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Diversion head works, also called weirs or barrages, are structures constructed across rivers or canals to store water or raise the water level. The design of diversion weir structures involves calculating the depth, length and thickness of the horizontal and sloping aprons and sheet pile cut-offs. The design parameters of a diversion weir structure, which have complex non-linear relationships, are traditionally determined using empirically derived recommendations and iterations to achieve structural stability against failures due to scour, uplift, sliding, piping and overturning. However, current design approaches do not explicitly explore the trade-offs between the many relevant design objectives and thus fail to reveal possibly superior designs. A multi-objective optimisation design approach for a diversion weir structure is proposed in this article. A free and open-source code that can be used as a design tool is also provided. The method is demonstrated on a stylised design problem. The results show that the method reveals solutions with diverse balances of stability metrics and cost, with the optimal relationships of parameter values of components also varying based on the relative cost of the construction materials for sheet piles and aprons. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the performance of compound gates in flow energy dissipation using a two-tiered structure (15 and 30 cm high). Four heights of the lower opening of the structure (0, 1, 2, 3 cm) were used, and seven values of flow depth over the edge of the structure (2, 3, 4, 5, 6, 7, 8 cm) were used for each case. The study concluded that the efficiency of compound gates in dissipating flow energy decreases with increasing flow depth over the edge of the structure. However, this performance increases in hydraulic structures with high elevations, especially when the height of the opening under those gates is increased, provided that the flow depth over the edge of these structures is constant. Compound gates are considered effective energy dissipaters for low-elevation structures if the opening under the gate is small. [ABSTRACT FROM AUTHOR]

The article deals with the determination of the influence of the relative width of an approach channel with a rectangular cross-section on the discharge of clean water flowing over thin-plated weirs with a triangular notch and zero height of the weir above the bottom of the approach channel. To evaluate the influence, the Kindsvater-Shen equation was modified by introducing the basic effective discharge coefficient and the coefficient of the relative width of the approach channel. The coefficient of the relative width of the approach channel was determined based on the evaluation of data from three extensive experimental research investigations. It is valid for the entire possible range of relative widths of the approach channel and for the range of notch angles from 5.25° to 91.17°. The relative error of discharge determination is approximately up to ±2% over the entire range of discharges used in the conducted experimental research. The evaluation made it possible to determine the boundary distinguishing the partially contracted weirs from the fully contracted weirs in terms of impact on discharge. [ABSTRACT FROM AUTHOR]

Herein, a novel filtering weir with multi-stepped orifices is proposed to solve the problem of ineffective removal of small inclusions with traditional flow control devices in tundishes. Without changing the installation position, three types of novel filtering weir were designed. The flow and heat transfer behavior, wall shear distribution of the weir and dam, and removal rate of inclusions with different sizes were compared and analyzed. A 1:0.4 scale water model was conducted to validate the flow field calculated by mathematical simulation. The results indicate that the filtering weir can extend the response time and promote the mixing of liquid steel, but has little impact on the residence time and dead volume fraction. Due to the influence of the flow, the near-wall velocity and wall shear stress of the weir and dam decrease, but the area of the low-temperature zone of liquid surface in tundishes increases. The multi-stepped orifices added on the weir increase the removal rate of inclusions below 50 μm, especially the removal rate of inclusion of 2 and 5 μm increases to 63 to 64 pct, which is 18 to 21 pct higher than that with a traditional weir. [ABSTRACT FROM AUTHOR]

Scour depth downstream of weirs is considered one of the most important hydraulic problems, which greatly influences the stability of weirs. Recently, artificial intelligence (AI) methods have become increasingly popular in modeling hydraulic variables, especially scour depth, because they can capture nonlinear relationships between input variables and their associated objectives. Despite their importance, these models have problems with hyperparameter tuning in scour depth modeling due to their structures, so algorithms must be used to tune the hyperparameters. Moreover, these algorithms are usually tuned by using the trial-and-error method to select the hyperparameters such as the number of hidden nodes, transfer function, and learning rate, and in this case, the main problem is overfitting during the training phase. To solve these problems, the high-order response surface method (HORSM), an improved version of the response surface method (RSM), is used as an alternative approach for the first time in this study to predict the scour depth. The HORSM model is based on high-order polynomial functions (from two to six) compared with the artificial neural network model (ANN). The findings indicate that the fifth order of the HORSM polynomial function yields the most precise predictions, with a higher coefficient of determination (R2) of 0.912 and Willmott Index (WI) of 0.972 compared to the values obtained using ANN (R2 = 0.886 and WI = 0.927). Moreover, the accuracy of the predictions is represented by a reduction of the mean square error by up to 44.17 and 29.01% compared to the classical RSM and ANN, respectively. The suggested model established an excellent correlation and accuracy with experimental values. [ABSTRACT FROM AUTHOR]

A weir is a structure consisting of an obstruction such as a dam that built across the open channel to change its flow characteristics. In the present study, a total 12 experiments were done in the laboratory of civil engineering department inside an open channel with 20 cm width and installing full width rectangular sharp crested weirs. Then the numerical runs were validated with experimental findings and additional runs were done. The implementation of Numerical Methods A volume of fluid (VOF) model was created for the situation when water and air are in direct contact with one another. Three distinct k-epsilon turbulence models were examined [standard, RNG, and realizable]. According to mass balance data, the greatest error in experimental measurements between the main channel's input and outlet discharges does not exceed 9.542%. Furthermore, average percentage of error between numerical and experimental outlet discharges for standard, RNG and realizable k-epsilon method was 7.235, 5.489 and 7.301 respectively. Cd increased with increasing the ratio of (H1/P). The water surface will be stable along 2 m of upstream channel length upstream of the sharp crested weir, and the longitudinal water levels will decrease slightly over the weir with a curved profile, as determined experimentally and numerically. [ABSTRACT FROM AUTHOR]

A brand-new type of multislot and pool–weir combined fishway (MSWF) is firstly proposed in this paper. In fact, six MSWF configurations (MSWF-1 to MSWF-6) are designed and compared, and numerical results demonstrate that MSWF-5 (i.e., weir height h=0.6 m and the vertical-slot width bs=0.62 m) has the best performance at a flow discharge (i.e., Q) of 600 L/s in terms of flow topology, velocity distribution, and turbulent kinetic energy among all the eight fishways considered. The introduction of the weir in MSWF not only contributes to improving the flow regime, but also offers an extra fish-passage channel for fishes. Moreover, the general superiority of MSWF-5 over the vertical-slot fishway (VSF) is exhibited by providing the numerical results at Q=600 , 800, 1,000, and 1,200 L/s. Additionally, fish-passage tests are carried out in a physical model (including the MSWF-5 part and the VSF part) with the aid of juvenile grass carps. As expected, the recommended MSWF-5 does outperform VSF with respect to passage success rate, mean fish transit time, entry efficiency, and mean entrance time, matching its excellent hydraulic properties. [ABSTRACT FROM AUTHOR]

Understanding the impact of human‐made structures on groundwater levels is essential, with structures like dams or weirs presenting unique challenges and opportunities for study. The Baekje weir in South Korea presents an interesting case as the weir has undergone full gate opening, which is generally not the case for weirs and reservoirs, providing valuable opportunity for simulating weir removal conditions. The main objectives are investigation of groundwater level fluctuations under various weir operations, distances from the weir, and seasonal variations. The study utilizes observed data that simulates conditions with and without the weir, including scenarios of full gate opening. Multiple machine learning algorithms—Random Forest (RF), Artificial Neural Network, Support Vector Regression (SVR), Gradient Boosting, and Extreme Gradient Boosting (XGBoost)—are used to develop accurate groundwater level prediction models. The models' performance is assessed using coefficient of determination, Root mean square error (RMSE), Mean Absolute Error (MAE) indices, and visualized through Taylor diagrams. Results indicate that XGBoost outperforms other models in all three groups during both training and testing phases. Specifically, XGBoost surpasses RF by 2.09% (R2), 5.66% (RMSE), and 10.1% (MAE) in training, and outperforms SVR by 11.2% (R2), 42.0% (RMSE), and 129.2% (MAE) in testing. Additionally, the study generates groundwater level maps, providing a practical tool for managing groundwater systems and informing decision‐making in weir operations. This study not only sheds light on the dynamic relationship between weir operations and groundwater levels but also provides actionable insights for effective water management in similar hydrological settings. Key Points: Predict daily groundwater level changes under different weir management policies, including the condition of fully opening the weir gatesApply machine learning algorithms to build the groundwater level prediction models and produce groundwater level map as the final productConclude that weir management policies (full and partial openings, normal), distance from the weir, and seasons impact groundwater level [ABSTRACT FROM AUTHOR]

Water diversions worldwide may entrain or impinge fish and have population‐level impacts, but barriers like fish screens can reduce such threats. Traditional barriers are ineffective in the San Juan River, USA, due to high sediment and debris loads, so the Hogback Diversion Canal, NM, employs a novel weir wall design to reduce entrainment of sub‐adult and adult fishes. We evaluated the effectiveness of the weir wall in reducing the entrainment of larval fish using a combination of experimental and overnight trials. Larval fish densities were compared between the irrigation canal that delivers water to irrigators and subsequently entrains fish and the bypass canal that conveys water and fish back to the river. The density of hatchery‐produced larval fish collected in the irrigation canal during the experimental trial (0.74 fish/m3) was 52% of their density in the bypass canal (1.43 fish/m3), suggesting entrainment reduction. The density of wild‐produced larvae during overnight trials indicated some minor, mostly nonsignificant, differences between catch rates in irrigation and bypass canals, ontogenetic phases, and sampling dates. Though entrainment rates of wild‐produced larvae were not significantly reduced, density differences among postflexion mesolarvae and metalarvae suggest possible entrainment reduction of more developed ontogenetic phases. More intensive research is necessary to better elucidate the efficacy of the novel weir wall for reducing the entrainment of larval fish. However, our larval fish results and the results from prior large‐bodied entrainment studies suggest the novel weir wall may reduce fish entrainment in water diversions and benefit fluvial ecosystems in which traditional screens are unfeasible. [ABSTRACT FROM AUTHOR]

The piano key weir (PKW) is an evolution with more hydraulic efficiency, compared to labyrinth weir. The studies on this type of weir have shown a significant increase in its discharge efficiency, especially at low heads. In this study, discharge coefficient of various shapes of piano key weir (i.e. rectangular, trapezoidal, and triangular) is investigated experimentally. Also, the aeration process of the studied weirs is described. According to the results, it was found that the discharge coefficient of the triangular PKW is about 28.2% more than the discharge coefficient of the rectangular PKW, and the discharge coefficient of the trapezoidal PKW is about 12.9% more than the discharge coefficient of the rectangular PKW. Also, the discharge capacity of the rectangular, triangular, and trapezoidal PKWs are 3.8, 3.96, and 3.96 times the sharp crest weir, respectively. The equations introduced for the discharge coefficient show good agreement (with R2 from 0.968 to 0.988 and average percentage error from 0.82 to 2.6%) between the actual and calculated values. [ABSTRACT FROM AUTHOR]

Weirs and gates are hydraulic structures installed in canals, mainly for controlling the discharge. Because of their existence, unfavorable influences regarding the downstream bed configurations were recorded. This study experimentally explores the combined effect of simultaneous flow through a hydraulic device consisting of a V-notch sharped weir with an inverted V-shaped gate, aiming to minimize the downstream bed scour. Eighty-one runs were carried out using nine weir-gate models with three different vertex angles. The tests were executed considering three upstream and three downstream water depths. A V-notch weir with an angle of 120º was tested under similar hydraulic conditions and was used for comparison. The results revealed that the length of backflow was increased by the decrease in weir angle under a fixed 120° gate angle. The bed configurations were sensitive to gate angle. The combined device showed a significant decrease in bed disturbances regardless of the angles used compared to the traditional V-notch weir. Simple formulas were developed to predict the scour parameters. [ABSTRACT FROM AUTHOR]

The study focuses on the four-strand tundish as the research object, aiming at the phenomenon of fewer strand casting (stable blockage) and sudden blockage of the tundish in industrial production. Numerical simulation methods are employed to compare the velocity vectors, flow fields, residence time distribution (RTD) curves, and outflow percentage curves under stable blockage and sudden blockage of the tundishes with a double-weir structure, U-shaped weir structure, and U-shaped weir structure with holes in the front. The results indicate that, after sudden blockage of the tundish strands, the flow field transitions from an unstable four-strand flow field to a stable three-strand flow field. Both the double-weir tundish and the U-shaped weir tundish reach a stable state after 200 s, while the U-shaped weir tundish with holes in the front reaches stability after 150 s. Additionally, compared to other structures, the tundish strands of the U-shaped weir with holes in the front are less affected by blockage, showing better consistency among strands and better adaptability under non-standard casting conditions. [ABSTRACT FROM AUTHOR]

This document discusses a research paper on the discharge coefficient of Type-A piano key weirs. The discussers appreciate the authors' efforts but suggest further analysis for one equation in the original paper. They conducted simulations and analysis, providing graphs and tables to support their findings. The document also includes a sensitivity analysis of input parameters affecting the discharge coefficient, showing the varying effects of different parameters. The study provides insights into estimating the discharge coefficient and was supported by funding from the Water Resources Department of Jiangxi Province and the Natural Science Foundation of Jiangxi Province in China. [Extracted from the article]

Two different arrangements of the weir (i.e., straight weir and rectangular labyrinth weir) were used to evaluate the effects of geometric parameters such as weir shape, weir spacing, presence of an orifice at the weir, and bed slope on the flow regime and the relationship between discharge and depth, variation and distribution of depth-averaged velocity, turbulence characteristics, and energy dissipation at the fishway. Computational fluid dynamics simulations were performed using FLOW-3D® software to examine the effects on flow conditions. The numerical model was validated by comparing the calculated surface profiles and velocities with experimentally measured values from the literature. The results of the numerical model and experimental data showed that the root-mean-square error and mean absolute percentage error for the surface profiles and normalized velocity profiles of plunging flows were 0.014 m and 3.11%, respectively, confirming the ability of the numerical model to predict the flow characteristics of the pool and weir. A plunging flow can occur at values of L/B = 1.83 (L: distance of the weir, B: width of the channel) and streaming flow at L/B = 0.61 for each model. The rectangular labyrinth weir model has larger dimensionless discharge values (Q+) than the conventional model. For the conventional weir and the rectangular labyrinth weir at submerged flow, Q is proportional to 1.56 and 1.47h, respectively (h: the water depth above the weir). The average depth velocity in the pool of a conventional weir is higher than that of a rectangular labyrinth weir. However, for a given discharge, bed slope, and weir spacing, the turbulent kinetic energy (TKE) and turbulence intensity (TI) values are higher for a rectangular labyrinth weir compared to conventional weir. The conventional weir has lower energy dissipation than the rectangular labyrinth weir. Lower TKE and TI values were observed at the top of the labyrinth weir, at the corner of the wall downstream of the weir, and between the side walls of the weir and the channel wall. As the distance between the weirs and the bottom slope increased, the average depth velocity, the average value of turbulent kinetic energy and the turbulence intensity increased, and the volumetric energy dissipation in the pool decreased. The presence of an opening in the weir increased the average depth velocity and TI values and decreased the range of highest TKE within the pool, resulted in larger resting areas for fish (lower TKE), and decreased the energy dissipation rates in both models. [ABSTRACT FROM AUTHOR]

Ecological assessments of the effects of hydropower plants (HPPs) are often limited to aspects of entrainment, mortality, injuries, and passage of fish, whereas the effects on riverine habitats and biological communities in proximity to these structures are hardly documented.In this study, aquatic communities comprising fish, macroinvertebrates, macrophytes and periphyton as well as physical and hydromorphological parameters were investigated in upstream and downstream river sections at five transverse structures at different seasons before and after the installation of an innovative HPP.At all study sites, significant differences in the aquatic community composition between the assessed upstream and downstream sections were found after HPP construction, indicating distinct serial discontinuity.Raising the damming target at the sites Großweil and Au deteriorated the habitat conditions in the upstream area close to the weir and presumably influenced in particular the macroinvertebrate community, where a significant decrease in the density of rheophilic mayfly, stonefly and caddisfly larvae was observed after HPP construction.Synthesis and applications: The installation of different types of innovative HPPs has not improved the habitat conditions for rheophilic species, contrary to the promises raised by the developers of these concepts. Conversely, retrofitting existing weirs accompanied by further damming even significantly increased the effects of serial discontinuity and deteriorated the habitat conditions for rheophilic species in upstream sections. As evident from the findings of this study, habitat and biological community effects resulting from serial discontinuity should become better integrated into ecological assessments of HPP developments. [ABSTRACT FROM AUTHOR]

Building in the river: major maintenance of the Kachlet weir system after 100 years of operation The Kachlet weir system is one of the largest weir systems on the German Rhine‐Main‐Danube waterway and is reaching a 100‐year service life. In order to ensure the continued navigability of the Danube, a major overhaul will be carried out in which the weir base will be preserved, the piers upgraded and the weir superstructure and hydraulic steelwork as well as the technical equipment completely renewed. New approaches are being considered for this particular challenge, especially in terms of construction logistics. As a construction aid for the planned construction project, a portal crane system will be erected above the weir system, which will enable the project to be carried out with a high degree of prefabrication and, as a result, a comparatively short construction period. However, the portal crane system also brings new challenges with it, that need to be taken into account during planning. [ABSTRACT FROM AUTHOR]

The study investigates the effect of the perception of text and task difficulty on adults' performance in reading tests in L1 and L2. The relationship between the following variables is studied: (a) readers' perception of text and task difficulty in L1 and L2 measured in a self-reported post-task questionnaire, (b) the number of correct answers to the reading tasks, (c) time spent on the task in each language, (d) the number and mean duration of fixations on areas of interest assigned to texts and each of four different task instructions as measured by an eye tracker. The study shows that for readers at an intermediate level of L2, the perceived and measured text and task difficulty is higher for L2, which results in longer mean fixation durations and a higher number of fixation counts. Tasks placed lower on the difficulty scale based on the 7-point scale of reading ability by Khalifa and Weir (2009) are prone to be treated by readers as typical of a specific task format and receive less attention, which often leads to incorrect answers. [ABSTRACT FROM AUTHOR]

Weirs are often used in laboratories, industries, and irrigation channels to measure discharge. The discharge capacity of a structure is vital for its safety and plays an important role in the combined gateweir flow, which is a complicated phenomenon in hydropower. This study carried out experiments on a combined hydraulic structure, which included a compound sharp-crested weir made up of two rectangles along with an inverted semicircular sharp gate. Installed on a straight channel, this structure served as a control instrument. The study aimed to investigate the downstream hydraulic jump characteristics of this combined structure, specifically, the sequent depth ratio (y2/y1), the hydraulic jump height ratio (Hj/y1), the energy loss ratio through the jump (EL/Eu), and the jump length ratio (Lj/y1). The width of the upper rectangle on the weir was set at 20 cm. The width of the lower rectangle (W2) was set at 5, 7, and 9 cm, while its depths (z) were fixed at 6, 9, and 11 cm. The gate's diameters varied between 8, 12, and 15 cm. These measurements were alternated with varying initial Froude numbers (Fn1) ranging between 1.32 and 1.5. The results showed that the dimensions of both the weir and the gate influenced the hydraulic jump characteristics. Empirical formulas were developed to predict y2/y1, Hj/y1, EL/Eu, and Lj/y1 based on the differing dimensions of the combined structure. The findings and analysis of this study are limited to the range of data that were tested. [ABSTRACT FROM AUTHOR]

Anthropogenic infrastructure in rivers (e.g. culverts, dams and weirs) can block the movements of fish and negatively impact their communities. Recent research has shown that fish passage at such barriers can be improved through the use of cylindrical bristle cluster (CBC) arrays. The relationship between the hydrodynamic environment created by different CBC array geometries and passage efficiency, the number of fish that passed as a percentage of those that attempted to do so, and swimming behaviour of a native wide spread European cyprinid species, the roach (Rutilus rutilus), was investigated. Passage efficiency was a function of cluster diameter and spacing; efficiency was highest (>80%) when the ratio of lateral cluster spacing (centre to centre) (Sc) to diameter was less than 5. Fish exhibited a range of swimming behaviours while manoeuvring through the CBC array to ascend the weir, the most common of which was zigzagging between two lines of clusters. Additionally, fish utilised lower velocity areas when swimming through a CBC array, often combining different swimming behaviours to successfully navigate at burst speeds. Fish passage efficiency can be improved by increasing the size of the wake behind clusters and the overall hydraulic resistance created within the array while ensuring sufficient space is available for fish to manoeuvre. [ABSTRACT FROM AUTHOR]

The phenomenon of local scour downstream of irrigation weir energy dissipators is one of the basic degradation problems in hydraulic structures on rivers. The hydraulic jump in the stilling basin, which is triggered by flow turbulence due to energy dampening, forms current vortices in horizontal and vertical directions. Eddy currents that are not fully controlled and damped in the stilling basin can cause scouring, especially in the vertical direction just downstream of the energy dissipators construction. Simultaneous accumulation of scour in the long term can endanger buildings around the weir, especially the stilling basin, both downstream wings and the main weir. This paper aims to assess weir safety by predicting scour characteristics under end sill energy dissipators using the hybrid model: HEC-RAS and Scour Empirical Equation. The simulation is carried out on three conditions, namely minimum, average and maximum discharges with input of sediment grain gradations obtained from field measurements. The three types of discharge are obtained from the transformation of daily rainfall into daily discharge using the HECHMS Model. The results of scour predictions in the 3 scenarios were compared with the results of scour measurements at the study location. The results of the study indicate that the greatest scour depth at the maximum discharge of almost 1.5 meters has reached the depth of the end sill of the energy dissipator. This prediction result was also verified by the observation scour depth of more than 1.5 meters. Observation results also show that the Energy Dissipator II has collapsed massively both in the center and on the left and right sides of the energy dissipator. Based on the results of the study and investigation, it can be concluded that the weir safety at the study location can be categorized as low with the potential for very large scour. [ABSTRACT FROM AUTHOR]

This study investigates the ecological effects of weirs on water quality and phytoplankton communities in the South Han River (SHR) over a two-year period. By focusing on three key weirs—Kangcheon Weir, Yeoju Weir, and Ipo Weir—the research examines how artificial structures influence river hydrodynamics, nutrient cycles, and algal growth patterns. Utilizing water quality measurements, phytoplankton analysis, and environmental factor assessments, the study identifies significant fluctuations in water quality parameters and phytoplankton abundance across the surveyed points. The analysis reveals a direct correlation between environmental conditions such as temperature, flow rates, and nutrient concentrations, particularly nitrogen and phosphorus, and the proliferation of harmful cyanobacteria, notably Microcystis. This research highlights the critical role of comprehensive management strategies that consider hydraulic residence time, nutrient balance, and temperature regulation to mitigate the impacts of weirs on river ecosystems and improve water quality in the SHR. [ABSTRACT FROM AUTHOR]

When settlements are located close to a dam, it is important to accurately predict the breach peak flow and the time to reach the peak. Therefore, the prediction of dam breach properties is essential in dam break studies. Dam breach parameters such as the breach side slope, final bottom width, final bottom elevation, weir coefficient, breach formation time, and initial elevation of reservoirs are the key variables for estimating the peak discharge during a dam break scenario. In this study, these six breach parameters were analyzed to investigate the impact of breach parameters on breach peak flow and the time to reach the peak. Thus, several scenarios were calculated and compared for Atasu Dam. The results revealed that the role of the initial water elevation, final bottom elevation, and breach development time had more of an impact on the breach peak flow and the time to reach the peak. In addition, the study indicated that the final bottom width and breach weir coefficient were less sensitive to both the peak discharge and peak discharge time. Furthermore, the analysis indicated that the breach side slope parameter had no major influence on the time to peak while also having an insignificant impact on the peak discharge. Understanding this breach mechanism provides a basis for relevant research in designating key parameters for dam break analysis. Thus, the results can contribute to decision making toward the design of flood mitigation and dam emergency action planning. [ABSTRACT FROM AUTHOR]

The last several decades have seen a rise in efforts to remove weirs, but there is little research investigating how projects are carried out, potential areas for improvement, or sharing of lessons to facilitate reconnection of more rivers. The aim of the study presented here was to explore how people involved in weir remediation perceive project processes, factors that facilitate or hinder action implementation, and possible ways processes could be improved to reconnect more rivers. We carried out semi‐structured interviews with people (n = 11) who had been actively involved in weir remediation processes in the Severn River Catchment, United Kingdom, and used their responses to create a group mental model. The group mental model was created to support learning and communication about weir remediation projects between individuals and groups. We found broad agreement from those involved in creating the group mental model about weir remediation project processes and potential areas for improvement. One of the only points of divergence within the group mental model was associated with the impact of different weir remediation actions, particularly weir removal. Based on the group mental model, we set out three calls to action to reconnect more rivers in the UK. First, move beyond opportunistic projects and establish national goals and catchment‐scale plans for weir remediation. Second, reform fish passage legislation and legislate weir ownership. Doing so would support more effective remediation solutions by recognizing the diversity of fish species that reside in UK rivers and help mitigate risks from hazardous weirs through owner accountability. Third, build cross‐sector and public partnerships to encourage removal or improved fish pass designs. We direct the three calls to action to policy makers and anyone already engaged in or envisioning weir remediation projects in the UK. The calls also have potential implications and relevance to people in other countries in Europe and beyond. [ABSTRACT FROM AUTHOR]

A large collection of laboratory measurements of piezometric head (h) and discharge (Q) were made over hydraulic models of a tilting weir at nine different angles, ranging from 25.7° to 90° within a 0.3-m-wide flume. These measurements were corroborated with additional laboratory data taken within a 1-m-wide flume across four inclination angles. The range of both inclination angle (θ) and flow scale examined in this study elucidate the nature of the head-discharge rating equation beyond previous work. Results show that as θ decreases under a constant Q , the h over the weir decreases in a monotonic fashion due to the shallower angle of attack of the flow, which results in less curvature of the streamlines over the crest and therefore less deviation from the upstream hydrostatic pressure condition. To incorporate this effect into the head-discharge rating equation, a transformation of the h term was applied by multiplying the measured h that occurs over a tilting weir by a correction factor to match the effective h that would occur if the weir were aligned perpendicular to the flow at the same discharge. Thus, a modified form of the classical sharp-crested weir rating equation can be used as a means for determining the value of Q for tilting cases to a high degree of accuracy. The degree of accuracy is dependent on dimensionless Reynolds and Weber numbers describing the flow inertia in the approach to the weir in relation to respective viscous and surface tension scale effects. This approach portends marked flow measurement enhancement for flow conditions above a suggested inertial threshold. To achieve reliable and equitable water distribution, it is necessary to accurately estimate the volumetric discharge of water to flow through "rivers and canals." One such method of accomplishing this is by using hydraulic structures, such as the tilting weir. This structure not only can be used to measure the discharge of water on a continuous basis, but also allows for regulating the water level upstream of the structure. Presently, tilting weirs are often used to control water levels, but the literature on their utilization as flow measurement structures has remained sparse. This study presents a thorough analysis of laboratory experiments on scaled models of tilting weirs, where the flow depth upstream of the structure and the inclination angle are used to calibrate an equation to estimate the discharge to a high degree of accuracy. Operational guidelines to ensure minimum uncertainty in measurement are also given. [ABSTRACT FROM AUTHOR]

Side weir is an effective control in streams. To study geometrical dimensions effect of the weir on the generated flow structure, here, experimental and numerical simulation analysis of the previous and present experimental studies was done on the flow around different geometric types of side weir. A triangular labyrinth side weir with three distinct included angles (θ = 30°, 45°, and 60°) and three weir heights (P = 10, 15 and 20 cm) has been tested, in addition normal rectangular side weir for comparison. The volume of fluid (VOF) approach was used for tracking free-surface subcritical flow conditions at the centerline of the main channel and near side weir banks. Accurate results were discovered by employing the Renormalization Group (RNG k-∈) turbulence model with the experimental outcomes. The smallest inclusion angle of side weir, generates smaller width of vortices zone near the upstream side weir wall which obstacles only a smaller length of crest as compared to the larger inclusion angle that hindrances larger length of this side for flowing water. In addition the contribution portion of the surface flow for the smallest inclusion angle which is indicated by streamlines is about 0.66 times the main channel width. Moreover, the maximum width of separation zone at the downstream of the main channel reached to 0.8 times the width of the main channel for the triangular labyrinth side weir. The stagnation point exists at the downstream end of side weir results the increase of surface elevation to reach maximum level. The coefficient of discharge of such weirs were 3.8, 2.7 and 2.12 times the coefficient of the normal rectangular side weir for θ = 30°, 45° and 60°, respectively. [ABSTRACT FROM AUTHOR]

In this study, experimental investigations were conducted on rectangular side weirs with different widths and heights. Corresponding simulations were also performed to analyze hydraulic characteristics including the water surface profile, flow velocity, and pressure. The relationship between the discharge coefficient and the Froude number, as well as the ratios of the side weir height and width to upstream water depth, was determined. A discharge formula was derived based on a dimensional analysis. The results demonstrated good agreement between simulated and experimental data, indicating the reliability of numerical simulations using FLOW-3D software (version 11.1). Notably, significant fluctuations in water surface profiles near the side weir were observed compared to those along the center line or away from the side weir in the main channel, suggesting that the entrance effect of the side weir did not propagate towards the center line of the main channel. The proposed discharge formula exhibited relative errors within 10%, thereby satisfying the flow measurement requirements for small channels and field inlets. [ABSTRACT FROM AUTHOR]

In this paper, the scour downstream of a trapezoidal Piano key weir (PKW) is investigated under free and submerged flow conditions. For this purpose, an experimental model was used in a laboratory channel with a length of 10 m, width of 0.75 m, and height of 0.8 m at various discharges and tailwater depths. The results showed an increase and decrease in the maximum scour depth with an increase in the discharge and submergence ratio, respectively. In addition, increasing the particle Froude number enhanced the geometric features of the scour hole downstream of the PKW. The rate of bed changes slowed down over time. The average values of maximum scour depth, the distance of the maximum scour depth from the weir toe, maximum scour hole length and weir toe scour depth increased in the free flow compared to the submerged flow. The scour hole volume and scour hole area in the submerged flow were less compared to the free flow. The average maximum level of the sedimentary ridge in the free flow is less than the submerged flow. New equations for calculating the geometric characteristics of the scour hole downstream of the trapezoidal PKW are presented with acceptable accuracy. [ABSTRACT FROM AUTHOR]

The present study used three machine learning models, including Least Square Support Vector Regression (LSSVR) and two non-parametric models, namely, Quantile Regression Forest (QRF) and Gaussian Process Regression (GPR), to quantify uncertainty and precisely predict the side weir discharge coefficient (Cd) in rectangular channels. So, 15 input structures were examined to develop the models. The results revealed that the machine learning models used in the study offered better accuracy compared to the classical equations. While the LSSVR and QRF models provided a good prediction performance, the GPR slightly outperformed them. The best input structure that was developed included all four dimensionless parameters. Sensitivity analysis was conducted to identify the effective parameters. To evaluate the uncertainty in the predictions, the LSSVR, QRF, and GPR were used to generate prediction intervals (PI), which quantify the uncertainty coupled with point prediction. Among the implemented models, the GPR and LSSVR models provided more reliable results based on PI width and the percentage of observed data covered by PI. According to point prediction and uncertainty analysis, it was concluded that the GPR model had a lower uncertainty and could be successfully used to predict Cd. [ABSTRACT FROM AUTHOR]

Objective: Inadequate flow capacity can compromise the safety of dams, especially during extreme floods. Using weirs is a common way to solve this problem. Numerical models can simulate the flow conditions downstream of piano key weirs with acceptable accuracy. With their help, the downstream energy loss can be investigated. Therefore, conducting more research to study the energy loss in piano key weirs seems necessary. Methods: This test was done in the hydraulic laboratory of the Khuzestan Water and Electricity Organization. The flume used in this experiment had a rectangular cross-section with a length of 7 meters and a width of 0.6 meters. The walls of the flume were 10 mm thick and were made of glass. In this experiment, 10 flow rates (from 10 to 50 liters per second) were used in free flow mode in the flume. Three piano keyboard weirs with different baffles were used. Baffles were circular, pentagonal, and cubic. The weirs were made of transparent plexiglass with a thickness of 5 mm. The numerical model of Flow3D software was used to check the amount of energy consumption and compare the baffles. Results: Due to increasing yc/H, the highest energy loss occurred in cubic, circular, and pentagonal baffles, respectively. The energy loss in cubic, circular and pentagonal baffles was 0.65, 0.62 and 0.61, respectively. Therefore, the best result happened in the cubic baffle. By changing the height of the baffles, it was observed that the highest energy loss was measured at a height of 2 cm and the lowest value was measured at a height of 1 cm. This indicated that at high speed, a smaller separation zone was created in the baffles with a height of 2 cm, which caused more energy loss. In general, with the increase of the Weber number, the energy loss also decreased. Weber's number can be ignored in heads larger than 5 cm. In the same conditions, the difference in the shape and height of the baffles has caused a difference in the amount of energy loss. The highest energy loss happened in the Weber number of 200 and the cubic baffle. The results demonstrated that with a 500% increase in the Weber number, the amount of energy loss was decreased by 10%, indicating the effect of low surface tension on energy loss. The obtained results illustrated that using the Ht/p ratio was a suitable method to check the amount of energy loss in these weirs. Conclusions: Based on the results of this experiment, it is recommended to use cubic baffles for more energy loss in piano key overflows. The best shape and dimensions of the baffle for this work are cubic and 2 * 2 cm. [ABSTRACT FROM AUTHOR]

In this study, a new empirical equation was established to predict the sedimentation volume resulting from the construction of a multi-purpose weir or low-head dam using experimental approaches. Applying the 1-D numerical model (STAFF), which is based on Exner's equation, 2545 cases were simulated and laboratory experiments were conducted with various sediment particle sizes, channel slopes, inlet discharge, and outlet water elevation. Short-term predictions were conducted through laboratory experiments with movable bed, and the results indicated that dimensionless unit stream power and the Shields parameter exhibited the most significant correlation with dimensionless deposition volume. In particular, we analyzed the phenomenon in which the backwater effect and reservoir delta. Using a multiple regression approach, the developed empirical equation was validated for predicting sedimentation in the upstream reservoir of the weir. [ABSTRACT FROM AUTHOR]

Objective: Hatchery‐produced salmon and steelhead Oncorhynchus mykiss mitigate for habitat loss and support valuable commercial, recreational, and tribal fisheries. However, excessive interactions between hatchery and wild fish can also cause harm to wild populations. Weirs have been implemented as a management tool to remove returning hatchery‐origin Chinook Salmon O. tshawytcha adults to reduce the proportion of hatchery‐origin spawners (pHOS) in spawning areas used by their wild counterparts. Using a decade of data since new weirs were implemented, our objective was to evaluate the efficacy of this management approach. Methods: Weirs were installed in six tributaries of the lower Columbia River, Washington. Using data from both weir operations and spawning ground surveys, we quantified weir efficiency (the proportion of upstream migrants captured by the weir) and resultant pHOS in wild spawning areas and evaluated evidence for unintended effects of weirs on naturally spawning salmon in years with (2011–2017) and without weirs (2002–2010) in one population by evaluating weir effects on spawner apparent residence time, distribution, and recruitment to the juvenile stage. Result: Weir efficiencies were highly variable across years and locations (7.3–100.0%). Estimates of pHOS were variable among populations and years (interannual population mean range: 11.9% to 75.2%) but were higher in all but 2 of the 43 population‐year combinations than needed to maintain recovery‐plan‐targeted levels of population viability using quantitative genetic model‐based standards identified by the Hatchery Scientific Review Group. Several factors contributed to the proportion of hatchery spawners exceeding pHOS standards at the population level, including fish passing weirs during freshets, spawning below weir sites and in tributaries without weirs, and imperfect marking of hatchery‐released juveniles. In the sole watershed with sufficient pre‐weir data to evaluate before–after changes, we documented a downstream shift in the spatial distribution of redds, lower apparent residence time of spawners, and lower production of parr in years following weir installation. Conclusion: Our results indicate that using weirs as a tool to reduce hatchery–wild interactions on the spawning grounds is challenging. Weir implementation reduced pHOS; however, in most cases, resulting pHOS was not low enough to facilitate fit and viable wild populations. Weirs also were associated with unintended negative impacts to the single population where we had adequate before and after weir implementation data to evaluate effects. These impacts may be harmful to recovery efforts and offset the intended benefits of weirs to wild populations. Our study highlights the need for adaptive management to realize the goals intended for weirs, underscores the need for experimental design approaches, and identifies opportunities for future work. Impact statementWeirs demonstrated limited efficacy in removing hatchery fall Chinook Salmon from wild spawning areas and were associated with negative impacts on spawner distribution and productivity, raising the possibility that alternative approaches will be needed to reduce the effects of hatcheries on wild populations. [ABSTRACT FROM AUTHOR]

Two-component composite hydraulic structures are commonly employed in irrigation systems. The first component, responsible for managing the overflow, is represented by a weir consisting of two rectangles. The second component, responsible for regulating the underflow, is represented by a semicircular gate. Both components are essential for measuring, directing, and controlling the flow. In this study, we experimentally investigated the flow through a combined two-rectangle sharp-crested weir with a semicircular gate placed across the channel as a control structure. The upper rectangle of the weir has a width of 20 cm, while the lower rectangle has varying widths (W2) of 5, 7, and 9 cm and depths (z) of 6, 9, and 11 cm. Additionally, three different values were considered for the gate diameter (d), namely 8, 12, and 15 cm. These dimensions were tested interchangeably, including a weir without a gate (d = 0), under different water head conditions. The results indicate that the discharge passing through the combined structure of the two rectangles and the gate is significantly affected by the weir and gate dimensions. After analyzing the data, empirical formulas were developed to predict the discharge coefficient (Cd) of the combined structure. It is important to note that the analysis and results presented in this study are limited to the range of data that were tested. [ABSTRACT FROM AUTHOR]

Stream flow weirs disrupt river flow regimes, physical conditions, and biological composition of rivers, posing significant threat to the river’s functionality, integrity, and sustainability. Home to diverse aquatic organisms, there is a lack of impact assessment of weirs on the stream of the Luvuvhu River Catchment (LRC). The aim of this study was to examine the impact of six weirs on aquatic macroinvertebrate assemblages and composition across five streams. A total of six sampling surveys on macroinvertebrates and physico-chemical parameters were conducted upstream and downstream of six weirs in 12 months between June 2021 and June 2022. The South African Scoring System score (SASS score) and Average Score per Taxon (ASPT) indices were used to compare organisms’ response between upstream and downstream of weirs. Generalized linear mixed models (GLMM) were used to determine the effect of physico-chemical variables on macroinvertebrate assemblage, while the CCA was employed to assess similarities between downstream and upstream sampling points across various sites. A total of 18,914 macroinvertebrate individuals were observed from 65 families during the survey. In upstream sections, the SASS score was driven by habitat integrity, electrical conductivity, and water depth, while ASPT responded significantly to habitat integrity, pH, dissolved oxygen and electrical conductivity. In the downstream sections, the SASS score increased with an increasing habitat integrity score and river width, while decreasing with elevation and pH levels. ASPT increased with increasing habitat integrity and elevation in the downstream sections, while decreasing with increasing river width and water temperature. This study’s findings suggest habitat integrity is largely driving aquatic abundance and assemblage in the LRC, and it is therefore important to maintain the ecological integrity of rivers.

This study quantified transfer losses over the 2021/2022 water year for irrigation releases from Darlington Dam into the Sundays River, which are diverted at the Korhaans Drift Weir. A one-dimensional (1D) hydrodynamic model was set up and calibrated to simulate the transfer losses which were assumed to consist primarily of evaporation and evapotranspiration (ET). Flow measurements were undertaken with an acoustic doppler current profiler (ADCP) to verify the calibrations of the Parshall flumes at Darlington Dam and at Korhaans Drift Weir. The ADCP results showed that the Department of Water and Sanitation's (DWS's) existing discharge tables underestimated lower flows by 13% and higher flows by 16%. The hydrodynamic model results also estimated transfer losses between Darlington Dam and Korhaans Drift to range between 2.0% and 5.3%. It was determined that the transfer losses were seasonal and were lower than those determined by similar studies for other South African rivers. [ABSTRACT FROM AUTHOR]

In this article I examine the responses of Ngöbe indigenous women to experiences of gender violence, aided by concepts from Mesoamerican cosmology and the concept of agency as a practice of belonging (Weir, 2013). Emphasis is placed on responses to gender violence that rely on the connection to the Ngöbe identity and the renegotiation of relationships within the community and with external institutions. I also highlight the aspirations of indigenous Ngöbe women to ensure a full experience of their culture and their beliefs for themselves and for future generations. The empirical data comes from the ethnographic fieldwork in a Ngöbe indigenous community in southern Costa Rica undertaken during 2015 and 2016. In this article I conclude that women's substantive connection with their identity can reinforce their status in the community and expand the scope of their actions and as a result impact on the possibility of generating safe spaces for themselves and for other women in the community. Likewise, women have managed to establish and maintain supportive networks that offer spaces of protection. In the context of these networks, they have begun to renegotiate and reconfigure prevalent forms of relationship in the community and with external institutions. By setting these processes in motion, they promote respect for women's dignity and improve the well-being of the whole community. [ABSTRACT FROM AUTHOR]

In 1997, The Weir would become the first major success of young Irish dramatist Conor McPherson. Using the model of embedded narrations, McPherson adds a new dimension to the scene. As it happened in gothic novels, women will become the nexus between the supernatural and the quotidian. A fairy, an old lady with alcoholic tendencies, a molested girl, and a rural schoolmistress will mark the milestones of this path. Through the character of Valerie, it will also be appreciated how women will leave their traditional role as victims, which will be substituted for a new role as narrators. This article has a double purpose. On one hand, I am to analyze how the female characters articulate the play; on the other hand, I also aim to discern the mixture of drama and narration offered by the author. [ABSTRACT FROM AUTHOR]

To achieve net-zero emissions by the year 2050, carbon capture, utilization, and storage technologies must be implemented to decarbonize sectors with hard-to-abate emissions. Pressurized chemical looping (PCL) with a novel reactor design called a plug flow with internal recirculation (PFIR) fluidized bed is proposed as an attractive carbon capture technology to decarbonize small- and medium-scale emitters. The objective of this work is to examine the solid circulation rate between redox reactors in a cold flow chemical looping facility using an energy balance approach. The effects of static bed height, weir opening height, purge configuration, and gas flow rate on solid circulation rate were investigated. It was determined that parameters that greatly affected the total gas momentum, such as the fluidization ratio or number of purge rows, tended to also have a large effect on solid circulation rate. Parameters that had a small effect on total gas momentum, such as bed height, did not have a measurable effect on solid circulation rate. It was noted that parameters that posed a restriction to solids flow, such as a vertical purge jet or the weir itself, decreased the solid circulation rate compared to similar tests without restrictions. [ABSTRACT FROM AUTHOR]

The baffle effect of inserting a filter within a tundish was investigated using a combination of water model experiments and numerical simulations. The filter, which is a cost-effective device used to enhance the quality of molten steel by removing inclusions, was studied for its impact on the removal rate of inclusions. In the water model experiments, a scaled-down model of the tundish system was created with a geometric ratio of 1:4. Polyethylene particles of varying sizes were used to simulate the inclusions. Additionally, a three-dimensional numerical model of the water model was developed to validate the experimental findings, provide supplementary data for analysis, and propose an optimized tundish configuration by moving the weir away from the filter by 50, 100, and 150 mm. The flow patterns were also thoroughly examined. The results revealed that the presence of the filter increased the flow resistance within the tundish, leading to changes in the residence time distribution. This resulted in the formation of a 'dead zone' with a significantly prolonged residence time. The higher flow resistance hindered the entry and exit of particles from the last chamber of the tundish. As a result, the distribution of particles in the last chamber became more dispersed, reducing the detrimental effects of inclusions in the steel. The removal efficiency of the seven types of particles was improved by 2–7%. Furthermore, by moving the weir away from the filter by 50 mm, the removal ratio could be further increased by approximately 2%. [ABSTRACT FROM AUTHOR]

In this research, flume experiments were conducted on stepped weirs to investigate the effect of step shape on the energy dissipation of flow. Four configurations with a constant number of steps were considered, namely, horizontal steps, inclined steps, horizontal steps with rounded sills, and inclined steps with rounded sills. The slopes of inclined steps were 13% and 23%, and the diameters of the rounded sills of the step ends were 10 and 15 cm. The majority of previous studies focused on energy dissipation in stepped weirs in horizontal and inclined steps. In this research, new step geometries were used, such as horizontal steps with rounded sills and inclined steps with rounded sills. Dimensional analysis was applied to correlate the different variables affecting the flow hydraulics. Flow rates in the range of 0.61-9.12 lit/sec were used with each step shape. Results showed that the inclined steps with rounded sills had the highest flow energy dissipation in comparison to the other types. Rounded sills at the end of steps had more effective energy dissipation than did the horizontal step. However, the 23% inclination slope with rounded sills of a 7.5 cm radius was the most effective in dissipating flow energy. [ABSTRACT FROM AUTHOR]

Circular crested weirs have been used for a long time due to their simplicity in design, low cost and accurate measurement. The Computational Fluid Dynamics (CFD) based software ANSYS FLUENT has been used in this investigation. The CFD model has been applied to explore various flow features over a circular crested trapezoidal weir. The volume of fluid (VOF) technique was used in this work. Two weir conditions with and without roughness elements and three discharges values for each weir case were used. The flow characteristics investigated include coefficient of discharge, water surface profiles and velocity profiles. The roughness element remained submerged in all the simulation cases. The k-1 turbulence model was used for the CFD simulation. After validation, the flow characteristics like the free surface profiles, coefficient of discharge, vertical velocity profiles at the upstream and downstream of the weir and the velocity contours were investigated for varying discharges and roughness. A comparison was drawn for these properties for a channel with and without roughness element. [ABSTRACT FROM AUTHOR]

A piano key weir is a more modern type of hydraulic infrastructure designed to increase a dam's discharge in spillway hydraulics to release more flow and enhance performance. Piano key weirs are very important to increase the current system's discharge capacity, even though they can also be very effective in reducing reservoir flood stress. There are more benefits to piano key weirs than to labyrinth weirs. Due to its complex of shape, there is no standard design for a safe and economical design. In free flow conditions within an open channel, this study examines the energy dissipation and coefficient of discharge of trapezoidal piano key weirs under various geometric configurations. Using Piano key weir model to the flow direction and varying crest heights (Pi/Po = 1.00 cm, 1.17 cm, and 1.25 cm) a total of seven different discharges were utilized in an open channel flow. Here, Pi is the inlet crest height while Po is outlet crest height. This work aims to experimentally assess the impact of geometry on a piano key weir's energy dissipation (E) and coefficient of discharge (Cd). To determine the Cd in each of the experiment and flow depths have been recorded at up and downstream of the weir. The collected data showed that changing the geometric parameter, or crest height, have a significant impact on Cd. The results 32.5cm, 32cm and 30cm were found on higher heads (h/P >20) and 23cm, 22cm, 21.5 were found on lower heads (h/P<20). The 32.5 cm had the highest value of Cd, while the 21.5 cm had the lowest value of Cd. When considering energy dissipation, the rate of energy dissipation was found as 56% at lower heads and 44% at higher heads. However, Pi/Po = 1.17, and 1.25, the energy dissipation rate were found to be 2%, 4%, respectively lesser than Pi/Po=1.00. When the crest height was 22cm, the value of energy dissipation E was at its highest, and when it was 32.5cm, it was at its lowest. [ABSTRACT FROM AUTHOR]

Flood Frequency analysis is done for calculating flood peaks for different Return Periods. Hydraulic Structures like Dams, Bridges, Weirs and Barrages etc are designed on the basis of Flood Frequency Analysis. There are different statistical methods that are used to calculate Flood Frequency Analysis. Results are solely based on the quality and quantity of data and method employed for calculation of Flood Frequency Analysis. Typically, focus is given on only one type of method and there is always an ambiguity exists whether which method should be used. In this study Flood Frequency Analysis has been performed for Nallah Mahal Bagh AJK using all the major methods like Gumble's Extreme Value Distribution, Log Normal (LN), Log Pearson Type III (LP III) Distribution and General Extreme Value Distribution (GEV) to make a comparison of different methods used for prediction of maximum flood peaks of different return periods. After data collection from reliable source Flood frequency analysis was performed using all four methods by dividing the data into different data sets A, B, C and D and then results ware compared with original data. After Detailed investigation it can be established that Gumble's Extreme Value Method is the most suitable approach for predicting the peaks against different return periods. [ABSTRACT FROM AUTHOR]

Innovative structures called piano key weirs are used in hydraulic engineering to regulate flow. This study intends to investigate the effects of changes in the geometry of the piano key weir, namely the number of cycles, on discharge performance. The study looked at how a piano key weir's discharge capacity would change as the number of cycles changed. In this work, a series of controlled laboratory tests were carried out in which several piano key weir models were examined at various heads in the range of 0.042m to 0.078m. The findings showed that some modifications to the geometric parameters can have a substantial effect on the PKW's discharge efficiency. The piano key weir's discharge rates increased as the number of cycles was reduced, showing that fewer cycles enable better flow control and water management capabilities. Furthermore, the value of discharge capacity of PK weir with number of cycles 3 was found to be 3.36% and 5.95% greater than PK weir with number of cycles 4 and 5 respectively. The research's conclusions offer useful information for engineers and professionals working on water resource projects, assisting them in making wise choices when putting piano key weirs to use in practical situations. [ABSTRACT FROM AUTHOR]