980s, climate change explained more than 80%, while the land-use change explained only 10% of the riverflow change. The relative contributions were 45 and 45% in the 1980s-1990s and 35 and 55% in the 1990s-2000s respectively for climate change and land-use change. Since the 1990s land-use change has also contributed more to runoff change than climate change. The opposite trend was found for changes in evapotranspiration. Water availability for agriculture in northern China is simultaneously stressed by extensive changes in land-use and rapid climate change. Adaptation of ecological principles, such as the ＂returning farmland/grazing land to forest and grassland＂ policy, and other adjustments of economic developmental strategies can be effective tools to mitigate the water shortage problem in northern China and promote sustainable agricultural and food development.

China's Grain Production and Its Requirement for Water Resources Allocation

Agricultural water is directly related with grain production security. This article analyzes how to allocate the water resources in terms of grain production. Firstly,for the whole country,we established the VAR mathematical model with the data of 1983 to 2008 to test the relationships between the total amount of water and the agriculture production and forecast the water consumption in 2020. Then focusing on the major grain producing areas,we examine the main index and the pressure index,from which we find that the amount of agricultural water in major areas fail to satisfy the demand of production,and that unbalanced development exists between different areas with several areas especially serious. At last,we point out that,to ensure the security of agriculture production and the sustainable utilization of water resources,the government should take measures not only to prevent water pollution and reduce water consumption,but also to improve inter-basin water transfer planning.

An Integrated Water Resources and Economic Approach for Optimizing Water Allocation Policies

Reservoir/river systems analysis models are generally used in the formulation and evaluation of alternative plans for responding to water related problems and needs. One of the main problems is the water resources allocation and the cost associated with pumping, if needed. Taking the appropriate decision is considered as a techno-economic issue. The case study presented in this paper involves a complex system of three dams, two pumping stations and two diversion structures all serving an agricultural production unit. The objective of this research is to determine a suitable and feasible water allocation/pumping policy as a “trade-off” between minimizing the water deficiency and the cost of pumping. To achieve this objective, a water resources model was developed using HEC-5. A multi-criteria decision approach was implemented to determine the most appropriate water release policy and the capacity of the water diversion facilities. The parameters used were subject to a sensitivity analysis to assess their relative impact on the determined policy. The suggested release policy allows a reduction of half the total of the pumping costs with only 3% reduction in the water allocation reliability, as measured by the failure frequency of demand satisfaction and the average shortage index.

CAS-based Water Resources Optimal Allocation and Dynamic Simulation for Sewage Irrigation Area

Based on the theory of complex adaptive system(CAS),the optimal allocation model of water resources in sewage irrigation areas was established,which provided new ideas and application value for the rational utilization of agricultural production and waste water resources.The results demonstrated that the difference of crop energy capture mainly depended on the development stage.Waste water with a certain concentration was able to promote crop growth,while excessive concentration inhibited crop growth.The correlation between water absorption rate and leaf area index was close(R=0.9498,p<0.01).The amount of bad seeds increased at a speed of 34.7·d^-1,when system irrigated randomly in the seedling stage,while it tended to remain stable at a speed of 0.3·d^-1 after plants entering the mature stage which impacted the total yields of crops.