Dam Maintenance Research Articles

A mileage correction method of pipeline inertial measurement for dam internal deformation monitoring

Internal deformation monitoring is of great significance to the safe operation and maintenance of dams. Some scholars have carried out dam internal deformation monitoring by pipeline inertial measurement with a pipeline measurement robot, which has improved the monitoring accuracy and efficiency considerably, compared with the traditional monitoring methods. However, there are still shortcomings in this method. Because the odometer on the pipeline measurement robot will slip or slide, resulting in errors in the mileage of the multiple measurement routes, which hinders the development of the accuracy of pipeline inertial measurement. This paper proposes a mileage correction method based on junction detection to improve the accuracy of pipeline inertial measurement for better dam internal deformation monitoring. The mileage correction method establishes a reference model of pipeline junction location, detects the locations of pipeline junction welds on the measurement routes using two k-mean clustering, and corrects the odometer data based on the difference between the detected and reference locations. We evaluate the enhancement of this mileage correction method on the internal accuracy and deviation values compared with other method for pipeline inertial measurement. The proposed method is validated using measured data from the internal pipeline of Tianchi Dam. The results show that compared with the results directly fused without detection–correction, the method proposed in this paper reduces the root-mean-square error of the results by an average of 30.30% and improves the deviation compared with the reference deformation by an average of 2.3 mm. Therefore, the method has good results and practical applications.

An Exploratory Study of the Impact of the One-Village-One-Dam Initiative in Northern Ghana

This study is an exploratory examination of the effect of the Ghana government’s flagship program known as the One-Village-One-Dam (1V1D) initiative on the livelihoods of rural farmers in the five regions of Northern Ghana. A total of 15 constituencies proportionate to the number of constituencies in each of the five beneficiary regions were selected from the region. Data were collected from a total of 1585 respondents, comprising 785 from the control group and 800 from the treatment group. The survey focused on access to water, crop and livestock productivity, income generation, and overall well-being. Four main findings are reported. First, the results show differential effects of the 1V1D initiative. There was an increase in reliance on 1V1D dams for water, particularly in the Northern region, where challenges such as insufficient water storage and poor dam maintenance hindered their effectiveness for irrigation and livestock rearing. Second, the use of water from boreholes was more popular in the other parts of Northern Ghana. Third, the shallowness of most of the dams meant that they dried up during the dry season and, therefore, did not have a significant effect on crops and livestock productivity. Finally, the dams had a marginal effect on food security, income levels of the farmers, and consequently on their overall livelihoods. The findings of this exploratory study will provide insights to enrich further studies based on the second and third rounds of data collection.

Failure analysis of arch dam under fault action based on inter-generational coordination

Complex geological faults play a crucial role in the site selection and construction of dams. In this paper, considering the intergenerational coordination theory and addressing the complex geological fault conditions of the LCGX hydropower project, the entire life cycle of the arch dam is divided into four stages: initial state, dam foundation excavation, arch dam casting, and reservoir operation. Improved multiple linear regression with modified boundary conditions is employed for the inversion of initial stress, considering the unloading effects caused by dam foundation excavation and the temperature differentials arising from concrete hydration during arch dam casting, and considering the effective stress principle during the water storage operation stage. Based on the above considerations, the whole life cycle of LCGX arch dam from initial state to excavation and casting operation and maintenance is analyzed, including the impact of faults in the LCGX dam site area on the arch dam. The water pressure overload method is employed to evaluate the safety of the arch dam. And the concrete grid backfill replacement is carried out by the combination of open excavation and hole excavation. The results indicate that faults have varying degrees of influence across different stages of intergenerational coordination, with f119 and F115 showing more pronounced effects. In the overload calculation, the f119 fault, along with the hazardous rock mass formed by cutting the foundation surface, and the f124 fault, cause the arch dam to undergo displacement, thus the arch dam occurs shear failure, the reinforcement greatly improves the safety of arch dam. This study systematically investigates the arch dam and slope displacement caused by complex geological faults in the LCGX hydroelectric project dam site area. It explores the specific impact of faults on the arch dam, providing essential references for structural safety during dam maintenance.

Technical requests on maintenance of dams in regard with dam safety standards

Technical requests on maintenance of dams in regard with dam safety standards

Improvements and maintenance of embankment dams - are guidelines in respect of nature law considered positive?

Improvements and maintenance of embankment dams - are guidelines in respect of nature law considered positive?

Determining aspects of techno-ecological dam maintenance on the river Mur

Determining aspects of techno-ecological dam maintenance on the river Mur

Challenges of ecological and technical dam maintenance using the example of the Marchfeld protective dam (Lower Austria)

Challenges of ecological and technical dam maintenance using the example of the Marchfeld protective dam (Lower Austria)

Monitoring and Quantifying Soil Erosion and Sedimentation Rates in Centimeter Accuracy Using UAV-Photogrammetry, GNSS, and t-LiDAR in a Post-Fire Setting

Remote sensing techniques, namely Unmanned Aerial Vehicle (UAV) photogrammetry and t-LiDAR (terrestrial Light Detection and Ranging), two well-established techniques, were applied for seven years in a mountainous Mediterranean catchment in Greece (Ilioupoli test site, Athens), following a wildfire event in 2015. The goal was to monitor and quantify soil erosion and sedimentation rates with cm accuracy. As the frequency of wildfires in the Mediterranean has increased, this study aims to present a methodological approach for monitoring and quantifying soil erosion and sedimentation rates in post-fire conditions, through high spatial resolution field measurements acquired using a UAV survey and a t-LiDAR (or TLS—Terrestrial Laser Scanning), in combination with georadar profiles (Ground Penetration Radar—GPR) and GNSS. This test site revealed that 40 m3 of sediment was deposited following the first intense autumn rainfall events, a value that was decreased by 50% over the next six months (20 m3). The UAV–SfM technique revealed only 2 m3 of sediment deposition during the 2018–2019 analysis, highlighting the decrease in soil erosion rates three years after the wildfire event. In the following years (2017–2021), erosion and sedimentation decreased further, confirming the theoretical pattern, whereas sedimentation over the first year after the fire was very high and then sharply lessened as vegetation regenerated. The methodology proposed in this research can serve as a valuable guide for achieving high-precision sediment yield deposition measurements based on a detailed analysis of 3D modeling and a point cloud comparison, specifically leveraging the dense data collection facilitated by UAV–SfM and TLS technology. The resulting point clouds effectively replicate the fine details of the topsoil microtopography within the upland dam basin, as highlighted by the profile analysis. Overall, this research clearly demonstrates that after monitoring the upland area in post-fire conditions, the UAV–SfM method and LiDAR cm-scale data offer a realistic assessment of the retention dam’s life expectancy and management planning. These observations are especially crucial for assessing the impacts in the wildfire-affected areas, the implementation of mitigation strategies, and the construction and maintenance of retention dams.

Modified Andersen and Modified ICOLD (DOISP-2) Methods of Risk Score for Dams in West Region of Indonesia

Risk assessment for the dams in West Java Province with a method of Modified Andersen and Modified ICOLD (DOISP-2) have been done; the assessment is part of the activities of Dam Operation Improvement Safety Project-2 (DOISP-2) at Central Project Implementation Unit (CPIU), Ministry of Public Works and Housing. Dams were studied to analyse the risks of the deficiency of the structure due to the load under normal operating conditions, flood conditions, and earthquake conditions. This article summarizes the risk assessment process, assessment results, conclusions and recommendations for both risk index methods. The document also includes an assessment of the risk assessment process and policy recommendations for the operation and maintenance of dams. The results are risk rankings between the two methods give different sequences; this is due to differences in the risk assessment approach of both methods. Modified Andersen focused on structural deficiencies, especially visually, and modification ICOLD Method (DOISP-2) focused on design flaws and risks downstream of the dam. Although both methods have different approaches, both methods can be used in risk analysis of the dam’s adjusted purposes of risk index assessment.

Efficiency Study of Combined UAS Photogrammetry and Terrestrial LiDAR in 3D Modeling for Maintenance and Management of Fill Dams

Low-cost unmanned aerial system (UAS) photogrammetry and terrestrial laser scanner (TLS, terrestrial LiDAR) technologies are being used as noncontact measurement methods for collecting unstructured data for the maintenance of construction infrastructure facilities. This study investigated the possibility of settlement, which is a maintenance condition evaluation item for fill-dam bodies, using point clouds based on the UAS (unmanned aerial system) structure from motion (UAS-SfM) and TLS (terrestrial laser scanner) point clouds. Specifically, the Z-axis RMSE of the point cloud improved to 0.012 m and the shape reproducibility rate to 98.53% by complementing the heterogeneous data of the UAS and TLS by combining the two systems with block coordination and ICP algorithms. The maximum settlement height and volume (heaving) of the dam crest and upstream and downstream slopes were derived from the combined UAS/TLS point-cloud-based 3D model. The quantitative values for the settlement of the fill-dam body were derived using the combined 3D model with high accuracy and density. This result verified the possibility of using the combined 3D model for evaluation of the maintenance condition.

TRANSBOUNDARY RIVER BASIN EUPHRATES-TIGRIS: INTERNATIONAL LEGAL REGULATION

Countries all around the globe have shown a strong desire to restrict the utilization of international water channels for non-navigational uses since they are important to human civilisation. This is to avoid issues that may occur because of the usage purposes of international water bodies such as rivers and streams. This research covers a narrow scope, which is limited to legislation addressing the use of international water channels to effectively settle international water disputes, to cover the lawful use of international watercourses. It also provides an overview of transboundary water interactions in the Euphrates-Tigris River basin, followed by a discussion of key topics. From the standpoint of international law, this study discusses the connections among Turkey, Syria, and Iraq regarding their shared water, the Euphrates and the Tigris. Finally, the paper concluded that Iraq must review its entire water policy and identify its flaws, including irrigation methods, dam maintenance, and the management of water resources by international standards. Iraq's deviation from these matters constitutes a violation of the international obligations to which it is bound by international treaties, particularly the framework agreement. This study concludes that Iraq's evaluation of its internal legislation and all of its projects built on the Tigris and Euphrates rivers adds significantly to the resolution of these issues.

The Reliability of Stored Water behind Dams Using the Multi-Component Stress-Strength System

Dams are essential infrastructure for managing water resources and providing entry to clean water for human needs. However, the construction and maintenance of dams require careful consideration of their reliability and safety, specifically in the event of extreme weather conditions such as heavy rainfall or flooding. In this study, the stress-strength model provides a useful framework for evaluating the reliability of dams and their ability to cope with external stresses such as water pressure, earthquake activity, and erosion. The Shasta reservoir in the United States is a prime example of a dam that requires regular assessment of its reliability to guarantee the safety of communities and infrastructure. The Gumbel Type II distribution has been suggested as a suitable model for fitting the collected data on the stress and strength of the reservoir behind the Shasta dam. Both classical and Bayesian approaches have been used to estimate the reliability function under the multi-component stress-strength model, and Monte Carlo simulation has been employed for parameter estimation. In addition, some measures of goodness-of-fit are employed to examine the suitability of the suggested model.

Optimized variable selection of Bayesian network for dam risk analysis: A case study of earth dams in the United States

Dams are vital infrastructure for water resource management, and their safety is threatened by the complex interplay of multiple risk factors. Consequently, for dam safety maintenance, it is significant to conduct dam risk analysis by detecting the relationship between dam failure and risk factors and identifying the critical risk factors. Bayesian network (BN) is an effective tool for this issue and has been widely used in previous studies. However, there is still a lack of variable selection methods in BN that can automatically select predictors from numerous candidates by considering both predictability and parsimony. Herein, an optimized variable selection is proposed for BN and used in the risk analysis of widespread earth dams in the United States. The results showed that the proposed method can automatically determine the optimal predictor set. The BN with selected predictors not only exhibits good performance but also has a significantly more concise network than the BN without variable selection and significantly weakens overfitting. Using the established BN, the clear causal network of earth dam failure and 12 risk factors were quantified through influence strength analysis. The three foremost risk factors based on their sensitivity analysis were identified to be insufficient spillway capacity, extreme flood, and slope instability, which can serve as a reference for the safety maintenance of earth dams in the United States. Our study highlights that the proposed variable selection is a powerful step of BN for dam risk analysis and contributes to the development of an intelligent BN modeling framework.

07. Deaths of overwintering Nanorana spp. tadpoles due to desiccation during check dam maintenance in a western Himalayan stream, India

07. Deaths of overwintering Nanorana spp. tadpoles due to desiccation during check dam maintenance in a western Himalayan stream, India

Laboratory-Controlled Experiments Reveal Microbial Community Shifts during Sediment Resuspension Events.

In freshwater ecosystems, dynamic hydraulic events (floods or dam maintenance) lead to sediment resuspension and mixing with waters of different composition. Microbial communities living in the sediments play a major role in these leaching events, contributing to organic matter degradation and the release of trace elements. However, the dynamics of community diversity are seldom studied in the context of ecological studies. Therefore, we carried out laboratory-induced leaching experiments, using sediments from the Villerest dam reservoir (Villerest, France). To assess whole microbial community diversity, we sequenced the archaeal and bacterial 16S rRNA genes using Illumina MiSeq. Our results suggest that the degree of dissolved oxygen found in the water during these resuspension episodes influenced community dynamics, with anoxic waters leading to drastic shifts in sedimentary communities compared to oxic waters. Furthermore, the release of microbial cells from sediments to the water column were more favorable to water colonization when events were caused by oxic waters. Most of the bacteria found in the sediments were chemoorganotrophs and most of the archaea were methanogens. Methylotrophic, as well as archaeal, and bacterial chemoorganotrophs were detected in the leachate samples. These results also show that organic matter degradation occurred, likely participating in carbonate dissolution and the release of trace elements during freshwater resuspension events.

Mathematical modelling of hydraulics and water quality characteristics for small dam maintenance

Mathematical modelling of hydraulics and water quality characteristics for small dam maintenance

Strategies of GIS‐Based Urban Country Park Planning and Ecological Restoration

Purpose. This study centers around the Wangzhanghe Country Park located in Jiaozuo City as the research object. Through analysis of the site’s evolution by GPS and its status‐quo by GIS, the map of spatial distribution suitability has been illustrated. Design. Based on the major principle of achieving sustainable development of the ecosystem and the derived concept of building a diversified landscape, we have developed the overall scheme of planning and landscape layout of the country park. Specifically, the area of ecological restoration is further divided into the areas of quarry restoration, bare land restoration, slope protection, vegetation, and dam maintenance, and restorative measures are put forward accordingly. Findings. Our research findings indicate that thanks to the vegetation restoration of the side slope, the area of bare land in mountain farmland has been evidently reduced, whereas the severely damaged ash pits and green spots have also been restored. Originality: in the meantime, we have leveraged the flat space at the foot of the mountain to foster a viewing experience and provide recreational activities for citizens, so that they are able to effectively increase their access to outdoor events and improve their sense of engagement and experience in the events, thereby providing a reference for building a green, diverse, and sustainable system of ecological services for the urban country park.

Mosul Dam: Challenges and Innovative Solutions

Reservoir siting, permitting, construction and operation can, at times, face insurmountable challenges. Mosul Dam, a multipurpose dam located in Northern Iraq, is constructed on a dissolvable anhydrite, gypsum and limestone formation. To mitigate long-term impacts to the foundation, the dam designers opted for a structural solution. They incorporated into the design a grouting gallery for long-term maintenance grouting of the foundation cutoff grout curtain. In 2016, concerns with the risk posed by the deteriorating foundation resulted in the execution of the Mosul Dam emergency grouting and maintenance project. This paper illustrates how the international community proactively came together to prevent an incident of potential tragic proportions well before it could manifest itself. The emergency grouting work is an excellent example of Governments investing in preventing a disaster rather than investing in fixing a disaster. The paper presents the general approach adopted for the execution of the emergency project and discusses how the scope of work (SOW) evolved to address the myriad of requirements, including the training and transfer of information and equipment to the Iraqi Ministry of Water Resources that could not have been foreseen during the scoping of the work. Additionally, this paper illustrates the success that can be achieved when team members share a strong commitment to cooperation and a determination to succeed.

Discrete Phase Modelling of Sediment Transport and Scouring of Suspended Particles in Dam Spillway

One of foremost issue arise in the dam management and dam reliability assessment is the sedimentation of suspended particles. Sedimentation affected the energy production and efficiency, storage, discharge capacity, and flood attenuation capabilities. In this paper, the sediment transport and scouring in the dam spillway structure was modelled using finite volume method (FVM) based software, ANSYS. The trajectory of suspended particles in the water flow was formulated based on the discrete phase model (DPM). To access the simulation model, particle image velocimetry (PIV) experiment using scaled-down dam spillway model was conducted. The discrepancy between the findings attained from simulation and PIV experiment is less than 4.89%, inferred the numerical model was acceptable. It was found that the maximum scouring rate and maximum deposition rate are respectively 4.20×10−9 kg/s and 2.00×10−6 kg/s. As such, it was empirically approximated the dam maintenance should be scheduled once every 8.9 years, based on sole consideration on resolving the scouring and deposition of suspended particles. This work demonstrated the viability of DPM based numerical simulation in study the fluid-particle interaction of sediment transport problem, particularly for the application of dam reliability.

Laboratory study on the frost-proof performance of a novel embankment dam in seasonally frozen regions

In construction and maintenance of embankment dams in seasonally frozen regions, frost-proof is a key factor to keep the stability of embankment dams, and the water-heat-mechanics process is the basis to reveal the evolution of frost damage for embankment dams in cold regions. In this paper, a novel embankment dam with two-phase closed thermosyphons (TPCTs) for reducing frost heave in seasonally frozen regions was presented. Two embankment dam cases with and without TPCTs during freeze–thaw processes under different reservoir water levels were tested in laboratory. The variations of temperature, volumetric unfrozen water content and deformation were monitored. It is found that, to some extent, the frozen depths at the downstream sides of the two dam cases were larger than those at the upstream sides because of the different thermal properties among the concrete slab, soil materials and reservoir water. Meanwhile, during the cold periods, the frozen depths and vertical deformations at the upstream sides of the embankment dam case 1 with TPCTs were far less than those of the embankment dam case 2 without TPCTs. Furthermore, the volumetric unfrozen water contents for the embankment dam case 1 with TPCTs were larger than those for the embankment dam case 2 without TPCTs at the same freezing position. This is from the fact that, after the TPCTs begin to work during the cold periods, the TPCTs are transferring the heat in the dam from below the reservoir water levels to above it, which effectively reduces the freezing of the embankment dam. Therefore, the embankment dam with TPCTs could be applied as an effective measure to alleviate the frost heave in seasonally frozen regions.