Hydraulic Engineering Commons^™

Piano Key Weir With Orifice Sluice, Dau Xuan Thuy

4th International Workshop on Labyrinth and Piano Key Weirs

In recent years, many Piano Key Weirs (PKW) have been built around the world. In Vietnam there are more than 18 PKWs in operation to the present. However, during the operation, some experience has been drawn on the design and application conditions. This paper is about the Dak Mi 3 reservoir with a PKW that operated well for more than 4 years until an exceptional flood following typhoons in October 2020, making reservoir fully filled with mud and sand. The result is the PKW became ineffective and the hydropower plant unable to operate. In order to dredge the reservoir and …

Honey, I Shrunk The Pk Weir: A Case Study Of Burton Pond Dam, David Bisio

4th International Workshop on Labyrinth and Piano Key Weirs

Between a low-head tidal environment, razor-thin hydraulic margins, and a long list of site restrictions, the Burton Pond Dam Rehabilitation project offered the chance to pursue a one-of-a-kind solution: a miniature stainless steel piano key weir as part of a new mixed active-passive spillway. This case study will explore how established hydraulic designs were modified specifically for the site and verified with computational flow dynamics; how the innovative cantilevered geometry was analyzed structurally with finite element modeling; and how detailing, fabrication and constructability were considered throughout the design process. From conceptual-level design submissions to the final construction walkthrough, the whole …

Research And Application Of Piano Key Weirs In Vietnam (2025), M. Ho Ta Khanh, Dau Xuan Thuy

4th International Workshop on Labyrinth and Piano Key Weirs

Since the Piano Key Weirs (PKW) were introduced by F. Lempérière and A. Ouamane (2003) many such structures have been built for irrigation, hydroelectricity and water regulation due to their outstanding efficiency. In Vietnam, PKWs have also attracted significant attention. There have been several laboratory hydraulic model studies to test the discharge capacity, flow characteristics, and energy dissipation downstream the spillway. Vietnam had also issued PKW design standard for easy of application in 2018. This paper describes shortly 18 Piano Key Weirs in operation in Vietnam (among other existing PKWs) : Dak Mi 4B, Dak Mi 3, Dak Rong 3, …

Lessons Learned From The Hydraulic Design Of The Prado Dam Labyrinth Spillway, Yajayra Diaz, Mike Phillips, Brian M. Crookston, Julie D. Allen

4th International Workshop on Labyrinth and Piano Key Weirs

The U.S. Army Corps of Engineers has completed the design of a new labyrinth weir spillway at Prado Dam, in southern California. The proposed labyrinth weir would consist of an arced configuration, 7-cycles, with varying weir wall height from 28 ft to 41 ft with upstream head over the weir cycles of up to 30 ft. This paper highlights the key lessons learned from the hydraulic design of the new labyrinth weir, including significant fluctuating negative pressures at the weir wall resulting in hydrodynamic loads that should be considered during structural design and submergence of the weir at high heads.

Investigation Of Flow Field Near A Type-A Piano Key Weir, S. Hussain, M. S. Quamar, Z. Ahmad

4th International Workshop on Labyrinth and Piano Key Weirs

Piano Key Weirs (PKWs) enhance spillway capacity and induce complex flow patterns around their inlet and outlet keys. This study investigates the flow near a Type-A PKW using Computational Fluid Dynamics (CFD). Velocity fields in the vicinity of the PKW keys were analyzed for different discharges and validated with the experimental results. As flow approaches the inlet key, the streamwise, vertical, and lateral velocity components increase significantly, with the highest velocities near the inlet key. However, near the outlet key the streamwise velocity decreases while the vertical and lateral components increase. For all the discharges, the maximum velocity was observed …

Key Width Ratio Influence On Discharge Coefficients Of Trapezoidal Piano Key Weirs Via Openfoam Simulations, Lisa Lüddecke, Mario Oertel

4th International Workshop on Labyrinth and Piano Key Weirs

Piano key weirs are characterized by complex three-dimensional flow structures with multiple parameters describing their geometry. The variation of these parameters can affect several flow characteristics such as efficiency, energy dissipation and air entrainment. Identifying the optimal geometry for enhanced hydraulic performance represents a significant challenge. Physical or numerical modeling of multiple geometric variants is necessary to identify the relevant optimal parameters. The key width ratio (between an inlet and an outlet key) represents one of the parameters that influences the hydraulic behavior of the piano key weir. In particular, it affects the discharge coefficient, which in turn affects the …

Experimental And Numerical Investigation Of A-Type Rectangular Side Piano Key Weir, Sabir Hussain, Zulfequar Ahmad

4th International Workshop on Labyrinth and Piano Key Weirs

A side weir is a structure installed along the side wall of a channel, serving multiple purposes, such as raising water levels for irrigation and drainage and diverting excess flow from rivers or channels during floods. Most studies have focused so far on linear rectangular and labyrinth side weirs, with relatively limited research conducted on side Piano key weirs. In this paper, an experimental and numerical simulation was performed on an A-type rectangular side piano key weir and a rectangular sharp-crested side weir. The diversion discharge of Piano key side weirs was within the range of ± 10% with numerical …

Sensitivity Analysis Of Piano-Key Weirs Design: Optimizing Discharge Performance Through Cfd Modeling And Empirical Insights, Fatna Oukaili, Yvan Bercovitz, Thomas Fonty, Benoit Blancher, Julien Vermeulen

4th International Workshop on Labyrinth and Piano Key Weirs

Piano-key weirs (PKWs) are widely recognized for their efficiency in enhancing spillway discharge capacity while maintaining a compact footprint. This study focuses on a parametric and sensitivity analysis of PKW discharge performance, exploring the influence of key design parameters on hydraulic behavior. By integrating experimental data with advanced computational fluid dynamics (CFD) modeling using the open-source code_saturne software, we aim to refine predictive capabilities and establish guidelines for effective PKW design. The analysis emphasizes understanding the interplay between PKW geometry and flow characteristics. The analysis considers a range of geometrical configurations, including variations in key width ratios, and inlet-to-outlet dimensions, …

An Innovative Use Of Piano Key Weirs Or Labyrinth Weirs For Long Dams In Plains, Michel Ho Ta Khanh

4th International Workshop on Labyrinth and Piano Key Weirs

Piano Key Weirs (PKW) are labyrinth type weirs but with upstream and/or downstream overhangs which allow them to have a reduced footprint at their base. The new solution of a combination of gates and PKW (or labyrinth weir) for a long dams has many advantages of costs for investment, operation and safety during high floods. If a new dam is built on a broad river where a large footprint is possible, the choice between a PKW and a labyrinth weir can arise as the difference of specific discharges of the two alternatives are relatively small and the construction of the …

An Innovative Association Of Fusegate And Pk-Weir, F. Lempérière, A. Chapuis, F. Del Rey, C. Bessière

4th International Workshop on Labyrinth and Piano Key Weirs

The combination on the same dam of Piano Key weir (PK-Weir) and fusible structures offers a highly effective passive solution for managing flood discharges. This concept first introduced by Hydrocoop in 2015 as « Innovative Associated Spillways » can leverage the strength of each system. More than 30 years after its first application, the returns of experience of the Hydroplus Fusegate® system applications on more than 80 dams in 25 different countries have confirmed their reliability in terms of sequentially overturning on the downstream side for the correct design flood. With their high discharge capacity at low head, PK-Weirs optimize …

Enhancing The Hydraulic Efficiency Of Piano Key Weir (Pkw) — Some Research Achievements, James Yang, Shicheng Li, Anders Ansell, Erik Skepparkrans, Chen Lin

4th International Workshop on Labyrinth and Piano Key Weirs

As an effective flood control structure, the piano key weir (PKW) typically features a rectangular planform for its overhangs. However, this design offers room for improvement. To enhance hydraulic efficiency, two modified PKW layouts are proposed. In the first, the floor of each key is lowered with a semicircular cross-section, forming an elliptical planform and crest. In the second, the floor is lowered with an isosceles triangular prism, creating an equilateral triangular overhang. Both modified PKW models, manufactured by 3D printing, were tested in a large-scale experimental setup. Compared to the reference weir, the elliptical-overhang PKW increases the developed crest …

Theoretical And Experimental Studies Of Non-Rectilinear Weirs -From Labyrinth To Pk-Weir, Ahmed Ouamane, François Lempérière

4th International Workshop on Labyrinth and Piano Key Weirs

Free-flow rectilinear spillways, while simpler and safer than gated or shaft spillways, have a low specific discharge, requiring a significant water head and resulting in a storage loss of more than 20% for some small reservoirs. To overcome this drawback, labyrinth weirs provide an effective alternative, allowing high discharge under a reduced head while maintaining lower construction and maintenance costs. For several decades, global research has focused on optimizing their design. In this context, a research project was initiated in 1995 at the University of Biskra to enhance the understanding of the hydraulic behavior of these structures. This project was …

Physical Model Investigations On Nappe Instabilities At Labyrinth Weirs, Michael Gebhardt, Fabian Belzner

4th International Workshop on Labyrinth and Piano Key Weirs

Free overflow hydraulic structures operating at low heads tend to develop nappe instabilities when there is no ventilation. A detailed investigation has been undertaken with a relatively large-scale labyrinth weir in the hydraulic laboratory of the BAW. A quarter-round crest was selected, because nappe instabilities mainly occur at sharp-crested weirs, which favor the development of an air pocket behind the nappe. The headwater ratios for which nappe instabilities could be observed were determined. Pressure fluctuations were measured and the frequencies determined. Adding splitters to the crest is one way to vent the air pocket and to avoid vibrations. Another possibility …

Model-Prototype Upscaling Of Pkw Discharge Capacity, James Yang, Pär Nilsen, Mats Billstein, L Johnsson, Shicheng Li

4th International Workshop on Labyrinth and Piano Key Weirs

In Sweden, many dams are undergoing upgrades to comply with the revised dam safety guidelines, which mandate higher spillway discharge capacities that their existing ones. As part of an ongoing project, a piano key weir (PKW) is proposed to replace an embankment dam and simultaneously increase the facility’s discharge capacity. The PKW configuration is evaluated in a 2 m wide flume at two geometric scales (1:35 and 1:12) to assess potential scale effects. The former comprises eight units, while the latter includes three, with all components produced using 3D printing. Results indicate that the 1:35 model exhibits a slightly lower …

Interfacial Velocity Characteristics Downstream Of A Piano Key Weir Versus A Linear Weir In A Horizontal Channel, Biruk Belay, Mario Oertel

4th International Workshop on Labyrinth and Piano Key Weirs

The downstream flow characteristics of piano key weirs (PKWs) are highly complex, manifested by significant localized self-aeration due to nape collisions and plunging jets impacting the downstream free-surface. For PKWs installed in horizontal channels, the interfacial velocity characteristics have received limited attention in previous research. In this experimental study, air-water flow measurements were conducted using a double-tip conductivity probe downstream of a PKW and a reference ogee-crested linear weir to evaluate the velocity trends under comparable hydraulic boundary conditions. The findings reveal the existence of two distinct velocity profiles downstream of piano key weirs: quasi-wall-jet and uniform profiles. The occurrence …

Floating Trees At Co-Existing Pkw & Gated Spillway, James Yang, A. Helgesson, L. Johnsson, Sc Li

4th International Workshop on Labyrinth and Piano Key Weirs

During extreme flood events, floating trees (driftwood) can pose serious risks to the safety and operation of dams. In upgrading an existing dam, a piano key weir (PKW) is introduced to replace the aging embankment dam and to increase the discharge capacity of its gated spillway. This upgrade necessitates a detailed understanding of driftwood behavior at both discharge structures, which differ significantly in design and operating conditions. To investigate this, hydraulic model tests were conducted using small, freshly cut trees—some with branches and roots—to simulate natural trees moving towards the dam. The results indicate that tree accumulation at the gated …

The Performance Of Satellite-Based Precipitation Data To Reproduce Observed Precipitation In Tanzania's Little Ruaha Catchment, Florence H. Mahay

Tanzania Journal of Engineering and Technology (TJET)

Satellite-based precipitation datasets have emerged as promising tools for addressing rainfall data scarcity in regions with limited ground observations, such as Sub-Saharan Africa. This study evaluates the performance of five satellite-based precipitation products CHIRPS, CPC, GPCC, MERRA-2, and ERA5 in capturing rainfall characteristics over the Little Ruaha Catchment in Tanzania. The assessment was carried out at daily, monthly, and seasonal timescales and focused on key rainfall indices including onset and cessation dates, length of the rainy season, total rainfall, and frequency of rainy days. Validation was conducted using statistical indicators such as the correlation coefficient (r), Nash–Sutcliffe Efficiency (NSE), Root …

Morphological Changes Downstream Beni-Suef Bridge On The Nile River In Egypt, Muhammad Ahmad Abdul-Muttalib, Ahmed Moustafa Moussa, Gamal Helmy Elsaeed, Suzan Ahmed Mohammed

Journal of Engineering Research

The construction of the Beni-Suef bridge, spanning 550 meters over the Nile River, resulted in sediment accumulation and hindered navigation. This study investigates the causes of the morphodynamic changes and explores the impact of dredging as a mitigation measure through the area which extended approximately 2.6 kilometers downstream the bridge. A one-dimensional numerical model (HEC-RAS) was employed, utilizing bathymetric surveyed cross-sections from 1982, 2002, and 2004, along with discharge data from downstream Assuit Barrage and water levels from upstream Delta Barrage as boundary inputs. The model was calibrated and validated using measured water and bed levels. Sediment properties and bed …

Assessment Of Safety Monitoring Indexes Of High Rcc Gravity Dams Considering Hydraulic Fracture, Mohamed Ramdan, Jinsheng Jia Professor, Xu Li Professor

Journal of Engineering Research

High concrete gravity dams, particularly Roller-Compacted Concrete (RCC) types, face long-term safety challenges due to weak interlayer formation and crack propagation. This study presents a comprehensive evaluation of safety monitoring indexes for the Guxian high RCC dam (currently under construction in China) using both numerical and theoretical models. A Finite Element Method (FEM) was applied with two approaches: the strength reduction method, which considers weak layers, and the overloading method, which simulates extreme loading without accounting for material degradation. A comparative analysis between these two methods was conducted to determine which more effectively evaluates dam safety under varying conditions. Additionally, …

Using Hydraulic Simulations To Determine The Effects Of Tidal Behavior And Riparian Restoration On Chorro Creek, Jonathan L. Maas

Master's Theses

This thesis examines how tidal backwater effects and riparian restoration influence flooding in the Chorro Creek watershed, a major tributary to the Morro Bay Estuary on California’s Central Coast. Restoration efforts, including levee removal, floodplain reconnection, and revegetation have attempted to improve ecological function and reduce sediment transport. However, recent flood events suggest that these changes may also affect local hydraulics in ways not fully anticipated, particularly under the influence of tides and sea level rise. To analyze these dynamics, a two-dimensional HEC-RAS model was developed using LiDAR terrain, historical imagery, and field data collected from pressure and ultrasonic gauges. …

Stormwater Treatment Practices - Guidance For Maintenance And Targeting Pollutants, Peter T. Weiss

Stormwater Drainage Conference

Stormwater Drainage Conference

Biochar-Based Filtration And Barrier Systems For Urban Stormwater Treatment, Krishna R. Reddy

Stormwater Drainage Conference

Conference that deals a wide range of issues dealing with stormwater drainage. Professor Krishna Reddy of University of Illinois Chicago presented an invited talk titled "Biochar-Based Filtration and Barrier Systems for Urban Stormwater Treatment"

Gradually Varied Flow In Horizontal Circular Open Channels, Sanaa M. Hashim, I.M.H. Rashwan, Hewida Omara

Journal of Engineering Research

In investigations of gradually varied flow, open channels are categorized according to bed slope as horizontal, mild, critical, steep, and adverse. A canal is referred to as horizontal if its bed slope is zero. In open-channel hydraulics, calculating the water surface profile in an open channel is regarded as a crucial part of channel design. The objective of this present study is to solve the gradually varied flow in open circular channel with horizontal slope by using two mathematical methods called; direct integration method and Runge-Kutta method. The presented study used the experimental works to offer an explicit closed-form semi-analytical …

Flow Characteristics In Open Channel Confluences: Comparison Of Different Turbulence Models, Abdelrahman Mostafa Elazab None, Ibrahim Mohamed Rashwan, H. Omara

Journal of Engineering Research

This study uses numerical simulations in ANSYS Fluent to analyze the flow characteristics of open channel confluences. The primary objective is to assess the accuracy and predictive performance of three widely used turbulence models: the standard k–ε, the realizable k–ε, and the k–ω SST models. Simulations were performed under steady-state conditions. The results were validated against experimental data. Comparative analysis based on roots mean square error (RMSE) and flow behavior evaluation shows that all models can capture the main flow structures. However, the k–ω SST model demonstrated superior agreement with the experimental results, exhibiting the lowest RMSE and providing the …

An Eulerian-Pfem Approach To Model Transient Capillary Forces On Moving Contact Lines Of Spreading Liquid Drops: Applications In Hydraulic And Fluid Dynamics, Elaf N. Mahrous, Syed Yousufuddin, Muhammad Saleem Professor, Mohammed N. Iqbal, Muhammad T. Bin-Saleem

Journal of Engineering Research

This study addresses the complexities of simulating multiphase flows, particularly the dynamics of droplet behaviour on solid substrates, which are influenced by intricate capillary interactions. Despite advancements in fixed-grid and moving-grid methodologies, there remains a critical gap in accurately modelling transient phenomena and dissipative forces at the solid-liquid interface. We introduce a novel Eulerian-particle finite element method (PFEM) framework that captures the transient capillary forces associated with the movement of contact lines in liquid droplet spreading scenarios. Through a numerical assessment of three established dissipative force models—Jiang’s, Bracke’s, and Seeberg’s we identify Jiang's model as the most effective and stable …

Using Hydrologic And Hydraulic Simulations To Predict Near-Term Effects Of Beaver Habitat Restoration On Flood Flows, Luke S. Stewart

Master's Theses

There is a growing need to predict the complex hydrologic and hydraulic effects of beaver-maintained wetlands. This study uses relatively simple inputs and a replicable methodology to predict flood flow impacts of beaver habitat restoration at the site design scale using the engineering industry’s customary hydrology and hydraulic modeling approach. This study focuses on Toro Creek, the primary drainage for a 15.2 square mile watershed on the California Central Coast.

A hydrologic model of Toro Creek watershed was developed in HEC-HMS to approximate saturated soil conditions typical of late-spring flooding events observed in the region. The hydrologic model was calibrated …

Hickory Street Square Revitalization, Spencer Knight, Grace Dungan, Tim Kula, Evan Lauritsen, Lindsey Mennenga

Honors Program: Senior Projects (Public)

The Hickory Street Square Revitalization Project seeks to transform a central public space in Sidney, Nebraska into a dynamic, community-oriented area that supports local events, economic activity, and cultural heritage. The project addresses six core objectives: 1) convertible street design, 2) parking lot reconfiguration, 3) public amenities, 4) event flexibility, 5) lighting and signage, and 6) old electric plant renovation. A conceptual design was developed by the design team (S.T.E.E.L. Sentinel Solutions) by synthesizing the most effective features of three preliminary alternatives, shaped further through community feedback and evolving project constraints. The final project design minimizes disruption to existing activity …

Analysis Of Hydrological Model Uncertainty In The Response Of Farmers' Decision Models: A Case Study From The Lower Mississippi River Basin Region, Aayush Khadka

LSU New Orleans Theses and Dissertations

Ever since human have evolved on planet earth, they have been dependent on water resources for almost every aspect of their lives. From food production to industry, water has been an integral part of the ever-growing human civilization. Increasing reliance on water has resulted in development of effective and sustainable management strategies. However, water management has remained a complex task due to different human and natural stressors. Hydro-economic models are powerful tools that have been widely used to study water resource systems, management options, economic values, and infrastructures. They have been used to analyze the Water-Energy-Food nexus, climatic interactions, and …

Irrigation Performance Connection To Water Quality In Big Creek, Sena Bildim

All Graduate Theses and Dissertations, Fall 2023 to Present

Due to new technologies and improved water management strategies, sprinkler irrigation systems are becoming more common in Utah and nearby areas. These systems are generally thought to be more efficient, but their effects on water quality are not well understood. This study focuses on the Big Creek watershed, which flows into Bear Lake—an area where water quality concerns are increasing.

The purpose of this research was to explore how different irrigation systems—sprinkler and surface—affect both water use and water quality. Field tests were conducted to measure how evenly water was applied and how efficient each system was. Water and soil …

Exploring Variations In High-Resolution Downstream Hydraulic Geometry Of The Logan River, Gabriel V. Benitez

All Graduate Theses and Dissertations, Fall 2023 to Present

Rivers are dynamic systems that change shape due to natural events like floods, landslides, and wildfires, as well as human-made structures like bridges. These changes create unique and complex river patterns. However, measuring these changes accurately is challenging because traditional field surveys are time-consuming and often focus on easily accessible areas, which may not represent the whole river. Thanks to new high-resolution mapping technology and detailed river flow records, we can now see these changes in greater detail than ever before.

In this study, we focused on the Logan River, which flows through a canyon with a mix of rocky …