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1

An efficient self-cleaning Dam-Type Sediment Excluder upstream of the dam reservoir

Pishgar Reza, Keshavarzi Ali Reza, Aslani Kordkandi Abolfazl

Acta Geophysica

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2022

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Vol. 70, no 5

2389--2401

EN

Sedimentation is almost a serious problem for reservoir dams due to loss of storage, malfunction of bottom intakes, corrosion, and damage to power generators, increased food risk, water quality degradation, and other environmental degradation problems. There are some methods of sediment removal from the reservoir, such as dredging and flushing. The above techniques are not feasible for all reservoirs due to high cost and low efficiency. In this paper, a new sediment extractor referred hereafter as Dam-Type Sediment Excluder (DTSE) is introduced. The self-cleaning DTSE excludes suspended sediment from the river flow upstream of the reservoir and then bypasses the river downstream of the reservoir. The efficiency of the proposed DTSE was examined under different excluding flow rates, opening heights, inlet flow Froude numbers, and sediment concentrations. This research also investigates the influence of suspended- sediment concentration profile on the model efficiency. The results indicate that the efficiency of the DTSE is highly sensitive to the flow velocity and the middle intake location and height. The maximum extracted efficiency of the model was found to be about 40%, while the average optimal efficiency was 26%.

2

Features of the Sediment Runoff Regime Downstream the Ile River

Duskayev Kassym, Myrzakhmetov Akhan, Zhanabayeva Zhanar, Klein Igor

Journal of Ecological Engineering

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2020

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Vol. 21, nr 2

117--125

EN

This paper is devoted to study on the sediment runoff of the Ile River downstream. The article analyses the Kapshagai reservoir impact on the regime and characteristics of the sediment runoff in the Ile River downstream before and after construction of the reservoir in 1970. Along with the calculation of characteristics of sediment runoff, an assessment of the amount of the suspended sediment, which is in the bowl of the reservoir, was shown. Furthermore, the impact reservoir on the granulometric composition of the suspended and bed sediment of Ile River was calculated.

3

A two-decade record of variations in suspended sediment in the Warta River, a lowland river in western Poland

Skolasińska Katarzyna, Nowak Bogumił, Bradtke Katarzyna

Geological Quarterly

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2020

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Vol. 64, No. 4

1048--1060

EN

Fluctuations in suspended sediment concentration (SSC) has been investigated in the Warta River(western Poland), based on data obtained for the period 1961-1980 from three gauge stations located in upstream, middle-stream and downstream areas. Over the two decades, the SSC values demonstrated wide fluctuations and an overall increase at each gauge station. No significant correlation was generally observed between SSC and discharge but high SSC was found to follow low discharge and increasing temperature during the summer seasons in some years. Measurements of SSC and discharge were used to estimate total annual suspended sediment load (SSL). SSL values were found to increase downstream along with an increase in discharge. SSC decreases along the river course. However, when it comes to changes over time, SSL variability was mainly determined by SSC changes. The maximum SSC values were primarily caused by anthropogenic factors: the disposal of mine wastewater upstream, river training works, increased urbanisation and the intensification of sewage disposal. Where the river catchment has been greatly affected by anthropogenic factors, a denudation index calculated solely based on SSC and discharge does not appear to reflect the actual denudation rate, and must be treated with caution.

4

Wpływ obciążenia podwieszonego za pomocą łączników jednostronnych na nośność płyt warstwowych

Studziński Robert, Ciesielczyk Katarzyna

Builder

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2020

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R.24, nr 3

16--19

PL

W artykule zostały omówione wyniki badań doświadczalnych przedstawiające wpływ podwieszenia obciążenia zewnętrznego do rozciąganej okładziny płyty warstwowej na nośność tych płyt. Podwieszenie zostało zrealizowane za pomocą łączników jednostronnych (ang. blind rivets). W tym celu zostały wykorzystane nity rozchylne BulbTite. W praktyce połączenie z wykorzystaniem łączników jednostronnych jest połączeniem nieprzelotowym, tj. nie wymaga stosowania podkonstrukcji i nie tworzy punktowych mostków termicznych. W badaniach posłużono się schematem belki czteropunktowo zginanej. Badanie obejmowało kilka poziomów obciążenia podwieszonego oraz jego wpływ na belki warstwowe z rdzeniem wykonanym z pianki poliuretanowej, z wełny mineralnej i styropianu. W wyniku przeprowadzonych badań określono siły niszczące, sztywności sieczne i mechanizmy zniszczenia badanych elementów warstwowych.

EN

The article discusses the results of experimental tests presented the impact of suspended loads to the tensioned sandwich panel facing on the load capacity of these panels. The blind rivets were used to suspend the loads. For this purpose, BulbTite rivets were used. In practice, this type of connection is called the blind connection i.e. it does not require the use of a secondary structure and does not create point thermal bridges. In the research, the four-point bending static scheme was used. The study included several levels of suspended loads and its effect on sandwich beams with a core made of polyurethane foam, mineral wool, and styrofoam. As a result of the tests, the ultimate loads, the secant stiffnesses, and the failure mechanisms of the tested sandwich elements were determined.

5

A performance evaluation of neuro‑fuzzy and regression methods in estimation of sediment load of selective rivers

Varvani J., Khaleghi M. R.

Acta Geophysica

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2019

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Vol. 67, no. 1

205--214

EN

Sediment rating curves (SRCs) have been recognized as the most popular method for estimating sediment in the hydrology of river sediments and in watersheds. In this regard, in order to compare and correct estimation methods of river sediment load, estimated rates of several univariate types of SRCs and a multivariate type of SRCs (MSRCs) were studied using the neuro-fuzzy and tree regression models in five selective hydrometric stations of different climatic zones of Iran and with various indexes of the accuracy (AI) and the precision (PI). The results of the data analysis showed that the mean of the AI of neuro-fuzzy and tree regression models in selective stations is 151 and 536%, respectively, which shows the low efficiency compared with SRCs. Also according to the results, the best rate of the AI of the MSRCs belongs to the Glink station with the rate of 1.12. Also, the average value of the AI of MSRCs is 1.15 which is an acceptable amount of the other considered various methods.

6

Sedimentation of load in a step-pool rock ramp fishway with biotechnical embedded elements

Tymiński T., Mumot J., Karpowicz D., Jianxin X.

Meteorology Hydrology and Water Management. Research and Operational Applications

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2017

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Vol. 5, Iss. 2

35--42

EN

such structures has resulted in a more and more conventional approach to their design. However, every single hydraulic engineering structure with a negative impact on the possibility of a watercourse in fact requires an individual approach. Often, the solutions which are the most convenient and the easiest for a designer are not in the least the best ones for migratory fish. Semi-natural fishways in particular pose a technical challenge that requires an interdisciplinary approach. Designing and constructing them correctly is not an easy task, but once it is achieved, the structure is highly effective in terms of fish migration and the formation of new habitats. Another, equally important issue related to fishways of this type is their long-term usage and proper maintenance. In this case, it is crucial to consider the transport of load through the fishway channel, and more particularly its sedimentation in zones of lower flow velocities. This paper presents a qualitative analysis of the sedimentation of load based on laboratory research carried out on a model of a vegetated fishway. This research was performed to investigate and confirm the expected locations of accumulation of load in a semi-natural vegetated step-pool rock ramp fishway. Experiments show that the sedimentation of load in fish passes may be a highly problematic issue and may require that more attention be given to the proper upkeep of fishways. It may be necessary to address the problem of fishway maintenance and deal with fishways as structures that change over time not only because of hydrological conditions, but also due to the yearly growth cycle of vegetation.