The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area d...The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area downstream. The concept covers the cemented sand, gravel, and rock dam （CSGRD）, the rockfill concrete （RFC） dam （or the cemented rockfill dam, CRD）, and the cemented soil dam （CSD）. This paper summarizes the concept and principles of the CMD based on studies and practices in projects around the world. It also introduces new developments in the CSGRD, CRD, and CSD.展开更多
Underpinned by the ultrahigh-core rockfill dam at the Nuozhadu Hydropower Station,comprehensive studies and engineering practices have been conducted to address several critical challenges:coordination of seepage defo...Underpinned by the ultrahigh-core rockfill dam at the Nuozhadu Hydropower Station,comprehensive studies and engineering practices have been conducted to address several critical challenges:coordination of seepage deformation in dam materials,prevention and control of high-water-pressure seepage failure,static and dynamic deformation control,and construction quality monitoring.Advanced technologies have been developed for modifying impermeable soil materials and utilizing soft rocks.Constitutive models and high-performance fine computational methods for dam materials have been improved,along with innovative seismic safety measures.Additionally,a“Digital Dam”and an information system for monitoring the construction quality were implemented.These efforts ensured the successful construction of the Nuozhadu Dam,making it the tallest dam in China and the third tallest dam in the world upon completion.This achievement increased the height of core dams in China by 100 m and established a design and safety evaluation framework for ultrahigh-core rockfill dams exceeding 300 m in height.Furthermore,the current safety monitoring results indicate that the Nuozhadu Dam is safe and controllable.展开更多
Based on raw data from dams damaged in the Wenchuan earthquake, including many that were severely damaged, characteristics and factors that influenced the damage are discussed in this paper. Findings from this study i...Based on raw data from dams damaged in the Wenchuan earthquake, including many that were severely damaged, characteristics and factors that influenced the damage are discussed in this paper. Findings from this study include： severely damaged dams were densely distributed along the seismologic fault; small dams, especially small earth-rock dams, had the most serious damage that was caused by a variety of factors; the most serious damage was caused by seismic waves; damage was aggregated by aftershocks; and the extent of the damage patterns increased with the seismic intensity. Damage patterns varied in different intensity zones and cracking was the most common type of damage. Most of the dams had a good base with relatively high bearing capacity, and the walls of the earth-rock dams were mostly of clay soil. This type of base and body material mitigated some of the damage to dams. Reservoir maintenance and other factors also have a significant impact on the seismic safety of the dam. Finally, some recommendations to reduce seismic damage to dams are proposed.展开更多
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 environment...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.展开更多
In the application of regression analysis method to model dam deformation, the ill-condition problem occurred in coefficient matrix always prevents an accurate modeling mainly due to the multicollinearity of the varia...In the application of regression analysis method to model dam deformation, the ill-condition problem occurred in coefficient matrix always prevents an accurate modeling mainly due to the multicollinearity of the variables. Independent component regression （ICR） was proposed to model the dam deformation and identify the physical origins of the deformation. Simulation experiment shows that ICR can successfully resolve the problem of ill-condition and produce a reliable deformation model. After that, the method is applied to model the deformation of the Wuqiangxi Dam in Hunan province, China. The result shows that ICR can not only accurately model the deformation of the dam, but also help to identify the physical factors that affect the deformation through the extracted independent components.展开更多
Hydroelectric power production from Garafiri dam and rainfall are essential elements with the observation of hydroelectric power production in West African power system,particularly in Guinea.This article focuses on t...Hydroelectric power production from Garafiri dam and rainfall are essential elements with the observation of hydroelectric power production in West African power system,particularly in Guinea.This article focuses on the study and the influence of climate variability on hydroelectric power production at Garafiri dam over 16-year period(2008-2023).The aim of this work is to show the correlation between rainfall anomalies and hydroelectric power production at Garafiri dam.The method used consists of calculating precipitation anomalies at Garafiri site and those for the production of hydroelectric power from Garafiri dam over the study period.This approach led us to calculate the anomalies,leading to the study on climatic variability,in order to establish correlation between rainfall and hydroelectric power dam’s production.The trend with the correlation found made it possible to carry out a significance test between these two variables.These results clearly show that rainfall in Garafiri site increases hydroelectric power production and vice versa,which explains the interdependence between these two parameters,i.e.climatic variability and hydroelectric power production.展开更多
This study addresses the pressing need to evaluate the quality of water resources in the Oued Guir watershed,highlighting the importance of monitoring both surface water and groundwater in the context of environmental...This study addresses the pressing need to evaluate the quality of water resources in the Oued Guir watershed,highlighting the importance of monitoring both surface water and groundwater in the context of environmental and public health.It focuses on the evaluation of physicochemical and bacteriological water quality downstream of the Kaddoussa Dam,as well as the characterization of wastewater from the Boudnib treatment plant discharged into Oued Guir.The goal is to assess the health of aquatic ecosystems and understand the impact of anthropogenic activities on these sensitive environments.A comprehensive analysis was conducted at 15 selected stations during a sampling campaign in November 2023.Groundwater and surface water were assessed using 10 physicochemical parameters,while bacteriological quality was evaluated based on fecal coliforms and Escherichia coli.In addition,38 parameters were studied to characterize the wastewater discharge.All analyses followed standard procedures and the results were compared to Moroccan and World Health Organization(WHO)standards.The study revealed that surface water and groundwater in the study area exhibited strong mineralization,with Electrical Conductivity(EC)exceeding 1400µS/cm at all stations.Nitrogen quality,in terms of Nitrates(NO₃⁻),was moderate across stations,while Ammonium(NH₄⁺)quality was consistently excellent.Physicochemical parameters of surface waters indicated overall excellent quality.Bacteriological analysis showed minimal contamination by fecal coliforms and Escherichia coli,with levels deemed negligible.However,wastewater from the Boudnib treatment plant exceeded Moroccan standards for organic load,presenting a potential environmental risk.展开更多
As the country with the highest number of dams in the world,China’s dam safety management and risk control are crucial to public safety and economic development.This paper systematically analyzes the current status o...As the country with the highest number of dams in the world,China’s dam safety management and risk control are crucial to public safety and economic development.This paper systematically analyzes the current status of dam safety in China,explores the causes of accidents such as design and construction defects,poor operation management,the impact of natural disasters,and proposes comprehensive dam safety management measures based on these analyses.展开更多
Landslide dams,as frequent natural hazards,pose significant risks to human lives,property,and ecological environments.The grading characteristics and density of dam materials play a crucial role in determining the sta...Landslide dams,as frequent natural hazards,pose significant risks to human lives,property,and ecological environments.The grading characteristics and density of dam materials play a crucial role in determining the stability of landslide dams and the potential for dam breaches.To explore the failure mechanisms and evolutionary processes of landslide dams with varying soil properties,this study conducted a series of flume experiments,considering different grain compositions and material densities.The results demonstrated that grading characteristics significantly influence landslide dam stability,affecting failure patterns,breach processes,and final breach morphologies.Fine-graded materials exhibited a sequence of surface erosion,head-cut erosion,and subsequent surface erosion during the breach process,while well-graded materials typically experienced head-cut erosion followed by surface erosion.In coarse-graded dams,the high permeability of coarse particles allowed the dam to remain stable,as inflows matched outflows.The dam breach model experiments also showed that increasing material density effectively delayed the breach and reduced peak breach flow discharge.Furthermore,higher fine particle content led to a reduction in the residual dam height and the base slope of the final breach profile,although the relationship between peak breach discharge and the content of fine and coarse particles was nonlinear.To better understand breach morphology evolution under different soil characteristics and hydraulic conditions,three key points were identified—erosion point,control point,and scouring point.This study,by examining the evolution of failure patterns,breach processes,and breach flow discharges under various grading and density conditions,offers valuable insights into the mechanisms behind landslide dam failures.展开更多
Earthquakes are predominantly associated with tectonically active regions,yet the rising frequency of seismic events globally has raised concerns about the role of industrial activities,such as fluid injection,convent...Earthquakes are predominantly associated with tectonically active regions,yet the rising frequency of seismic events globally has raised concerns about the role of industrial activities,such as fluid injection,conventional oil-gas,mining,and reservoir impoundment,in triggering significant earthquakes.While natural processes like tectonic stress changes,fluid migration,and surface loading are critical in earthquake nucleation,human-induced seismicity is becoming increasingly recognized.The Atatürk Dam,Türkiye's largest clay-core rockfill dam,situated near the East Anatolian Fault System,Adyaman Fault Zone,and Bozova Fault,offers a compelling case to explore the interplay between tectonic and anthropogenic seismicity.This study presents the first trenching studies along the Bozova Fault,revealing evidence of surface ruptures and localized seismicity linked to reservoir impoundment and conventional oil and gas.Temporal and spatial analyses suggest that reservoir-induced mechanisms,including pore pressure diffusion and stress redistribution,significantly influence seismicity,recurrence interval,alongside dominant tectonic forces.By integrating trenching investigations,seismic analyses,and stress inversion techniques,this research highlights the critical role of anthropogenic factors in modulating seismic hazards.The findings emphasize the importance of paleoseismological and geophysical studies for distinguishing induced seismicity from natural tectonic activity,thereby contributing to improved seismic hazard assessment and mitigation strategies in tectonically active,reservoir-influenced regions.展开更多
In recent years,to better address soil erosion,the Loess Plateau area has seen a surge in the construction of warping dam projects.Warping dams have strong functions in soil and water conservation as well as warping f...In recent years,to better address soil erosion,the Loess Plateau area has seen a surge in the construction of warping dam projects.Warping dams have strong functions in soil and water conservation as well as warping for farmland creation,serving as a key support for ecological restoration and economic development in the Loess Plateau area in the new era.However,in light of practical conditions,there are many problems in their construction process,which have affected their actual operation quality.In this regard,while expounding on the value and significance of warping dam project construction in the Loess Plateau area,this paper discusses the existing problems and effective countermeasures,aiming to provide some references for relevant personnel.展开更多
The implementation of the cascade check dam system, which integrates beam and closed-type dams, has been extensively adopted as a pivotal engineering measure for mitigating debris flow in Southwest China. In the post-...The implementation of the cascade check dam system, which integrates beam and closed-type dams, has been extensively adopted as a pivotal engineering measure for mitigating debris flow in Southwest China. In the post-debris flow events, it is imperative to quantitatively assess the volume of sediment volume captured by the cascade check dams and to monitor their impact on sediment dynamics. This study investigates the cascade check dams in Guanmenzi Gully, Beichuan County, Sichuan Province in Southwest China, surveying the reservoir topography of the dams on two occasions over a fiveyear period. The #3 closed-type dam, located in the upper upstream, the #2 closed-type dam, located in the middle stream(which was manually cleaned), and the beam dam, located in the downstream were all surveyed. A simplified yet accurate method was developed to estimate sediment volume within check dam reservoirs under complex topographic conditions. A combination of terrestrial surveys and Unmanned Aerial Vehicle(UAV) based surveys was employed, resulting in the acquisition of two high-resolution Digital Elevation Models(DEMs) at different temporal intervals. The utilization of DEMs of Difference(DoD) facilitated the quantification of terrain variations and the sediment transport. The following conclusions were obtained: firstly, it was found that the volume of sediment trapped in the reservoirs of #2 closed-type dam and #1 beam dam were almost the same, with #3 closed-type dam being the smallest. The validation of the results in conjunction with the geometric method demonstrated that the percentage error was less than 7%, proving the reliability of the results. In addition, an analysis of changes in the detailed topography of the reservoirs revealed that the sediment deposit occurred in areas distant from the structures, while erosion exhibited concentration in specific areas close to the dams. The percentage volume of sediment deposit was found to be significantly higher than that of erosion(all higher than 85%). Furthermore, the excessive sediment deposition reduces the storage capacity of closed-type check dams, whereas in the case of beam dams, the maximum erosion amount in the reservoir is 35.8 m^(3) and the percentage of the maximum erosion amount is 14.00%. This suggests that the self-cleaning of beam dam can effectively slow down the sediment deposition process. Finally, the current study proposes an expression for storage capacity composition and suggests that, in engineering practice, emphasis should be placed on maintenance programs that synergize manual cleaning and self-cleaning of open-type check dams. The conclusions may facilitate the refinement of maintenance strategies of cascade check dams, thereby effectively preventing and mitigating debris flows.展开更多
文摘The first author proposed the concept of the cemented material dam （CMD） in 2009. This concept was aimed at building an environmentally friendly dam in a safer and more economical way for both the dam and the area downstream. The concept covers the cemented sand, gravel, and rock dam （CSGRD）, the rockfill concrete （RFC） dam （or the cemented rockfill dam, CRD）, and the cemented soil dam （CSD）. This paper summarizes the concept and principles of the CMD based on studies and practices in projects around the world. It also introduces new developments in the CSGRD, CRD, and CSD.
基金National Natural Science Foundation of China,Grant/Award Number:52309153Key Science and Technology Projects of China Power Construction Group,Grant/Award Numbers:DJ-ZDXM-2022-01,DJ-ZDXM-12025-45。
文摘Underpinned by the ultrahigh-core rockfill dam at the Nuozhadu Hydropower Station,comprehensive studies and engineering practices have been conducted to address several critical challenges:coordination of seepage deformation in dam materials,prevention and control of high-water-pressure seepage failure,static and dynamic deformation control,and construction quality monitoring.Advanced technologies have been developed for modifying impermeable soil materials and utilizing soft rocks.Constitutive models and high-performance fine computational methods for dam materials have been improved,along with innovative seismic safety measures.Additionally,a“Digital Dam”and an information system for monitoring the construction quality were implemented.These efforts ensured the successful construction of the Nuozhadu Dam,making it the tallest dam in China and the third tallest dam in the world upon completion.This achievement increased the height of core dams in China by 100 m and established a design and safety evaluation framework for ultrahigh-core rockfill dams exceeding 300 m in height.Furthermore,the current safety monitoring results indicate that the Nuozhadu Dam is safe and controllable.
基金Special Scientific Found for Seismic Industry Under Grant No.201008005
文摘Based on raw data from dams damaged in the Wenchuan earthquake, including many that were severely damaged, characteristics and factors that influenced the damage are discussed in this paper. Findings from this study include： severely damaged dams were densely distributed along the seismologic fault; small dams, especially small earth-rock dams, had the most serious damage that was caused by a variety of factors; the most serious damage was caused by seismic waves; damage was aggregated by aftershocks; and the extent of the damage patterns increased with the seismic intensity. Damage patterns varied in different intensity zones and cracking was the most common type of damage. Most of the dams had a good base with relatively high bearing capacity, and the walls of the earth-rock dams were mostly of clay soil. This type of base and body material mitigated some of the damage to dams. Reservoir maintenance and other factors also have a significant impact on the seismic safety of the dam. Finally, some recommendations to reduce seismic damage to dams are proposed.
基金National Natural Science Foundation of China,Grant/Award Number:42330719National Natural Science Foundation of China,Grant/Award Number:U2443228+1 种基金Power Construction Corporation of China,Grant/Award Number:DJ-ZDXM-2021-51China Institute of Water Resources and Hydropower Research,Grant/Award Number:GE121003A0042022。
文摘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.
基金Project(41074004)supported by the National Natural Science Foundation of ChinaProject(2013CB733303)supported by the National Basic Research Program of China
文摘In the application of regression analysis method to model dam deformation, the ill-condition problem occurred in coefficient matrix always prevents an accurate modeling mainly due to the multicollinearity of the variables. Independent component regression （ICR） was proposed to model the dam deformation and identify the physical origins of the deformation. Simulation experiment shows that ICR can successfully resolve the problem of ill-condition and produce a reliable deformation model. After that, the method is applied to model the deformation of the Wuqiangxi Dam in Hunan province, China. The result shows that ICR can not only accurately model the deformation of the dam, but also help to identify the physical factors that affect the deformation through the extracted independent components.
文摘Hydroelectric power production from Garafiri dam and rainfall are essential elements with the observation of hydroelectric power production in West African power system,particularly in Guinea.This article focuses on the study and the influence of climate variability on hydroelectric power production at Garafiri dam over 16-year period(2008-2023).The aim of this work is to show the correlation between rainfall anomalies and hydroelectric power production at Garafiri dam.The method used consists of calculating precipitation anomalies at Garafiri site and those for the production of hydroelectric power from Garafiri dam over the study period.This approach led us to calculate the anomalies,leading to the study on climatic variability,in order to establish correlation between rainfall and hydroelectric power dam’s production.The trend with the correlation found made it possible to carry out a significance test between these two variables.These results clearly show that rainfall in Garafiri site increases hydroelectric power production and vice versa,which explains the interdependence between these two parameters,i.e.climatic variability and hydroelectric power production.
文摘This study addresses the pressing need to evaluate the quality of water resources in the Oued Guir watershed,highlighting the importance of monitoring both surface water and groundwater in the context of environmental and public health.It focuses on the evaluation of physicochemical and bacteriological water quality downstream of the Kaddoussa Dam,as well as the characterization of wastewater from the Boudnib treatment plant discharged into Oued Guir.The goal is to assess the health of aquatic ecosystems and understand the impact of anthropogenic activities on these sensitive environments.A comprehensive analysis was conducted at 15 selected stations during a sampling campaign in November 2023.Groundwater and surface water were assessed using 10 physicochemical parameters,while bacteriological quality was evaluated based on fecal coliforms and Escherichia coli.In addition,38 parameters were studied to characterize the wastewater discharge.All analyses followed standard procedures and the results were compared to Moroccan and World Health Organization(WHO)standards.The study revealed that surface water and groundwater in the study area exhibited strong mineralization,with Electrical Conductivity(EC)exceeding 1400µS/cm at all stations.Nitrogen quality,in terms of Nitrates(NO₃⁻),was moderate across stations,while Ammonium(NH₄⁺)quality was consistently excellent.Physicochemical parameters of surface waters indicated overall excellent quality.Bacteriological analysis showed minimal contamination by fecal coliforms and Escherichia coli,with levels deemed negligible.However,wastewater from the Boudnib treatment plant exceeded Moroccan standards for organic load,presenting a potential environmental risk.
文摘As the country with the highest number of dams in the world,China’s dam safety management and risk control are crucial to public safety and economic development.This paper systematically analyzes the current status of dam safety in China,explores the causes of accidents such as design and construction defects,poor operation management,the impact of natural disasters,and proposes comprehensive dam safety management measures based on these analyses.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U22A20602,U2040221,and 42207228)the Sichuan Science and Technology Program(2022NSFSC1060)the Fundamental Research Funds for Central Public Research Institutes(Grant No.Y324006)。
文摘Landslide dams,as frequent natural hazards,pose significant risks to human lives,property,and ecological environments.The grading characteristics and density of dam materials play a crucial role in determining the stability of landslide dams and the potential for dam breaches.To explore the failure mechanisms and evolutionary processes of landslide dams with varying soil properties,this study conducted a series of flume experiments,considering different grain compositions and material densities.The results demonstrated that grading characteristics significantly influence landslide dam stability,affecting failure patterns,breach processes,and final breach morphologies.Fine-graded materials exhibited a sequence of surface erosion,head-cut erosion,and subsequent surface erosion during the breach process,while well-graded materials typically experienced head-cut erosion followed by surface erosion.In coarse-graded dams,the high permeability of coarse particles allowed the dam to remain stable,as inflows matched outflows.The dam breach model experiments also showed that increasing material density effectively delayed the breach and reduced peak breach flow discharge.Furthermore,higher fine particle content led to a reduction in the residual dam height and the base slope of the final breach profile,although the relationship between peak breach discharge and the content of fine and coarse particles was nonlinear.To better understand breach morphology evolution under different soil characteristics and hydraulic conditions,three key points were identified—erosion point,control point,and scouring point.This study,by examining the evolution of failure patterns,breach processes,and breach flow discharges under various grading and density conditions,offers valuable insights into the mechanisms behind landslide dam failures.
文摘Earthquakes are predominantly associated with tectonically active regions,yet the rising frequency of seismic events globally has raised concerns about the role of industrial activities,such as fluid injection,conventional oil-gas,mining,and reservoir impoundment,in triggering significant earthquakes.While natural processes like tectonic stress changes,fluid migration,and surface loading are critical in earthquake nucleation,human-induced seismicity is becoming increasingly recognized.The Atatürk Dam,Türkiye's largest clay-core rockfill dam,situated near the East Anatolian Fault System,Adyaman Fault Zone,and Bozova Fault,offers a compelling case to explore the interplay between tectonic and anthropogenic seismicity.This study presents the first trenching studies along the Bozova Fault,revealing evidence of surface ruptures and localized seismicity linked to reservoir impoundment and conventional oil and gas.Temporal and spatial analyses suggest that reservoir-induced mechanisms,including pore pressure diffusion and stress redistribution,significantly influence seismicity,recurrence interval,alongside dominant tectonic forces.By integrating trenching investigations,seismic analyses,and stress inversion techniques,this research highlights the critical role of anthropogenic factors in modulating seismic hazards.The findings emphasize the importance of paleoseismological and geophysical studies for distinguishing induced seismicity from natural tectonic activity,thereby contributing to improved seismic hazard assessment and mitigation strategies in tectonically active,reservoir-influenced regions.
文摘In recent years,to better address soil erosion,the Loess Plateau area has seen a surge in the construction of warping dam projects.Warping dams have strong functions in soil and water conservation as well as warping for farmland creation,serving as a key support for ecological restoration and economic development in the Loess Plateau area in the new era.However,in light of practical conditions,there are many problems in their construction process,which have affected their actual operation quality.In this regard,while expounding on the value and significance of warping dam project construction in the Loess Plateau area,this paper discusses the existing problems and effective countermeasures,aiming to provide some references for relevant personnel.
基金jointly funded by the National Key R&D Program of China (2024YFC3012705)the CAS Light of West China Program (Grant Recipient:Wanyu Zhao)+1 种基金the National Natural Science Foundation of China (Grant No.42201095)the Postdoctoral Research Project Special Funding of Sichuan (Grant No.TB2023028)。
文摘The implementation of the cascade check dam system, which integrates beam and closed-type dams, has been extensively adopted as a pivotal engineering measure for mitigating debris flow in Southwest China. In the post-debris flow events, it is imperative to quantitatively assess the volume of sediment volume captured by the cascade check dams and to monitor their impact on sediment dynamics. This study investigates the cascade check dams in Guanmenzi Gully, Beichuan County, Sichuan Province in Southwest China, surveying the reservoir topography of the dams on two occasions over a fiveyear period. The #3 closed-type dam, located in the upper upstream, the #2 closed-type dam, located in the middle stream(which was manually cleaned), and the beam dam, located in the downstream were all surveyed. A simplified yet accurate method was developed to estimate sediment volume within check dam reservoirs under complex topographic conditions. A combination of terrestrial surveys and Unmanned Aerial Vehicle(UAV) based surveys was employed, resulting in the acquisition of two high-resolution Digital Elevation Models(DEMs) at different temporal intervals. The utilization of DEMs of Difference(DoD) facilitated the quantification of terrain variations and the sediment transport. The following conclusions were obtained: firstly, it was found that the volume of sediment trapped in the reservoirs of #2 closed-type dam and #1 beam dam were almost the same, with #3 closed-type dam being the smallest. The validation of the results in conjunction with the geometric method demonstrated that the percentage error was less than 7%, proving the reliability of the results. In addition, an analysis of changes in the detailed topography of the reservoirs revealed that the sediment deposit occurred in areas distant from the structures, while erosion exhibited concentration in specific areas close to the dams. The percentage volume of sediment deposit was found to be significantly higher than that of erosion(all higher than 85%). Furthermore, the excessive sediment deposition reduces the storage capacity of closed-type check dams, whereas in the case of beam dams, the maximum erosion amount in the reservoir is 35.8 m^(3) and the percentage of the maximum erosion amount is 14.00%. This suggests that the self-cleaning of beam dam can effectively slow down the sediment deposition process. Finally, the current study proposes an expression for storage capacity composition and suggests that, in engineering practice, emphasis should be placed on maintenance programs that synergize manual cleaning and self-cleaning of open-type check dams. The conclusions may facilitate the refinement of maintenance strategies of cascade check dams, thereby effectively preventing and mitigating debris flows.
