Lessons Learned From The Hydraulic Design Of The Prado Dam Labyrinth Spillway,
2025
USACE Risk Management Center
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,
2025
IIT Roorkee
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,
2025
Helmut-Schmidt University
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,
2025
IIT Roorkee
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,
2025
EDF-R&D
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,
2025
VNCOLD- CFBR Independent Consultant
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,
2025
Hydrocoop
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,
2025
Royal Institute of Technology
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,
2025
University of Biskra - Algeria
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,
2025
Federal Waterways Engineering and Research Institute
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,
2025
Vattenfall
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,
2025
Helmut-Schmidt-University Hamburg
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,
2025
Vattenfall R&D
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,
2025
Department of Water Resources, University of Dar es Salaam, P.O. Box 35131 Dar es Salaam, Tanzania
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,
2025
Assistant Professor, Civil Engineering Department, Faculty of Engineering at Shoubra, Benha University, Egypt
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,
2025
Beijing Jiaotong University
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,
2025
California Polytechnic State University, San Luis Obispo
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,
2025
Valparaiso University
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,
2025
University of Illinois Chicago
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,
2025
Faculty of Engineering of Tanta University
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 …
