scholarly journals Bathymetric components towards ensuring navigable channel along a section of lower river Niger, lokoja, kogi state, Nigeria

2021 ◽  
Vol 5 (5) ◽  
pp. 231-238
Author(s):  
Olanrewaju M Oye ◽  
Lawrence Hart ◽  
Sika Orupabo
Keyword(s):  
Flow Velocity ◽  
River Flow ◽  
Classical Method ◽  
Research Work ◽  
Economic Benefits ◽  
Main Channel ◽  
Secondary Channel ◽  
Cross Sectional ◽  
Single Beam ◽  
River Niger

Navigation in Lower River Niger is seasonal because of insufficient water depth during the dry season. This is a limitation to economic benefits derivable compared to when the river is navigable throughout the year. Government and stakeholders alike have exerted efforts in the past years to create an unimpeded navigable channel without much success. The need to ensure all-year-round navigation in the Lower River Niger for industrial and commercial purposes necessitated this research work. The main thrust of this work is to determine bathymetric components parameters of the river necessary for the design of an appropriate river training structure to divert river flow from the secondary channel to the main channel. The specific objective hereto is to assess the extent and geometry of the river banks, the configuration of the river bed, the river flow velocity and discharge. The approach deployed in this work is the classical method of acoustic principle premised on Remote Sensing techniques. The shape of the river was obtained through waypoint survey using Garmin eTrex 10 handheld GPS, while the riverbed configuration was determined through bathymetric survey using Odom Echotrack MK III single beam Echo Sounder and the flow velocity data was acquired using Valeport 106 Current Meter. Data processing and analysis were achieved using Garmin Basecamp 4.7.3, Wintopo V7.03, Valeport Datalog X2 and Surfer 13 software. The length of the study area measured along the main channel was obtained as 5.94km while that of secondary channel gave 4.30km. Area occupied by the main channel was found to be 2,636,331.3m2 and 1,759,045.4m2 for the secondary channel. Average depth on the main channel was 0.21m while on the secondary channel was -0.89m, depth figures referred to Lokoja local datum. The average flow velocity was obtained to be 0.449m/s and the cross-sectional area of the river as 1568.75m2, which gave a value of 704.2m3/s for the river discharge. The research produced the digital terrain model (DTM) and bathymetric charts of the study area. The parameters obtained in this study is a useful tool in defining an appropriate embankment dam suitable to divert the flow from the secondary channel to the main channel to enhance depth towards all-season navigation in Lower River Niger.

Principles of designing secondary channels along the river rhine for the benefit of ecological restoration

1995 ◽  
Vol 31 (8) ◽  
pp. 379-382 ◽  
Author(s):  
M. H. I. Schropp
Keyword(s):  
Ecological Restoration ◽  
Threshold Value ◽  
Main Channel ◽  
River Rhine ◽  
Secondary Channel ◽  
Frequency Curve ◽  
Cross Sectional ◽  
Design Value ◽  
Ecological Targets ◽  
Flow Velocities

Secondary channels present a favourable opportunity for ecological restoration of the River Rhine and its branches. However, they have to be fitted into the landscape without affecting existing interests such as inland shipping and protection against flooding. Also the ecological targets have to be met with a minimum of human interference. In this article some design principles for secondary channels are presented in which these aspects are taken into account. To avoid silting up of the secondary channel it is recommended to prevent sediment from entering the channel at all. Flow velocities have to be below the threshold value for initiation of motion of sediment, but still high enough to satisfy the ecological targets. The secondary channel discharge is a function of the maximum allowable aggradation of the main channel. Discharge and flow velocities together determine the required cross-sectional area and thus the design value of the bank slopes. In order to have flowing water in the secondary channel all year round, the thalweg level is to be chosen on the basis of the water level frequency curve of the main channel.

scholarly journals Application of an Entropic Method Coupled with STIV for Discharge Measurement in Actual Rivers

2021 ◽  
Vol 945 (1) ◽  
pp. 012036
Author(s):  
Yoshiro Omori ◽  
Ichiro Fujita ◽  
Ken Watanabe
Keyword(s):  
Velocity Distribution ◽  
Flow Velocity ◽  
River Flow ◽  
Measurement Techniques ◽  
Vertical Direction ◽  
Acoustic Doppler Current Profiler ◽  
Surface Flow ◽  
Surface Velocity ◽  
Cross Sectional ◽  
Current Profiler

Abstract In recent years, due to the frequent occurrence of floods that exceed the facility maintenance level due to climate change, non-contact flood flow measurement techniques have been paid attention and actually some measurements have been conducted by applying them instead of the conventional float method. The space-time image velocimetry (STIV) which can measure the surface flow velocity distribution from video images is one of such techniques. In order to calculate the river flow from the surface velocity distribution, it is necessary to determine an appropriate surface velocity coefficient, which is the ratio of the average depth velocity to the surface velocity. However, at present, empirical default value has been still used in practice. In this study, the cross-sectional velocity distribution was calculated using an entropic method by utilizing the surface velocity distribution measured by STIV and compared with Acoustic Doppler Current Profiler (ADCP) observation. It was confirmed that the introduction of the velocity dip system express the flow velocity distribution in the vertical direction, where the velocity dip occurs due to the influence of vegetation.

scholarly journals Analisis Potensi Pembangkit Listrik Tenaga Mikro Hydro Pada Anak Sungai di Bulungan

2021 ◽  
Vol 4 (1) ◽  
pp. 61-66
Author(s):  
Dady Sulaiman ◽  
Wibowo Romadhoni ◽  
Purnama Purnama
Keyword(s):  
Renewable Energy ◽  
Data Collection ◽  
Flow Velocity ◽  
River Flow ◽  
Electrical Energy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Remote Areas ◽  
Fall Height

ABSTRAK Energi listrik merupakan energi utama masyarakat pada era globalisasi. Perusahaan Listrik Nasional (PLN) masih belum bisa menjangkau daerah – daerah terpencil khususnya daerah kabupaten Bulungan yang memiliki banyak daerah terpencil. Masalah ini dapat diatasi dengan memanfaatkan anak sungai yang ada di kabupaten Bulungan sebagai sumber energi listrik. Penelitian ini dimulai dengan survey memilih 20 titik anak sungai yang akan diteliti di kabupaten Bulungan. Selanjutnya pengambilan data yaitu luas penampang sungai, kecepatan aliran sungai, dan tinggi jatuh air. Data ini akan dianalisis dengan menggunakan rumus agar memperoleh nilai daya teoritis yang dihasilkan oleh masing – masing sungai yang telah ditentukan. Hasil penelitian inimenunjukkan diantara 20 anak sungai yang diteliti hanya 2 anak sungai yang memiliki potensi yaitu sungai 9 dengan daya 5,5 kW dan sungai 14 dengan daya 8,5 kW. Hasil penelitian ini dapat dikembangkan lagi agar dapat bermanfaat bagi pengembangan daerah – daerah terpencil yang tidak terjangkau PLN. Kata kunci : Daya, Energi Terbarukan, PLTMH ABSTRACT Electrical energy is the main energy of society in the era of globalization. Perusahaan Listrik Nasional (PLN) is still unable to reach remote areas, especially the Bulungan district which has many remote areas. This problem can be overcome by utilizing tributaries in Bulungan district as a source of electrical energy. This research began with a survey selecting 20 tributary points to be studied in Bulungan district. Furthermore, data collection was the cross-sectional area of the river, river flow velocity, and water fall height. This data was  analyzed using a formula in order to obtain the theoretical power value generated by each predetermined river. The results of this study indicatde that among the 20 tributaries studied, only 2 tributaries have potential, namely river 9 with a power of 5.5 kW and river 14 with a power of 8.5 kW. It is hoped that the results of this research can be further developed so that they can be useful for the development of remote areas that are not reached by PLN. Keyword: PLTMH, Power,  Renewable Energy

Impacto de la comunicación de la responsabilidad social universitaria en la selección de universidad y efecto mediador de la reputación

2020 ◽  
Author(s):  
Lucy Erazo-Coronado ◽  
Sergio Llano-Arristizábal ◽  
Miguel Garcés-Prettel ◽  
Ana-María Erazo-Coronado
Keyword(s):  
Social Responsibility ◽  
Professional Training ◽  
Research Work ◽  
Community Support ◽  
Human Beings ◽  
Cross Sectional ◽  
Public And Private ◽  
University Selection ◽  
Cross Sectional Design ◽  
Institutional Websites

The emerging concept of university social responsibility (USR) consists in the fulfillment of the mission of the university in terms of ethical standards, community support, respect for human beings, and respect for the environment. Thus, universities must not only provide professional training but also instill ethical principles in students to allow them to behave as good citizens and help solve community problems. On the other hand, competition for students requires efficient management of university reputation and communication with their stakeholders, to demonstrate the accomplishment of the university’s mission and attract potential students. The objective of this paper is thus to explain the causal relationship between communication about university social responsibility (USR) activities through institutional websites and university selection, as well as the role of reputation. Research work was carried out based on an explanatory cross-sectional design, with a sample of 356 subjects from a population of 11th-grade students from public and private schools in the City of Barranquilla (Colombia). The results revealed that USR communication through institutional websites has a significant influence on university selection, not only directly but also indirectly, through reputation as a mediating variable. These findings contribute at a theoretical level by providing empirical evidence to understand and explain the analyzed topic. Furthermore, the results provide useful information to evaluate USR disclosure and implement strategies to make progress on USR issues. Resumen El naciente concepto de responsabilidad social universitaria (RSU) consiste en el cumplimiento de la misión de la universidad dentro de unos estándares éticos, de apoyo a la comunidad, respeto al ser humano y al medio ambiente. Así, pues, la universidad no sólo debe impartir formación profesional, sino inculcar a sus estudiantes principios éticos que les permitan comportarse como buenos ciudadanos y contribuir a la solución de los problemas de la comunidad. Por otra parte, la competencia entre universidades exige una gestión eficiente de su reputación y de la comunicación con sus distintos stakeholders, para demostrar a la sociedad el cumplimiento de su misión social, y para atraer estudiantes potenciales hacia la institución. Por lo tanto, este artículo tiene como objetivo explicar la relación de causalidad entre la comunicación de las prácticas de RSU en los sitios web institucionales y la selección de universidad, y el papel mediador de la reputación en esta relación. Para lograrlo, se llevó a cabo una investigación cuantitativa de nivel explicativo experimental y diseño transversal, con una muestra conformada por 356 sujetos, de una población de estudiantes de grado 11º de colegios públicos y privados de la ciudad de Barranquilla (Colombia). Los resultados revelan que la comunicación de las prácticas de RSU en los sitios web institucionales ejerce una influencia significativa directa en la intención de selección de universidad, e indirecta, a través de la reputación como variable mediadora. La evidencia empírica aportada representa un avance teórico en la comprensión y explicación del fenómeno estudiado, e igualmente servirá para que las universidades evalúen si están comunicando adecuadamente su responsabilidad social y adopten estrategias para avanzar en este aspecto.

scholarly journals Hydraulic Evaluation of the Levee System Evolution on the Kurobe Alluvial Fan in the 18th and 19th Centuries

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4406
Author(s):  
Tadaharu Ishikawa ◽  
Hiroshi Senoo
Keyword(s):  
Channel Capacity ◽  
Flood Control ◽  
River Flow ◽  
Global Climate ◽  
Flow Simulation ◽  
Japan Sea ◽  
Main Channel ◽  
Alluvial Fan ◽  
Flood Peak ◽  
Levee System

The development process and flood control effects of the open-levee system, which was constructed from the mid-18th to the mid-19th centuries, on the Kurobe Alluvial Fan—a large alluvial fan located on the Japan Sea Coast of Japan’s main island—was evaluated using numerical flow simulation. The topography for the numerical simulation was determined from an old pictorial map in the 18th century and various maps after the 19th century, and the return period of the flood hydrograph was determined to be 10 years judging from the level of civil engineering of those days. The numerical results suggested the followings: The levees at the first stage were made to block the dominant divergent streams to gather the river flows together efficiently; by the completed open-levee system, excess river flow over the main channel capacity was discharged through upstream levee openings to old stream courses which were used as temporary floodways, and after the flood peak, a part of the flooded water returned to the main channel through the downstream levee openings. It is considered that the ideas of civil engineers of those days to control the floods exceeding river channel capacity, embodied in their levee arrangement, will give us hints on how to control the extraordinary floods that we should face in the near future when the scale of storms will increase due to the global climate change.

scholarly journals The δ subunit and NTPase HelD institute a two-pronged mechanism for RNA polymerase recycling

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hao-Hong Pei ◽  
Tarek Hilal ◽  
Zhuo A. Chen ◽  
Yong-Heng Huang ◽  
Yuan Gao ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Nucleic Acids ◽  
Rna Polymerase ◽  
Active Site ◽  
Genome Stability ◽  
Slow Growth ◽  
Coiled Coil ◽  
Main Channel ◽  
Dependent Manner ◽  
Secondary Channel

AbstractCellular RNA polymerases (RNAPs) can become trapped on DNA or RNA, threatening genome stability and limiting free enzyme pools, but how RNAP recycling into active states is achieved remains elusive. In Bacillus subtilis, the RNAP δ subunit and NTPase HelD have been implicated in RNAP recycling. We structurally analyzed Bacillus subtilis RNAP-δ-HelD complexes. HelD has two long arms: a Gre cleavage factor-like coiled-coil inserts deep into the RNAP secondary channel, dismantling the active site and displacing RNA, while a unique helical protrusion inserts into the main channel, prying the β and β′ subunits apart and, aided by δ, dislodging DNA. RNAP is recycled when, after releasing trapped nucleic acids, HelD dissociates from the enzyme in an ATP-dependent manner. HelD abundance during slow growth and a dimeric (RNAP-δ-HelD)2 structure that resembles hibernating eukaryotic RNAP I suggest that HelD might also modulate active enzyme pools in response to cellular cues.

scholarly journals Experimental Investigations of Interactions between Sand Wave Movements, Flow Structure, and Individual Aquatic Plants in Natural Rivers: A Case Study of Potamogeton Pectinatus L.

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1166 ◽  
Author(s):  
Łukasz Przyborowski ◽  
Anna Łoboda ◽  
Robert Bialik
Keyword(s):  
Flow Velocity ◽  
Three Dimensional ◽  
Potamogeton Pectinatus ◽  
Sand Wave ◽  
Experimental Investigations ◽  
Cross Sectional ◽  
Bending Tests ◽  
Long Duration ◽  
Elevation Changes

Long-duration measurements were performed in two sandy bed rivers, and three-dimensional (3D) flow velocity and bottom elevation changes were measured in a vegetated area and in a clear region of a river. Detailed flow velocity profiles downstream and upstream of a single specimen of Potamogeton pectinatus L. were obtained and the bed morphology was assessed. Potamogeton plants gathered from each river were subjected to tensile and bending tests. The results show that the existence of the plants was influenced by both bottom and flow conditions, as the plants were located where water velocity was lower by 12% to 16% in comparison to clear region. The characteristics of the flow and sand forms depended on the cross-sectional arrangement of the river, e.g., dunes were approximately four times higher in the middle of the river than in vegetated regions near the bank. Furthermore, the studied hydrophytes were too sparse to affect water flow and had no discernible impact on the sand forms’ movements. The turbulent kinetic energy downstream of a single plant was reduced by approximately 25%. Additionally, the plants’ biomechanical characteristics and morphology were found to have adjusted to match the river conditions.

scholarly journals A Study of Sedimentation at the River Estuary on the Change of Reservoir Storage

2018 ◽  
Vol 31 ◽  
pp. 03001 ◽  
Author(s):  
Iskahar ◽  
Suripin ◽  
Isdiyana
Keyword(s):  
Flow Velocity ◽  
Water Level ◽  
Physical Model ◽  
River Estuary ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Sedimentation Pattern ◽  
Cross Sectional ◽  
Channel Angle ◽  
Reservoir Storage

Estuary of the river that leads to the reservoir has characteristics include: relatively flat, there is a change in the increase of wet cross-sectional area and backwater. The backwater will cause the flow velocity to be reduced, so that the grains of sediment with a certain diameter carried by the flow will settle in the estuary of the river. The purpose of this research is to know the distribution and sedimentation pattern at the river estuary that leads to the reservoir with the change of water level in the reservoir storage, so the solution can be found to remove / reduce sediment before entering the reservoir. The method used is the experimental, by making the physical model of the river estuary leading to the reservoir. This study expects a solution to reduce sedimentation, so that sedimentation can be removed / minimized before entering the reservoir. This research tries to apply bypass channel to reduce the sedimentation at the river estuary. Bypass channels can be applied to overcome sedimentation at the river estuary, but in order for the sediment to be removed optimally, it is necessary to modify the mouth of bypass channel and channel angle.

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