Abstract:Cutoff wall is a common measure for hydraulic structures to reduce uplift pressure and hydraulic gradient,and its length and position have significant effects on anti-seepage control.To optimize the design of cutoff wall and control seepage risks,this paper adopts a genetic algorithm and finite element programming coupled model(GA-FEP),with construction cost minimization as the objective function and the safety factors of uplift pressure and hydraulic gradient meeting requirements as the main constraints.Quantitative analysis of the seepage field is conducted through finite element programming,and the genetic algorithm is used to determine the optimal depth and position of the cutoff wall.The results show that the model can obtain the optimal design scheme of the cutoff wall under specific head and hydraulic conductivity conditions.

Abstract:Bends of flood channels and areas near diversion projects are prone to varying degrees of erosion and siltation after floods.The state has invested massive funds to support post-disaster reconstruction.Analysis of post-disaster channel erosion and siltation reveals that some river sections show inner bank erosion and outer bank deposition,some sections experience channel bending deformation and elevated flood water levels due to erosion and bank collapse,and some sections form vortices and scour pits due to sudden flow changes,even causing uneven inlet gate flow distribution.This paper considers that the sudden changes in flow velocity and direction caused by deflected flow in the channel,along with changes in river sediment concentration,are the main influencing factors for the formation of erosion and siltation phenomena in flood channels.On this basis,countermeasures and suggestions for preventing erosion and siltation disasters in flood channels and control projects from the source are proposed.

Abstract:To accurately grasp the crop water consumption patterns in irrigation areas of karst mountainous regions in Guizhou Province and promote efficient water resource utilization and sustainable agricultural development,based on NASA(National Aeronautics and Space Administration)remote sensing images and other data from 2021 to 2023,this paper adopts the flux decomposition method to interpret crop water consumption,and verifies and analyzes the interpretation results combined with evaporation data from typical meteorological stations.The results show that in terms of temporal distribution,crop water consumption exhibits obvious seasonal variation,reaching its peak in summer due to high temperatures and vigorous crop growth,with decadal water consumption of 30-50 mm;it drops to its lowest value in winter due to low temperatures and crop dormancy,with decadal water consumption less than 10 mm;interannual differences are mainly affected by precipitation fluctuations.In terms of spatial distribution,water consumption is relatively high in some areas of the south and east,with local areas exceeding 650 mm,corresponding to the distribution of rice-growing areas and high precipitation zones;low-value areas are locally below 250 mm,corresponding to dry farming areas,low precipitation zones,and karst landform areas;other areas have water consumption mainly concentrated at 400-500 mm.Terrain water retention capacity and differences in crop water demand coefficients(rice>flue-cured tobacco>corn)jointly drive the spatial differentiation of crop water consumption.Verification results show a high correlation between observed values and modeling results,and the interpretation results have reliable accuracy.The research results can provide reference for agricultural water resource management and crop water consumption monitoring in irrigation areas of Guizhou Province.

Abstract:Water-sediment variation is an important factor affecting river ecological health.In recent years,under the combined effects of climate change and human activities,the water-sediment characteristics of the Ganjiang River have changed significantly.To investigate the water-sediment variation characteristics and their causes in the Ganjiang River,this paper is based on data from 40 meteorological stations in the Ganjiang River basin and Ganjiang River hydrological data from 1960 to 2018,sorting out water-sediment variation characteristics in different periods and quantitatively analyzing the attribution of water-sediment variation.The results show that precipitation and runoff in the Ganjiang River basin both show a non-significant increasing trend,while sediment transport shows a significant decreasing trend;the difference in precipitation-runoff relationship over time is significantly smaller than that in precipitation-sediment transport relationship,especially after the construction of the Wan′an Reservoir,where the difference becomes even more pronounced.Sediment reduction by the Wan′an Reservoir mainly occurs from March to October,of which the sediment reduction from March to June accounts for 77.3%of the annual total;large reservoirs on the main stream of the Ganjiang River have significantly stronger sediment reduction capacity than those on tributaries.Overall,climate change is the main cause of the increase in runoff,while human activities play a dominant role in runoff variation and sediment transport reduction.The research results can provide reference for water-sediment regulation,reservoir operation management,and river ecological protection in the Ganjiang River basin.

Abstract:During the excavation of the spillway slope at Yazhai Reservoir,deformation occurred in the high slope on the left side.Combined with the site excavation exposure and engineering investigation data,the slope was identified as a deep overburden soil slope developed in a"U"-shaped ancient gully.Through comprehensive analysis of the causes of slope deformation,this paper proposes the use of anti-slide piles for treatment.After project implementation,slope deformation was controlled and safety hazards were addressed,thereby ensuring smooth construction progress and safe operation after completion.

Abstract:Aiming at the new challenges brought by frequent sudden drought-flood transition events to the operation of water conservancy facilities,this paper takes the bidirectional flow channel irrigation and drainage pumping station as the research object,and summarizes its application characteristics and design optimization methods under working conditions such as low head,large flow,and large water level fluctuation.Taking an X-type bidirectional flow channel irrigation and drainage pumping station built in Gaochun District,Nanjing in 2022 as an example,the design and operation scheme of the bidirectional flow channel and CFD simulation optimization results are described.The pumping station achieves irrigation and drainage function switching through double-layer flow channels,and operational practice shows that the design scheme is scientific and reasonable.Meanwhile,the room for improvement in high sediment-laden watershed application,standardization development,and simulation technology is analyzed,and the direction of promotion and application is prospected.

Abstract:Based on the measured data of 63 a from 1960 to 2022 at Baoqiao Hydrological Station,the control station in the lower reaches of Changhua River in Hainan,statistical methods such as linear trend analysis,R/S analysis and wavelet analysis are used to study the variation trend and periodic characteristics of runoff in the lower reaches of Changhua River.The results show that the runoff series in the lower reaches of Changhua River presents a weak downward trend on the whole,and there are frequent conversions between rise and fall in the local variation process.The runoff variation does not have a single continuous trend,but presents the fluctuation characteristics of multi-time scale nesting,among which about 10 months is the main period,showing obvious periodic fluctuation,and the variation trend of long time scale over 30 months gradually tends to be stable.The research results can provide reference for the optimal allocation and efficient utilization of water resources in the lower reaches of Changhua River under the background of Hainan Free Trade Port.

Abstract:Taking the law enforcement model of the Weihe River as the research object,this paper analyzes the complexity,particularity,and historical causes of the current Weihe River law enforcement environment,and points out the dilemmas and deficiencies of the traditional"punishment enforcement"model in modern watershed governance and management.The necessity of transforming the law enforcement model from"punishment enforcement"to"education enforcement"is demonstrated from three dimensions,and a"early-warning-communication-restoration"trinity law enforcement path and method are proposed.The research results can provide innovative resolution for improving the efficiency of watershed governance and management and building a modern water governance model of harmony between humans and water.

Abstract:Geomembrane is one of the important anti-seepage measures for core wall earth-rock dams.Defects in geomembrane can alter the seepage characteristics of geomembrane core wall dams,affecting the safe operation and benefit realization of dams.Taking a clay core wall dam as the research object,this paper conducts secondary development of finite element numerical simulation using open-source libraries to analyze the effects of geomembrane defect elevation,defect size,defect quantity,and reservoir water level decline rate on the seepage characteristics of the dam body.The results show that when the defect elevation is located at 1/2 of the calculated reservoir water level,the phreatic line height and seepage volume inside the dam body reach their maximum values;when the defect elevation approaches and exceeds the reservoir water level,the phreatic line height and seepage volume decrease rapidly.The phreatic line height and seepage volume of the dam body increase with the increase of defect size and decrease with the decline of reservoir water level;under the same reservoir water level change conditions,the seepage field calculation results corresponding to different decline rates are basically consistent.An increase in the number of geomembrane defects also leads to a rise in the phreatic line and an increase in seepage volume.Therefore,the occurrence of geomembrane defects should be avoided in practical engineering.

Abstract:The lower reaches of Gufeng River Basin are located in the eastern part of Nanling County,Anhui Province,at the confluence of Qingyi River and Zhanghe River.It is an important part of the"Three Rivers Basin"of Shuiyang River-Qingyi River-Zhanghe River in the lower reaches of the Yangtze River.The region features compound landforms of hills,plains,and polder areas,with complex water system structures and obvious superimposition effects of upstream and downstream floods,placing great pressure on the flood control and waterlogging prevention system.In recent years,affected by changes in regional engineering conditions and hydrological regimes,the original flood control and waterlogging prevention system can no longer meet the needs of economic and social development in the new era.Based on the assessment of the current flood control capacity of the basin,this paper proposes a planning and treatment scheme,conducts multi-scheme comparison based on engineering quantity,investment estimation,and implementation feasibility,and determines the engineering scheme meeting the planned treatment standards.Meanwhile,the project scale is verified through flood routing calculation.The research results can provide reference for flood control and waterlogging prevention planning in hill-plain-polder compound small basins.

Abstract:Taking City A as the research area,based on the maximum population-economy theory,combined with the maximum water resource population carrying capacity and water resource carrying capacity balance index,this paper evaluates the"hard investment"of the water diversion project in City A.Aiming at the deficiency of the traditional principal component analysis method in ignoring the degree of indicator differences,this paper proposes a normal standardized principal component analysis method to evaluate and analyze the"soft construction"of the water diversion project in City A.Combining the evaluation results of"hard investment"and"soft construction,"it is known that the water resource carrying capacity of City A has improved after the implementation of the water diversion project,but the contradiction between available water resources in each district and county and water demand of various departments remains obvious.It is recommended to continuously improve the"soft construction"content such as regional water use systems in combination with water conservancy projects supported by"two major"funds,plan utilizable water resources with the city as a whole unit,adhere to parallel development of water source expansion and water saving,and simultaneous implementation of"hard investment"and"soft construction"to alleviate the water supply and demand contradiction in City A.

Abstract:To better plan the construction of the digital twin water conservancy system for the Zhangwei River and accelerate the beneficial application of construction achievements,the Zhangweinan Canal Administration Bureau,starting from the intrinsic demands of its own business development,sorted out management pain points of core businesses including river basin flood control and water withdrawal management.Based on the existing overall framework of the digital twin Zhangwei River platform,through multi-source heterogeneous water conservancy data fusion and global business situation perception on one screen,intelligent water regime threshold diagnosis and multi-level early warning linkage,intelligent statistics and analysis of water conservancy monitoring data,high-performance vector map rendering,and other collaborative technological innovations,the administration developed and deployed the intelligent collaborative platform—the digital twin Zhangwei River business panorama,empowering various river basin water conservancy comprehensive governance and management businesses with digital intelligence.

Abstract:At the preliminary planning and design stage of irrigation district,optimizing construction schemes from social,economic,environmental,and technical perspectives and reasonably determining project layout can better avoid investment risks and increase investment benefits.Taking the newly constructed Wenyangtian Irrigation District in Shandong Province as an example,this paper analyzed the scope and area of the irrigation district,summarized existing problems in current irrigation,and used water from the Dawen River,Caohe River,and reservoirs within the irrigation district as water sources to formulate three project layout schemes.Comparative analysis was conducted from aspects of land occupation and investment,and a reasonable project layout was proposed.The results indicate that areas with groundwater well depths above 80 m should be taken as the irrigation scope;meanwhile,considering irrigation economy,the irrigation elevation should not exceed 130 m;the designed irrigation area of the district is 6,680 hm2;the scheme with dispersed water intake and the Bian'an Pumping Station located in the middle of the irrigation area occupies less land,has the minimum total investment,and the lowest annual operation cost,and can be recommended as the preferred scheme.The research findings can lay a foundation for determining the construction content of the irrigation district,and simultaneously provide important guidance for newly constructed irrigation districts currently being developed in China.

Abstract:Large and medium-sized reservoir projects are important supports for regional water resources allocation,and are of great significance for exerting social,economic,and ecological benefits of projects,while also producing certain impacts on river ecosystems.Through ensuring river ecological flow,the adverse impacts of dam construction on river ecosystems can be mitigated to a certain extent.Taking the large-scale Fushouyan Reservoir Project in Chongqing as a case study,this paper determines the components and staging of ecological flow based on the ecological protection targets in the river reaches affected by the project.The ecological base flow and sensitive-period ecological flow are calculated separately,and on the basis of analyzing their rationality,feasibility,and compatibility,the ecological flow for the project is comprehensively determined.The findings of this study can serve as a reference for the survey and design of other large and medium-sized reservoir projects.

Abstract:Since its operation,a certain large-scale water diversion project has maintained stable and standard-compliant water quality during water conveyance periods,playing an important role in ensuring urban water supply security,drought relief and water source replenishment,flood control and waterlogging elimination,navigation services,river and lake ecological protection,and facilitation of economic circulation between northern and southern regions.Under the new situation of the"15th Five-Year Plan"period,this project faces numerous challenges including increased operational pressure on pollution interception and diversion projects,shortcomings in environmental infrastructure,gradually intensifying pollution prevention pressure from inland shipping,and the need for improvement in the monitoring system of converging water systems.This paper systematically reviewed the relevant laws,regulations,and institutional construction for water quality safety guarantee of the large-scale water diversion project,summarized the effectiveness of water quality safety guarantee from aspects such as water quality along the conveyance route,ecological environment quality,comprehensive pollution control,water quality monitoring system,response to water pollution incidents,and institutional,mechanism,and legal construction,and identified the remaining challenges and problems in water quality safety guarantee for large-scale water diversion projects.Countermeasures and suggestions were proposed from aspects including constructing a systematic water pollution prevention system,an intelligent and modern water quality safety monitoring system,a comprehensive system of sudden water environmental risk prevention and control,and a multi-dimensional water quality safety linkage mechanism,providing references for ensuring water quality safety of large-scale water diversion projects.

Abstract:The slope at the exit of No.1 tunnel of the main canal in Niululing Irrigation District Project in Hainan Province is characterized by steep gradient and significant differences in weathering degree of rock and soil mass,and its stability directly affects the operation safety of the tunnel and the overall benefits of the irrigation district project.To clarify the stability state of this slope and formulate a reasonable reinforcement scheme,this paper takes the typical 1-1 section at the exit of No.1 tunnel as the research object,and employs GeoStudio software to comparatively analyze the safety factors of the slope under unsupported and supported conditions.The results indicate that the safety factor of the unsupported slope under normal operating conditions is only 0.867,which does not meet the code requirements;after reinforcement with the combined support of steel pipe piles,frame beams,and anchor cables,the safety factor under normal operating conditions reaches 1.236,and that under abnormal operating conditions is 1.126,both meeting the relevant code requirements.The research findings can provide theoretical basis and technical support for the engineering design,construction,and long-term safe operation of tunnel exit slopes.

Abstract:Lancao Reservoir is a crucial component of the flood control system in the Qujiang River Basin.While ensuring regional flood security,it inevitably exerts certain impacts on the basin's ecological environment.To mitigate the adverse effects of project construction and operation on the river ecosystem,it is essential to reasonably determine and release ecological flow.Taking the Lancao Reservoir Project in Sichuan Province as the research object,this paper employs multiple methods to separately calculate the basic ecological flow and sensitive-period ecological flow of the project,and systematically analyzes their coordination with the basin's eco-environmental protection requirements and relevant policy documents.On this basis,the ecological flow for the project is comprehensively determined.Corresponding ecological flow release and monitoring measures are proposed,and reservoir ecological operation design is carried out from three aspects:ecological flow regulation,water level regulation,and water temperature regulation.The research findings can serve as a reference for the determination of ecological flow and the design of regulation measures for large and medium-sized water conservancy projects.

Abstract:Sand and gravel materials are one of the main materials for water conservancy projects,and their accurate unit price calculation is key to investment control in project budget preparation.To study the pricing of sand and gravel materials in hub projects,this paper takes a reservoir project in Hunan Province as a practical case and conducts a systematic calculation study on the comprehensive unit price of sand and gravel materials.Strictly following the quota pricing specifications for water conservancy projects,and combining with actual working conditions of on-site extraction,processing,transportation,and loss of the project,the unit price of sand and gravel materials is explicitly broken down into cost components including overburden removal,raw material extraction and transportation,crushing,and finished product transportation.Through the process unit price method,the unit price calculation of sand and gravel materials for this reservoir project is calculated.Finally,the calculated unit price of manually self-extracted sand and gravel is compared with the direct purchase price from material yards to better control project investment.The calculation method and results of this case study can serve as a reference for the unit price calculation of sand and gravel materials and project cost control in similar water conservancy hub projects.

Abstract:At the project proposal and feasibility study stages,reasonably predicting project financial benefits according to market demand,formulating project financing schemes,calculating the loan amount the project can bear and the required capital,and recommending project water price,can provide basis for decision-making by the state,local governments,and relevant investors through scientific and reasonable financial feasibility evaluation.Taking the Jiabai Reservoir Project in Guizhou Province as an example,this paper conducted engineering financial cost estimation and allocation,analyzed the current water price,cost water price,and affordable water price in the water-receiving area,formulated loan schemes,calculated the loan capacity of each scheme,and preliminarily proposed a water price suitable for the sound operation of Jiabai Reservoir,aiming to provide reference for loan capacity calculation of similar reservoir projects.

Abstract:Marine aquaculture plays a pivotal role in the global supply of high-quality protein food.Marine aquaculture tailwater,especially industrial marine aquaculture tailwater,largely determines the water environmental quality of bay and estuary areas,which has a significant impact on the stability of coastal ecosystems.Clarifying the generation process and components of pollutants in marine aquaculture tailwater is of great significance for industrial aquaculture water purification treatment and enhancing marine ecosystem security.By synthesizing domestic and international research findings,this paper comprehensively reviews the transport processes and transformation mechanisms of pollutants in industrialized aquaculture tailwater from the perspectives of sources,generation mechanisms,and compositional characteristics of suspended solids,organic matter,nutrients,antibiotics,and microorganisms.The environmental behavior of pollutant components in aquaculture tailwater is emphasized,and the factors affecting the stability of nearshore marine ecosystems are discussed.With respect to the sources,transport processes,and treatment technologies of pollutant components in industrialized marine aquaculture tailwater,this paper proposes the establishment of an aquaculture tailwater assessment and regulatory system,the development of treatment technologies for industrialized marine aquaculture tailwater—with particular emphasis on investigating the ecotoxicity and treatment technologies of aquaculture antibiotics—interdisciplinary scientific research,and the construction of green and ecological industrialized marine aquaculture models,with the aim of providing scientific basis for whole-process supervision,assessment,and governance of marine environmental pollution.