River ethics encompasses the values, moral principles, and behavioral norms that govern and regulate the relationship between humans and rivers. Constructing rivers ethics breaks through the traditional ethical dimension that is limited to interpersonal judgment and extends the moral relationship from solely between humans to between humans and river life. China’s eco-civilization drive elucidates that harmony between humans and rivers are the core concept of constructing river ethics. This paper discusses the values, foundation, moral principles, and behavioral norms of river ethics, and forms the theoretical framework of river ethics.

This paper discusses collaborative planning principles as a means to improve water supply systems in the case of Delhi, India, through primary and secondary data analysis. The theory of collaborative planning is a well-established concept applied to obtain effective policies in planning through the collaboration of actors in a shared space. We use this framework to discuss strengths, weaknesses, and scope for collaboration in the current urban development plan formulation process of the city. Some of the principles of collaborative planning we use include communication, collective decision-making processes, and network power in a shared institutional environment. Our findings indicate a lack of consideration of water policies in the urban development plans. This underlines a major gap in the current process of plan formulation and provides evidence that the absence of collaboration between institutions in both sectors contributes to poor water supply for the population in Delhi. At the same time, it emphasizes the importance of collaborative practices between urban development and water institutions for better planning of water service provision in Indian cities.

The training effectiveness of the lower Yellow River (LYR) depends on the understanding of the regularity of flow-sediment transport and riverbed sedimentation. The measured data of daily flow discharge and sediment transport rate at the five hydrological stations (Xiaolangdi [Xld], Huayuankou [Hyk], Gaocun [Gc], Aishan [As], and Lijin [Lj]) in the LYR during the period from 1960 to 2017 are used to investigate the regularity of flow-sediment transport and sedimentation in the LYR. The Xld station is used as the inlet control station, and the LYR is divided into four segments using four other stations, and the whole year is divided into three periods, namely, the dry season, the flood period, and the nonflood period of the wet season. On this basis, the relationships between the sediment transport rates at the four stations (Hyk, Gc, As, and Lj) and the rates at their respective closest upstream stations are analyzed in each of the three periods. According to the incoming sediment coefficient of the Xld station, the flow and sediment processes in the three periods are classified, and the refined equations for the relationship between the sediment transport rates at the downstream station and its upstream station are established. The results show that the calculated amount and process of erosion and deposition in each period and each segment of the LYR using the equations are in good agreement with the measured values. The relationship equations established in this study can conveniently predict the amount of erosion and deposition in different periods and different segments of the LYR in the future, which is of great significance to the rapid decision of the impact of the construction and operation of hydraulic projects in the upper and middle reaches of the Yellow River on the sedimentation in the LYR.

This research is centered on a comprehensive investigation into the impact of turbulence on the movement and dispersion of materials within a threedimensional (3D) bedform, specifically when there is a continuous presence of rigid vegetation submerged in the flow. To achieve our research objectives, we conducted extensive velocity measurements within a channel featuring this submerged vegetation. The measurements were carried out using an Acoustic Doppler Velocimeter (ADV). Additionally, our study delved into the intricate structures and turbulent characteristics of the flow, considering the coexistence of submerged vegetation and a 3D gravel pool. This pool featured entrance and exit slopes measuring 3 and 2.5°, respectively. Our experimental setup took place in a straight flume, measuring 14 m in length, 0.9 m in width, and 0.6m in depth. The flume was equipped with transparent side walls to facilitate observations. Furthermore, our investigation extended to the spatial variations in velocity and turbulence distributions. We analyzed various parameters including turbulence kinetic energy, integral turbulence lengths, dispersion coefficients, and advective transport. The results revealed that integral length scales offer key insights into turbulent eddy behavior. In the presence of vegetation and a 3D bedform, turbulent eddies undergo notable changes, flattening in the longitudinal direction and expanding in the transverse and vertical directions. Moreover, longitudinal advection is notably higher compared to flows without vegetation in a uniform flow or bare channel, especially for z/H > 0.2. This indicates that the presence of vegetation and a 3D bedform leads to an increase in turbulent kinetic energy (k values) that surpasses the reduction in the time-averaged velocity component (“U”) in the U × k term, thereby enhancing longitudinal advection.

The escalation of compound extreme events has resulted in noteworthy economic and property losses. Recognizing the intricate interconnections among these events has become imperative. To tackle this challenge, we have formulated a comprehensive framework for the systematic analysis of their dependencies. This framework consists of three steps. (1) Define extreme events using Mahalanobis distance thresholds. (2) Represent dependencies among multiple extreme events through a point process-based method. (3) Verify dependencies with residual tail coefficients, determining the final dependency structure. Applying this framework to assess the extreme dependence of precipitation on wind speed and temperature in China, revealed four distinct dependency structures. In northern, Jianghuai, and southern China, precipitation heavily relies on wind speed, while temperatures maintain relative independence. In northeastern and northwestern China, precipitation exhibits relative independence, yet a notable dependence exists between temperatures and wind speed. In southwestern China, precipitation strongly depends on temperature, while wind speed remains relatively independent. The Qinghai–Tibet Plateau region displays a significant dependence relationship among precipitation, wind speed, and temperature, with weaker dependence between extreme wind speed and temperature. This framework is instrumental for analyzing dependencies among extreme values in compound events.

We demonstrate how to combine remote sensing data from satellite imagery (Sentinel-2) with in situ water quality gauging (USGS Super Gages and the Gybe hyperspectral radiometer) to create spatially dense maps of water quality parameters (chlorophyll-a concentration, turbidity, and nitrate plus nitrite concentration) along the lower Kansas River. The water quality maps are created using locally tuned models of the target water quality parameters, and this study describes the steps used to design, calibrate, and validate the empirical correlations. Water quality parameters such as chlorophyll-a concentration are correlated with well-studied absorption and scattering features in the visible spectrum (roughly 400–700 nm). Nutrients (such as nitrate plus nitrite concentration) lack strong absorption features in the visible spectrum, and in those cases we describe a novel surrogate data modeling approach that identifies overlapping water parcels between the in situ gauging and the remote sensing imagery. Measurements from the overlapping water parcels yield excellent correlations (R² > 0.9) for the target water quality parameters for limited windows of time (or limited sections of river reaches). Examples are provided illustrating how the water quality maps can be used to track river inputs from ungauged sources (such as creeks), or reveal the mixing patterns at the confluences.

Drought risk assessment plays a crucial role in effective drought management. However, it is often challenging due to the intricate relationships among various indicators and the lack of practical guidance. This study presents a drought risk assessment model developed using the Semi-partial Quadratic Subtraction Set Pair Potential (SQSSPP) method, which is derived from the theory of set pair analysis. The indicator system comprises 21 indicators divided into four subsystems. The SQSSPP method utilizes uncertainty information in the overall development trend of regional drought risk states by extracting connection numbers from the Subtraction Set Pair Potential (SSPP), improving the reliability of evaluation results. The SQSSPP method is validated through a case study of Suzhou City, China, from 2007 to 2017. Three grades are used to evaluate comprehensive drought risk. The result shows an overall decreasing trend over time, with a level III risk in 2010 and consistently at level II from 2011 to 2017. Indicators in the hazard and resilience subsystems are the primary factors influencing drought risk in the Suzhou City. Specific indicators requiring emphasis for improvement are identified, including arable land rate, agricultural population ratio, reservoir regulation rate, current water supply capacity, and irrigation index. The SQSSPP method not only provides targeted drought risk assessment but also provides valuable guidance for future water resource management. While the study focuses on Suzhou City, the proposed approach is applicable to broader-scale risk management evaluations and practices.

The broad-crested weir is convenient to construct and has a small amount of excavation, widely used in practical engineering. Discharge computing has been the focus of research on this structure, thus developing generalized regression neural network (GRNN), genetic programming (GP), and extreme learning machine (ELM) are used to predict the discharge coefficient (C_d) of the triangular broad-crested weir. The comprehensive analysis shows that the ELM model has high stability, predictive ability, and computational speed. The coefficient of determination (R^2) is 0.99982, the mean absolute percentage error (MAPE) is 0.000261, the Nash-Sutcliffe coefficient (NSE) is 0.99977, and the root means square error (RMSE) is 4.17E-05 in the testing phase. The apex angle θ is the most critical parameter affecting the C_d, and the contribution to the C_d is 52.45%. A new computational formula is proposed and compared with the accuracy of empirical formulas, showing that the intelligent method has higher accuracy and efficiency.

SWAT model is one of the primary tools for assessing irrigation district water management and water-saving measures. However, its incapacity to consider the diverse growth and water requirements of paddy during various growth stages, as well as the insufficient availability of external water sources. This study introduces the Penman-Monteith equation and Jensen model into the SWAT framework, setting crop coefficients, crop base coefficients, and growth stage sensitivity indices based on the different growth stage. Additionally, modifications are made to the external water source available for irrigation and paddy field leakage modules, establishing a distributed agricultural hydrological model suitable for accurately simulating water balance elements and paddy yield in multi-source irrigation districts. The Yangshudang watershed in the Zhanghe irrigation district is chosen for the evaluation of the modified model’s simulation performance, with a quantitative assessment of water-saving and yield-increasing effects. The results demonstrate that the modified model effectively meets the requirements for simulating paddy evapotranspiration of various growth stages, yield, agricultural irrigation water consumptions, and runoff, exhibiting a notable enhancement in performance. As two common water-saving measures in irrigation areas, intermittent irrigation and irrigation district renovation were used as two water-saving scenarios in the simulation of the modified SWAT model. Under intermittent irrigation, the watershed experiences a 6.58% reduction in net irrigation water use. In the scenario with irrigation district renovation, the water resources in the watershed are utilized more efficiently. The modified model from this study can be applied for assessing the synergistic effects of irrigation district water-saving and yield-increasing measures, providing crucial insights for the formulation of irrigation district water-saving strategies and water resource optimization plans.