Comprehensive decision-making simulation and control system advances ecological regulation of Yangtze River

BEIJING, May 20, 2024 /PRNewswire/ -- A news report from China.org.cn on Yangtze River Simulator which has been designed to achieve smart management of the river:

Relying on the support of the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences (CAS), Xia Jun, Academician of CAS, and other Chinese scientists have created a Yangtze River simulation and control system known as the Yangtze River Simulator using the power of hydro-physical models and big data, which has paved the way for comprehensive management and sustainable development of the 6,300-km-long, eastward-flowing waterway, according to a study covering the topic published by a think tank journal focused on strategic and decision-making research that is supervised and sponsored by the CAS known as the Bulletin of the Chinese Academy of Sciences (BCAS, in Chinese) in 2023.

As the chief scientist of the Yangtze River simulator and control system, Xia is also the foreign member of the Norwegian Academy of Sciences, and professor and director of the Research Institute for Water Security at Wuhan University. The study was first published on Journal of Hydraulic Engineering in 2022. In January, 2023, Xia, as the only Chinese scholar invited by the top publication Nature Water, published an article titled "Toward Water System Science and Technology." He pointed out that Yangtze River Simulator has been designed to achieve smart management of the Yangtze River through an integrated system that provides multi-dimensional strategies for water utilization, biodiversity and eco-environment protection, climate change adaptation and sustainable development.

The study published on the BCAS reveals that the Yangtze River plays an important role in protecting the environment and supporting China's sustainable development. Home to a diverse array of aquatic creatures, the Yangtze River Basin features over 400 species of fish, 145 species of amphibians, 296 species of mollusks, and 298 species of aquatic plants, which makes it a very important germplasm resource bank. Freshwater fish production in the basin accounts for more than 70 percent of China's total and 40 percent of the world's.

Some parts of the Yangtze River Basin are experiencing problems such as water scarcity, severe water pollution, and ecological damage due to human activities and resulting climate change, however, which has restricted the sustainable development of the region and created other difficulties. More than 50,000 reservoirs account for 37 percent of the Yangtze River Basin's total surface runoff at present, which has greatly altered its water cycle characteristics and aquatic environment.

The study mentions, the upper, middle, and lower reaches of the Yangtze River are each experiencing various challenges, some of which are summarized below. Cascade reservoirs have caused water ecology problems such as total dissolved gas (TDG) supersaturation in the upper reaches, which has had a long-term impact on fish. In 2014, supersaturated TDG water flow lasted over a week in the Xiluodu Dam area – a zone located at the border of Yunnan and Sichuan provinces where the Sichuan Basin begins to emerge after the Hengduan Mountains and Yungui Plateau recede – resulting in the death of 100 tons of fish downstream in the Jiaba Reservoir area, which is situated in north-central China's Gansu Province.

In addition, cascade reservoirs have led to significant changes in upstream rivers' hydrological conditions, such as decreased flow velocity and alterations in water temperature layers, blockage of fish migration channels, and damaged fish habitats, resulting in a significant decrease in fish diversity. The number of fish species present in a section of the Yangtze River's upper stretches located in northeast Yunnan Province and southeast Sichuan Province known as Suijiang decreased from 54 to 35 when two major hydropower stations – Xiluodu and Xiangjiaba – came into operation, for example.

Seasonal impoundment has led to the creation of a zone that suffers from severe soil erosion and vegetation degradation in the Three Gorges Reservoir Region, which is an upstream Yangtze River region situated where Chongqing Municipality meets Hubei Province, known as the hydro-fluctuation belt. Water bloom is also a problem in backwater areas, and spawning grounds have been submerged and the number of fish species continue to decrease in reservoir areas.

Growth conditions associated with aquatic plants and fish migration conditions have changed, spawning and development have been altered, and the self-purification ability of bodies of water has been weakened in the middle and lower reaches of the Yangtze River, the study indicates.

Reclamation, sedimentation, and urban construction have led to ongoing shrinkage of lake areas, a degradation of the function of lakeside areas, including a reduction in their ability to intercept pollutants and reduce endogenous pollution, and a decline in aquatic and coastal vegetation. Sand mining and waterway regulation in rivers and lakes has degraded aquatic habitats as well.

There is a high risk of algal blooms in some of the lakes that connect to the Yangtze River, which can damage community structure and reduce biodiversity. In recent years, frequent and sudden changes associated with droughts and floods have accelerated water withdrawal rates and caused abrupt reductions in water levels, which can cause fish and finless porpoises that are unable to retreat in time, getting stranded in low-lying bodies of water, where they are likely to dry up and die.

Chinese scientists have been addressing these types of challenges with the help of the Yangtze River Simulator. The river basin simulation system and its software and hardware devices put special emphasis on interaction between the upper, middle, and lower reaches of the Yangtze River as well as surrounding lakes, reservoirs, shorelines, and urban agglomerations and help facilitate Yangtze River Basin water management. Featuring monitoring, simulation, evaluation, warning, decision-making, and regulation functions, the simulator is designed to enable the realization of goals related to flood control, power generation and biodiversity protection.

The Yangtze River Simulator involves six key ongoing aspects: construction of an integrated three-dimensional monitoring system; establishment of a multi-source data sharing system; development of a comprehensive water system simulation model; creation of a green development evaluation system; establishment of a public participation and education platform covering ecological civilization; and creation of a communication platform for scientific research and government decision-making. The simulator has also helped facilitate the development of an ecological regulation model that encompasses fish growth in water courses for the Three Gorges Reservoir, though noticeable deficiencies exist at present.

Three Gorges Reservoir regulation involves aspects such as flood control, power generation, shipping, and ecological conservation, which requires communication and cooperation between various government departments. The model's power generation and shipping regulation modules are currently relatively simple, however. The lake ecology systems in the middle and lower reaches of the Yangtze River are affected by the numerous water conservancy projects that exist in the downstream basin area. It is thus necessary to conduct joint in-depth research pertaining to ecological regulation of the Three Gorges Reservoir and downstream water conservancy projects. A considerable distance exists between the reality of the simulator as a first-generation, large-scale watershed simulation device and planned goals, however.

The research team that wrote the study has proposed the following suggestions in order to promote greater management of the Yangtze River: First, list the Yangtze River Simulator as major national scientific and technological infrastructure as soon as possible. Second, conduct joint ecological regulation research and experiments on the Three Gorges Reservoir, upstream reservoirs, and the Dongting, which is a large lake located in northeastern Hunan Province, and Poyang, which is situated in the northwest part of east China's Jiangxi Province and is the country's largest freshwater lake. Third, conduct ecological regulation experiments pertaining to fish and finless porpoise protection in the Three Gorges Reservoir using the Yangtze River Simulator.

Comprehensive decision-making simulation and control system advances ecological regulation of Yangtze River

http://belt.china.org.cn/2024-05/14/content_117186798.htm

SOURCE China.org.cn