Check dams are widely constructed on China’s Loess Plateau, which had a total number of 58,776 by the end of 2019. Great achievements in check dam construction have been gained regarding the economic and environmental impacts. This study reviews the remarkable benefits of check dams on the land reclamation and environmental improvement on the Loess Plateau, and sediment reduction entering the Yellow River. However, the flood incidents on check dams have been frequently reported for the past decades, which has attracted more attention in the context of climate change and extreme rainfall events recently. Advances in the flood migration techniques achieved by the research group led by the first author have been highlighted to migrate the breach risk of check dams due to floods. The “family tree method” has been proposed to determine the survival status and critical rainfall threshold of each check dam in the complicated dam system. An updated dam breach flood evaluation framework and the corresponding numerical algorithm (i.e., DB-IWHR) have been developed. Moreover, innovative types of water-release facilities for check dams, including geobag stepped spillway and prestressed concrete cylinder pipe in the underlying conduit, have been proposed and developed. Finally, the perspectives concerning the check dam construction on the Loess Plateau have been put forward.
River ethics, a significant advancement inspired by Chinese President XI Jinping’s ecological civilization thought, embodies the philosophical essence of river governance and represents a legacy of innovation by generations of water resources professionals. Rooted in river ecology, it offers a framework for advancing modern water governance systems and capabilities. This paper examines eight dimensions of river ethics to provide actionable recommendations: enhancing knowledge systems on water, rivers, and lakes; addressing critical challenges in water governance to strengthen the foundational role of water authorities in ensuring water security, resource management, ecological sustainability and environmental protection; optimizing water project planning to mitigate ecological impacts; ensuring high standards in the lifecycle management of water projects; refining water diversion strategies for precise scheduling; utilizing ecosystem complexity for river and lake restoration; implementing tiered management of water-related disasters; and driving reforms to modernize water governance systems and mechanisms.
Recent studies suggest per- and polyfluoroalkyl substances (PFAS) are ubiquitous in rivers worldwide. In the Asia-Pacific region, the frequency of PFAS detection in rivers is increasing. However, the overwhelming majority of studies and data represent high population and urbanized river catchments. In this study, we investigate PFAS occurrence in major Philippines river systems characterized by both high and low population densities. In the Pasig Laguna de Bay River, which drains a major urban conurbation, we detected PFAS at concentrations typical of global rivers. Unexpectedly, we did not detect PFAS in river water or sediments in low population density river catchments, despite our instrument detection limits being lower than the vast majority of river concentrations reported worldwide. We hypothesize that septic tanks, as the dominant wastewater treatment practice in Philippines catchments, may control the release of PFAS into groundwater and rivers in the Philippines. However, no groundwater PFAS data currently exist to validate this supposition. More broadly, our findings highlight the need for more representative PFAS sampling and analysis in rivers to more accurately represent regional and global detection frequencies and trends.
Phytoplankton play a crucial role in maintaining the health of river ecosystems, and their communities are closely linked to river hydrodynamics. In inland waterways, disturbances generated by ship propellers alter flow dynamics and may affect phytoplankton communities. To clarify it, phytoplankton communities in the Zhenjiang section of the Beijing–Hangzhou Grand Canal (BHGC) in China, the world’s longest canal, were studied and compared them with its undisturbed tributaries. The results revealed major alternations in seasonal patterns of phytoplankton communities in the BHGC, shifting the peak of phytoplankton density from spring to autumn and the lowest diversity from summer to autumn. Ship disturbances increased water turbidity and created optimal N/P ratios, which provided Cyanobacteria with a competitive advantage in autumn. The proliferation of Cyanobacteria resulted in a phytoplankton density in the BHGC, exceeding that in the tributaries by more than tenfold, accompanied by a decrease in diversity to its lowest level. Due to habitat alterations, functional groups emerged that are resilient to strong disturbances and high turbidity. The findings add to the understanding of the impact of ship traffic on river ecosystems.
Decision support systems (DSS) based on physically based numerical models are standard tools used by water services and utilities. However, few DSS based on holistic approaches combining distributed hydrological, hydraulic, and hydrogeological models are operationally exploited. This holistic approach was adopted for the development of the AquaVar DSS, used for water resource management in the French Mediterranean Var watershed. The year 2019 marked the initial use of the DSS in its operational environment. Over the next 5 years, multiple hydrological events allowed to test the performance of the DSS. The results show that the tool is capable of simulating peak flows associated with two extreme rainfall events (storms Alex and Aline). For a moderate flood, the real-time functionality was able to simulate forecast discharges 26 h before the flood peak, with a maximum local error of 30%. Finally, simulations for the drought period 2022–2023 highlighted the essential need for DSS to evolve in line with changing climatic conditions, which give rise to unprecedented hydrological processes. The lessons learned from these first 5 years of AquaVar use under operational conditions are synthesized, addressing various topics such as DSS modularity, evolution, data positioning, technology, and governance.
Exploring optimal operational schemes for synergistic development is crucial for sustainable management in river basins. This study introduces a multi-objective synergistic optimization framework aimed at analyzing the interplay among flood control, ecological integrity, and desilting objectives under varying watersediment conditions. The framework encompasses multi-objective reservoir optimal operation, scheme decision, and trade-off analysis among competing objectives. To address the optimization model, an elite mutation-based multiobjective particle swarm optimization (MOPSO) algorithm that integrates genetic algorithms (GA) is developed. The coupling coordination degree is employed for optimal scheme decision-making, allowing for the adjustment of weight ratios to investigate the trade-offs between objectives. This research focuses on the Sanmenxia and Xiaolangdi cascade reservoirs in the Yellow River, utilizing three representative hydrological years: 1967, 1969, and 2002. The findings reveal that: (1) the proposed model effectively generates Pareto fronts for multi-objective operations, facilitating the recommendation of optimal schemes based on coupling coordination degrees; (2) as water-sediment conditions shift from flooding to drought, competition intensifies between the flood control and desilting objectives. While flood control and ecological objectives compete during flood and dry years, they demonstrate synergies in normal years (r = 0.22); conversely, ecological and desilting objectives are consistently competitive across all three typical years, with the strongest competition observed in the normal year (r = −0.95); (3) the advantages conferred to ecological objectives increase as water-sediment conditions shift from flooding to drought. However, the promotion of the desilting objective requires more complex trade-offs. This study provides a model and methodological approach for the multi-objective optimization of flood control, sediment management, and ecological considerations in reservoir clusters. Moreover, the methodologies presented herein can be extended to other water resource systems for multi-objective optimization and decision-making.
This study aims to develop a high-precision and cost-efficient method for the three-dimensional reconstruction of large particles in natural gravel and blasted rock fragments, utilizing Structure from Motion (SfM) and Multi-View Stereo (MVS) techniques. The proposed approach was applied to characterize the three-dimensional morphology of rockfill dam materials at a real construction site. Particle shape was quantitatively analyzed using shape indices of sphericity, convexity, and angularity. The predominant morphology of natural gravel is characterized as slightly elongated and slightly flat, while rock fragments are slightly elongated and not flat. Probability density distributions of shape indices follow a skewed normal distribution: sphericity and convexity show leftward skewness, whereas angularity is right-skewed. Skewness parameters of sphericity and angularity are consistent between natural gravel and blasted rock fragments, indicating comparable shape asymmetry. Convexity skewness is significantly higher in natural gravel compared to rock fragments, by approximately an order of magnitude. The relationship between size and particle shape shows that form ratios and associated shape descriptors change linearly with the logarithm of size; larger particles approach spherical or cubic forms. The innovative measurements contribute to the particle shape data set of rockfill dam materials, providing valuable insights into the three-dimensional and statistical morphological characteristics of relatively large particles in natural gravel and blasted rock fragments. This approach enhances understanding of particle morphology’s impact on the mechanical behavior of granular materials.
A total of 393 potholes (368 fluvial and 25 marine potholes) were studied at seven different sites in both the fluvial and marine environments. Diverse bedrock properties and large-scale delivery of tools and grinders regulate the dynamic growth, truncation, and amalgamation of potholes. Therefore, the principal objectives of the study are (i) to examine the relationship between the growth of potholes and substrate lithological with structural characteristics (applying geospatial and Schmidt hammer for rock strength analysis) and (ii) to measure the morphology, and size of tools and grinders, processes of truncation and amalgamation in hydro-geomorphic environment using various indices and field techniques. The result showed that large potholes are stretched in the direction of lineament axes and roughly parallel to the river flow direction. Here, the steady growth of pothole depth-diameter is controlled by active bedrock structures, tools, or grinders, and monsoonal high-velocity bank full discharge. Consequently, the deepening and widening of potholes are relatively slow at Bindu, Deuli, and marine beach Neil Island due to fewer structures and little supply of tools or grinders. In small stretches, (Damodar, Subarnarekha, and Rarhu) canyons and gorge-like features (bedrock incision) are formed at Rajrappa, Bhakuyadi, and Guridih sites due to cyclic truncation and amalgamation. Truncation and amalgamation processes restrict the vertical depth threshold value of potholes within 3m, particularly at Rajrappa, Bhakuyadi, and Guridih sites. Scientific study of the pothole’s dynamic growth is greatly necessary for the different environmental engineering and river hydraulic projects like excavation, dredging, and dam or barrage construction. Successively, it is essential to compute the cost of rock excavation or dredging, primarily for the mechanical strength of the bedrock river channel and its stability.
The Kuye River Basin has experienced a rapid depletion of groundwater due to the increased coal production. In this study, by introducing the empirical equations derived from the three zone theory in the coal mining industry in China as a boundary condition, a calculation model was developed by coupling the soil and water assessment tool and visual modular three-dimensional finite-difference ground-water flow model (SWAT-VISUAL MODFLOW). The model was applied to several coal mines in the basin to quantify the groundwater impact of underground mining. For illustration purposes, two underground water observation stations and one water level station were selected for groundwater change simulation in 2009, producing the results that agreed well with the observed data. We found that groundwater level was closely related to the height of the fractured water-conducting zone caused by underground mining, and a higher height led to a lower groundwater level. This finding was further supported by the calculation that underground mining was responsible for 23.20mm aquifer breakages in 2009. Thus, preventing surface subsidence due to underground mining can help protecting the basin’s groundwater.
Flooding remains one of the most destructive natural disasters, posing significant risks to both human lives and infrastructure. In India, where a large area is susceptible to flood hazards, the importance of accurate flood frequency analysis (FFA) and flood susceptibility mapping cannot be overstated. This study focuses on the Haora River basin in Tripura, a region prone to frequent flooding due to a combination of natural and anthropogenic factors. This study evaluates the suitability of the Log-Pearson Type III (LP-III) and Gumbel Extreme Value-1 (EV-1) distributions for estimating peak discharges and delineates flood-susceptible zones in the Haora River basin, Tripura. Using 40 years of peak discharge data (1984–2023), the LP-III distribution was identified as the most appropriate model based on goodness-of-fit tests. Flood susceptibility mapping, integrating 16 thematic layers through the Analytical Hierarchy Process, identified 8%, 64%, and 26% of the area as high, moderate, and low susceptibility zones, respectively, with a model success rate of 0.81. The findings highlight the need for improved flood management strategies, such as enhancing river capacity and constructing flood spill channels. These insights are critical for designing targeted flood mitigation measures in the Haora basin and other flood-prone regions.