Engineering Commons^™

Application Of The Optical Flow Method To Velocity Determination In Hydraulic Structure Models, D. B. Bung, Daniel Valero

International Symposium on Hydraulic Structures

Optical flow estimation is used in Computer Vision for detection of moving obstacles in a sequence of images. The optical flow (OF) is defined as the displacement of brightness patterns between two sequent images. In this paper,this method is applied to high-speed images taken in hydraulic structure models for determination of velocity fields.Water is seeded with tracer particles in two cases and is self-aerated in a third case. It will be shown that the OF method gives valuable results which compare well to other velocity measurements, e.g. by Particle ImageVelocimetry. The OF method is generally more time-consuming compared to PIV, …

Technical Developments In Fish Exclusion, Guidance, And Collection Materials, A. L. Peters

International Symposium on Hydraulic Structures

Construction of mills, dams and other structures in rivers and streams, and the withdrawal of water for irrigation or cooling industrial facilities vital to social and economic progress, have impacted the survival of marine life. Barriers and guidance or collection nets can protect fish and aquatic species while allowing water to flow unimpeded for commercial and industrial use. However, nets can attract aquatic growth, fill with debris, degrade with environmental stress, and be expensive to operate and maintain.

A closer look at the technical developments of materials and net designs in diverse settings can offer guidance that will be of …

Evaluation Of Spillway Stilling Basin Performance And Reservoir Sediment Flushing In A Physical Model Case Study: Due Hydroelectric Project In Ecuador, Ali Habibzadeh, Brian Hughes, Hernan Barahona

International Symposium on Hydraulic Structures

The Due Hydroelectric Project is a proposed 50 MW run-of-river hydroelectric project being developed by Hidroalto SA. The project will be located on the Rio Due in Ecuador. The civil works of the intake facility will be comprised of a 133.45 m wide diversion weir, with two overflow spillways and six gated sluice channels; a four bay intake structure with sediment excluder; and, a fish bypass facility. Northwest Hydraulic Consultants (NHC) evaluated the initial design of the Due intake and spillway facilities using a 1:35 Froude-scaled physical model for river discharges ranging from the intake design discharge of 57.2 m3 …

Impacts Of Tailwater On The Design Of Several Stilling Basins In The Usa, L. E. Shearin-Feimster

International Symposium on Hydraulic Structures

The dissipation of excess energy from flows exiting a spillway is often needed to prevent or reduce to acceptable levels conceivable negative impacts to the downstream channel, spillway, and dam (e.g., erosion, undermining). The optimization of a hydraulic jump type stilling basin using general purpose published design methodologies (i.e., USBR, SAF, etc.) for a project can be challenging, as these methodologies may not account for all site specific conditions and structure formulations by designers. Also, it is not often clear to a designer as to which flow rates (and corresponding flood events) will have the greatest influence on the basin …

A Risk Based Framework For Evaluating Gated Spillway Operations, Greg Paxson, Marty Mccann Jr, Mark Landis

International Symposium on Hydraulic Structures

Gated spillways are often necessary to provide both operational flexibility and discharge capacity to pass large flood events. However, gated spillways present operational challenges to dam owners and operators, often necessitating development of a flood operations plan (FOP) that is used in tandem with the dam’s emergency action plan (EAP). Even a well-intentioned and robust FOP/EAP can require personnel to predict flooding, use judgment particular to the requirements of the plan, and react quickly. In addition, all of the equipment required to operate the gates need to function as designed and be operated in accordance with the FOP.

This paper …

A Remotely Controlled Siphon System For Dynamic Water Storage Management, Arturo Leon, Ali Alnahit

International Symposium on Hydraulic Structures

Previous research has concluded that upland wetlands could be effective to control small floods, yet for large floods their value may be greatly reduced as their storage capacity may be exceeded. A potential solution could be to release water from wetlands ahead of (e.g., few days before) a heavy rainfall event that is forecasted to produce flooding. In this case, the wetlands would be partially empty when this rainfall occurs. This work is part of a long term project which aims at developing a decision support system (DSS) that will determine optimal flooding scenarios with dynamic management of wetlands using …

Unsteady-Flow Modeling For Emergency Shutdown Of The Cap Canal, Bert Clemmens, Brian Wahlin, Marcus Shapiro, Patrick Dent

International Symposium on Hydraulic Structures

The Central Arizona Project (CAP) is designed to bring about 1.9 ML of Colorado River water per year to Maricopa, Pima, and Pinal counties in Arizona. CAP carries water from the Colorado River at Lake Havasu toTucson. The CAP canal system is a 540 km long system of conveyance system aqueducts, tunnels, pumping plants,pipelines and a large reservoir (just north of Phoenix, AZ). Water is pumped uphill from the Colorado River. This study was conducted for the Hayden-Rhodes Aqueduct of the Central Arizona Project (CAP), which starts at the after bay of the Bouse Hill Pumping Plant and extends to …

Managing Dam Safety Risks Related To Hydraulic Structures, W. R. Fiedler

International Symposium on Hydraulic Structures

The Bureau of Reclamation’s Dam Safety Program manages risk for over 300 high and significant hazard dams.When risk estimates for potential failure modes indicate increasing justification to take action to reduce risk, dam safety recommendations are typically made. The dam safety recommendations can focus on collecting additional data/performing studies to better quantify risk or on initiating corrective actions to address well defined risks. Dam safety recommendations within Reclamation’s inventory address a number of different issues, such as those related to internal erosion, flood overtopping of dams and seismic stability of dams. Dam safety recommendations related to hydraulic structure potential failure …

Decision-Making Through Sustainability, F. Pardo-Bosch, A. Aguado

International Symposium on Hydraulic Structures

From immemorial time, dams have contributed significantly for the progress of civilizations. For this reason, nowadays, there is a vast engineering heritage. Over the years, these infrastructures can present some ordinary maintenance issues associated with their normal operation or with ageing processes.

Normally, these problems do not represent an important risk for the structure, but they have to be attended. To do it, owners of dams have to finance many ordinary interventions. As it is impossible to carry out all of them at the same time, managers have to make a decision and select the most “important” ones. However, it …

Water System Operator Training For The Central Arizona Project, Brian Wahlin, Bert Clemmens

International Symposium on Hydraulic Structures

The Central Arizona Project (CAP) is designed to bring about 1.85 billion cubic meters (1.5 million acre-feet) of Colorado River water per year to Maricopa, Pima, and Pinal counties in Arizona. The CAP canal system is a 540-km (336-mile) long system of conveyance aqueducts, tunnels, pumping plants, and pipelines that is monitored and remotely controlled using Supervisory Control and Data Acquisition (SCADA) software from CAP headquarters in Phoenix, AZ. Because the CAP is crucial to the renewable water supply in Arizona, operating the canal effectively is of utmost importance. Typical day-to-day operations for Water System Operators on the CAP involve …

Junction Chamber At Vortex Drop Shaft: Case Study Of Cossonay, G. Crispino, D. Dorthe, T. Fuchsmann, C. Gisonni, M. Pfister

International Symposium on Hydraulic Structures

The drainage network of the city of Cossonay (Switzerland) is currently being adapted for future needs. In particular, it is required to drain increased storm discharges due to a population augmentation, and to provide an adequate concept to overcome unfavorable geotechnical conditions.

Vortex drop shafts are sewer manholes commonly applied in steep urbanized topographies to connect conduits across large elevation differences. In Cossonay, the existing 48 m high vortex drop shaft, with a diameter of 1.5 m, allowed the storm discharge to flow from the city to a watercourse issued at half of the valley height. The discharge capacity was …

Experimental Study Of Head Loss Over Laser Scanned Rock Tunnel, L. R. Andersson, I. A.S. Larsson, J. G.I. Hellstrom, P. Andreasson, A. G. Andersson

International Symposium on Hydraulic Structures

Flow in hydropower tunnels is characterized by high Reynolds number and often very rough rock walls. Due to the roughness of the walls, the flow in the tunnel is highly disturbed, resulting in large fluctuations of velocity and pressure in both time and space. Erosion problems and even partial collapse of tunnel walls are in some cases believed to be caused by hydraulic jacking from large flow induced pressure fluctuations. The objective of this work is to investigate the effects of the rough walls on the pressure variations in time and space over the rock surfaces. Pressure measurement experiments were …

Effects Of Hydraulic Jump Motion On Air Entrainment In Closed Conduits, J. D. Mortensen, J P. Kubitschek

International Symposium on Hydraulic Structures

Air vent systems are designed to protect hydropower penstocks and reservoir outlets under various operating conditions. During an emergency closure of an upstream gate the hydraulic jump that forms downstream of the gate is not stationary and may advance downstream potentially increasing the total air demand. A lab-scale physical model of a general outlet works piping configuration was constructed at Reclamation’s Hydraulics Laboratory in Denver, CO to observe hydraulic jump behavior during emergency gate closures. Parameters including gate discharge, gate closure rate, air vent size, and downstream pipe pressure were tested at two different pipe slopes. Results indicate that the …

Numerical Investigation Of The Flow Field Inside A Manhole-Pipe Drainage System, Md Nazmul Azim Beg, Rita Carvalho, Pedro Lopes, Jorge Leandro, Nuno Melo

International Symposium on Hydraulic Structures

Urban drainage networks contain a large number of structures. Manhole is the most common and the most important as it connects pieces of sewer pipes to form sewer networks. Understanding the hydraulics of a manhole-pipe drainage system is either important as this may sometimes become the bottlenecks of the sewer systems. In this study, the flow structure and flow hydraulics of a specific manhole-pipe sewer system was analysed numerically in view of further research to investigate sediment/ suspended solid transport in the system. The numerical model was compared with discharge and water pressure/depth data from experimental model. Different discharges and …

Determining Optimal Discharge And Optimal Penstock Diameter In Water Turbines, Arturo S. Leon

International Symposium on Hydraulic Structures

Minimizing water consumption for producing hydropower is critical given that overuse of flows for energy production may result in a shortage of flows for other purposes such as irrigation and navigation. This paper presents a dimensional analysis for finding optimal flow discharge and optimal penstock diameter when designing impulse and reaction water turbines for hydropower systems. The objective of this analysis is to provide general insights for minimizing water consumption when producing hydropower. This analysis is based on the geometric and hydraulic characteristics of the penstock, the total hydraulic head and the desired power production. As part of this analysis, …

Predicting Velocity At Limit Of Deposition In Storm Channels Using Two Data Mining Techniques, H. Bonakdari, I. Ebtehaj

International Symposium on Hydraulic Structures

In storm channel system design, the system should have the ability to transfer the entire input flow to the system as well as prevent sediment settling. Existing methods of determining the velocity at limit of deposition are minimum velocity or regression-based equations. Because minimum velocity methods fail to consider the effective flow and sediment transfer parameters, while regression-based equations are not flexible in terms of various hydraulic conditions and they do not perform well. Thus, using such equations leads to a lack of designs with optimum, confident coefficients. In this study, Extreme Learning Machines (ELM) are employed to predict velocity …

Stepped Chute Training Wall Height Requirements, S. L. Hunt, K. C. Kadavy

International Symposium on Hydraulic Structures

Stepped chutes are commonly used for overtopping protection for embankment dams. Aerated flow is commonly associated with stepped chutes if the chute has sufficient length. The aeration and turbulence of the flow can create a significant amount of splash over the training wall if not appropriately accounted for in the design of the structure. According to the United States Department of Agriculture (USDA)-Natural Resources Conservation Service (NRCS) Technical Release 60 Earth Dams and Reservoirs, a structural spillway should be designed to pass the freeboard hydrograph such that it does not cause serious damage to the embankment or the structure itself. …

Cabinet Gorge Dam Spillway Modifications For Tdg Abatement - Design Evolution And Field Performance, S. L. Dunlop, I. A. Willig, G. E. Paul

International Symposium on Hydraulic Structures

Avista is implementing spillway modifications to reduce TDG supersaturation downstream of Cabinet Gorge Dam.The key feature of the modifications is the addition of roughness elements, similar to supercavitating baffle blocks,to break up the spillway jet thereby reducing the depth of plunge and TDG supersaturation. The work is progressing in a step-wise manner. A single bay was modified in 2012 and field tested in 2013. Following the initial field tests, aCFD model was developed to aid in design refinements for the prototype and to improve the design prior to modification of subsequent spillway bays. The prototype demonstrated that spillway modifications are …

Turbulence And Energy Dissipation In The Developing Non-Aerated And The Fully-Developed Aerated Flows On A Stepped Spillway, G. Zhang, H. Chanson

International Symposium on Hydraulic Structures

Stepped spillways are characterised by highly turbulent air-water flows and a large rate of energy dissipation compared to smooth chutes. Herein detailed measurements were performed in both the developing non-aerated and fully-developed air-water flow regions on a large 1V:1H stepped spillway model. In the developing flow region, large total pressure fluctuations and turbulence intensities were recorded next to the pseudo-bottom. Downstream of the inception point, large total pressure fluctuations were recorded which were mainly induced by density fluctuations. The water turbulence intensities in the air-water flow region did not differ significantly from those in the developing flow region. The steps …

Free-Surface Aeration In A Steep Stepped Spillway, G. Zhang, H. Chanson

International Symposium on Hydraulic Structures

Self-aeration has important civil and environmental applications in stepped chutes, ranging from cavitation protection to enhanced air-water mass transfer. Air bubble entrainment occurs when the turbulent stresses in the boundary layer exceed the combined effects of surface tension and buoyancy. The governing equations for air diffusion in the rapidly-varied region next to, and in the gradually-varied region away from the inception point of aeration are introduced. New and existing solutions to these equations are discussed and compared with new experimental data. An analytical model for flow bulking is introduced. The concept of negative diffusivity is discussed.

Physical Modeling Of An Aerating Stepped Spillway, S. Erpicum, M. Lodomez, J. Savatier, P. Archambeau, B. J. Dewals, M. Pirotton

International Symposium on Hydraulic Structures

To mitigate the negative effects on the water quality in the downstream river of a projected large dam, and in particular to increase the dissolved oxygen concentration during low flow periods within the first 10 years of dam operation, an aerating weir has been designed and tested on a physical model at the Laboratory of Engineering Hydraulics (HECE) of the Liege University. The design of the structure has been done considering data from the literature. The selected solution is a 3 m high stepped spillway designed to operate in nappe flow conditions within the range of design discharges (25 – …

Effect Of Deflector Aerator On Stepped Spillway Flow, Stéphane Terrier, Michael Pfister, Anton J. Schleiss

International Symposium on Hydraulic Structures

Systematic physical model tests are performed on a stepped spillway equipped with a bottom aerator at the beginning of the stepped part. A deflector is used to issue a jet in order to initiate air entrainment into the flow. A horizontal slot located in the vertical face of the first step allows for air supply underneath the flow. The cavity subpressure was measured to ensure optimal aerator performance, namely atmospheric pressure conditions. The air discharge entrained below the jet is measured to derive the aerator air entrainment coefficient. The local air concentrations are spatially measured downstream of the aerator at …

Tsallis Entropy Theory For Hydraulic Modeling, Vijay P. Singh

International Symposium on Hydraulic Structures

Hydraulic structures serve a multitude of human needs. They are needed for water supply, water transfer, water diversion, irrigation, land reclamation, drainage, flood control, hydropower generation, river training, navigation, coastal protection, pollution abatement, and transportation. Many of the structures, such as channels, culverts, and impoundments, have been with us since the birth of human civilization; some, such as spillways, dams, and levees, are more than two centuries old; and some are of more recent origin. In the beginning, structures were designed more or less empirically. Then, engineering and economics constituted the sole foundation of design. Nearly fifty years ago, planning …

Columbia River Treaty And System Reservoir Operations, Pete Dickerson

International Symposium on Hydraulic Structures

The river headwaters of the Columbia River originate in British Columbia and ultimately enter the Pacific Ocean near Astoria, Oregon (1,214 miles). About 15% of the basin is in Canada, and 35% of the average annual flow comes from Canada (as measured at The Dalles, Oregon). Historically, the largest flood run-offs occur in the spring, primarily driven by snowmelt. The basin has the most hydropower capacity, ~37 GW, in North America. U.S. federal projects are authorized to meet multiple purposes: flood risk, hydropower, fish and wildlife, navigation, irrigation, recreation, and municipal and water supply.

Colorado River System - Planning And Operations During Extended Drought, Daniel Bunk

International Symposium on Hydraulic Structures

Today, between 35 and 40 million people rely on the Colorado River and its tributaries for some, if not all, of their municipal water needs. These same water sources irrigate nearly 4.5 million acres (1.8 million hectares) of land within the basin and adjacent areas that receive Colorado River water. The Colorado River and its tributaries also provide essential cultural and economic resources to 22 federally recognized tribes, as well as recreational opportunities and environmental benefits to 11 National Park Service units and seven national wildlife refuges. Additionally, the Colorado River is a vital resource to the United Mexican States …

Management Of River System Flows, Keil Neff

International Symposium on Hydraulic Structures

The Tennessee Valley Authority (TVA) operates a system of 49 dams and reservoirs in the Tennessee River and Cumberland River watersheds of the southeastern United States. TVA operates this system for the purposes of navigation, flood control and power production; management of water supply, water quality and aquatic habitat; and recreation and other public benefits. TVA, created by the U.S. Congress under the TVA Act of 1933, is the largest public power supplier in the U.S. and is fully self-financed with no federal appropriations. The Tennessee River is the only basin in the U.S. that is operated by a single …

Reconfiguring, Replumbing, And Repurposing Hydraulic Structures - Responding To New Realities, P. H. Burgi

International Symposium on Hydraulic Structures

We look into an ever-changing future filled with challenges to continue developing new water resources but with an increased emphasis on water conservation and preserving our natural environment. This is a different approach to that of the 20^th century, where the emphasis was generally on development of water resources. As water engineers and managers facing an increasingly limited water supply, our challenge is to build, and in some cases change, infrastructure for a resilient future. The built infrastructure for water systems must protect life and provide a safe living environment, including an adequate supply and quality of fresh water. …

Continuing Sediment Management At Mount St. Helens: Raising The Spillway Of The Sediment Retention Structure, J. P. Britton, C. J. Nygaard, S. J. Schlenker

International Symposium on Hydraulic Structures

The Sediment Retention Structure (SRS) was constructed by the U.S. Army Corps of Engineers (USACE) from 1987 – 1989 to trap sediment eroding from the Mount St. Helens debris avalanche, for the purpose of maintaining flood risk levels downstream in the Cowlitz River. In 1998 the operation of the SRS changed and the sediment trapping efficiency decreased. The USACE began studies and an alternatives analysis to identify a long-term plan given the current conditions. The studies and alternatives analysis led to a preferred adaptive-management plan including up to three incremental SRS spillway raises to trap more sediment. The first spillway …

Experimental Study Of Sequent Depths Ratio Of Hydraulic Jump In Sloped Trapezoidal Chanel, Sonia Cherhabil, Mahmoud Debabeche

International Symposium on Hydraulic Structures

The hydraulic jump in a sloped trapezoidal channel of 72.68°sides inclination angle is experimentally examined.The study aims to determine the effect of the channel’s slope on the sequent depths ratio of the jump. An experimental analysis is proposed to determine experimental relationships of the inflow Froude number as a function of the sequent depth ratio of the jump and the channel slope. For this purpose, positive and negative slopes are tested.

Cross-Section Influence On Velocity Distribution & Energy Dissipation Of A Moderately Sloped Spillway Chute Flow, A. Tohidi, Farzam Safarzadeh Maleki

International Symposium on Hydraulic Structures

Erosion at the dam toe due to potential to kinetic energy conversion of the outlet release is a complex yet fascinating engineering challenge. The energy dissipation due to flow separation at sharp cornered geometries effects the flow stream and causes the lower velocity at the dam’s toe. To date, many of the conventional dam engineering techniques consider the dam toe as the examination point. In this research, by the use of OpenFOAM numerical model, the water flow in the spillway chute is modeled. The velocity profile of the chute flow in three different cross-sections is considered for the same outlet …