Temat: sediment load - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: The changing sediment loads of the world’s rivers
Zmieniające się ładunki rumowiska rzek świata
Autorzy:: Walling, D.E.
Tematy:: world
river
trend
suspended sediment load
anthropogenic impact
reservoir trapping
buffering effect
sediment transfer
sediment load
soil conservation
sediment control programme
river basin
hydrology; Pokaż więcej
Wydawca:: Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Powiązania:: https://bibliotekanauki.pl/articles/81877.pdf Link otwiera się w nowym oknie
Opis:: This contribution reviews available evidence of recent changes in the sediment loads of the world’s rivers and identifi es the key drivers of such change. Land clearance, land use change and other facets of catchment disturbance, soil conservation and sediment control programmes and dam construction are shown to have resulted in signifi cant recent changes in the sediment loads of many world rivers. Some rivers have been characterized by signifi cant increases in sediment load, whereas others show signifi cant decreases. Interpretation of the resulting trends requires consideration of aggregation and storage and buffering effects within a river basin, such that the downstream response of a river may not clearly refl ect the changes occurring in the upstream basin and in the loads of tributary rivers.
W artykule przedstawiono dostępne informacje wskazujące na aktualne zmiany w ładunku rumowiska rzek świata oraz wskazano na podstawowe czynniki powodujące te zmiany. Wycinanie lasów, zmiany użytkowania terenu, a także inne działania związane zarówno z degradacją, jak i ochroną gruntów, oraz programy redukcji erozji gleb i budowa zapór, znacząco wpływają na ładunki rumowiska wielu rzek świata. Niektóre rzeki charakteryzują się znaczącym wzrostem ilości rumowiska, podczas gdy inne wskazują na znaczący ich spadek. Interpretacja wynikowych trendów wymaga rozważenia czynników mających cechy oddziaływania zagregowanego, opóźnionego i buforującego z całej zlewni, jako że informacje z ujściowych odcinków rzek nie w pełni odzwierciedlają zmiany zachodzące w górnej części rzeki i w jej dopływach.
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Sediment transport and water quality in Machovo Lake [Czech Republic]
Transport sedymentu i jakosc wody w Jeziorze Mahovo [Republika Czeska]
Autorzy:: Dostal, T
Krasa, J.
Vrana, K.
Dockal, M.
Koudelka, P.
David, V.
Vokurka, A.
Tematy:: sediment transport
water quality
sediment load
phosphorus
soil erosion
pollution source
Lake Machovo
Czech Republic; Pokaż więcej
Wydawca:: Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Powiązania:: https://bibliotekanauki.pl/articles/81797.pdf Link otwiera się w nowym oknie
Opis:: Máchovo Lake is a historical reservoir founded by Czech King Charles IV. in 14th century. Located in northern part of central Bohemia it has been widely used for recreation purposes for many decades (or even centuries). Its catchments (ca 100 sq km) consist of intensively used agricultural land (ca 25% of area) and of large forested area under nature protection. Several other lakes (ponds) are chained on the two reservoir’s inlets. Irrespective of its great recreation potential Máchovo Lake is one of the Bohemian lakes known for its problems with eutrophication and water quality. The project was set up to point out sources of nutrients and to search for proper solutions. Sediment loads in every lake within the catchments were measured and sampled in order to quantify the nutrients and other pollution. Point and non point sources of phosphorus and other nutrients were searched. Sediment transport within catchments was modelled using WaTEM/SEDEM model. Interestingly, the water quality in the particular ponds varies signifi cantly even though each one of several hundred years old ponds is heavily silted. Soil erosion protection measures within catchments were proposed altogether with flood protection measures in the stream valleys and waste water treatment facilities in surrounding villages. Setting up water quality sampling devices in selected stream profi les was tested and designed. The continual proper management should lead to water quality improvement.
Położone w północnych Czechach Jezioro Máchovo jest zbiornikiem dla celów rekreacyjnych zbudowanym w XIV wieku przez czeskiego króla Karola IV. Jego zlewnia o powierzchni 100 km2 jest w 25% intensywnie użytkowana rolniczo, a pozostały zalesiony obszar podlega ochronie. Jakość wody i eutrofizacja wód jeziora oraz towarzyszących mu silnie zamulonych stawów stanowi poważny problem ekologiczny. Celem badań było określenie punktowych i powierzchniowych źródeł dostawy składników pokarmowych i rozwiązanie tego problemu. Do oceny dostawy sedymentu zastosowano WaTEM/SEDEM model. Została zaproponowana przeciwpowodziowa i przeciwerozyjna ochrona gleby przed erozją oraz gospodarka ściekami w obrębie zlewni. Działania te powinny doprowadzić do polepszenia jakości wody.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A comparative study of artificial intelligence models for predicting monthly river suspended sediment load
Autorzy:: Rezaei, Khalil
Vadiati, Meysam
Tematy:: artificial intelligence
data-driven methods
Karaj dam
suspended sediment load
the Karaj River; Pokaż więcej
Wydawca:: Instytut Technologiczno-Przyrodniczy
Powiązania:: https://bibliotekanauki.pl/articles/292569.pdf Link otwiera się w nowym oknie
Opis:: When high precision modelling is required, for example, with the estimation of suspended sediment load (SSL), data-driven models are preferred over physically-based numerical models for their real-time, short-horizon prediction ability. The investigation of SSL, as an important index in engineering practices assessment, like design and operation of the hydraulic structures not only shows the hydrological behaviour of the river, but also illustrates the valuable information about the water quality deterioration, surface-groundwater interaction and land-use changes of the watershed. The following data-driven methods were compared in order to predict SSL at the Seyra gauging station on the Karaj River in Iran: Fuzzy logic (FL), two adaptive neuro-fuzzy inference systems (i.e., ANFIS-GP and ANFIS-FCM models), an artificial neural network (ANN), and least squares support vector machine (LSSVM). Monthly average river flow and SSL data for 50 years were obtained from the Tehran Regional Water Authority (TRWA). The data was first divided into training, validation and test sets and the SSL was then predicted using the ANN, FL, ANFIS, and LSSVM models. The reliability of the applied models was evaluated by the correlation coefficient (R), root mean square error (RMSE), and mean absolute error (MAE). The results showed that the ANFIS models outperformed the ANN, FL, and LSSVM models for predicting SSL using the given input and output data. Overall, the performances of the artificial intelligence models used in the present study were satisfactory in predicting the non-linear behaviour of the SSL.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Some aspects of the sediment transport during the 2005 floods in Switzerland
O pewnych aspektach transportu rumowiska w czasie powodzi z 2005 roku w Szwajcarii
Autorzy:: Jaeggi, M.
Tematy:: sediment transport
Switzerland
flood
mountain stream
bed morphology
numerical simulation
heavy sediment load
Lutschine River
agricultural land
sediment deposition; Pokaż więcej
Wydawca:: Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Powiązania:: https://bibliotekanauki.pl/articles/81617.pdf Link otwiera się w nowym oknie
Opis:: In August 2005 a very severe fl ood hit large parts of Switzerland. Strong erosion occurred in several steep, apparently stable reaches of mountain streams, what produced heavy sediment loads. Where these were deposited, they caused channel avulsion or channel obstruction with subsequent inundations. Numerical simulation proved to be a useful tool to analyse the processes and to plan mitigation measures. In particular, it could be shown that the fl ooding of the Schächen river had its origin in a lateral overspilling in the fi nal reach of this tributary and a subsequent blocking of the flow section. The load eroded in the upstream reach, which is normally stable because of the presence of big boulders, was suffi cient to feed this process. A detention basin with an open slit dam located upstream did only retain a limited amount of sediment temporarily. During fl ow recession, most of these deposits were eroded. This was in agreement with the original concept, but was not very useful in this fl ood situation. On the Lütschine river, a similar massive erosion in a steep reach caused widespread deposition in an area where such phenomena did probably not occur over the last 150 years. For such rare events, it is reasonable to plan a deposition area where limited agricultural land use is allowed. Sediment deposition occurs only in function of slope reduction and channel widening; no special structures are planned.
Bardzo groźna powódź nawiedziła dużą część Szwajcarii w sierpniu 2005 roku. Efektem była bardzo silna erozja na kilku górskich, dotychczas stabilnych, odcinkach rzek, co wywołało transport olbrzymich ilości rumowiska rzecznego. W miejscach odkładania się rumowiska następowały ograniczenia przepustowości i przetasowania koryta oraz wywołane nimi podpiętrzenia. Symulacja komputerowa okazała się być użytecznym narzędziem w analizie procesu i w planowaniu usuwania skutków powodzi.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Comparative study for deriving stagedischarge – sediment concentration relationships using soft computing techniques
Autorzy:: Sihag, P.
Sadikhani, M. R.
Vambol, V.
Vambol, S.
Prabhakar, A. K.
Sharma, N.
Tematy:: sediment load concentration
Baitarani river
M5P
random forest
ładunek osadu
stężenie
rzeka Baitarani
las losowy; Pokaż więcej
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:: https://bibliotekanauki.pl/articles/1818806.pdf Link otwiera się w nowym oknie
Opis:: Purpose: Knowledge of sediment load carried by any river is essential for designing and planning of hydro power and irrigation projects. So the aim of this study is to develop and evaluating the best soft-computing-based model with M5P and Random Forest regressionbased techniques for computation of sediment using datasets of daily discharge, daily gauge and sediment load at the Champua gauging site of the Upper Baitarani river basin of India. Design/methodology/approach: Last few decades, the soft computing techniques based models have been successfully used in water resources modelling and estimation. In this study, the potential of tree based models are examined by developing and comparing sediment load prediction models, based on M5P tree and Random forest regression (RF). Several M5P and RF based models have been applied to a gauging site of the Baitarani River at Odisha, India. To evaluate the performance of the selected M5P and RF-based models, three most popular statistical parameters are selected such as coefficient of correlation, root mean square error and mean absolute error. Findings: A comparison of the results suggested that RF-based model could be applied successfully for the prediction of sediment load concentration with a relatively higher magnitude of prediction accuracy. In RF-based models Qt, Q(t-1), Q(t-2), S(t-1), S(t-2), Ht and H(t-1) combination based M10 model work superior than other combination based models. Another major outcome of this investigation is Qt, Q(t-1) and S(t-1) based model M4 works better than other input combination based models using M5P technique. The optimum input combination is Qt, Q(t-1) and S(t-1) for the prediction of sediment load concentration of the Baitarani River at Odisha, India. Research limitations/implications: The developed models were tested for Baitarani River at Odisha, India.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Forecasting suspended sediment load using regularized neural network: Case study of the Isser River (Algeria)
Prognozowanie ładunku zawiesiny z zastosowaniem regularyzowanej sieci neuronowej: przykład rzeki Isser w Algierii
Autorzy:: Tachi, S. E.
Ouerdachi, L.
Remaoun, M.
Derdous, O.
Boutaghane, H.
Tematy:: artificial neural network
Beni Amran reservoir
early stopping
Isser River
sediment load
ładunek zawiesiny
rzeka Isser
sztuczne sieci neuronowe
technika Early Stopping
zbiornik Beni Amran; Pokaż więcej
Wydawca:: Instytut Technologiczno-Przyrodniczy
Powiązania:: https://bibliotekanauki.pl/articles/292434.pdf Link otwiera się w nowym oknie
Opis:: In the management of water resources in different hydro-systems it is important to evaluate and predict the sediment load in rivers. It is difficult to obtain an effective and fast estimation of sediment load by artificial neural network without avoiding over-fitting of the training data. The present paper comprises the comparison of a multi-layer perception network once with non-regularized network and the other with regularized network using the Early Stopping technique to estimate and forecast suspended sediment load in the Isser River, upstream of Beni Amran reservoir, northern Algeria. The study was carried out on daily sediment discharge and water discharge data of 30 years (1971–2001). The results of the Back Propagation based models were evaluated in terms of the coefficient of determination (R²) and the root mean square error (RMSE). Results of the comparison indicate that the regularizing ANN using the Early Stopping technique to avoid over-fitting performs better than non-regularized networks, and show that the overtraining in the back propagation occurs because of the complexity of the data introduced to the network.
Ocena i przewidywanie ładunku zawiesiny w rzekach są istotne w zarządzaniu zasobami wodnymi w różnych hydrosystemach. Trudno jest uzyskać efektywne i szybkie oszacowanie ładunku zawiesiny za pomocą sztucznych sieci neuronowych bez uniknięcia przepełnienia danymi. W niniejszej pracy porównano wyniki zastosowania wielowarstwowej sieci w dwóch wariantach – sieci nieregularyzowanej i sieci regularyzowanej z użyciem techniki Early Stopping do oceny i prognozowanie ładunku zawiesiny w rzece Isser powyżej zbiornika Beni Amran w północnej Algierii. Badania bazowały na notowaniach dobowego odpływu zawiesiny i danych dotyczących odpływu wody w ciągu 30 lat (1971–2001). Wyniki modeli opartych na metodzie wstecznej propagacji oceniono za pomocą współczynnika determinacji (R²) i pierwiastka ze średniego błędu kwadratowego. Porównanie wyników dowodzi, że sieć neuronowa regularyzowana przy pomocy techniki Early Stopping celem uniknięcia przeładowania sprawdza się lepiej niż sieć nieregularyzowana. Wyniki wskazują, że przeładowanie wstecznej propagacji ma miejsce z powodu złożoności danych wprowadzonych do sieci.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Ecological risk assessment of heavy metals in soil developed on coastal marine sediment along coastal area in Anantigha, Calabar, Nigeria
Autorzy:: Aki, E. E.
Isong, I. A.
Tematy:: ecological risk factor
geo-accumulation Index
heavy metal
pollution load index marine sediment; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1076124.pdf Link otwiera się w nowym oknie
Opis:: Coastal areas in Anantigha are utilized as dumpsite for industrial and domestic wastes including effluent from local industries and inhabitants of the area despite their usage for crop cultivation. Thus, the present study was designed to assess the concentration, pollution load and ecological risk of heavy metal in Anantigha coastal area. Standard pollution indices such as contamination factor (Cf), degree of contamination, pollution load index (PLI), enrichment factor (EF), geo-accumulation index (Igeo) and ecological risk index were deployed to assess the level of heavy metals contamination in the area. The results showed that the sediment was acidic under dried conditions and low in conductivity. The mean concentration levels of all the heavy metals were lower than their mean background values except for Al. The orders of dominance for concentration of heavy metals were: Al>Fe>Mn>Cu>Zn (Station 1) and Al>Fe>Mn>Zn>Cu (Stations 2, 3 and 4). Analyzed data showed that the sediments in the area are contaminated with Al with Igeo result showing station 2 and 4 been moderately to heavily contaminated with Al while station 4 was heavily contaminated with aluminium. Station 1 had low degree of contamination, whereas station 2 and 4 had moderate degree of contamination, and station 3 showed considerable degree of contamination. The PLI result indicates unpolluted condition and the area were not enriched by the studied heavy metals as shown by EF values. Hence, the sediment in Anantigha coastal marine area was classified as having low ecological risk factor. However, the levels of these metals are not static; there is tendency for increase as a result of increased human input and activities. Hence, there is a need for regular soil testing.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Features of the Sediment Runoff Regime Downstream the Ile River
Autorzy:: Duskayev, Kassym
Myrzakhmetov, Akhan
Zhanabayeva, Zhanar
Klein, Igor
Tematy:: sediment transport
sediment runoff characteristic
suspended load
bed load
granulometric composition; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/125037.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Sedimentological distinction in glacigenic sediments between load casts induced by periglacial processes from those induced by seismic shocks
Autorzy:: Van Loon, Antonius Johannes
Pisarska-Jamroży, Małgorzata
Woronko, Barbara
Tematy:: load casts
pseudonodules
soft-sediment deformation structures
cryoturbation
seismites; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2060257.pdf Link otwiera się w nowym oknie
Opis:: Loading processes and the resulting load structures induced by processes related to periglacial conditions are compared to those induced by seismic shocks. The load structures themselves are relatively easily recognizable but the responsible trigger mechanism is, though depending on the geological context, commonly difficult to establish. Load structures like load casts, pseudonodules, ball-and-pillow structures and flame structures are commonly ascribed to instable density gradients within sediments and to differential loading, but their formation always requires liquefaction. In glacigenic sediments, deformation structures have most commonly been ascribed to periglacial processes (as a type of cryoturbations), but it becomes ever more clear that glacigenic sediments can, particularly during ice-front fluctuations, be affected by faulting-related earthquakes (due to glacio-isostatic adjustment), and the thus triggered seismic shocks may result in deformations, including - most commonly - load structures. We inventory the evidence that may help to distinguish, on the basis of textural and structural features, load structures with a seismic origin from those that result from periglacial processes, taking into account that truly diagnostic criteria do not exist.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Sedimentation of load in a step-pool rock ramp fishway with biotechnical embedded elements
Autorzy:: Tymiński, T.
Mumot, J.
Karpowicz, D.
Jianxin, X.
Tematy:: fishway
biotechnical embedded elements
suspended load
transport of sediment; Pokaż więcej
Wydawca:: Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/108516.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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