Upstream Water Level Research Articles

Determining the Flow Resistance of Racks and the Resulting Flow Dynamics in the Channel by Using the Saint-Venant Equations

Racks retain debris in wastewater treatment plants and shield sensitive machinery in numerous engineering applications. In open-channel flows, racks impound the upstream water level by posing local obstacles in the flow. Based on experimental investigations, empirical approaches usually predict the flow resistance by relying on Bernoulli’s energy principle. Since this principle does not correctly consider downstream conditions such as submerged flows, we present a more accurate workflow to determine the flow resistance based on the Saint-Venant equations. We will demonstrate how the loss coefficient and the hydraulic head loss are determined more reliably without adding complexity to the engineering realisation. In contrast to relying solely on two cross-sections with Bernoulli’s energy principle, applying the Saint-Venant equations enables determining the flow depth profile and the flow velocity in the entire channel. This workflow additionally allows predicting the channel’s hydraulic capacity and freeboard in arbitrary applications.

Water Level Prediction Model Applying a Long Short-Term Memory (LSTM)–Gated Recurrent Unit (GRU) Method for Flood Prediction

The damage caused by floods is increasing worldwide, and if floods can be predicted, the economic and human losses from floods can be reduced. A key parameter of flooding is water level data, and this paper proposes a water level prediction model using long short-term memory (LSTM) and a gated recurrent unit (GRU). As variables used as input data, meteorological data, including upstream and downstream water level, temperature, humidity, and precipitation, were used. The best results were obtained when the LSTM–GRU-based model and the Automated Synoptic Observing System (ASOS) meteorological data were included in the input data when experiments were performed with various model structures and different input data formats. As a result of the experiment, the mean squared error (MSE) value was 3.92, the Nash–Sutcliffe coefficient of efficiency (NSE) value was 0.942, and the mean absolute error (MAE) value was 2.22, the highest result in all cases. In addition, the test data included the historical maximum water level of 3552.38 cm in the study area, and the maximum water level error was also recorded as 55.49, the lowest result. Through this paper, it was possible to confirm the performance difference according to the composition of the input data and the time series prediction model. In a future study, we plan to implement a flood risk management system that can use the predicted water level to determine the risk of flooding, and evacuate in advance.

Development of PLC and SCADA-Based Automation Systems for Control of Irrigation Dam Gates

The control and monitoring system presented is based on Supervisory Control and Data Acquisition concept. It provides GUI service for operators and data visualization capability to display data trends using an appropriate DBMS (database management system). The SCADA system also incorporates Alarm and PAS (public address system) for operational and functional safety. The remote control of the gates is carried out through PC based SCADA software from a centrally located control room. The SCADA system consists of a Master Terminal Unit (MTU) located in the control room, MicroLogix 1400 PLC-based Remote Terminal Units (RTUs) located in the control panels of dam gates, and ultrasonic sensors equipped with MODBUS/ RTU interface to measure upstream and downstream water levels. RTUs-MTU communication is realized using a dedicated LAN. This paper presents the system design along with hardware layout and software programs for both, RTUs and MTU. The program for PLC has been written in ladder logic using RSLogix 500, a powerful development software from Rockwell Automation.

A two-layer control architecture for operational management and hydroelectricity production maximization in inland waterways using model predictive control

This work presents the design of a combined control and state estimation approach to simultaneously maintain optimal water levels and maximize hydroelectricity generation in inland waterways using gates and ON/OFF pumps. The latter objective can be achieved by installing turbines within canal locks, which harness the energy generated during lock filling and draining operations. Hence, the two objectives are antagonistic in nature, as energy generation maximization results from optimizing the number of lock operations, which in turn causes unbalanced upstream and downstream water levels. To overcome this problem, a two-layer control architecture is proposed. The upper layer receives external information regarding the current tidal period, and determines control actions that maintain optimal navigation conditions and maximize energy production using model predictive control (MPC) and moving horizon estimation (MHE). This information is provided to the lower layer, in which a scheduling problem is solved to determine the activation instants of the pumps that minimize the error with respect to the optimal pumping references. The strategy is applied to a realistic case study, using a section of the inland waterways in northern France, which allows to showcase its efficacy.

Research on influence of the unilateral surge chamber about the main surge chamber

The hydropower station diversion tunnel is long. When the upstream water level is low, the minimum upsurge of the surge chamber is likely to be lower than its bottom, which may cause dangerous conditions such as liquid column separation. In order to solve the problem, an engineering measure that an unilateral surge chamber is set up near the main surge chamber was proposed in this paper. Its effect was analyzed. Based on establishment of mathematical model, the transition process of hydropower station water conveyance system was numerically simulated. The influence of different diameter, injection flow rate and position on minimum upsurge was researched. The results showed that increasing diameter and position of unilateral surge chamber has little effect on rising of minimum upsurge, but increasing injection flow rate of unilateral surge chamber has great effect on it. The study provides references for engineering design.

Study on the transformation of surface water and groundwater in the water source area of Baima-Jili River Basin

Abstract The exploitation of groundwater in a riverside water source area is a complex process of conversion of surface water and groundwater. At present, the numerical model for simulating the exploitation of riverside water sources often generalizes rivers to the specified head boundary (CHD) or the river boundary (RIV). The CHD generalizes the river into an infinite supply of water, which is obviously unrealistic for seasonal rivers, and the RIV does not have the function of the river confluence. The above two methods directly affect the calculation accuracy of river water and groundwater conversion amount due to inherent loopholes, so the simulation of the riverside exploitation amount has some errors. This study uses the Streamflow-Routing (SFR) model to generalize the Baima-Jili River. By calculating the stream flow, the upstream, and downstream water levels of the rainy, normal, and dry seasons through the permeability parameter between river water and groundwater (parameters such as riverbed permeability coefficient, riverbed thickness, water depth, and cross-sectional shape), a coupling model of surface water and groundwater is established. In order to verify the accuracy of the SFR model simulation, the CHD and RIV conditions are used to generalize the river, and the simulation results of the three models are compared. The results show that the available groundwater exploitation simulated by the SFR model, the CHD, and the RIV boundary conditions are 27.798 × 106, 35.11 × 106, and 25.76 ×106 m3/a, respectively. The known available groundwater exploitation in the study area is 2,870 × 104 m3/a. Therefore, the SFR simulation results are more realistic, indicating that the SFR model is more suitable for coupling simulation of the surface water and groundwater interaction in riverside water sources of a seasonal river.

Numerical study of the weir angle on the flow pattern and scour around the submerged weirs

In this study, the flow pattern and scouring around the submerged sharp edge weir, with different slope angles, have been numerically simulated using the Flow-3D model. After validating the results of the numerical model in simulating the flow pattern and scour around the weir with a 90∘ angle, the effect of the weir angles relative to the upstream and downstream on the flow and scour field had been investigated. The results showed upstream and downstream of the weir, vortex flows were formed and by taking an angle of 90∘, the vortex flows were weakened. In addition, the downstream slope of the weir had little effect on the upstream water level and most changes occurred in the downstream flow depth with a 90∘ angle. The downstream scour depth was independent of the upstream slope angle and the upstream scour depth was independent of the downstream slope. When the upstream angle became closer to the horizon, scouring was reduced in this area. The depth of scour downstream was greater than the depth of scouring upstream. Angles of 50∘, 70∘, 110∘ and 130∘ had slight changes in the depth of the downstream scour, but compared to the angle of 90∘, the depth of the downstream scour for these angles decreased significantly.

FLOW ENGINEERING TO REMEDIATE CONTAMINATED WATER QUALITY DUE TO DOMESTIC WASTE DISPOSAL IN BELIK RIVER, YOGYAKARTA

The Belik River Basin is located in an urban area and is affected by rapid population growth. Belik River flows from north of the UGM campus (Karangwuni Subvillage in Caturtunggal, Depok, Sleman) to Umbulharjo District then feeds into Gajah wong River before emptying into Opak River. This study sought to examine the effects of flow engineering on the quality of domestic waste-contaminated waters. The flow engineering is in the form of a small weir or pile of stones aiming to elevate the upstream water level and create a free fall or plunge that aerates the overflowing water. The water was sampled from four river segments twice: upstream and downstream of the designed weir. Water sampling from one element to the next factored in water travel time and settlement density in the surroundings with the assumption that these factors would produce different concentrations of domestic waste. The water quality parameters tested were D.O., BOD, COD, phosphate, nitrate, ammonia, and iron. The results showed that the flow engineering improved water quality in the four segments differently, as evident from some of the decreased or increased parameter values after the plunge. These different effects are influenced by the number of sources of domestic waste pollutants and the dominant land use in each segment. Keywords: Belik River, Small Weir, Aeration

Study on water level correlation of key nodes in the north line of East Zhejiang Water Diversion Project

Eastern Zhejiang is an important area for the economic development of Zhejiang Province. However, water resources in eastern Zhejiang are relatively poor. After the completion of the north line of East Zhejiang Water Diversion Project, the catchment and drainage connecting rivers of all counties and cities have been dredged, the flood control and drainage capacity of all counties and cities has been improved, the river channels along the line have also been comprehensively renovated, the river network water environment of Shangyu City, Yuyao City and Cixi City along the water diversion line has been significantly improved, and the environmental quality of the area around Hangzhou Bay on the South Bank of Qiantang River has been improved. In order to find out the correlation between the water levels of key nodes of the project and provide more targeted guidance for future scheduling, this paper uses the partial least square method to calculate the relationship between the water levels of each node. It is found that there is a significant correlation between the upper water level of Sanxing sluice and the water level under Xinsan sluice and Mashan sluice, and there is a certain correlation with the upper water level of xinsanjiang sluice and Mashan sluice. The correlation between the upstream water level of Xiaoshan hydroproject and the water levels under xinsanjiang sluice, Heshan sluice and Mashan sluice is obvious; There is the most significant linear correlation between the water level of Hengjiang River in xisantang and the water level of Lingshan, Lingshan, Qitang, Sitou and Sitou. The correlation between the water level of Yangxun bridge, Puqian gate and Qitang gate is also significant, and the correlation of other water level stations is poor. In addition, there is a great correlation between the water level of Yangxun bridge and the downstream water level. Attention should be paid to observing the water level of Yangxun bridge during the dispatching process.

Prediction of floodwater impacts on vehicle blockages at bridges using artificial neural network

During extreme flood events, various debris like floating vehicles can block the bridges in urban rivers and floodplains. Blockage of vehicles can influence the floodwater hydrodynamics and potentially on the flood risk implications. Such obstructions often raise upstream water levels with back water effects, causing more water to be redirected into nearby metropolitan areas. This study attempts at evaluating artificial neural network (ANN) model in predicting the variations in floodwater depths and velocities along the channel centreline based on the changes in flowrate and distances from the inlet. The floodwater depth and velocity variations were obtained for three different types of bridges at specified sites along the channel centreline with three incoming discharges. A multilayer feedforward neural network (FFNN) model was used to investigate the effects of discharge (Q) and distance, on depth variation rate (D) or velocity (V). Additionally, a comparison study was done between 2 input 1 output and 2 input 2 output i.e. single output (depth variation rate (D) or velocity (V) versus multi-output depth variation rate (D) and velocity (V) for all the three models of bridges that are blocked by vehicles. The study has applied 12 training algorithms (TA) in the ANN modelling to optimize the TA that is most suitable for the dataset of three different bridges. The optimization is based on the performance criterion namely regression (R), mean squared error (MSE), mean absolute error (MAE), mean absolute percentage (MAPE), accuracy and coefficient of determinant (R2). Bayesian regularization backpropagation (BR) training algorithm gives a highest accuracy when compared in all three bridges. The scenario 2 input 2 output gave greatest accuracy results compared to 2 input 1 output. The findings showed a reliable estimation of significant impacts on the flow propagations and the hydrodynamic processes along rivers and floodplains. This study can help the decision makers in effective river and floodplain management practices.

Probability assessment of the Kyiv reservoir overflow

Reservoirs are an integral part of the world’s hydraulic infrastructure and form the basis of modern water management in most countries including Ukraine. However, reservoirs are also sources of an essential danger to the environment, infrastructure, and population. The potential danger and risks to the population living near reservoirs especially downstream may be no less than to people living near nuclear facilities or chemical plants, with which experts and the public usually associate problems of technogenic safety. Moreover, statistics show that about a third of all accidents on dams and levees occurred due to overflow of reservoirs when upstream water levels exceeded allowable values.There are 1103 reservoirs in Ukraine with a total water volume of about 55,500 million m3. The Kyiv reservoir is the third one by volume and water surface area in the country. In addition, the reservoir is created by one of the longest dams in the world; the total dam length of the reservoir reaches 70 km.Admittedly, the overflow of a reservoir can be caused by an extreme flood with inflow parameters exceeding the capacity of hydraulic structures. The challenge is that the capacity of water passage structures may be insufficient both due to the inaccuracy of the hydrological forecast and because of faults, poor functioning, or failures of the hydraulic structures during a design flood. In particular, long-term forecasts of floodwater discharges maxima of the inflow into the Kyiv reservoir based on using various probability distribution functions show the essential divergence of the obtained results. As well, as practice shows, the unavailability of some water passage tracts of the reservoir can reach several months in a year. Sometimes repair works were performed even during floods.The aim of the study consisted of probabilistic forecasting the emergency situation on the Kyiv reservoir as a result of its uncontrolled overflow through the possible inaccuracy of the hydrological forecast concerning an actual water inflow into the reservoir and due to failures of water passage hydraulic structures during floods. To achieve the study aim the following tasks were solved: (1) there was proposed a method of hydrological forecasting, which allows taking into account results of long-term forecasts of floodwater discharges maxima based on using various probability distribution functions and fuzzy modelling; (2) there was performed hydrological forecasting of floodwater discharges maxima of the Dnieper affecting the condition of the Kyiv reservoir based on the actual data collected the Vyshgorod water level gauge; (3) there was assessed the probability of the Kyiv reservoir overflow taking into account the occurrence possibility of a shortage of the capacity of water passage structures with using the failure and fault tree method. Totally, six incompatible hypothetical emergency situations at the Kyiv reservoir were considered. The calculations showed the total probability of the Kyiv reservoir overflow equal to 3.84*10–4 (year–1), which is acceptable to guarantee the hydrological safety of infrastructure and the population.

Fish Upstream Passage through Gauging Stations: Experiences with Iberian Barbel in Flat-V Weirs

The monitoring of river discharge is vital for the correct management of water resources. Flat-V gauging weirs are facilities used worldwide for measuring discharge. These structures consist of a small weir with a triangular cross-section and a flat “V”-shaped notch. Their extensive use is a consequence of their utility in the measurement of both low and high flow conditions. However, depending on their size, local morphology and river discharge can act as full or partial hydraulic barriers to fish migration. To address this concern, the present work studies fish passage performance over flat-V weirs considering their hydraulic performance. For this, radio-tracking and video-monitoring observations were combined with computational fluid dynamics (CFD) models in two flat-V weirs, using Iberian barbel (Luciobarbus bocagei) as the target species. Results showed that fish passage is conditioned by both hydraulic and behavioral processes, providing evidence for scenarios in which flat-V weirs may act as full or partial barriers to upstream movements. For the studied flat-V weirs, a discharge range of 0.27–8 m3/s, with a water drop difference between upstream and downstream water levels lower than 0.7 m and a depth downstream of the weir of higher than 0.3 m can be considered an effective passage situation for barbels. These findings are of interest for quantifying flat-V weir impacts, for engineering applications and for establishing managing or retrofitting actions when required.

Modeling and simulation of water levels control in open canals using Simulink

This paper discusses the question of modeling and simulation of water levels control in open canals as a key decition of water and energy resources scarsity in the vegetation period of agricultural irrigation. The mathematical model of the water levels control in open canals is developed and the outcomes are evaluated using by Matlab’s tool Simulink. In addition, the paper proposes that the pivot weir or overshot gate for water levels control in open canals is simple in terms of precise and quality control of the upstream and downstream water levels control. Then dynamic equation of control object that describes dynamic state of the water levels control was obtained. A functional diagram has been developed and PID control was applied for the water levels control in the open canals. PID control was applied for the water levels control in the open canals to know how faster response the object to disturbance. Based on functional diagram the model of the system was built in Simulink environment and obtained the dynamic response.

Estimation of discharge coefficient of the overshot gates, based on the brink depth, under free and submerged conditions

ABSTRACT Overshot gates are used as a flow measuring device to fix the upstream water level. Flow through the overshot gates under submerged conditions often has many problems, mainly due to the need to measure the tail-water depth. In this research, the application of the brink depth, instead of tail-water depth, has been selected to overcome this problem. Many experiments were conducted with nine different angles of the overshot lip under free and submerged conditions. The discharge coefficient of the gate was estimated based on the brink depth. Besides, the flow discharge through the gate was evaluated through an equation based on the energy equation and the stage-discharge relation. The results showed good consistency and high accuracy under free and submerged conditions which refers to the suitability of the proposed equations for flow discharge and water depth because of their theoretical basis.

Spillway hydraulic performance assessments of the Belogorsk reservoir

The article presents the calculation of the hydraulic performance of the spillway structure of the Belogorsk reservoir, one of the largest freshwater bodies on the Crimean Peninsula. Due to its geographical location and natural features, Crimea has always been and remains one of the poorest regions of Russia with water resources and water delivery to the consumers is a priority. Hydraulic performance assessment of the spillway structure is carried out for two design cases: 1) with a variable upstream water level rate and a fully open gate with a = 1.00 m; 2) with a constant upstream water level (UWL) equals highest water level (HWL) and a variable value of the shutter opening. Based on the results of determining the hydraulic performance of the water intake structure, the maximum discharge flow rate (at the mark UWL equals HWL) was obtained, which was Q = 6.06 m3 / s, which is 1% higher than the design data of the throughput of the structure (Q = 6.00 m3 / s) and the total throughput of all spillway structures is Qtotal = 79.32 m3 / s, which differs from the design data by less than 1% and indicates the accuracy and reliability of the obtained data.

Ice roughness estimation via remotely piloted aircraft and photogrammetry

Abstract. The monitoring of fluvial ice covers can be time intensive, dangerous, and costly if detailed data are required. Ice covers on a river surface cause resistance to water flow, which increases upstream water levels. Ice with a higher degree of roughness causes increased flow resistance and therefore even higher upstream water levels. Aerial images collected via remotely piloted aircraft (RPA) were processed with structure from motion photogrammetry to create a digital elevation model (DEM) and then produce quantitative measurements of surface ice roughness. Images and surface ice roughness values were collected over 2 years on the Dauphin River in Manitoba, Canada. It was hypothesized that surface ice roughness would be indicative of subsurface ice roughness. This hypothesis was tested by comparing RPA-measured surface ice roughness values to those predicted by the Nezhikhovskiy equation, wherein subsurface ice roughness is proportional to ice thickness. Various statistical metrics were used to represent the roughness height of the DEMs. Strong trends were identified in the comparison of RPA-measured ice surface roughness to subsurface ice roughness values predicted by the Nezhikhovskiy equation, as well as with comparisons to ice thickness. The standard deviation and interquartile range of roughness heights were determined to be the most representative statistical metrics and several properties of the DEMs of fluvial ice covers were calculated and observed. No DEMs were found to be normally distributed. This first attempt at using RPA-derived measurements of surface ice roughness to estimate river ice flow resistance is shown to have considerable potential and will hopefully be verified and improved upon by subsequent measurements on a wide variety of rivers and ice covers.

Hydrostatic Pressure Wheel for Regulation of Open Channel Networks and for the Energy Supply of Isolated Sites

The Hydrostatic Pressure Wheel is an innovative solution to regulate flow discharges and waters heights in open channel networks. Indeed, they can maintain a water depth while producing energy for supplying sensors and a regulation system. To prove the feasibility of this solution, a complete model of water depth–discharge–rotational speed relationship has been elaborated. The latter takes into account the different energy losses present in the turbine. Experimental measurements achieved in IMFT laboratory allowed to calibrate the coefficients of head losses relevant for a large range of operating conditions. Once the model had been validated, an extrapolation to a real case showed the possibility of maintaining upstream water level but also of being able to produce sufficient energy for supplying in energy isolated sites. The solution thus makes it possible to satisfy primary energy needs while respecting the principles of frugal innovation: simplicity, robustness, reduced environmental impact.

Predicting the scour depth downstream single step broad crested weirs

The main purpose of broad crested weir used in open channels is to raise and control upstream (U/S) water level. The most important problems for downstream of hydraulic structures are the local scour formed at the downstream of hydraulic structures. Scour control process considered as the main objective to ensure safety and economical design of hydraulic structures to prevent any serious failure in the future. In this study, four models of Single-Step-Broad-Crested weirs with different angles were tested under different flow intensity for duration of 6 hours. Acoustic Doppler Velocimeter (ADV) was used to investigate the velocity field. The results showed that, the model C reduces local scour hole volume was about 87.6%, 55.58% and 44.8% and the maximum depth of scour reduced 73.43%, 32.56% and 24.22% as compared with model D at each discharge.

Flow Field in a Sloped Channel with Damaged and Undamaged Piers: Numerical and Experimental Studies

This paper analyzed the flow pattern around damaged and undamaged bridge piers in a channel with a mild slope. The experiments were carried out on a straight channel with a length of 12 meters and a slope of 0.008. Acoustic Doppler velocimeter (ADV) was employed to collect three-dimensional flow velocity data, and the results were analyzed and compared with particle image velocimetry (PIV) data. Sediment Simulation in Intakes with Multiblock option (SSIIM) was incorporated for the numerical simulation of the flow in this study. Generally, the results obtained from the comparisons referred to the appropriate agreement between the numerical and the experimental data. The results showed that an undular hydraulic jump occurred at a distance of two meters from the channel entrance in every case; the maximum bed shear stress in the sloped channel was 12 times that in a horizontal channel for installing two damaged and undamaged piers. With this position of the piers in the sloped channel, the upstream water level underwent a 72.5% reduction compared to similar conditions in a horizontal channel, while the amount of this water level decrease was equal to 8.3% compared to the other cases in a sloped channel. In addition, with the presence of both piers, the maximum Froude number was 5.7 times that in a horizontal channel.

Modelling deformations in water retention structures with unsaturated material point method

To conduct landslide risk assessment and assess the consequences of dam and levee failures, it is important to understand the overall failure evolution process that ranges from small-strain initiation to large-strain post-failure runout. To achieve this goal and simulate such landslide events, emerging large-strain numerical approaches, such as the material point method (MPM), show promising potential as tools to model the entire instability mechanism. While successfully incorporating multi-phase interactions in granular porous media. Soil–water interaction in unsaturated soils is critical when dynamic hydraulic loads act on levees, such as when the fluvial upstream water levels oscillate and in episodes of heavy rainfall infiltration. Recently, MPM has been successfully used in many geotechnical engineering applications, which in turn motivated further advancements of multi-phase formulations. This study presents an application of a novel single-point two-phase MPM formulation to model unsaturated soils subjected to transient hydraulic boundary conditions. The potential of this approach is discussed by analysing a large-scale slope failure experiment. Results are compared with the finite-element method and limit equilibrium method. It is concluded that similar results are obtained at small strains, but MPM allows the post-failure behaviour to be estimated, which is essential for risk management.