Search Results (32)

Accurate discharge measurement in irrigation channels is critical for improving water use efficiency and optimizing water allocation. To investigate the controlling factors of sediment deposition and its influence on the stage–discharge relationship, controlled experiments were conducted in a rectangular glass flume. Sediment concentration (4–16 kg/m³), bed slope (0.0005–0.002), and discharge (15–45 L/s) were systematically varied, and longitudinal deposition thickness and corresponding water stages were measured. Results indicate that sediment concentration is the dominant factor controlling deposition thickness, exhibiting a downstream-decreasing influence, with pronounced differences upstream and convergence downstream. Bed slope and discharge mitigate deposition by enhancing near-bed hydraulics; upstream deposition thickness decreased by approximately 35% and 23% as slope increased from 0.0005 to 0.002 and discharge increased from 15 to 45 L/s, respectively, with the regulatory effect diminishing along the flow direction. Three-dimensional response analysis revealed a compound “concentration-dominated and hydraulically regulated” mechanism: under low-discharge, low-slope, and high-concentration conditions, the ratio of deposition thickness to measured water depth (h_d/h) exceeded 15%, whereas it decreased below 5% under high-discharge, high-slope, and low-concentration conditions. Sediment deposition elevated the overall water stage by approximately 3–4% and caused systematic overestimation of stage-based discharge, with errors reaching 31.4% under low-discharge and high-concentration conditions and decreasing to 4.94% under high-discharge and steep-slope conditions. These findings provide quantitative evidence for discharge measurement and stage–discharge relationship calibration in sediment-laden open channels. Full article

Both water and sediment resource allocation are critical for achieving sustainable development in sediment-laden river basins. However, current understanding lacks a holistic perspective and fails to capture the inseparability of water and sediment. The Yellow River Basin (YRB) is the world’s most sediment-laden river, characterized by pronounced ecological fragility and uneven socio-economic development. This study introduces integrated water-sediment allocation frameworks for the YRB based on the perspective of the water-sediment nexus, aiming to regulate their impacts on socio-economic and ecological systems. The frameworks were established for both artificial units (e.g., irrigation zones and reservoirs) and geological units (e.g., the Jiziwan region, lower channels, and estuarine deltas) within the YRB. The common feature of the joint allocation of water and sediment across the five units lies in shaping a coordinated water–sediment relationship, though their focuses differ, including in-stream water-sediment processes and combinations, the utilization of water and sediment resources, and the constraints imposed by socio-economic and ecological systems on water-sediment distribution. In irrigation zones, the primary challenge lies in engineering-based control of inflow magnitude and spatiotemporal distribution for both water and sediment. In reservoir systems, effective management requires dynamic regulation through density current flushing and coordinated operations to achieve water-sediment balance. In the Jiziwan region, reconciling socio-economic development with ecological integrity requires establishing science-based thresholds for water and sediment use while ensuring a balance between utilization and protection. Along the lower channel, sustainable management depends on delineating zones for human activities and ecological preservation within floodplains. For deltaic systems, key strategies involve adjusting upstream sediment and refining depositional processes. Full article

To address frost heave in winter-lined canals and sediment accumulation in the Hetao Irrigation District of Inner Mongolia Autonomous Region, while reducing long-term maintenance costs of canal linings and relocating sediment as solid waste, this study proposes the use of low-toxicity, environmentally friendly octadecyltrichlorosilane (OTS) to modify channel sediment. This approach aims to improve the frost heave resistance of canal sediment and investigate optimal modification conditions and their impact on frost heave phenomena, aligning with sustainable development goals of low energy consumption and economic efficiency. Water Droplet Penetration Time (WDPT) tests and unidirectional freezing experiments were conducted to analyze frost heave magnitude, temperature distribution, and moisture variation in modified sediment. A coupled thermal–hydraulic–mechanical (THM) model established using COMSOL Multiphysics 6.2 software was employed for numerical simulations. Experimental results demonstrate that the hydrophobicity of channel sediment increases with higher OTS concentrations. The optimal modification effect is achieved at 50 °C with a silane-to-sediment mass ratio of 0.001, aligning with the economic efficiency of sustainable development. The unidirectional freezing test results indicate that compared to the 0% modified sediment content, the 40% modified sediment proportion reduces frost heave magnitude by 71.3% and decreases water accumulation at the freezing front by 21.1%. The comparison between numerical simulation results and experimental data demonstrates that the model can accurately simulate the frost heave behavior of modified sediment, with the error margin maintained within 15%. In conclusion, OTS-modified channel sediment demonstrates significant advantages in enhancing frost heave resistance while aligning with the economic and environmental sustainability requirements. Furthermore, the coupled thermal–hydraulic–mechanical (THM) model provides a reliable tool to guide sustainable infrastructure development for hydraulic engineering in the cold and arid regions of Inner Mongolia, effectively reducing long-term maintenance energy consumption. Full article

Sediment accumulation in irrigation channels poses a significant challenge to water resource management, impacting hydraulic efficiency and agricultural sustainability. This study introduces an innovative multidisciplinary framework that integrates advanced image analysis (FIJI/ImageJ 1.54p), statistical validation (RStudio), and vector field modeling with a novel Sinusoidal Morphodynamic Bedload Transport Equation (SMBTE) to predict sediment deposition patterns with high precision. Conducted along the Malacatos River in La Tebaida Linear Park, Loja, Ecuador, the research captured a natural sediment transport event under controlled flow conditions, transitioning from pressurized pipe flow to free-surface flow. Observed sediment deposition reduced the hydraulic cross-section by approximately 5 cm, notably altering flow dynamics and water distribution. The final SMBTE model (Model 8) demonstrated exceptional predictive accuracy, achieving RMSE: 0.0108, R²: 0.8689, NSE: 0.8689, MAE: 0.0093, and a correlation coefficient exceeding 0.93. Complementary analyses, including heatmaps, histograms, and vector fields, revealed spatial heterogeneity, local gradients, and oscillatory trends in sediment distribution. These tools identified high-concentration sediment zones and quantified variability, providing actionable insights for optimizing canal design, maintenance schedules, and sediment control strategies. By leveraging open-source software and real-world validation, this methodology offers a scalable, replicable framework applicable to diverse water conveyance systems. The study advances understanding of sediment dynamics under subcritical (Fr ≈ 0.07) and turbulent flow conditions (Re ≈ 41,000), contributing to improved irrigation efficiency, system resilience, and sustainable water management. This research establishes a robust foundation for future advancements in sediment transport modeling and hydrological engineering, addressing critical challenges in agricultural water systems. Full article

Emitter clogging in drip irrigation systems is a recurring issue, affecting water application uniformity and system lifespan. This study investigated the anti-clogging performance of emitters and the accumulation patterns of solid particles in dripper labyrinths with varied geometric configurations, combining laboratory experimentation and computational fluid dynamics simulations. Fifteen labyrinth models were tested, divided into two groups: (Model A) emitters with well-defined vortexes and (Model B) emitters with uniform flow. The tests were conducted with solid particle concentrations of 125 and 500 mg L⁻¹ over 200 h of operation. The results showed that none of the emitters became clogged, even under severe particle concentration conditions. However, distinct deposition patterns were observed. Emitters with vortex formation accumulated particles in low-velocity zones, especially in the first baffles of the labyrinth. In contrast, emitters with uniform flow minimized sediment buildup, maintaining high velocities throughout the channel section. Simulations confirmed that the relationship between labyrinth geometry and flow velocity directly influences particle deposition. Dripper design strategies aimed at reducing low-velocity zones in the channel could help mitigate clogging risks. The findings of this study provide valuable guidelines for developing more clogging-resistant emitters, contributing to the improvement of drip irrigation systems. Full article

Developing efficient water-saving irrigation technologies that utilize high sand-laden water is an important approach to alleviating agricultural water scarcity in the Yellow River Basin. This study aims to investigate sedimentation patterns and fluid movement characteristics in drip irrigation emitters under such challenging water conditions. The dynamic changes in Dra and Cu were determined through short-period intermittent clogging tests to evaluate the anti-clogging performance of four different emitter types. The distribution and particle size composition of the deposited sediments inside the emitters were analyzed using a high-resolution electron microscope and a laser particle size analyzer. Additionally, the RNG k-ε turbulence model was used to simulate the fluid movement inside the emitters. The results showed that the B drip irrigation belt had better sediment tolerance and operational stability. The anti-clogging capacity of drip irrigation can be improved by optimizing the combination of emitter channel structure and sediment content. The fluid in the channel was divided into mainstream zone and vortex zone. Sediment particles increased in the backing-water zone and vortex center, where particles of 0.05–0.1 mm were more prone to settling due to reduced transport capacity. Energy dissipation primarily took place at the curvature of the emitter channel, and within each channel unit, gradually decreasing along the vortex flow direction, with the lowest dissipation aligning with sediment deposition zones. These findings provide a theoretical basis for mitigating clogging in high sand-laden water drip irrigation systems, offering valuable insights for improving the effective utilization of water resources in the Yellow River Basin. Full article

As irrigation districts rapidly advance in terms of informatization, research on intelligent water quantity control technologies for open channels has gained increasing importance. This study aims to investigate the flow capacity and hydraulic characteristics of gates in open channels, focusing on the flow measurement and the hydraulic behavior around water-measuring structures. Although automated control in irrigation systems has achieved significant development, research on the flow characteristics near gates remains limited. To address this gap, an integrated approach combining indoor physical model experiments with theoretical analysis was used. This study explored the water surface profile, cross-sectional flow velocity distribution, vertical velocity distribution, and turbulent kinetic energy under various gate opening conditions and flow rates. The findings reveal that the water surface exhibits a sharp rise upstream of the gate, followed by a steep decline and stabilization downstream, influenced by the gate’s water-blocking effect. The flow velocities near the gate opening differ significantly in direction and magnitude from those in other cross-sections, affecting both longitudinal and vertical velocities. The turbulent kinetic energy is concentrated near the gate opening, and the turbulent kinetic energy is primarily concentrated near the sidewalls and the channel bottom; the gate’s opening size plays a crucial role in its diffusion and distribution. Linear regression analysis was utilized to fit the gate flow coefficient formula, and a comparative analysis of the measurement accuracy was conducted. The relative error between the calculated flow values and the actual measured values is within ±5%, which meets the precision requirements specified in the water measurement standards for irrigation canal systems in the irrigation district. This study pioneers an integrated approach for investigating the hydraulic characteristics of gates in open channels, merging physical model experiments with theoretical analysis. It provides novel insights into how gate openings affect water surface profiles, flow velocity distributions, and turbulent kinetic energy. This research also underscores the role of gate discharge in turbulent kinetic energy distribution, offering technical insights to enhance flow measurement accuracy and prevent sediment deposition, thereby optimizing gate applications for efficient water management. Overall, this study significantly advances the understanding of open channel flow dynamics and holds substantial significance for the refinement of water quantity control techniques in irrigation districts. Full article

Symmetric lateral inlet pumping stations are commonly utilized for water lifting in agricultural multi-crop irrigation districts, but they often share non-ideal flow patterns, which can easily cause pump vibration and sediment deposition. In this paper, a symmetrical lateral pumping station in an irrigation district is taken as the research object, and CFD (Computational Fluid Dynamics) technology is used to study it. The model test used a model scale ratio of ${\lambda }_L$ = 1:18. Results: By comparing the CFD data and test data, the average relative error for the left station is found to be 3.213%, while that for the right station is 5.107%, indicating that the numerical simulation method is reliable. Six different rectification measures are proposed, the cross sectional flow pattern of the pumping station is observed, and the longitudinal profile of axial velocity distribution in the sump is analyzed. The velocity-weighted average angle and hydraulic loss of each case study are also analyzed. The flow operates smoothly in case study 7. The vortex in the approach channel disappears when the columns and bottom sill are finally installed. Compared to the original case study, the velocity-weighted average angle at the 5# station in case study 7 increased by 14%, and it increased by 13.9% at station #9. The flow became more stable, and hydraulic losses were minimized. The simulated hydraulic loss in case study 7 decreased by 14.2%. These findings can serve as a reference for similar pump station projects. Full article

To enhance the efficiency of irrigation water utilisation, China is progressively converting irrigation ditches into pipelines. The water distribution outlets in irrigation zones are predominantly right-angled, and there are typically occurrences of erosion, sedimentation, and structural deterioration in the surrounding areas. This article employs a synthesis of indoor physical model experiments and theoretical analysis to examine the distribution of channel flow velocity and variations in water surface profile, pipeline flow rate, diversion ratio, circulation intensity, and turbulence energy across different relative water depths. The experimental results indicate that the water surface adjacent to the main canal wall demonstrates a pattern of initial decline, followed by an increase and subsequently another decline; furthermore, as the water level in the main channel rises, the magnitude of this fluctuation progressively diminishes. In some sections of the canal, the water surface elevation progressively increases, albeit with minimal amplitude. With a constant relative water depth, an increase in main channel flow results in a corresponding increase in pipeline flow; however, the diversion ratio is inversely related to the main channel flow. Conversely, when the main channel flow rate is constant, the diversion ratio increases as relative water depth rises. The vertical flow velocity near the water diversion outlet has a negative value, signifying the existence of a backflow zone, while the horizontal flow velocity varies considerably, facilitating the formation of circulation and resulting in localised deposition and erosion. The water flow near the pipe inlet downstream of the lower lip of 0.5 times the pipe diameter is impacted by the return zone, which has a higher turbulence energy and circulation strength and is more susceptible to siltation. The turbulence energy of the water flow is higher in the range of 0.5 times the pipe diameter upstream and downstream of the pipe inlet. This research is highly significant in facilitating the conversion of irrigation channels into pipelines. Full article

To address the current challenge of climate change at the local and global levels, this article discusses a few important water resources engineering topics, such as estimating the energy dissipation of flowing waters over hilly areas through the provision of regulated stepped channels, predicting the removal of silt deposition in the irrigation canal, and predicting groundwater level. Artificial intelligence (AI) in water resource engineering is now one of the most active study topics. As a result, multiple AI tools such as Random Forest (RF), Random Tree (RT), M5P (M5 model trees), M5Rules, Feed-Forward Neural Networks (FFNNs), Gradient Boosting Machine (GBM), Adaptive Boosting (AdaBoost), and Support Vector Machines kernel-based model (SVM-Pearson VII Universal Kernel, Radial Basis Function) are tested in the present study using various combinations of datasets. However, in various circumstances, including predicting energy dissipation of stepped channels and silt deposition in rivers, AI techniques outperformed the traditional approach in the literature. Out of all the models, the GBM model performed better than other AI tools in both the field of energy dissipation of stepped channels with a coefficient of determination (R²) of 0.998, root mean square error (RMSE) of 0.00182, and mean absolute error (MAE) of 0.0016 and sediment trapping efficiency of vortex tube ejector with an R² of 0.997, RMSE of 0.769, and MAE of 0.531 during testing. On the other hand, the AI technique could not adequately understand the diversity in groundwater level datasets using field data from various stations. According to the current study, the AI tool works well in some fields of water resource engineering, but it has difficulty in other domains in capturing the diversity of datasets. Full article

The construction of large dams in the upper tributary basin of the Chao Phraya River (CPR) has been linked to a significant decrease in sediment load in the CPR system, estimated between 75–85%. This study, utilizing historical and recent river flow and sediment data from 1922 to 2019, examines the impact of three major dams constructed in the Nan River basin (the Sirikit, Naresuan, and Khwae Noi dams) on river runoff and sediment loads in the CPR. The investigation employed the Mann–Kendall (MK) test and the double mass curve (DMC) for analysis. Findings indicate that the Nan River is a major contributor to the CPR, accounting for around 40% of the runoff and 57% of the total sediment load (TSL). The Naresuan diversion dam’s water regulation was found to significantly reduce annual runoff and TSL downstream of the dam. Despite an initial increase in sediment load at the CPR headwater (C.2) post the construction of the Sirikit dam, attributed to expanded irrigation downstream and channel improvements in the lower Nan River, the operation of the three dams eventually led to a 31% reduction in sediment load at C.2 compared to pre-construction levels. Full article

Optimizing the flood limit water level (FLWL) of reservoirs in sediment-laden rivers under changing water and sediment conditions is an important research topic that could improve comprehensive utilization benefits. Because reservoir operation has multiple objectives in sediment-laden rivers, this study established a water–sediment mathematical model, a comprehensive benefit evaluation model, and an evaluation index system. Taking the Xiaolangdi Reservoir of the Yellow River as an example, the operation mode of the FLWL under changing water and sediment conditions was studied. Under the scenarios of incoming sediment amounts of 300–800 million tons, when using the operation mode of gradually raising the FLWL, the sediment retention period was 4–13 years longer; the lower average annual siltation of the downstream channel and minimum bank-full discharge of the downstream channel after 50 years was larger by 150–260 m³/s than the operation mode of raising the FLWL at one time. However, with enhanced benefits of sediment blocking and siltation reduction, other benefits such as water resources supply, hydropower generation, and ecological improvement are reduced. The average annual number of days that do not meet the downstream water resources supply requirements, irrigation, and ecological improvement was increased by 0.64–2.16 days, and 91–197 million kW·h reduced average annual hydropower generation. The critical amount of incoming sediment was 350 million for conversion between the two FLWL operation modes, and it will increase to 450 million tons if the incoming runoff of the Yellow River increases by 20%. After constructing the Guxian Reservoir in the middle of the Yellow River, the critical amount of incoming sediment will increase to 600 million tons. This study is of great significance for improving the utilization efficiency of water resources and promoting the socio-economic development of river basins. Full article

Important for irrigation, the transboundary river basin between Kyrgyzstan and Kazakhstan is vulnerable to geochemical and anthropogenic sources of pollution. The use of water use indices, together with measurements of the elemental and radionuclide composition of the water and bottom sediments, provides a means for evaluating the continued use of the water from this region. Recent monitoring shows the highest concentrations of hazardous contaminants include lead and thorium contained in the bottom and banks of the Kichi-Kemin River. These contaminants are likely remnants of an accidental spill at the Aktyuz tailing dump in 1964. The specific activity of the Th-232 of the bottom and banks of the Kichi-Kemin River is 107–189 Bq/kg. There is evidence of anthropogenic sources of additional pollution from uranium in both the bottom sediments and the water in the Oyrandy River. The geochemical origins of uranium and other associated elements in the water of the Shu River are likely the Kamyshanovskoye deposit. Contact between the riverbed and ore bodies in this region likely leads to elevated concentrations of several geogenic contaminants, including lithium, strontium, uranium, and boron (Li, Sr, U, B), increasing by as much as 60–130%. The uranium concentrations in the water of channels that are used for irrigation exceed the maximum allowable contaminant levels by 3.8 times. Future work is needed to evaluate the ecological and human health impacts of these contaminants in irrigation and drinking water. Full article

Irrigation water for agriculture in Ningxia during the summer is primarily sourced from the Yellow River self-flow irrigation region. However, the water conveyance system in this region is significantly influenced by hydrodynamic factors, morphological factors, human factors, and the infrastructure used for social purposes, all of which directly impact the irrigation water utilization coefficient. In order to improve the irrigation water utilization coefficient, reduce suspended sediment deposition in the water conveyance channels, and mitigate negative effects on the water supply system, this study implemented a sediment diversion system at the channel head. This is expected to increase water usage efficiency to a certain degree. Using actual data on hydrodynamic factors from the Shizuishan section of the Yellow River in Ningxia, a two-dimensional numerical simulation was performed, and a two-dimensional hydrodynamic model and sediment model of the Shizuishan section of the Yellow River in Ningxia were developed using MIKE 21. The water conveyance method at the channel head was simulated under two different operating conditions. Results indicated that compared to operating condition 1, operating condition 2 had a beneficial effect on diverting and reducing sediment at the fish mouth of the channel head: the sediment accumulation thickness of one day in operating condition 1 was 0.16 m, 0.003 m, 0.15 m, and 0.21 m under actual flow, scenario 1, scenario 2, and scenario 3, respectively; whereas in operating condition 2, the sediment accumulation thickness of one day was 0.11 m, 0.001 m, 0.09 m, and 0.12 m under the same conditions, respectively. Additionally, as the computation period lengthened, the sediment accumulation thickness of operating condition 2 was significantly smaller than that of operating condition 1. In conclusion, operating condition 2 is superior for the design of the channel head in the Yellow River self-flow irrigation region. Full article

Complex freshwater–saltwater exchanges characterize most Holocene groundwater aquifers in low-lying coastal plains around the world, particularly in mechanically drained territories. This is due to the combination of several factors that control groundwater dynamics, including the high variability of the Holocene coastal deposits that host the shallow aquifers and the water management practices. The relationships between the stratal architecture of sedimentary deposits and the vertical changes in the salinity of the phreatic aquifer are poorly studied although they represent an issue of primary importance for a sustainable use of water resources and for agriculture. This research work is focused on the influence of sedimentary constraints, i.e., stratigraphic discontinuities and related changes in permeability in shaping salinity stratification into the unconfined aquifer at the southern margin of the Venice lagoon (Italy). Nine sites have been investigated by collecting sediment cores for facies analysis and monitoring water electrical conductivity in piezometric wells. The results show that buried channelized sandy deposits can enhance salinity mitigation of the phreatic aquifer in conjunction with precipitations and sufficient freshwater supply from nearby rivers and irrigation channels. Our analyses also reveal that the differences in stratigraphic architecture of the upper 10 m of the subsoil determine different fresh–saltwater dynamics of the phreatic aquifer. In particular, three possible behaviors can occur: (i) where the subsurface is characterized by the presence of a thick, up to 5 m, paleochannel, a freshwater lens is always present in the most surficial part of the phreatic aquifer; (ii) where the subsurface is composed by fine-grained sediments of marsh and lagoon paleo-environment, the phreatic aquifer tends to be salt-contaminated over its entire thickness; (iii) where the subsurface contains thin, up to 2–3 m, paleochannel deposits, the fresh–saltwater dynamics of the most surficial part of the phreatic aquifer varies more during the year, as a result of seasonal precipitation trend. The provided characterization of saltwater dynamics represents the basis for planning mitigation measures to improve the farmland productivity of the Venetian coastal plains. Full article