Reservoir Capacity Research Articles

Impact of the Aboral Pouch in Roux-en-Y Reconstruction after Laparoscopic Total Gastrectomy for Elderly Patients.

The number of elderly people with stomach cancer is increasing; therefore, minimally invasive surgical treatments are required. Elderly patients have multiple comorbidities and are prone to postoperative weight loss, nutritional disorders, Postgastrectomy syndrome (PGS), and decreased quality of life (QOL). Total gastrectomy is particularly associated with these complications, although aboral-pouch creation reportedly improves the condition by compensating for lost reservoir capacity. However, there is no consensus regarding its significance. This study aimed to investigate the impact of the aboral pouch on total gastrectomy outcomes in elderly patients. Thirty-six patients who met the eligibility criteria, defined as elderly patients aged ≥75 years, were retrospectively analyzed. The patients had undergone Roux-en-Y reconstructions with an aboral pouch in laparoscopic total gastrectomy procedures performed at Juntendo University from July 2016 to June 2022. The main outcomes were postoperative nutritional status, PGS, and QOL. The average postoperative period was approximately 1 year (12.0 vs. 13.5 months, P=0.536), for 14 elderly and 22 non-elderly patients, respectively. Elderly patients had more comorbidities (78.5% vs. 40.9%, P=0.041). The outcome of nutritional status demonstrated no differences in weight-loss rate (-5.3% vs. -8.6%, P=0.651) or prognostic nutritional status (-7.9% vs. -5.9%, P=0.243). There was no significant difference in PGS and QOL between elderly and non-elderly patients. Total gastrectomy with an aboral-pouch creation could be beneficial for elderly 43 patients from the perspective of postoperative nutritional status, PGS, and QOL.

Assessment of Left Atrial Phasic Volumes and Functions During Third Trimester of Healthy Pregnancy

Background: Conception represents a physiological progression associated with adaptations in the structure, blood flow dynamics, and operational aspects of the cardiac response to temporary alternation in both preload and afterload. Ventricular volume and LA dimensions gradually and continuously increase due to increasing cardiac output and preload. The increased volume burden during the last trimester aggravates the possible cardiovascular disorders. Limited echocardiographic information exists on left atrium (LA) volume and function during the third trimester of standard conception among Iraqi women. Aim: To estimate the capacity and functionality of the left atrium throughout the last trimester of standard conception. Methods: This research was carried out on 75 normal gravid females (cases ) and 75 nonpregnant females (control ); women were given attention at Al-Furat Teaching Hospital from the 1 of April 2022 to the 30 of May 2023, the comprehensive 2D echocardiographic study had been done for each one of them. Results: Pregnant women category revealed a high noteworthy rise in left atrial maximum volume LA Max, left atrial minimum volume (LA Min) and pre-atrial volume (LA Pre- A) hn contrast to nonpregnant women group vs. vs. and vs. respectively. As well, the study showed that in pregnant women group there is high significant increase in Left atrium reservoir capacity, Left atrium conduit role and LA booster duty vs. vs. vs. contrasted with control. Additionally, the total emptying fraction% , LA Active ejection fraction % significantly higher in pregnant women than the control , vs. while the LA Passive EF% had no significant difference between pregnant women about control . Conclusion: In normal gravid females in the last trimester, there is an increase in LA volumes(LA maximum volume, LA minimum volume, and LA pre-A volumes) and enhancement in LA reservoir capacity, conduit role, and booster functions by using 2DE, which can quickly assess LA phasic volumes and function.

Kontribusi Budidaya Keramba Jaring Apung terhadap Peningkatan Faktor Pembatas Fosfor dan Nitrogen di Ekosistem Waduk Pulau Jawa

Floating net cage (KJA) cultivation activities have had a significant impact on the community, especially in terms of providing food, increasing employment opportunities and economic growth in the surrounding area. However, we need to realize that KJA has negative impacts that can affect water quality and community activities. Article reviews aims to determine the contribution of phosphorus and nitrogen as limiting factors in reservoir ecosystems due to floating net cages and identify methods that can reduce their negative impacts. KJA activities cause an increase in excessive accumulation of phosphorus and nitrogen in reservoir waters, which comes from food waste and fish metabolism. In addition, the KJA population that fills the reservoir's capacity provides a significant contribution to this increase. The impact of this accumulation is an increased potential for eutrophication, which can damage aquatic ecosystems by causing excessive growth of algae and air plants and decreasing water quality. This is a serious problem that can endanger fisheries cultivation in reservoir waters. Therefore, there are various strategies that can be implemented. This includes implementing stricter regulations regarding KJA practices, educational efforts for cultivators, as well as anti-collaboration between stakeholders (pentahelix). Therefore, the use of cleaning organisms and the use of innovative technology can also be an effective solution in preserving the aquatic environment.

Hydrological Analysis Before and After Embankment-Raising Project of Agricultural Reservoir Watershed: A Case Study of Suyang Reservoir

We selected the SWAT hydrological model to analyze the hydrological changes before and after an embankment-raising project in agricultural reservoirs. The model was calibrated and validated from 2015 to 2016 using discharge data from the Songsan gauge station, which serves as a watershed outlet that includes the Suyang Reservoir. The dam height of Suyang Reservoir was raised from 13.5 m to 15.1 m, which resulted in a total storage capacity increase from 7.472 million cubic meters to 11.926 million cubic meters. The calibrated model demonstrates an efficiency of 0.9. Scenarios for pre- (2001-2012) and post-embankment raising (2014-2016) were simulated, and the results for various hydrological components (precipitation, runoff, infiltration, evapotranspiration, percolation, soil moisture, groundwater evaporation, and groundwater recharge) were summarized. The model results revealed average precipitation, runoff, infiltration, evapotranspiration, and groundwater recharge for the pre-embankment raising period (2001-2012) as 1,479.3 mm, 864.1 mm, 550.8 mm, 584.2 mm, and 165.0 mm, respectively. For the post-embankment raising period (2014-2016), the simulated values were 1,290.4 mm, 678.0 mm, 494.0 mm, 587.9 mm, and 145.9 mm, respectively. Below-average precipitation during the post-embankment raising period did not have a significant impact on the operation of the agricultural reservoir. The increased reservoir capacity through the embankment-raising project suggests the potential for additional water supply in the face of future water shortages and abnormal drought conditions. Additional research, including the determination of an appropriate water storage rate, will be necessary through long-term investigations and analyses, and climate change scenarios should be incorporated.

The hydraulic investigation of harmonic plan weirs

Existing dams and reservoirs need to be revised to meet safety standards. For the existing reservoirs where flood control is important and the maximum water level is limited, the best method to increase reservoir capacity is to build a labyrinth weir on the dam. In labyrinth weirs, the collision of two nappe flows produces nappe interference, and this reduces the weir performance. In this study, the semi-circle weirs are placed in an open channel harmonically to increase the efficiency of the labyrinth weirs to make the areas more efficient and increase the flow capacity because of the nappe interference and to ensure the flow moving perpendicular to the weir as possible. In the experimental study of the asymmetrically placed circular weirs, 3 different weir heights (P = 20 cm, 30 cm and 40 cm) and 3 different labyrinth cycle numbers (N = 2, N = 3 and N = 4) were used. As a result of the experiments, although there was a 13 % decrease in the discharge coefficients (Cd) compared to the linear weirs, it provided a 57 % increase in the net crest length (Lnet). Discharge coefficient (Cd) is decreased 3.4 %, as the number of cycles (N) increases. As the weir height (P) decreases, Cd increases 7.5 % due to the vacuum effect.

Multi-purpose reservoir operation concomitant with estimating hydropower potential using multifarious hydrological models

The research aims at determining the optimal release rule to increase the capacity of Rib reservoir. The reservoir inflow using HBV-light hydrological model embracing optimal reservoir operation through HEC-ResSim model were used to prepare an optimum operational plan. The potential of the river for hydropower generation prioritise the demand at a specified level regarding storage capacity (m3), level of reservoir (m), and the relation between inflow and outflow of the reservoir. From the model performance features, the coefficient of correlation (R2) and Nash Sutcliffe Efficiency (NSE) were determined to be, respectively, 0.77 and 0.73 for calibration and 0.72 and 0.70 for validation. The Sobol approach was used for detailed sensitivity analysis of DROP model parameters based on the performance of C2M on outflows and volumes. The results suggest that the threshold coefficient characterizing the demand-controlled release level is the most significant parameter. According to the simulation's findings, the reservoir's average regulated release is calculated to be 22.86 m3/s, and its average monthly hydropower output is 6.73 MW. Average annual hydropower energy was estimated as 58.955 GW h/year and mean annual inflow of reservoir volume of water to be 223.54 Mm3. This volume of water is adequate to accommodate total annual irrigation demand, environmental obligation, and other respective requirements in the downstream. The demand for hydropower and irrigation and supply from reservoir capacity can be counterbalanced from the simulated result without any hindrance.

Differential Development Mechanisms of Pore Types under the Sequence Stratigraphic Constraints of the Wufeng–Longmaxi Formation Shale from the Upper Yangtze Platform

Various types of pores, including organic and inorganic variations, exhibit distinct impacts on the storage capacity of shale gas reservoirs and play a significant role in shale gas occurrence. However, there is a limited number of studies that have quantitatively addressed the developmental characteristics of these diverse pore types and their primary controlling factors. This paper explores the development of inorganic pores, specifically interparticle pores and intraparticle pores, as well as organic matter (OM) pores within the shales of the Wufeng–Longmaxi Formation in the Upper Yangtze region. Parameters such as areal porosity, pore diameter, and pore number based on the FE-SEM and image digitization are discussed. Additionally, the influence of the sedimentary environment on the development of various pore types through integrated wavelet transform techniques and geochemical analysis are analyzed. This analysis reveals the distinctive mechanisms governing the development of pore types under the sequence stratigraphic constraints. The findings reveal that the Wufeng–Longmaxi Formation within the study area can be classified into four systems tracts (transgressive systems tracts TST1 and TST2, and highstand systems tracts HST1 and HST2). Within TST1+HST1, OM pores emerge as the predominant pore type, contributing to over 65% of the porosity. TST2 similarly displays OM pores as the dominant type, comprising over 45% of the total porosity, with an average OM areal porosity of 7.3%, notably lower than that of TST1+HST1 (12.7%). Differences in OM pore development between TST1+HST1 and TST2 shales are attributed to variations in OM abundance and type. In HST2, inorganic pores are the dominant pore type, primarily consisting of interparticle pores associated with clay minerals, contributing to more than 50% of the porosity, while OM pores remain almost undeveloped. The frequent sea level fluctuations during the sequence stratigraphic evolution caused variations in sedimentary environments across different depositional sequences. These differing depositional environments lead to varying OM content and types, mineral genesis, and content, ultimately resulting in disparities in the development of shale pore types within different sequences.

Understanding the cost of soil erosion: An assessment of the sediment removal costs from the reservoirs of the European Union

Soil erosion is both a major driver and consequence of land degradation with significant on-site and off-site costs which are critical to understand and quantify. One major cost of soil erosion originates from the sediments delivered to aquatic systems (e.g., rivers, lakes, and seas), which may generate a broad array of environmental and economic impacts. As part of the EU Soil Observatory (EUSO) working group on soil erosion, we provide a comprehensive assessment of the existing costs of sediment removal from European Union (EU) catchments due to water erosion. These quantifications combine continental average and regionally explicit sediment accumulation rates with published remediation costs, integrating numerous figures reported in the grey literature. The cost of removing an estimated 135 million m3 of accumulated sediments due to water erosion only is likely exceeding 2.3 billion euro (€) annually in the EU and UK, with large regional differences between countries.Considering the sediment delivered through all soil loss processes (gullies, landslides, quarrying, among others) through extrapolating measured reservoir capacity losses, the sediment accumulation in the circa 5000 EU large reservoirs exceeds 1 billion m3 with a potential cost of removal ranging between 5 and 8 billion € annually. These estimates, although not accounting for already implemented catchment mitigation measures, provide insights into one of the off-site costs of soil erosion at both the continental scale as well as the regional differences in economic burden. The provided estimates contribute to support policies such as the Soil Monitoring Law, the Zero Pollution Action Plan, the Farm to Fork strategy and the Water Framework Directive.

DOM hydrophilic components of organic fertilizers increased the soil nitrogen retention capacity and succession of the microbial community.

Application of organic fertilizers affects soil properties and microbial communities, which in turn alters soil N transformation processes. Unfortunately, it is not clear how the difference in the character of the organic fertilizer DOM affects the soil nitrogen retention capacity and its microbial processes. According to the principle of equal nutrients, the treatments of chemical fertilizer alone (treatment CF), chemical fertilizer with organic fertilizer DOM hydrophilic components (treatment H), and chemical fertilizer with organic fertilizer DOM hydrophobic components (treatment P) were set up, where the characteristics of soil nitrogen transformation and changes in microbial community structure were studied with soil culture conditions for 24 days. It was discovered that the addition of organic fertilizer DOM components (H and P) slowed nitrification rate and increased protease activity resulting in a higher NH4+-N content compared to the CF treatment. The DOM addition (H and P) increased the microbial biomass nitrogen (MBN) levels in the soil and increased the soil nitrogen pool capacity. Moreover, the carbon use efficiency of the hydrophilic components is higher than that of the hydrophobic components, resulting in its further increase in nitrogen reservoir capacity and higher nitrogen retention capacity. Network analysis showed that the addition of organic fertilizer DOM hydrophilic components increased network complexity and synergy between microorganisms. In combination with random forest analysis, it was shown that Sphingomonas and Massilia were key species influencing soil nitrogen retention capacity and nitrogen availability characteristics.

ОПТИМИЗАЦИЯ ВОДОХОЗЯЙСТВЕННОГО КОМПЛЕКСА НА ОСНОВЕ СИНЕРГЕТИЧЕСКОЙ ОЦЕНКИ СТОИМОСТИ ГИДРОРЕСУРСА

The purpose of this article is to solve the multicriteria problem of optimizing the operation of hydroelectric power stations based on the selection of the optimal activities of the water-chemical complex (water management complex). The work has developed a universal methodology that combines the optimization method and the theory of marginal utility assessment. The proposed approach is based on the construction and analysis of a matrix of contradictions between participants in the water management complex and the use as the main criterion of the minimum deviation of the actual volume of water consumption (consumption) by participants in the water-chemical complex from its optimal value. The work also analyzes the conflicting interests of the water and chemical complex participants by comparing the requirements for issuing guaranteed power of hydroelectric power plants and ensuring guaranteed navigation depths as the most significant participants in the water-energy complex based on the use of Pareto optimization - the optimal set. Using the example of the Novosibirsk hydroelectric power station and water-chemical complex, it is expected to obtain an assessment of the economic effect from the implementation of the proposed criterion and the developed methodology for optimizing the water-chemical complex. Based on the results of implementing the developed approach at the Novosibirsk HPP, it was possible to find the optimal regime for managing the capacity of the HPP reservoir and achieve an increase in the level of the upper and lower pools.

Reservoir Sedimentation Assessment Using Geospatial Technology: A case Study of Dukan Reservoir, Sulaimani Governorate, Kurdistan Region, Iraq

The accumulation of sediment in reservoirs poses a major challenge that impacts the storage capacity, quality of water, and efficiency of hydroelectric power generation systems. Geospatial methods, including Geographic Information Systems (GIS) and Remote Sensing (RS), were used to assess Dukan Reservoir sediment quantities. Satellite and reservoir water level data from 2010 to 2022 were used for sedimentation assessment. The satellite data was used to analyze the water spread area, employing the Normalized Difference Water Index (NDWI) and Modified Normalized Difference Water Index (MNDWI) to enhance the water surface in the satellite imagery of Dukan Reservoir. The cone formula was employed to calculate the live storage capacity of the reservoir within two elevations. According to the study results, the live storage capacity of Dukan Reservoir at elevation 511.78 m had decreased from 8000 MCM to 7007.77MCM and 6923.53 MCM using NDWI and MNDWI respectively, due to sedimentation, resulting in a capacity loss of 14.59% and 15.83% for NDWI and MNDWI respectively. The annual sedimentation was 13.78 MCM and 14.95 MCM for NDWI and MNDWI, respectively. Joglekar's equation and Khosla's formula have demonstrated that the sedimentation rate in the Dukan reservoir exceeds the critical rate. The findings of this study will inform the development of sediment management strategies aimed at preserving the reservoir's capacity.

Structural characteristics of continental carbonate-rich shale and shale oil movability: A case study of the Paleogene Shahejie Formation shale in Jiyang Depression, Bohai Bay Basin, China

Based on rock mineral and geochemical analysis, microscopic observation, physical property measurement, and thin laminae separation test, etc., the characteristics of typical laminae of the Paleogene Shahejie Formation carbonate-rich shale in the Jiyang Depression were analyzed, and the organic matter abundance, reservoir properties, and oil-bearing properties of different laminae were compared. Typical shale storage-seepage structures were classified, and the mobility of oil in different types of shale storage-seepage structure was compared. The results show that the repeated superposition of mud laminae and calcite laminae are the main layer structure of carbonate-rich shales. The calcite laminae are divided into micritic calcite laminae, sparry calcite laminae and fibrous calcite vein. The mud-rich laminae are the main contributor to the organic matter abundance and porosity of shale, with the best hydrocarbon generation potential, reservoir capacity, and oil-bearing property. The micritic calcite laminae also have relatively good hydrocarbon generation potential, reservoir capacity and oil-bearing property. The sparry calcite laminae and fibrous calcite vein have good permeability and conductivity. Four types of shale storage-seepage structure are developed in the carbonate-rich shale, and the mobility of oil in each type of storage-seepage structure is in descending order: sparry calcite laminae enriched shale storage-seepage structure, mixed calcite laminae enriched shale storage-seepage structure, fibrous calcite vein enriched shale storage-seepage structure, and micritic calcite laminae enriched shale storage-seepage structure. The exploration targets of carbonate-rich shale in the Jiyang Depression Shahejie Formation are different in terms of storage-seepage structure at different thermal evolution stages.

Numerical Analysis of the Impacts of Multiscale Fractures on Geothermal Reservoir Capacity

Numerical Analysis of the Impacts of Multiscale Fractures on Geothermal Reservoir Capacity

Complementary scheduling rules for hybrid pumped storage hydropower-photovoltaic power system reconstructing from conventional cascade hydropower stations

The reconstruction of conventional cascade hydropower plants (CHP) into hybrid pumped storage hydropower plants (HPSH) by adding a pumping station has the potential to increase the hydropower's flexibility and promote the consumption of renewable energy into the power grid. However, the complex hydraulic and electric connections between cascade hydropower stations and multi-energy sources pose challenges to safe and economic operation. This study explores the complementary scheduling for hybrid pumped storage hydropower-photovoltaic (HPSH-PV) system and evaluates the operation benefit and risk. First, the complementary scheduling rules that consider the demand for long-distance and across-regions power transmission are proposed to guide the peak-shaving operation of the system. Then a case study is performed with a hydro-PV complementary project in China, and the benefit and risks are evaluated quantitatively while considering the uncertainty of PV power prediction. The results demonstrate that after a pumping station is added (1) the power generation profit can be increased, especially in the dry seasons and the upstream reservoir; (2) the regulation capacity and power-supply reliability of the upstream reservoir is increased, while that of the downstream reservoir is slightly reduced; (3) the reservoir water level fluctuation and operation risk increase, but it can be lowered as the inflow increases.

Impact of intensive water use from farm dams on the storage dynamics in strategic reservoirs

ABSTRACTThe construction of dams and interbasin water transfers are major strategies to adapt to water scarcity. In the semi-arid Jaguaribe basin, Brazil, large strategic reservoirs supply water for urban centres, while farm dams serve multiple demands of rural communities. We used the Model of Water Availability in SemiArid Environments (WASA) to assess the water storage dynamics of strategic reservoirs impacted by: (i) water withdrawal from farm dams located upstream; (ii) interbasin water transfer to the Jaguaribe basin. Simulations show that intensive water use from smaller reservoirs reduces large reservoir volumes by less than 10%, whereas inflows from the São Francisco Integration Project to the basin can increase by 6% the period of time in which reservoir capacity is above the alert volume. The practice of saving water from small dams can be abandoned, enabling higher agricultural production without compromising the water supply of large urban centres.

A Toolbox for generalized pumped storage power station based on terrain in ArcGIS Environment

China proposed the goal of carbon peak by 2030 and carbon neutrality by 2060 at the 75th session of the United Nations General Assembly. Accelerating the development of clean energy is the key to achieve this carbon peak and neutrality goal. However, large-scale grid connection of new energy brings great challenges to the stable and safe operation of power grid. As a regulating power source and energy storage power source, pumped hydro energy storage (PHES) has strong regulating ability and is characterized as a reliable operation with broad prospects for development. However, the current field-survey-based method of site selection for PHES is time consuming, labour intensive, and costly. Improper site selection would cause ecological environment damages among other problems. A scheme or protocol that enables the automated site selection of PHES is therefore urgently required. The objective of this study was therefore to develop a new tool based on digital elevation model (DEM) and geographic information system (GIS) hydrological analysis function to screen out the potential PHES sites. ArcGIS, as a leading geospatial software, provides a set of geoprocessing (GP) tools for raster analysis. ArcPy is a Python package that runs in the ArcGIS environment. It can quickly invoke existing tools in ArcGIS to create custom extension modules. In this study, ArcPy was used to screen the site of PHES based on reservoir capacity and dam height, etc. Taking the southern Shaanxi Province, China as an example, comprehensive evaluation method integrating objective weighting method and multi-factor statistical analysis method is proposed and tested. This new method can promote the solution of the PHES site selection planning and preliminary reserve of PHES, and provide scientific reference and theoretical basis for the development and construction of PHES.

Hydrogeochemical Characteristics of Geothermal Water in Ancient Deeply Buried Hills in the Northern Jizhong Depression, Bohai Bay Basin, China

The Jizhong Depression boasts rich geothermal resources with a lengthy history of geothermal exploitation. Buried hill geothermal reservoirs, which serve as primary thermal sources for hydrothermal resource exploitation, are prevalent in this region and have advantages such as extensive development potential, significant geothermal reservoir capacity, superior water quality, and straightforward recharge. This study investigates the formation and evolution of deep geothermal water in the Jizhong Depression by analyzing the hydrochemical and isotopic data of geothermal water samples collected from buried hill geothermal reservoirs in the northern part of the depression. The findings reveal that the subsurface hot water samples from the carbonate geothermal reservoirs in this region were predominantly weakly alkaline water with a pH ranging between 6.61 and 8.87. The hot water samples collected at the wellhead exhibited temperatures varying from 33.9 °C to 123.4 °C and total dissolved solids (TDS) lying between 473.9 mg/L and 3452 mg/L. Based on the δ2H-δ18O stable isotope analysis, the geothermal fluids in the Jizhong Depression are predominantly sourced from atmospheric precipitation and exist in a somewhat isolated hydrogeological environment, exhibiting pronounced water–rock interactions and deep water circulation (with depths ranging from 1324 m to 3455 m). Through a comparison of various methods, it is deduced that the most appropriate geothermometer for deep karst geothermal reservoirs in the Jizhong Depression is a chalcedony geothermometer, and when using it, the deep reservoir temperature was estimated at 63–137.6 °C. The precipitation in the adjacent mountainous areas enables the groundwater to infiltrate and descend deep into the earth along piedmont faults. Subsequently, lateral runoff over extended periods replenishes the groundwater into the depression. This process allows for the groundwater to fully absorb heat from deep heat sources, resulting in the formation of the deep geothermal reservoirs in the northern Jizhong Depression. The insights obtained from this study offer a theoretical and scientific foundation for the exploitation and utilization of regional geothermal resources and the transformation of the energy structure in China.

An Engineering Geological Appraisal of the Leakage Problem in Dora-1 Earthen Dam, Tigray: Implications for its Stability

Leakage is one of the major problems facing the functionality and sustainability of dams. It occurs through the embankment body, reservoir, foundation, and abutments. This study was conducted to identify the main causes of the leakage problem at the Dora-1 dam, located in the northern part of Ethiopia. It is an earthfill dam with a height of 43.5 m, crest length of 454 m, and reservoir capacity of 4.67 million cubic meters. Part of the embankment body was wet and swampy up to 20 m high from the ground due to leaking water. Geological investigation, laboratory test of the construction materials (including grain size analysis, specific gravity and water absorption, Atterberg limit, free swell, dispersion, permeability, and shear strength), and electrical resistivity investigation were used to identify and pinpoint the possible causes of the leakage problem. Results of the study show that the favorable geological features responsible for the occurrence of leakage include: (a) geological contact between sandstone and moderately to highly weathered basalt unit at the left abutment, (b) the gravelly sand deposit at the central foundation and (c) dyke outcrop at the river course within the reservoir running in the upstream-downstream direction. Results of laboratory tests for clay core show medium to high compressibility, good to poor workability, and semi-pervious to impervious permeability when compacted. The water absorption and the percentage finer of the filter material don’t satisfy the filter criteria and the shell material was found to be semi-previous. The anomalous in the resistivity survey result confirms the situation. Slope stability analysis of the embankment showed instability conditions at full reservoir level. Close follow-up and a downstream stabilization structure, including rock and gravel support, were recommended.
 Construction material; Embankment dam; Site investigations; Ethiopia.

Reservoir capacity loss and sedimentation assessment of Dholbaha dam located in Punjab, India using remote sensing and bathymetric survey techniques

Abstract A study was undertaken to assess the live storage capacity of the Dholbaha reservoir located in Punjab, India using remote sensing and bathymetric survey techniques. The primary objectives included comparing the estimated capacity with findings from a bathymetric survey, refining the elevation-area-capacity curve, and determining the rate of capacity loss due to sediments deposition. This analysis utilized water elevation data spanning from 1987 to 2022 and satellite imageries from Landsat 7, 8 & 9. The satellite data was processed using software tools such as Erdas Imagine and ArcGIS. The water extent of the reservoir was calculated using Modified Normalized Difference Water Index (MNDWI). Over the course of 34 years, the reservoir experienced reductions in its dead, active, and total storage capacities by 81.5%, 19.7%, and 28.9%, respectively. These changes correspond to annual depletion rates of 2.40%, 0.58%, and 0.85%, respectively. The sediment yield from the surrounding catchment area was determined to be approximately 1203.56 m3/km2/year. The findings demonstrate substantial declines in Dholbaha reservoir storage capacities over a 34-year period (1987-2022) attributable to sedimentation. This underscores the critical need for sustainable water management and provides key insights for monitoring and strategic planning. The study advocates immediate, targeted interventions within the catchment area to mitigate sedimentation in the Dholbaha reservoir, highlighting the importance of ongoing sedimentation rate monitoring and collaboration with stakeholders for informed reservoir management and sustainable solutions to maintain water capacity for the region.

Reservoir concatenation and the spectrum distribution of concatenated reservoir state matrices

Reservoir computing, one of the state-of-the-art machine learning architectures, processes time-series data generated by dynamical systems. Nevertheless, we have realized that reservoir computing with the conventional single-reservoir structure suffers from capacity saturation. This leads to performance stagnation in practice. Therefore, we propose an extended reservoir computing architecture called reservoir concatenation to further delay such stagnation. Not only do we provide training error analysis and test error comparison of reservoir concatenation, but we also propose a crucial measure, which is the trace associated with a reservoir state matrix, that explains the level of responsiveness to reservoir concatenation. Two reservoir dynamics are compared in detail, one by using the echo state network and the other by using a synchronization model called an explosive Kuramoto model. The distinct eigenvalue distributions of the reservoir state matrices from the two models are well reflected in the trace values that are shown to account for the different reservoir capacity behaviors, determining the different levels of responsiveness.