Ecological Environment Water Requirement and Water Resources Carrying Capacity Calculation Based on Land Use – A Case Study of Beijing

The ecological environment (eco-environmental) water requirement is the basic water consumption to ensure healthy and sustainable development of the regional ecological environment. Research on the regional eco-environmental water requirement and water resources carrying capacity is directly related to the macroeconomic disposition and micro-engineering practice of water resources, and is of great importance to sustainable development in a region. Although research on water requirements for the ecological environment has made great achievements, it has often been limited to single objects such as rivers, lakes, and wetlands. This limitation is caused by an excessive demand for basic monitoring data. Simulation of the eco-environmental water requirement of an entire region still poses the challenge of missing data. Based on land-use data that are interpreted using remote sensing images, this paper presents the calculation of the eco-environmental water requirement for urban, grassland, woodland, lake wetland, and river types. Taking Beijing as an example, the total eco-environmental water requirement and its distribution were calculated using four periods of land-use data (2000, 2005, 2010, and 2015). Under the premise of meeting the water requirement of the ecological environment, the carrying capacity of regional water resources is studied. The results show that the water requirement of the ecological environment calculated by the presented method is basically the same as other research results. The method has the advantages of small data requirements and quick access to the regional eco-environmental water requirement and its distribution. Further, the method is suitable for estimating the total amount and distribution of the water requirement in the regional ecological environment. The simulation results show that from 2000 to 2015, the total eco-environmental water requirement in Beijing stabilized at 2.3 billion m³. Compared with the actual eco-environmental water consumption, though the eco-environmental water supply in Beijing has continuously risen over 15 years and reached 1.04 billion m³ in 2015, there is still a large gap compared with water demand. To achieve a healthy and sustainable water cycle, Beijing still needs to ensure constant water replenishment in order to further restore and enhance its aquatic ecology.