China Water Resources

Pilot studies and refections on deep groundwater recharge and restoration in North China

Overdraft of confned deep groundwater remains a serious issue in North China, where natural recovery is difficult due to limited recharge and slow renewal of deep aquifers. This has led to the long-term existence of groundwater depression cones, further triggering a series of ecological damages and geological hazards such as ground subsidence and seawater intrusion, exerting ongoing impacts on regional production, livelihoods, and ecological security. To address the groundwater depletion caused by long-term overdraft, a coordinated “point-line-area” approach and a comprehensive governance and restoration model integrating “suppression, recharge, and reinjection” have been proposed. This paper introduces the conditions and progress of recharge experiments conducted at four established pilot sites, and summarizes the fndings and outcomes of a series of thematic studies carried out in conjunction with these recharge trials. Existing challenges of the pilot projects are identifed, including short experimental durations,insuffcient research, unoptimized water sources, and the need for improved test site conditions. In response, several targeted recommendations are proposed: extending the duration and depth of experimental studies, optimizing recharge areas and water sources, advancing research on anti-blocking and permeability-enhancement technologies,strengthening scientific and technical support, evaluating recharge effectiveness, improving research platform infrastructure, and increasing dedicated fnancial support, aiming to provide experiences for systematic recharge and restoration of deep groundwater and ensure sustainable utilization of groundwater resources.

Thoughts and suggestions on accelerating high-quality development in hydrology

To provide strong hydrological support for promoting high-quality development in water resources management and ensuring national water security, this paper elaborates on the necessity, importance, and urgency of accelerating high-quality development in hydrology. It briefly summarizes the achievements in recent years in areas such as the construction of hydrological monitoring station networks, the development of automated hydrological monitoring technologies and equipment, advancements in flood forecasting techniques, the application of the “three defense lines” for rainfall and food monitoring and forecasting, and the enhancement of hydrological support service capabilities. It analyzes the new requirements for hydrological work arising from the implementation of the new development philosophy and the promotion of high-quality development in water conservancy in the new stage, the new challenges posed by the increasing frequency of extreme weather events to hydrological monitoring and forecasting, and the new opportunities brought by the development of new quality productive forces to the modernization of hydrology. The paper outlines the general approach and target tasks for future high-quality hydrological development, and proposes key measures such as building a modern national hydrological station network system, improving a precise hydrological monitoring and forecasting system integrating “sky-space-earth-water-project”, enhancing a progressive forecasting and warning service covering short-term, medium-term and long-term periods, strengthening public hydrological services to meet social needs, improving independent innovation capabilities in hydrological science and technology, deepening reforms in hydrological institutions and mechanisms, and building a highlevel hydrological talent team. These efforts aim to provide technical guidance and reference for the scientifc formulation of hydrological development plans under the 15th Five-Year Plan.

Ideas, strategies, and measures for the compilation of the water security safeguarding plan during the 15th Five-Year Plan period in the Huaihe River basin

The Huaihe River basin is a region with a high concentration of multiple national strategic initiatives, and its water security is critical to the region's high-quality development and the quality of life for people. This paper summarizes the basin's achievements in food and drought disaster prevention,water conservation and intensive utilization, ecological protection and restoration, and the development of governance systems and legal frameworks. It analyzes the challenges faced during the 15th Five-Year Plan period, including weaknesses in the food control system, the incomplete system for water resources development and allocation, the continuing severity of river and lake protection and governance issues,and defciencies in the “four unifcations” of basin governance and management. In response, the plan's formulation should be based on the actual conditions of the basin and focus on six key areas: improving the food control system, implementing major national water network projects, establishing and improving water-saving policies and institutions, restoring river and lake ecosystems, promoting the development of digital twin water conservancy, and strengthening institutional, legal, and governance systems. These efforts aim to provide a solid water security safeguarding for the region's high-quality economic and social development.

The “four principles” of engineering ecology and typical application

Different river basins have different natural backgrounds and complex ecological and environmental issues. Against the changing climate and intensified human activities, river ecosystems are facing severe challenges. The protection and high-quality development of river basins urgently require theories that adapt to the harmonious development of human and nature. To understand ecology from an engineering perspective,help engineers establish the concept and disciplinary framework of engineering ecology, and promote the harmonious development of engineering ecosystems, we proposed the “four principles” of engineering ecology,namely “background, adaptability, systematization, and integrity”. In engineering ecosystem, human is regarded as one of the key ecological elements. Accordingly, we explore the scientifc principles of the natureengineering composite ecosystem, and the connotation and assessment of the “four principles”. Based on the typical application of the “four principles” of engineering ecology in the Qinghai-Tibetan rivers, we analyzed the background and adaptability of the plateau rivers, and proposed the nature-based solutions for enhancing the systematization and integrity of the rivers from the perspectives of hydropower cascade development.This study also provides a scientifc basis for the protection and high-quality development of river basins, by coordinating development of energy, ecology, and socioeconomics in the mountainous areas of Southwest China.

The characteristics of long-term spatiotemporal changes in land surface water bodies in China

The dynamic change of land surface water bodies is one of the key indicators refecting variations in water resources. Accurately understanding such dynamics is of great signifcance for studying the water cycle of the Earth system and its responses to climate change and human activities. However, existing data products on land surface water body distribution are limited in terms of spatiotemporal resolution, coverage,and continuity. To address these issues, a high-precision land surface water body distribution model was constructed by integrating multi-source geospatial data and applying machine learning algorithms, resulting in a monthly 30 m resolution water body dataset covering China from 1985 to 2021. Using third-level basins as the analysis unit and employing time series decomposition methods, the spatial distribution patterns and temporal evolution trends of land surface water bodies across China were analyzed. The results show that:(1) The land surface water body distribution model developed through the fusion of multi-source geospatial data and machine learning effectively compensates for the limitations of remote sensing-based water body monitoring.(2) The constructed monthly dynamic dataset from 1985 to 2021 demonstrates good spatiotemporal continuity. The area of land surface water bodies in China ranged between 116,900 km² and 157,600 km², showing an overall declining trend. The decline was more pronounced before 2003, followed by a stabilization and slight rebound thereafter. There is a clear spatial heterogeneity in the seasonal variation of water body areas, with an overall increasing trend. The seasonal difference becomes more prominent from the southeastern coastal areas(slope <-0.005) to the northwestern inland regions(slope > 0.2).(3) Human activities, such as urban construction and reservoir development, are the primary driving factors of seasonal changes in water bodies, accounting for 70% of the variation. The average contribution of human factors across basins is 56.26%. This study provides valuable data support for research on water resources management and land surface water cycles in China under the infuence of global climate change and human activities.

Pilot studies and reflections on deep groundwater recharge and restoration in North China

Overdraft of confined deep groundwater remains a serious issue in North China, where natural recovery is difficult due to limited recharge and slow renewal of deep aquifers. This has led to the long-term existence of groundwater depression cones, further triggering a series of ecological damages and geological hazards such as ground subsidence and seawater intrusion, exerting ongoing impacts on regional production, livelihoods, and ecological security. To address the groundwater depletion caused by long-term overdraft, a coordinated “point-line-area” approach and a comprehensive governance and restoration model integrating “suppression, recharge, and reinjection” have been proposed. This paper introduces the conditions and progress of recharge experiments conducted at four established pilot sites, and summarizes the findings and outcomes of a series of thematic studies carried out in conjunction with these recharge trials. Existing challenges of the pilot projects are identified, including short experimental durations,insufficient research, unoptimized water sources, and the need for improved test site conditions. In response, several targeted recommendations are proposed: extending the duration and depth of experimental studies, optimizing recharge areas and water sources, advancing research on anti-blocking and permeability-enhancement technologies,strengthening scientific and technical support, evaluating recharge effectiveness, improving research platform infrastructure, and increasing dedicated financial support, aiming to provide experiences for systematic recharge and restoration of deep groundwater and ensure sustainable utilization of groundwater resources.

Construction of spatiotemporal multi-source and multi-scale fusion framework based on digital twin data base of irrigation districts

To address issues like varied data types, inconsistent formats, differing monitoring frequencies,mismatched geographic spatial scales, overlapping business domains, and diffculties in data fusion, this study proposes a framework and methodology for multi-source data fusion in the digital twin base of irrigation districts. The multi-source data fusion paths are elaborated from several perspectives, including integrating unifed water resource object models, object fusion(fusion of entity object relationships, oblique photography models and BIM models, vector objects and oblique photography models), feature fusion(integration of features from multi-source remote sensing data, fusion of terrain features at different resolutions), and numerical fusion(merging station monitoring data, spatial scale fusion of point and grid data, and spatiotemporal interpolation fusion of long-, medium-, and short-term rainfall grid forecast data). In the application of the Ouyanghai Irrigation District project, scenarios such as crop planting area estimation, drought monitoring using multi-source data fusion, and inundation analysis based on multi-source data fusion were implemented. These applications enable the digital twin irrigation district to achieve multi-level visibility, usability, and traceability,transitioning from overall to local perspectives, from abstraction to detail, and from two-dimensional to threedimensional representations.

Safety of river courses of middle and lower mainstreams of the Yangtze River and measure study

Safety of the middle and lower reaches of the Yangtze River relates directly to flood control, water supply, navigation and ecology of the basin. After years of practices, great achievements have been made in improving river regime, flood control safety, ecology and navigation. Key issues were examined including failure to ciontrol high flood peak due to insufficient storage and discharge capacity, unstable conditions of local rivers and mainstreams caused by erosion and sedimentation, water level drops during dry seasons, and degradation of water environment that fail to meet the water quality requirements specified for water function zones. New situations in the new stage and under new water-sediment condition are examined. First, highquality development of the Yangtze River Economic Belt makes new and higher requirements for the safety of the river. Second, erosion and sedimentation of the middle and lower reaches and the relationship between river and lake have undergone changes and will continue to be adjusted in the long term in the future. Further analysis was conducted on the characteristics of water and sediment change since the operation of the Three Gorges Dam and the evolution pattern and impact of different river type. Future trend of water and sediment and changes of river lake relationship were analyzed. In response to the existing problems, fully considering the trend of strategic adjustments in the new period, and focusing on the multi-objective synergy needs, a series of main measures have been implemented to ensure river safety, including formulating relevant laws and plans, upgrading river and canal regulation and dredging projects, improving the river lake administration and supervision system, strengthening the coordinated operation of reservoir groups, and promoting the construction of digital twin Yangtze River.

Water Rights and Water Markets: Discussing Economic Means for Achieving Optimal Allocation of Water Resources

This article serves as a speech outline prepared for the 2000 annual conference of the China Institute of Water Resources. On March 30, 1999, during the Seventh National Congress of the China Institute of Water Resources, I presented the viewpoint of "transitioning from engineering water resources to resource-based water resources." That speech cannot be considered a purely academic theoretical article; rather, it was a set of requirements for water resources work based on the practical development of water resources. It aimed to initiate a major discussion on "how China's water resources should face the 21st century" and fulfilled my responsibilities as a leader. Similarly, "Water Rights and Water Markets", although discussing issues of water economics, does not make me an expert in this field. Instead, the urgent demand for the reform and development of water resources in China requires us to research and address such topics. I have merely laid the groundwork to draw attention to this issue.

Analysis of Water Supply and Demand in 21st Century China: Ecological Water Conservancy Research

Facing the resource and environmental challenges in 21st-century China, the issue of water is particularly severe. Scarcity and wastage coexist; abundance and ecological imbalance coexist; contamination and poor management coexist. In fact, there are interconnected and transformative relationships among water resources, water disasters, and water environments. Water, as a core element of ecology and the environment, has positive effects when utilized efficiently as a water resource. However, fluctuations in its abundance and scarcity can lead to water-related disasters, while its quality evolution is closely related to water management and environmental protection efforts...

The Outline of the 14th Five-Year Plan(2021—2025) for National Economic and Social Development and the Long-Range Objectives Through the Year 2035 of P. R. China

Speech at the Symposium on Ecological Protection and High-quality Development of the Yellow River Basin

Objectives of River Ecological Restoration

While water conservancy engineering construction has brought significant benefits to the economy and society, it has also posed threats to river ecosystems. Reflecting on this, people have raised questions about how to restore river ecosystems to compensate for the damage. Scholars from various countries have different views and definitions regarding the objectives of river ecological restoration. Considering the national conditions of China, when researching and implementing river ecological restoration, it is essential to base the efforts on the current status of river ecosystems. Creating favorable conditions and harnessing the self-recovery mechanisms of ecosystems are crucial steps in gradually restoring river corridor ecosystems.

A preliminary discussion of the engineering ethics and advanced cultural in Dujiang Weir

The Chinese people has thousands years of history for water governance.The practices of water governance,utilization and management of successive dynasties have left us with rich material,institutional and spiritual wealth.In order to explore the multiple values of this world cultural heritage,discussions are made on the contribution of those outstanding water projects represented by Dujiang Weir,so that Chinese wisdom and China's plan can be developed to address issues of imbalance between water supply and demand and other water crisis.Eco-friendly water project construction in the new age should be led by advanced water culture,with learning from good practices of Dujiang Weir from conservation and cultural prospective,so as to build a society with harmony of man and water and water structures in a modernized and eco-friendly ways.

Human activity and the global climate change and its impact on water resources

In understanding the effect of human activity on the global climate change for recent 100 years, IPCC (Intergovernmental Panel on Climate Change) has played a key role. During 17 years from 1990, IPCC has continuously gained insight into better understanding on the global climate change during the recent 100 years mainly caused by human activity, with its four assessment reports. This achievement has been made with provision of three aspects of evidences: (1) rapid increase in greenhouse gases since preindustrial era (after 1750); (2) temperature rise or warning of surface, tropospospere and oceans; (3) 100-yr climate simulations since 1900 for detection and attribution of the past climate change. These results have shown that recent 100-yr warming is jointly caused by natural climate fluctuation and anthropogenic activity, but most of recent 50-yr climate change is caused by the authropogenic activity. The present paper has first reviewed this issue. Then, the debates and uncenrtainties of global climate change issue have been discussed. The global climate change has had a significant impact on global water resources and management. This issue is further discussed based on changes in temperature, precipitation, sea level rise and evapotranspiration, which may be a necessary scientific basis for adaptation.

Discussions on key issues of water ecological civilization construction

How to understand water ecological civilization construction? On the basis of the interpretation of the spirit of the 18th National Congress of the Communist Party of China,this paper analyses and discusses several key issues of water ecological civilization as follows.First,the definition and connotation of water ecological civilization are given and the links between water ecological civilization construction and ecological civilization construction proposed by the state are elaborated.In addition,this paper analyses the crucial issues which should be paid attention to during the process of advancing water ecological civilization,and proposes specific recommendations to help to make the 5 goals of water ecological civilization come to be realized.

Thought of ancient "sponge city" : experiences of applying water-adaptive landscape

"Sponge city" is regarded as a new approach to deal with serious ecological and environmental problems under the process of fast urbanization at present. In ancient times, we have accumulated valuable experiences of building adaptive landscapes in the process of water resources management over a long period of time and fighting against various water disasters, such as selection of site of settlement, water resources management in cities and formation of cities. This approach has reflected the thought of "sponge city" that has great significance to the design of city landscape. Research and studies on adaptive landscape in ancient cities by academic field both home and abroad in recent decades are introduced, among which the study results from the Middle East, Ancient Greece, Ancient Rome and ancient mayan civilization are plenty and most of the studies focus on water diversion and storage works. The contents and type of adaptive landscape are affected by precipitation and landscape characters. The key areas of current studies have transformed from single factors such as flood control or drought relief into comprehensive research including examining complex structure and complicated functions of water landscape. Along with development of modern technology, how to improve theories of "sponge city" construction and practice has become a key subject for modern landscape design, facing the increasingly degradation of water environment and ecosystem and the fact of heritages of water landscape in ancient cities have been damaged and disappeared with each passing day.

Countermeasures for rainstorm and flood prevention in high-density cities——the “7·20” heavy rain revelation in Zhengzhou

Urban rainstorm flood disaster is the most prominent urban flood disaster in China. Combined with the "7·20" heavy rain revelation in Zhengzhou, through in-depth analysis of the main characteristics and causes of heavy rainfall and flood in high-density cities in China, from the three aspects of "resilience of defense system, resilience of infrastructure, and less loss in extreme rainstorm", the countermeasures of rainstorm flood prevention and control in high-density cities are proposed. It provides a new idea for solving urban flood problems systematically and improving urban flood defense and resilience.