scholarly journals Grey box modelling for river control

2002 ◽  
Vol 4 (4) ◽  
pp. 265-280 ◽  
Author(s):  
Björn Sohlberg ◽  
Mats Sernfält
Keyword(s):  
Water Level ◽  
Water Flow ◽  
Energy Demand ◽  
Power Plants ◽  
Energy Requirement ◽  
River System ◽  
Measured Data ◽  
Water Levels ◽  
Unknown Parameters ◽  
Power Stations

This paper deals with modelling and identification of a river system using physical insights about the process, experience of operating the system and information about the system dynamics shown by measured data. These components together form a linear model structure in the state space form. The inputs of the prospective model are physical variables, which are not directly measured. However, the model inputs can be found by a nonlinear transformation of measured variables. Unknown parameters of the model are estimated from measured data. The modelling work focuses on the principle of parsimony, which means the best model approach is the simplest one that fit the purpose of the application. The goal of the model is to control the water level of the river, where the water flow is mainly determined by the demand for energy generation produced by the hydropower stations along the river. The energy requirement increases in the morning and decreases in the evening. These flow variations, caused by the energy demand, have to be compensated by controlling the power plants downstream, in such a way that the water level between the power stations is guaranteed. Simulation of the control system by using an adaptive model predictive controller shows that the water levels vary less and can be maintained at a higher level than during manual control. This means that more electric power can be produced with the same amount of water flow.

scholarly journals Feedback Mechanism in Bifurcating River Systems: the Effect on Water-Level Sensitivity

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1915
Author(s):  
Matthijs R.A. Gensen ◽  
Jord J. Warmink ◽  
Fredrik Huthoff ◽  
Suzanne J.M.H. Hulscher
Keyword(s):  
Water Level ◽  
Flood Risk ◽  
River System ◽  
Feedback Mechanism ◽  
Water Levels ◽  
River Systems ◽  
Water Level Variations ◽  
System Water ◽  
Discharge Distribution ◽  
Single Branch

Accurate and reliable estimates of water levels are essential to assess flood risk in river systems. In current practice, uncertainties involved and the sensitivity of water levels to these uncertainties are studied in single-branch rivers, while many rivers in deltas consist of multiple distributaries. In a bifurcating river, a feedback mechanism exists between the downstream water levels and the discharge distribution at the bifurcation. This paper aims to quantify the sensitivity of water levels to main channel roughness in a bifurcating river system. Water levels are modelled for various roughness scenarios under a wide range of discharge conditions using a one-dimensional hydraulic model. The results show that the feedback mechanism reduces the sensitivity of water levels to local changes of roughness in comparison to the single-branch river. However, in the smaller branches of the system, water-level variations induced by the changes in discharge distribution can exceed the water-level variations of the single-branch river. Therefore, water levels throughout the entire system are dominated by the conditions in the largest branch. As the feedback mechanism is important, the river system should be considered as one interconnected system in river maintenance of rivers, flood-risk analyses, and future planning of river engineering works.

scholarly journals Can GNSS-R Detect Abrupt Water Level Changes?

2020 ◽  
Vol 12 (21) ◽  
pp. 3614
Author(s):  
Sajad Tabibi ◽  
Olivier Francis
Keyword(s):  
Water Level ◽  
Vertical Velocity ◽  
Energy Demand ◽  
Water Surface ◽  
Spatial Scales ◽  
Satellite System ◽  
Water Levels ◽  
Level Gauge ◽  
Surface Reflection ◽  
Microwave Radar

Global navigation satellite system reflectometry (GNSS-R) uses signals of opportunity in a bi-static configuration of L-band microwave radar to retrieve environmental variables such as water level. The line-of-sight signal and its coherent surface reflection signal are not separate observables in geodetic GNSS-R. The temporally constructive and destructive oscillations in the recorded signal-to-noise ratio (SNR) observations can be used to retrieve water-surface levels at intermediate spatial scales that are proportional to the height of the GNSS antenna above the water surface. In this contribution, SNR observations are used to retrieve water levels at the Vianden Pumped Storage Plant (VPSP) in Luxembourg, where the water-surface level abruptly changes up to 17 m every 4-8 h to generate a peak current when the energy demand increases. The GNSS-R water level retrievals are corrected for the vertical velocity and acceleration of the water surface. The vertical velocity and acceleration corrections are important corrections that mitigate systematic errors in the estimated water level, especially for VPSP with such large water-surface changes. The root mean square error (RMSE) between the 10-min multi-GNSS water level time series and water level gauge records is 7.0 cm for a one-year period, with a 0.999 correlation coefficient. Our results demonstrate that GNSS-R can be used as a new complementary approach to study hurricanes or storm surges that cause abnormal rises of water levels.

The hydrologic regime of Mackenzie River and connection of "no-closure" lakes to distributary channels in the Mackenzie Delta, Northwest Territories

1995 ◽  
Vol 32 (7) ◽  
pp. 926-937 ◽  
Author(s):  
C. R. Burn
Keyword(s):  
Water Level ◽  
Drainage Basin ◽  
Late Summer ◽  
River System ◽  
Water Levels ◽  
Ice Thickness ◽  
Mackenzie Delta ◽  
Lake Ice ◽  
Discharge System ◽  
Mackenzie River

Mackenzie Delta lakes have been classified by the seasonal duration of their connection to Mackenzie River. "No-closure" lakes are determined on the basis of minimum summer water level. Such lakes may become disconnected from the Mackenzie in autumn or winter, as water level falls or if the sills between lakes and distributary channels are frozen through and so sealed. Water level in the central delta rises continuously after late November–early December, at first because discharge into the delta increases once the Mackenzie drainage basin has frozen over, and then as sea and channel ice thickens in the outer delta, impounding discharge. Since 1973 this seasonal increase in stage from its minimum in early December to the level on 1 April has been between 29 and 95 cm. Between 1987 and 1994, the rise in stage near Inuvik has been slightly greater than increases in lake-ice thickness (30–68 cm). Channels and lakes that are connected to the Mackenzie discharge system in December may remain connected throughout winter. A critical sill elevation for connection of such lakes to the river system is the minimum stage minus mid-December ice thickness. Recently, these elevations have been from 1.0 to 1.6 m lower than late summer water levels. Lakes with sill elevations still lower may remain connected to the Mackenzie throughout the year. In 1993-1994, only 3 of 16 "no-closure" lakes surveyed near Inuvik remained open to the Mackenzie discharge throughout winter, representing 2% of the lakes in this portion of the delta.

scholarly journals CONTRIBUTION OF LARGE RIVER SYSTEM ON WATER LEVEL DUE TO A STORM

2018 ◽  
pp. 14
Author(s):  
Abdul Al Mohit ◽  
Yoshihiko Ide ◽  
Mitsuyoshi Kodama ◽  
Masaru Yamashiro ◽  
Noriaki Hashimoto
Keyword(s):  
Water Level ◽  
Water Discharge ◽  
Interaction Model ◽  
River System ◽  
Large River ◽  
Water Levels ◽  
Sea Surface ◽  
Surface Elevation ◽  
Small Rivers ◽  
Open Boundary

Bangladesh is a riverine country in South Asia, which contain about 700 big or small rivers. The major Ganges- Brahmaputra-Meghna river system makes the coast of Bangladesh more complex and disaster vulnerable area. This river system may or may not have its impact on the height of the water level due to a storm. This area is a suitable place for research, but there is no such mention of suitable research conducted in this area. Worth mentioning works done by some scholars are Dube et al. (2004), Agnihotri et al. (2006). All the works are important to the Bay-River interaction for the storm surge simulation, but these studies were also limited by the lack of a representation of proper geometry of the river system. Some of them considered idealized river system with constant water depth and some of them did not consider the proper tidal resume. The present study is a step towards the development of an operational surge forecasting nonlinear Bay-River interaction model that incorporates the major river system with realistic geometry. Both the bay and river model equations are discretized by finite difference method with central in space and forward in time and are solved by a conditionally stable, semi-implicit manner on a staggered Arakawa C-grid system. A stable tidal condition was made by forcing the sea level with the most energetic tidal constituent, M2 , along the southern open boundary of the parent model (Bay model). The developed model was applied to foresee sea-surface elevation associated with the catastrophic cyclone 1991 and a recent cyclone MORA 2017 along the coast of Bangladesh. We also investigated how the river influences the sea surface elevation with and without fresh water discharge. We also intend to investigate the effect of river discharge with sediment. It is observed that the water levels are found to be influenced by the river system.

scholarly journals INTEGRASI SIG-INFOWORKS RIVER SIMULATION UNTUK PEMODELAN HIDRODINAMIK SUNGAI SADDANG DAN SUNGAI MATA ALLO

2020 ◽  
Vol 2 (2) ◽  
pp. 178
Author(s):  
Srie Wulandarie
Keyword(s):  
Water Level ◽  
Water Flow ◽  
Cross Section ◽  
Cross Sections ◽  
Hydrodynamic Model ◽  
Simulation Models ◽  
Water Levels ◽  
Average Increase ◽  
Hydrodynamic Models ◽  
Gis Data

AbstractThe purpose of this study was to determine the hydrodynamic model of the river so that can know the capacity of the river to accommodate the incoming water flow. The simulation models can be used in structural mitigation plan as an attempt to prevent flooding in the future. The application program used to create hydrodynamic models that Infoworks River Simulation integrated with GIS. Data cross-section of the river as much as 39 points inputted into Infoworks River Simulation program. Furthermore, the discharge input the Saddang River and the Mata Allo River to determine variations in water level at each cross-section. The results of this study showed an average increase in water level of the Saddang  and Mata Allo River in the event of the maximum discharge of 2.59 meters. Sectional increased water levels are all cross sections along the Saddang and Mata Allo River Saddang used in modeling the variation of the rise in water level of 0.8 to 5.39 meters.

scholarly journals Borehole water-level variations and implications for the subglacial hydraulics of South Cascade Glacier, Washington State, U.S.A.

1994 ◽  
Vol 40 (135) ◽  
pp. 293-304 ◽  
Author(s):  
Andrew G. Fountain
Keyword(s):  
Hydraulic Conductivity ◽  
Water Level ◽  
Water Flow ◽  
Washington State ◽  
Diurnal Variations ◽  
Water Levels ◽  
Seasonal Evolution ◽  
Borehole Water ◽  
Water Level Variations

AbstractBoreholes were drilled in South Cascade Glacier to investigate the hydraulics of subglacial water flow. Results indicate that subglacial water pressures are generally close to local ice-overburden pressures and that a subglacial debris layer probably exists. Calculations indicate that the range of hydraulic conductivity of this layer is 10−7-10−4m−1. The borehole water levels generally increased during the ablation season and may be caused by a seasonal evolution in the permeability of the debris layer. Water in the debris layer drains to a subglacial conduit, the existence of which is inferred by large diurnal variations in the water level of one borehole. These levels commonly reached the bottom of the glacier, indicating near-atmospheric pressures in the conduit.

scholarly journals DESENVOLVIMENTO E AVALIAÇÃO DE DISPOSITIVOS DE CONTROLE DE VAZÃO DERIVADA EM CANAIS DE IRRIGAÇÃO

Irriga ◽  
2007 ◽  
Vol 12 (4) ◽  
pp. 439-455 ◽  
Author(s):  
Camilo De Lelis de Andrade ◽  
Bruno Leite Teixeira Perroni ◽  
Paulo Emílio Pereira de Albuquerque ◽  
Gabriel Roberto Oliveira ◽  
Fernando Falco Pruski ◽  
...  
Keyword(s):  
Water Level ◽  
Water Flow ◽  
Flow Direction ◽  
Water Hammer ◽  
Water Levels ◽  
Irrigation Canal ◽  
Hydraulic Characteristics ◽  
Canal Water ◽  
Water Measurement

DESENVOLVIMENTO E AVALIAÇÃO DE DISPOSITIVOS DE CONTROLE DE VAZÃO DERIVADA EM CANAIS DE IRRIGAÇÃO  Camilo de Lelis Teixeira de Andrade1; Bruno Leite Teixeira Perroni2; Paulo Emílio Pereira de Albuquerque1; Gabriel Roberto Oliveira1; Fernando Falco Pruski3; Flávio Aparecido Gonçalves31Embrapa Milho e Sorgo,  Sete Lagoas, MG,  [email protected] de Engenharia, Universidade Federal de Lavras, Lavras, MG3Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, MG  1 RESUMO Em comportas que operam como orifícios retangulares, a variação do nível da água no canal afeta a vazão do orifício, o que provoca erros na estimativa do volume de água derivada. Objetivou-se com esse projeto desenvolver e avaliar dispositivos que possibilitem melhor controle da derivação de água para os lotes. A comporta tipo Módulo de Máscara XX1, comumente utilizada no perímetro,foi aferida no local e suas características hidráulicas comparadas com os dados do fabricante. Três tipos de dispositivos de derivação de água foram desenvolvidos e avaliados, todos baseados na manutenção do nível da água sobre um orifício. No protótipo 1, procura-se manter o nível da água fechando ou abrindo uma portinhola que atua contra o fluxo de entrada de água. No protótipo 2, uma portinhola atua no sentido do fluxo de água como em um carneiro hidráulico. No protótipo 3 o nível da água é mantido constante fechando ou abrindo a saída de um mangote flexível. O módulo de 10 Ls-1 da comporta XX1 apresentou erros de até 20% da vazão nominal quando submetida a níveis de água no canal acima ou abaixo do valor recomendado, conforme reportado no catálogo do fabricante. Dos três protótipos desenvolvidos, o que proporcionou melhor resultado foi de número 3. Testes com o protótipo 3 indicaram que variações máximas de 3,4% na vazão derivada foram observadas para oscilações de30 cm no nível do canal. UNITERMOS: comporta, orifício, medição de água.  ANDRADE, C. L. T.; PERRONI, B. L. T.; ALBUQUERQUE, P. E. P.; PRUSKI, F. F.; OLIVEIRA, G. R. DEVELOPMENT AND EVALUATION OF IRRIGATION CANAL DEVICES FOR WATER TURNOUT CONTROL  2 ABSTRACT In water turnouts that operate by gravity as a rectangular gate, variation on the canal water level affects the estimated discharge to plots. This work objective was to develop and evaluate devices for a better water turnout to plots. An existing commercial gate model XX1, was evaluated in situ and its hydraulic characteristics compared to manufacturer´s data. Three types of water turnout devices were developed and evaluated, all of them based on the principle of maintaining a constant water level over an orifice. In prototype 1, water level is maintained by opening or closing a gate against the inlet water flow. In prototype 2, the gate is positioned in the flow direction, like in a water hammer. In prototype 3, water level is kept by opening or closing a flat hose outlet. The 10 Ls-1 module of a XX1 gate causes errors of up to 20% of the nominal discharge when operated under water levels above or below the recommended value by the manufacturer. Considering three developed prototypes, a better water turnout control was obtained with prototype 3. Tests with prototype 3 indicated that a maximum of 3.4% of the derived discharged was observed for fluctuations of up to30 cm on the canal level.  KEYWORDS: gate, orifice, water measurement.

scholarly journals Modeling of water flow in multi-channel river system in the Narew National Park

2017 ◽  
Vol 49 (3) ◽  
pp. 167-177 ◽  
Author(s):  
Paweł Marcinkowski ◽  
Adam Kiczko ◽  
Tomasz Okruszko
Keyword(s):  
Water Flow ◽  
National Park ◽  
Industrial Development ◽  
Optimization Procedure ◽  
Field Measurements ◽  
River System ◽  
Hydraulic Modeling ◽  
Water Levels ◽  
Channel System ◽  
Channel Systems

Abstract Modeling of water flow in multi-channel river system in the Narew National Park. Anastomosing rivers constitute a rare example of multi-channel systems, which used to be very common before the agricultural and industrial development. Presently few of them remain worldwide and the only example in Poland is the Upper River Narew within Narew National Park. Although hydraulic modeling using one-dimensional models is commonly used to describe water flow in rivers, for multi-channel rivers problem is more complicated. For this type of rivers it is expected that the feedback between process of plants growth (expressed by Manning’s coefficient) and distribution of flow in anabranches is high. However, assignment procedure on roughness coefficients in splitting and rejoining channels is laborious and difficult. Therefore, for efficient water flow modeling in multi-channel systems a stand-alone hydraulic model equipped with automatic optimization procedure was developed. Optimization and validation stages, based on field measurements data of discharge and water levels, indicated that the model accurately simulates water flow in multi-channel system.

scholarly journals Identification of Hydrological Droughts in Lithuanian Rivers

2021 ◽  
pp. 87-99
Author(s):  
Gintarė Kugytė ◽  
Gintaras Valiuškevičius
Keyword(s):  
Water Level ◽  
Water Flow ◽  
Flow Rate ◽  
Hydrological Drought ◽  
Water Levels ◽  
True Value ◽  
Level Data ◽  
Water Level Data ◽  
Lithuanian Rivers ◽  
Hydrological Droughts

Globally, hydrological droughts are most commonly identified based on various indices calculated from water flow values. However, the water flow rate is calculated from a flow rate curve that needs to be updated constantly, so it takes a long time to resolve its true value. For this reason, the possibility of identifying a hydrological drought on the basis of hourly and prompt treated water levels seems much more attractive. 8 water gauging stations (WGS) operating along 7 important rivers and covering the hydrological areas of visas in the Lithuanian region were selected for the study. In this study, a modified SPI function of the R programming language SPEI package (traditionally used to calculate the standardized precipitation index, SPI) was applied for the streamflow drought index (SDI) calculations. Given how it was applied to the SDI calculation, just like the baseline data, this was the ten-day mean water flow and then the water level. The suitability of water level data for SDI calculations was assessed by analyzing the relationships between SWLI (Standartized Water Level Index) calculated from water level data and SDI calculated from water flow information. SWLI and SDI in all 8 WGS are closely interconnected. It was found that the possibility of recurrence of droughts of different severity identified by both methods is significantly influenced by the profile of the river bed in a specific section. In areas where riverbanks have steeper slopes, the SWLI and SDI similarly describes the water situation and the recurrence of droughts. It is believed that a modified SDI methodology (SWLI), which is based on water level data, may become a good alternative in our country for identifying hydrological droughts. Keywords: Lithuanian rivers, hydrological drought, identification of droughts, water level, SDI, SWLI.

scholarly journals The Functioning of Drainage Canal Near Barrage “Brzeg Dolny” on the Odra River in 1971–2009

2014 ◽  
Vol 22 (1) ◽  
pp. 61-66
Author(s):  
Beata Olszewska ◽  
Leszek Pływaczyk ◽  
Wojciech Łyczko
Keyword(s):  
Water Level ◽  
Water Flow ◽  
Cross Section ◽  
Water Levels ◽  
Drainage Canal ◽  
Water Conditions ◽  
Odra River ◽  
Flow Intensity ◽  
The Difference ◽  
Similar Location

Abstract The paper analyses the amount of water flowing into the drainage canal in comparison to the levels of the Odra waters in the Brzeg Dolny – Wały cross section (upper water in the barrage). The results of the measurement of the flow intensity in the canal in 1971–2009 provided the basis for the evaluation. The analysis led to the conclusion that with the same ordinate of damming in the barrage the average yearly flow in the canal in the Warzyna section decreased from 196 m3s–1 to about 80 dm3s–1 as the Odra's riverbed and the area between the embankments became tighter. The flow into the canal changes in time and depends on the difference between water levels in the Odra and in the canal. The paper presents the dynamics of changes in the water flow into the canal in relation to 1 m of difference between the level of water in the Odra and the drainage canal. It was shown that in a similar location, ground and water conditions as well as similar damming levels, the value of the drained water can be estimated to be about 35–40 dm3s–1km–1 for 1 meter of difference of the water level in the river and the canal.

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