Sedimentation Problems Research Articles

RESERVOIR SEDIMENTATION MANAGEMENT: A SUSTAINABLE DEVELOPMENT CHALLENGE IN THE KENYIR LAKE BASIN, MALAYSIA

Reservoir sedimentation poses a significant challenge to the sustainable development of water resources, with profound implications for ecosystem health and water management. These lead to cause changes and challenges for rivers, such as floods, river erosion, sedimentation processes, and anthropogenic interference, which contribute to problems for humans and specifically for river basin ecosystems. This research examined the issue of sedimentation, a critical water body for the region's hydrology and socio-economic activities and proposed a multi-faceted management strategy that integrates sediment control measures, regular monitoring, and community involvement to enhance the sustainability of reservoir operations and safeguards the ecological integrity of the Kenyir Lake Basin. Through a combination of field surveys and sedimentation problem analysis, we assessed the current state of sediment accumulation and its impact on reservoir capacity, water quality, and downstream ecosystems. There are several aspects of processes such as erosion, sedimentation and the overflow of the river that have been found. The sedimentation problem in the Kenyir Lake Basin is caused not only by the flow rate of water but the land use activities also contribute to the increasing sediment levela. The implementation of recommendations should be carried out more specifically for reservoir sedimentation problems to avoid and minimise various other problems.

Mitigating the Negative Impact of Certain Erosion Events: Development and Verification of Innovative Agricultural Machinery

This paper aims to solve the problem of erosion sediment that negatively affects the quality of fallowed soil through the development of a new type of agricultural machinery. The transported erosion sediment will be quantified locally to evaluate the danger of these negative effects on the fallowed soil and on the functionality of the grass cover. Subsequently, a new type of machinery will be proposed for the remediation of eroded sediment and conservation of the fallowed soil. In various fallow research areas with different management methods (such as biobelts, grassed valleys, and grassed waterways), agricultural land affected by eroded sediment was examined, and appropriate machinery was designed to rehabilitate the stands after erosion events. By identifying the physical and mechanical properties of the soil, as well as the eroded and deposited sediment/colluvium, the shape, material, attachment method, and assembly of the working tool for the relevant mobile energy device were designed. The developed tool, based on a plow–carry system using a tractor, features flexible tools that separate the eroded sediment from the fallow land surface, transfer it over a short distance, and accumulate it in a designated area to facilitate subsequent removal with minimal damage to the herbaceous vegetation. The calculated erosion event was 196.9 m3 (179.0 m3 ha−1), corresponding to 295 tons (268.5 t ha−1) deposited from the area of 90 ha. Afterward, the proposed machinery was evaluated for the cost of the removal of the eroded sediment. Based on experience from the field, we calculated that 174 m3 per engine hour results in EUR 0.22 m−3. From the performed experiment, it is evident that the proposed machinery offers a suitable solution for eroded sediment removal locally, which prevents further erosion and subsequent sediment deposition in water bodies where the costs for sediment removal are higher. Moreover, we have proven the potential negative impact of invasive plant species because their seeds were stored in the sediment. Finally, it is credible to state that the proposed agricultural machinery offers an effective solution for the eroded sediment relocation, which subsequently can be used for other purposes and monetized. This results in an increase in the profitability of the erosion sediment removal process, which is already in place at the source before further transportation to aquatic systems where the costs for removal are significantly higher.

Numerical Investigations of Superconducting Material Cooling Using Buoyancy-Driven Heat Transport in Cryogenic Nanofluids

This study explores the effect of nanoparticle addition on the overall heat-carrying capacity of base liquid nitrogen in natural convection. Moreover, the work also addresses the nanoparticle sedimentation problem that is prominent in natural convection and proposes subtle modifications in heat source location to avoid sedimentation. For this, a 6 mm superconducting material is immersed in a cooling tub filled with liquid nitrogen. The cooling capacity of cryogenic fluids without boiling is considerably low. Hence, the alumina, silicon oxide, and titania nanoparticles are suspended in the base liquid nitrogen. A computational model, which relies on phase-averaged Eulerian tracking of nanoparticle suspensions, is employed to accurately predict the enhancement in heat transfer characteristics. Furthermore, the study addresses the influence of nanoparticle sedimentation in natural convection and proposes modifications to the cooling domain and superconducting material locations to mitigate sedimentation issues. The findings reveal a remarkable 70% increase in the heat transfer coefficient for 0.5% alumina nanoparticles suspension in the base liquid nitrogen. These results demonstrate the potential for significantly improving heat transfer performance in superconducting systems while minimizing the adverse effects of nanoparticle sedimentation.

Revolutionizing High-Pressure Well Cementing: Enhancing Geopolymer Cement with Laponite for Sustainable and Sedimentation-Free Applications

Summary Sustainable geopolymer cement emerges as a prospective substitute to traditional Portland cement systems in the petroleum industry. Geopolymers offer different advantages over Portland cement, including reduced carbon emissions due to lower energy requirements during production, improved durability and chemical resistance, and the ability to use industrial byproducts as raw materials. This technology promotes sustainable waste management practices while maintaining high performance in various applications. This research aims to explore and maximize the geopolymer technology potential by addressing the issue of sedimentation in high-pressure well cementing applications. By incorporating Laponite particles into hematite-based Class F fly ash (FFA) geopolymer cement formulations, a solution is presented to mitigate sedimentation problems and ensure homogeneity and density uniformity along cement columns. Through the application of American Petroleum Institute (API) and non-API techniques, this study uncovers the remarkable benefits of Laponite in mitigating sedimentation problems and enhancing key characteristics such as strength and rheological properties. The findings reveal that Laponite-based geopolymer systems exhibit improved yield point (YP) and gel strength (GS), as well as reduced porosity and density variation. Adding 3% by weight of FFA of Laponite to the cement formulation reduced the density difference between cement sections from 39.38% when no Laponite was present in the system to only 0.58%. Additionally, the measured elastic properties indicate enhanced flexibility compared with Portland cement systems. By determining the optimal Laponite concentration, this study achieves a step forward in promoting sedimentation-free and environmentally friendly non-Portland cementing methods in the petroleum industry.

Potential unitization of sediment deposited in Mrica Reservoir, Banjarnegara, Central of Java

Abstract The Serayu Watershed is considered one of the invaluable areas as it has a crucial role in the ecosystem, water supply, and sustainability of local communities. Land conversion into agricultural areas has become inevitable and has caused immense erosion along the Serayu watershed. Consequently, the degradation in Serayu upstream has promoted a significant sedimentation in Mrica Reservoir. As sedimentation continues to increase, the storage capacity of the reservoir drops and triggers its inherent challenges for reservoir management. PT Indonesia Power has implemented dredged sedimentation to overcome these issues; however, waste from deposited sediment poses a new concern that requires a solution. Considering that most of the accumulated soil in the reservoir is part of the topsoil, which is generally rich in nutrients such as nitrogen, phosphorus, and potassium, deposited sediment employment for a planting media should serve as one of the alternatives to overcome the sedimentation problem in the Mrica Reservoir as these elements are essential for plant growth. Using sediment as a planting medium will help reduce the volume of sediment in the reservoir as a sustainable approach, as it also increases the reservoir’s storage capacity and efficiency. Studies related to the utilization of Mrica-deposited sedimentation into planting media will be discussed in this paper. The utilization of deposited sediment from the Mrica Reservoir as a planting medium might possess an innovation that has great potential to overcome sedimentation problems while increasing agricultural productivity.

Determining the Location of Coastal Protection Structures in Sealing with Sedimentation Problems using Hydrodynamic Modeling

Abstract Lamong Bay is a water area located between the coasts of Gresik and Surabaya. The geographical condition, which is the estuary of several rivers, makes this bay area face sedimentation problems. The process of sedimentation is caused by the movement of sediment, which is divided into 3 types: Bed Load, Suspended Load, and Wash Load. The relatively gentle slope of the topography also affects the accumulation of sediment. One very effective solution in dealing with sedimentation is the existence of coastal protection structures. The existence of coastal structures aims to resist the movement of sediments influenced by ocean currents. Thus, this study aims to determine the type and location of coastal protection structures in reducing the rate of sediment transport in the study area. The method used is numerical modeling using Delft3D software. Modeling validation is done by finding the deviation value of the modeled tides with tides from the BIG tide station. The validation calculation method uses statistical calculations with the Root Mean Square Error (RMSE) method, Mean Absolute Percentage Error (MAPE), and R correlation to find the relationship between modeling and measurement. Sediment types in the Lamong Bay area consist of silt, clay, and sand, with the largest composition in the silt type at 84%. Alternative 1, where the structure is placed in the south of the bay area, shows a cumulative sedimentation value of 0.130 m, while alternative 2 in the north shows 0.180 m. Hence, alternative 1 is more effective. This study contributes to SDG 9 by promoting resilient infrastructure to manage sedimentation issues effectively.

Effectiveness of the VFSMOD Model in Simulating Sediment Trapping by a Vegetative Filter Strip: Case of the Lobo Reservoir in Daloa (Central–West Côte d’Ivoire)

The Lobo reservoir, designed to supply water to the Daloa city population (central west of Côte d’Ivoire), is facing the phenomenon of eutrophication due to the agricultural plots located upstream of the reservoir inputs. Studies have highlighted the reservoir pollution and sedimentation problems. This study was initiated to test the effectiveness of a transfer model in the fight against the eutrophication problem. The objective of this study was to determine the optimal width of a vegetative filter strip on the banks of the Lobo reservoir, where the water intake installations of the drunk water company SODECI are located, using the VFSMOD model. The methodological approach is structured into four (4) main stages: 1—Evaluation of runoff from the source of pollution (contributing surface) during a rainy episode; 2—Calculation of the incoming runoff volume and the sediment load; 3—Simulation of runoff reduction and incoming sediments within the grassy filter strip; and 4—Determination of the optimal width of the grassy strip. The results obtained showed a contributing source area of 13.5 ha and 2% as the average slope. A runoff volume of 4680 m3 coming from the source of pollution is reduced by 1119 m3 (24%) through a grassy strip that is 3 m wide. The sediment load goes from 132 kg to 33 kg, a reduction of 75% in the quantity of sediment entering. The scenarios tested showed that a grassy strip width equal to 3 m should allow for a reduction of 75% of upstream sediments. This grassy strip width of 3 m should be considered for implementing a vegetative filter strip around the Lobo reservoir.

A divergence‐conforming method for flow and double‐diffusive transport

AbstractThe results of a recent extension of the analysis of an ‐conforming method for a model of double‐diffusive flow in porous media introduced in [Bürger, Méndez, Ruiz‐Baier, SINUM (2019), 57:1318–1343] to the time‐dependent case are summarized. These include the efficiency and reliability of residual‐based a posteriori error estimators for the steady, semi‐discrete, and fully discrete problems. The method consists of Brezzi–Douglas–Marini approximations for velocity and compatible piecewise discontinuous pressures, whereas Lagrangian elements are used for concentration and salinity. Novel numerical tests confirm the accuracy of the method and illustrate its application to a salinity‐driven problem of sedimentation.

Estimation of Suspended Sediment Loads in Diyala River Watershed, Iraq, using SWAT Model

Suspended sediment loads (SSL) transported from the watershed of the Diyala River (WODR) are the most important and dangerous forms of sediment as they drift to the stream flow of the Diyala River and are then transferred to the reservoirs of Hemren Dam (HD) and Derbendikhan Dam (DD), which are located in the study area, affecting the capacity storage of the reservoirs and reducing electrical energy production. Therefore, it is necessary to apply a hydrological model that can simulate the SSL distribution in the WODR to enable decision-makers to develop an appropriate plan to solve the sediment problem. In WODR, the data of SSL are very rare, as sediment measurements have not been conducted for more than 40 years. Due to the lack of historical data for sediment values for the study area and the need to reduce uncertainty, sediment measurements were conducted from November 2022 to April 2023. The motivation of the present study is to study and address the limitations imposed on the Soil and Water Assessment Tool (SWAT) model during the estimation of SSL in the WODR that have scarce data and whose quality is inaccurate. The observed monthly flow data from two gauging stations, HD and DD, from January 2000 to April 2023 and suspended sediment concentration, which was measured in the field from November 2022 to April 2023, were used for calibration and validation of the model, respectively, using the Sequential Uncertainty Fitting Version 2 (SUFI-2) algorithm and SWAT-Calibration Uncertainty Procedures (CUP). Statistically, using the coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), and percent of bias (Pbias) the performance of the model was evaluated, with good agreement between observed and simulated values for both stream flow and SSL. The results showed that the values of the SSL in the WODR from January 2000 to April 2023 were equal to 115.240 t/ha/yr. Sub-basins 5 and 12 have the highest SSL values of 15.125 t/ha/yr and 9.098 t/ha/yr, respectively, and the most important factor in SSL formation is the slope of the land, with a correlation coefficient (R2=0.94).

An innovative disc shell-making method for preparing porous eco-concrete with cold-bonded lightweight aggregates

Porous eco-concrete (PEC) can achieve safety protection and ecological protection. This study utilized cold-bonded lightweight aggregates (CBLAs) as coarse aggregates and improved the PEC preparation process via the disc shell-making method. The compressive strength, void ratio, pH value, sand permeability, and plant growth of PECs were studied. The use of CBLAs can reduce the amount of cement used, reduce the total amount of Ca(OH)2, and improve the living environment of plants. The new technology of using a disc to prepare PECs helps wrap the cement slurry evenly around CBLAs, reducing the problem of bottom slurry sedimentation and slurry blockage in fresh concrete and ensuring space for plant root growth. The germination rate of plants cultivated with CBLAs is more than twice that of plants cultivated with natural aggregates. In summary, this study provides a new avenue for the widespread application of CBLAs and AAPEC.

BORROWED ILLUSTRATIONS OF GLOSSOPETRAE WITH SHARK’S HEAD: STENO AND THE VATICAN COLLECTION OF MERCATI

ABSTRACT It is well known that fossils of shark’s teeth were named as ‘tongue stones’ (glossopetrae in Latin) because of their similarity in shape to the tongues of animals. However, Nicolaus Steno (1638–1686) decidedly revised this kind of explanation in the latter half of the seventeenth century. He recognized them as shark’s teeth in his treatise of 1667, adopting the figures of a shark head with teeth in its mouth and fossil ‘tongue stones’ borrowed from the then unpublished manuscript on the Vatican mineral collection by Michele Mercati of San Miniato (1541–1593). This article reconsiders the role of the palaeontological illustrations in this process because Mercati himself had recognized the similarity of the shapes of the shark teeth and glossopetrae but he could not neglect the difference of material between them. Although Steno’s skill as a comparative anatomist convinced him of the organic origin of the fossils, there were still problems of sedimentation to solve. We will first review the opinions of early modern naturalists concerning fossil objects and then focus on how Steno solved the problem to pave the way for his epoch-making dissertation Prodromus (1669). At the same time, we will pay attention to how the set of figures would continue to be borrowed by such authors as Paolo Silvio Boccone (1674), Michael Bernhard Valentini (1704), and Gottfried Wilhelm Leibniz (1749, originally circa 1691). In the meantime, the original manuscript with figures was published in 1717 as Metallotheca Vaticana by Giovanni Maria Lancisi, the Italian anatomist and one of Steno’s acquaintances. Lancisi made annotations to this text that suggested the fossil controversy was evolving, citing the names of Cesalpino, Steno, Boccone, and Vallisneri. Thus, we can understand how the illustrations with its hidden text functioned well in the fossil controversy by the strategic usage by Steno of the Vatican collection, a sort of ‘museum on paper’.

Framework for reservoir sedimentation estimation using the hydrological model and campaign—A case study of A Vuong Reservoir in central Vietnam

Sediment estimation would help practice sustainable watershed management and efficient reservoir operation. Different methods exist to estimate reservoir sedimentation based on the differences in sediment yield flowing in and releasing from the reservoir and successive bathymetric field measurements. This paper investigates the variability in sediment yield from watersheds and sedimentation in the A Vuong reservoir in central Vietnam using the soil and water assessment tool (SWAT) compared with bathymetry mapping. Bathymetry data were collected in 2003, 2015, and 2021 and conducted in 2022. SWAT was calibrated from 1996 to 2008 and validated from 2009 to 2020 using monthly observations. SWAT performs well and can accurately simulate monthly streamflow and sediment yield. The goodness-of-fit analyses suggested that the area list representation of the watershed behavior and satisfactory Sutcliffe efficiency (NSE = 0.86) values for streamflow were obtained during the calibration and validation periods. For sediment simulation, the efficiency is lower than streamflow's, with NSE in the validation values of 0.61. The results showed that the sedimentation estimate from the SWAT model is smaller than that from bathymetry. A Vuong reservoir's annual storage capacity loss due to sedimentation accumulation from the SWAT model and bathymetry was 0.08% and 0.38%, respectively. Based on the bathymetry data, we estimated that the average rate of sedimentation deposition of A Vuong reservoir was 1.3 Mm3/y. The average calculated net deposition value was 4.3 m (0.3 m per year) within fourteen years of operation. The study outcomes demonstrated that the framework approach may transfer to an ungauged catchment and address the complex sedimentation problem in tropical regions.

3D Printing Materials Mimicking Human Tissues after Uptake of Iodinated Contrast Agents for Anthropomorphic Radiology Phantoms.

(1) Background: 3D printable materials with accurately defined iodine content enable the development and production of radiological phantoms that simulate human tissues, including lesions after contrast administration in medical imaging with X-rays. These phantoms provide accurate, stable and reproducible models with defined iodine concentrations, and 3D printing allows maximum flexibility and minimal development and production time, allowing the simulation of anatomically correct anthropomorphic replication of lesions and the production of calibration and QA standards in a typical medical research facility. (2) Methods: Standard printing resins were doped with an iodine contrast agent and printed using a consumer 3D printer, both (resins and printer) available from major online marketplaces, to produce printed specimens with iodine contents ranging from 0 to 3.0% by weight, equivalent to 0 to 3.85% elemental iodine per volume, covering the typical levels found in patients. The printed samples were scanned in a micro-CT scanner to measure the properties of the materials in the range of the iodine concentrations used. (3) Results: Both mass density and attenuation show a linear dependence on iodine concentration (R2 = 1.00), allowing highly accurate, stable, and predictable results. (4) Conclusions: Standard 3D printing resins can be doped with liquids, avoiding the problem of sedimentation, resulting in perfectly homogeneous prints with accurate dopant content. Iodine contrast agents are perfectly suited to dope resins with appropriate iodine concentrations to radiologically mimic tissues after iodine uptake. In combination with computer-aided design, this can be used to produce printed objects with precisely defined iodine concentrations in the range of up to a few percent of elemental iodine, with high precision and anthropomorphic shapes. Applications include radiographic phantoms for detectability studies and calibration standards in projective X-ray imaging modalities, such as contrast-enhanced dual energy mammography (abbreviated CEDEM, CEDM, TICEM, or CESM depending on the equipment manufacturer), and 3-dimensional modalities like CT, including spectral and dual energy CT (DECT), and breast tomosynthesis.

An Analysis Management by Mike 21 Modelling at Rolak 70 Retention Pool in Jombang Regency, East Java Province, Indonesia

Some areas in Indonesia have high level of sedimentation problems that able to cause flooding, and one apparent solution is to build a retention pool. Sedimentation is deposition of material into the reservoir or dam due to environmental damage or erosion occurs in the river basin area. Sedimentation becomes the main factor in constructing the Rolak 70 Retention Pool, as an important component in controlling floods on the Konto River when the water discharge exceeds the maximum limit. From geography perspective, the modelling location is in waters located between 112° 11′ 22.85″ South Latitude and 7° 38′ 42.23″ East Longitude. The model area has northern boundary at the tip of Rolak 70 pool, while western boundary at the outlet of Rolak 70 pool. The lowest water depth value is located in upstream area of Konto River at coordinates of 112°11’27.81″ South Latitude and 7°38’49.27″ East longitude. Weight of soil sample taken from the research site was ± 1000 grams at each point, and the result of sediment sample test performed at the Soil Mechanics Laboratory of Civil Engineering Department, Sultan Agung University, Semarang showed that the research area is dominated by sand, followed by mud and gravel. There were several tests conducted include grain size analysis, hydrometer analysis, and specific gravity analysis to determine the D50 of the sediment. In the study area, several sampling points were taken, started from upstream area of the river in front of Rolak 70 building to the Rolak 70 Retention Pool. For this purpose, a MIKE 21 software modelling was used to determine distribution and lines of sedimentation in the study area. As visible from changes found in bed level morphology that occurred in Rolak 70 Retention Pool by cross section extraction, it can be seen that the largest change occurred in analysis for line 1 and the smallest bed level changes occurred in the analysis for line 6. Then, the result revealed that sedimentation tends to occur at large locations in upstream area of Rolak 70 Retention Pool, while the smallest sedimentation potential will happen at the downstream area of Rolak 70 Retention Pool. These results can be caused by changes of speed from the river flow which tends to decrease towards the end of Rolak 70 Retention Pool. So, the river flow has no more energy to carry heavy amount of sediments originating from the upstream area of the Konto River. By the existence of this retention pool, the need for rice field irrigation will not be disturbed by sediment deposits. In addition, the Rolak 70 Retention Pool can be used as temporary storage for material from Mount Kelud eruption where these materials can be utilized as building material or other useful purposes.

Conservation of the Mount Bawakaraeng Water Resources Area as a Form of Water Resources Management Through Sustainable and Environmentally Sound Development Strategies

Objective: To assess the impact of land cover change on the problems of erosion, sedimentation, flooding, and water scarcity in the Jeneberang watershed and to formulate comprehensive policy and strategy recommendations for the conservation and sustainable management of water resources in the Mount Bawakaraeng area. Metode: This research use of method of conducting legal research known as normative – empirical method, which combine aspects of normative law with data or empirical components. This method is also used to learn how normative legal provisions (laws) are applied to each specific legal event that takes place in community. Results: The change in land use has led to an increase in erosion, sedimentation, flooding, and water scarcity in the Jeneberang Watershed. Deforestation and forest degradation in the upstream area of the Jeneberang watershed have caused various problems related to unsustainable water resource management. Conclusion: the need for a comprehensive and integrated approach in water resources management in the Mount Bawakaraeng area, guided by Sustainable Development Goals (SDGs) and the principles of Integrated Water Resources Management (IWRM). This includes: Strengthening legal and regulatory frameworks for forest and land conservation, Promoting sustainable land management practices among local communities, Improving coordination and collaboration among stakeholders in watersheds, Improving monitoring, data collection, and evidence-based decision-making, Providing alternative livelihood opportunities to reduce pressure on natural resources.

The effect of lateral intake slope on sedimentation transport

Generally, The problem of sediments at the entrances to subsidiary channels is considered one of the most common problems for which water resources engineers seek to find appropriate solutions, as it causes significant damage to hydraulic installations, as the accumulation of these sediments in the canal rollers over time leads to the collapse of those channels, which results in many losses. In this study, a three-dimensional mathematical model was developed using the Ansys Fluent CFD program, and this model was matched with previous laboratory experiments, as this mathematical model showed clear accuracy and consistency. Work was done on changing the geometry of the sub-channel and studying the effect of changing the inclination of the sub-channel on reducing the amount of sediment entering the channel or not, since the channel used in this study is 2 m. Adjustments were made to the inclination of the canal in two different forms: The first is to make the first half (1 m) of the canal horizontal, and the inclination begins in the second half, at three different angles, namely 15, 30, and 45 degrees. The other form is to change the inclination along the total length of the sub-channel (2 m) with the same effect. Angles 15, 30 and 45. The results showed the ineffectiveness of changing the inclination of the sub-channel from the middle of the distance, while the results of changing the total inclination were different. It is possible that the slope angle of 45 is considered the best in terms of increasing the speed and clearly reducing the area of the separation zone and the erosion zone.

Reducing Sedimentation in Catchment Areas as Part of the Revitalization Efforts at Batujai Reservoir in Central Lombok

This research discusses efforts to revitalize the Batujai Reservoir in Central Lombok with a focus on sedimentation problems. Batujai Reservoir has a strategic role in meeting water needs in the surrounding area, but faces serious challenges due to significant sedimentation. In addition to assessing the effects of these changes on the reservoir's benefits�such as irrigation, flood control, and electricity production�this study intends to examine the effects of land use changes in the Dodokan Sub-Watershed Catchment Area (DTA) on the features and volume of sedimentation entering the reservoir. In addition, this study attempts to develop suggestions for efficient sedimentation management plans in order to increase the Batujai Reservoir's service life. Research methods include primary and secondary data collection, sedimentation modeling using the Water and Tillage/Sediment Delivery Model (WATEM/SEDEM), to evaluate the impact of sediment control structures such as check dams. Research variables include catchment area, population, annual rainfall, average daily evaporation, mainstay surface water availability, land surface erosion rate, sediment volume deposited in the reservoir, effective age of the Batujai Reservoir, and changes in land use in the Dodokan Sub-watershed. The results of this research will provide a better understanding of the main sources of sedimentation in the Batujai Reservoir and the impact of land use changes on the reservoir. It is hoped that the recommendations for sedimentation management strategies resulting from this research will help maintain reservoir storage capacity, which is important for meeting various water needs in the region.

River Morphological Change and Sedimentation Countermeasures Analysis in Miu River

One major floods problem in Miu River is huge amount of sediment which transported along the river channel. The decreasing of river capacity has been analysed and some channel courses changes also detected. These problems caused river morphological change and it is necessary to find comprehensive solution which not only decreasing the flood damage but also consider appropriate approach to natural environment. The complexity of these problems and possible solutions to overcome flood and sedimentation problem were investigated. Increasing of river capacity by channel excavation, protecting riverbank with revetment and construction of sediment control facilities were proposed as main solution. However, it is necessary to evaluate the effectiveness of these efforts by analysed sediment control facilities location and dimension of the structures. Some alternatives were investigated in order to find most effective solution to solve flood and sedimentation problem in Miu River.

Sedimentation Management Good Practice (SMGP) to Manage Sedimentation at Kawanua Flood Disaster, Seram Island

Flood natural disasters are almost certain to occur every rainy season. Rain with very high intensity occurred on July 9th, 2023 causing an increase in water discharge which made the river overflow and the Kawanua Bridge collapse. In the upstream area of the river, there is Kawa check dam which has experienced a huge amount of sedimentation due to the top of the crest check dam being covered by fallen trees. This study aims to determine the magnitude of the rate of erosion and sedimentation that occurs in the catchment area in the upper reaches of the river and find out where the source of sedimentation comes from, then the most appropriate solution can be decided, and a similar disaster does not occur. This research used a USLE method to calculate the erosion and sedimentation rate. The results showed that 37.88% of the catchment area was classified as a low level of erosion. Meanwhile, the moderate level of erosion represented 29.42%. Sedimentation Management Good Practice (SMGP) is a concept used to analyze erosion and sedimentation problems. The recommendations given by the SMGP concept have sustainable characteristics that minimize damage to the water environment. Additional recommendations are given by collaborating between government institutions related to catchment area and forest area management authority.

Perlite incorporation for sedimentation reduction and improved properties of high-density geopolymer cement for oil well cementing

Portland cement (PC) is known for its environmental and technical concerns and massive energy consumption during manufacturing. Geopolymer cement is a promising technology to totally replace the use of PC in the oil and gas industry. Although geopolymers are widely used in the construction industry, it is yet to see a full-scale application in the petroleum industry. High-density geopolymer cement development is essential to substitute heavy-weight Portland cement slurries for high pressure well cementing applications. Sedimentation issue is associated with high-density cement slurries which use high specific gravity solids such as weighting materials. This problem causes heterogeneity and density variation along the cemented sections. The main target of this work is to evaluate the use of perlite powder to address the sedimentation issue in the heavy weight geopolymer systems. Hematite-based Class F fly ash (FFA) geopolymer cement slurries with perlite concentrations of 0, 1.5, and 3% by weight of binder (BWOB) were prepared. The sedimentation problem was investigated using three techniques: API method, nuclear magnetic resonance (NMR), and computed tomography (CT) scan. The perlite effects on different geopolymer properties such as unconfined compressive strength (UCS), porosity, elastic and rheological properties were assessed. The results proved that perlite incorporation in high-density hematite-based FFA geopolymer significantly reduced sedimentation issue by increasing yield point and gel strength. NMR and CT scan showed that perlite decreases porosity and density variation across the geopolymer samples. The UCS increased with increasing perlite percentage from 0 to 3%. The measured Young’s moduli (YM) and Poisson’s ratios (PR) showed that the developed perlite based geopolymer systems are considered more flexible than Class G cement systems. It was found that the optimum perlite concentration is 3% BWOB for tackling sedimentation and developing a slurry with acceptable mixability and rheological properties.