**2.3 The spatial carrying capacity of River Basin**

*Environmental Issues and Sustainable Development*

**2. Spatial carrying capacity and sustainability**

**2.1 The analytical framework of spatial carrying capacity**

This chapter focuses on the relationship between the carrying capacity of different types of space and sustainability, taking the spatial carrying capacity of Chinese cities, river basins and regions under the influence of changes in resource and environmental elements as the research object, and discussing the direction on

Carrying capacity originally refers to the mechanical or engineering characteristics of manufactured objects or systems. It appears in the shipping field with steam power as a sign, and is used to evaluate wind and steam power [3]. In the 1870s, when carrying capacity was first applied to biological and natural systems, it was used to measure the maximum amount of animals and food from natural system extremes. The evolution of carrying capacity is the inevitable result of human transformation and development in nature. From the initial biosphere consideration of the maximum of individuals or populations to the planet-scale development, sustainability research on carrying capacity is playing an increasingly

China is one of the most populous countries in the world. The degree of governance of climate change and environmental degradation has a profound impact on the process of global sustainable development. Therefore, the establishment of carrying capacity as the core analysis tool selects three levels of cities, basins and regions, and through multi-scale and multi-level element coupling, respectively proposes promotion strategies and spatial layout models, in order to achieve the realization of China's economic society sustainable development goals. Cities are relatively small carrying capacity units, river basins are secondary carrying capacity units. The basic urban units constitute the spatial carrying capacity unit at the basin scale. The basin carrying capacity unit belongs to the regional carrying

A city is a multi-dimensional carrying space consisting of resources, environment, ecology, population, economy, and society, which are the foundation of sustainability. A city is an important carrying space not only consisting of population, ecosystems, industrial clusters, but also for resource consumption and environmental pollution. The space provided by the urban unit is a construction and industrial development space, such as economic output, city scale, traffic capacity, land resources, etc. The spatial scale and growth boundary are affected by the interaction of resources, environment and technology, human activity and environmental sustainability, which is coordinated to the ultimate goal, so that it can be protected

The preconditions oriented in multi-element expansion of urban space are spatial carrying capacity for the development of sustainable. Sustainability of urban units is the foundation of social economic development, which lie both in regional and higher levels of units. They are the fundamental area for various aggregation factors of production, which carry more and more efficient production through the expansion of space scale, population size, industry, transportation and urban infrastructures. Despite that, sustainability is the precondition for expansion of units,

the improvements on different units adapted to environmental changes.

important role under the constraints of global environmental change.

**250**

capacity unit.

**2.2 The spatial carrying capacity of cities**

and improved the resources for the survival of humans.

Basin scale is a spatial unit divided by natural geographical ecosystem. Due to the sharing of water resources in the basin, the upstream and downstream water resources competition is fierce, and the water resources carrying capacity of each city forms a common support and constraint, the total amount is fixed, and the relationship between this and the other changes. It is characterized by linking different administrative units and stakeholders through water resources. The sustainable development of river basin mainly focuses on the rational allocation of water resources and maximizes the economic, social and ecological conditions within the threshold value of water resources carrying capacity.

The basin carrying capacity should be innovated in management mode in upstream and downstream. In the new stage of coordinated development of river basin, it is necessary to take full account of the disharmonious separation of basin units, the limited overall development space of the basin, the enhancement of the correlation between the development activities of different units in the same basin and the constraint of the total amount threshold of the carrying capacity of resources and environment, so it is necessary to carry out fine management of water resources in the basin. The current basin development model still has many problems, such as low efficiency of water resources utilization, fierce competition between upstream and downstream water resources, and low overall water quality. Therefore, it is necessary to coordinate the cooperation among different units in the basin to enhance the overall carrying capacity of the basin.
