Hydraulic Engineering Commons^™

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 …

Nappe Vibration Mitigation Techniques For Free-Overfall Structures, M. Lodomez, Brian Crookston, Blake Tullis, M. Pirotton, Sébastien Erpicum

International Symposium on Hydraulic Structures

Nappe vibration is a phenomenon that has been witnessed in the field for a variety of different free overflow hydraulic structures operating at low heads, such as fountains, crest gates, and weirs. This phenomenon is visually characterized by oscillations in the thin nappe cascading downstream of the control structure. These oscillations can produce a significant level of noise and acoustic pressure waves, which can increase the environmental and societal impacts of the hydraulic structure. As a result, a detailed investigation has been undertaken to identify practical and effective mitigation solutions for free-overfall structures where nappe vibration may be of concern. …

Investigating Supercritical Flows In Curved Open Channels With Three Dimensional Numerical Modeling, Kortney Brown, Brian Crookston

International Symposium on Hydraulic Structures

The flow patterns observed in supercritical flows at bends in open channels are encountered in spillways, canals, and drainage works – this complex flow condition has been investigated more than 80 years ago, first with hydraulic models and more recently using numerical models. This paper presents a numerical investigation using a selection of experimental data from Dr. A. T. Ippen and a commercially available 3-dimensional CFD solver. A comparison of the numerical results to the physical data is presented, highlighting the ability of the numerical models to reproduce these complex water surface profiles including the magnitude and location of standing …

Effect Of A Large Bed Roughness On Positive Surge Propagation In Canals, S. C. Yeow, H. Wang, H. Chanson

International Symposium on Hydraulic Structures

In open channels and water supply canals, the brusque operation of control valves and gate may induce large unsteady flow motion called surges. To date the literature focused on the propagation of surges in smooth canals, ignoring the effects of large roughness and debris. Herein a physical study was conducted under controlled flow conditions to study the turbulent mixing in the close vicinity of a large bed roughness element during the upstream propagation of positive surges. Detailed free-surface and instantaneous velocity measurements were conducted with and without the cylindrical element. For some tests, the experiments were repeated 25 times and …

Spillway Deflector Design Using Physical And Numerical Models, M. Politano, T. Lyons, K. Anderson, S. Parkinson, L. Weber

International Symposium on Hydraulic Structures

Elevated total dissolved gas (TDG) can be a serious threat to migrating fish. Gas supersaturation downstream of a dam occurs due to bubble dissolution in deep high-pressure regions in the tailrace. TDG production depends on both air entrainment and depth of entrained bubbles. Deflectors, installed at the spillway face, are designed to change the regular plunging jets into surface jets, where bubbles are transported in a thin surface layer minimizing dissolution. Distinct flow conditions may, however, occur depending on the deflector geometry, spillway flowrate, and tailwater elevation. Deflectors are commonly designed based on jet regimes observed in physical and CFD …

Steady And Unsteady Turbulent Velocity Profiling In Open Channel Flows Using The Adv Vectrino Ii Profiler, X. Leng, Hubert Chanson

International Symposium on Hydraulic Structures

The Nortek Vectrino II profiler acoustic Doppler velocimeter (ADV) was developed for velocity profiling. Herein the study aims to: 1) demonstrate the applicability of the ADV profiler to steady and rapidly-varied unsteady open channel flows, 2) check the data quality, based upon a new systematically comparative analysis with traditional ADV data, and 3) conduct a sensitivity analysis on ensemble-averaged data collection in a positive surge. This was achieved by performing systematically steady and unsteady velocity measurements under controlled flow conditions in a relatively large laboratory facility. All experiments were repeated 25 to 50 times for each controlled flow condition and …

Effect Of River Levee With Geosynthetic-Reinforced Soil Against Overflow Erosion And Infiltration, Y. Kurakami, Y. Nihei, M. Morita, S. Futami, M. Itakura

International Symposium on Hydraulic Structures

Overflows from huge floods have caused levee breaches in a great number of places, including Japan. To prevent such destruction and thereby increase the resistance of armored levees to overflow erosion, in this study, we examined the performances of Geosynthetic-Reinforced Soil (GRS) levees against overflow erosion under various conditions, such as reinforcement, back slopes, and geo-grid layers. In addition, we investigated the effect of geo-grid layers on the infiltration of levees. The model tests revealed that 1) with scour protection in front of the toe of the back slope, the GRS levee exhibits much higher resistance against overflow erosion than …

Design And Monitoring Of A Small Living Shoreline Scaled For Private Properties On Exposed, Rapidly-Eroding Coasts, D. D. Mcgehee

International Symposium on Hydraulic Structures

Living shorelines on the scale of individual private lots are almost exclusively built at sites with reduced wave exposure. This paper describes the design and post construction monitoring of a residential-property-scale living shoreline project on a rapidly eroding, exposed shoreline. The project site is on the north-eastern side of Mobile Bay, AL with a maximum fetch of 129 km. Pre-construction shoreline retreat locally has averaged -80 cm/year since 1997. The final design was modelled on the award-winning (and much larger) Project Greenshores Phase II built in 2007 in nearby Pensacola Bay, FL. The novel feature for both projects is a …

Experimental Study Of Large Scale Plunging Jets, G. Guyot, M. Rodriguez, Michael Pfister, J. P. Matas, A. Cartellier

International Symposium on Hydraulic Structures

The lack of knowledge regarding air entrainment caused by large jets in hydraulic structures, such as downstream Pelton turbines, has led EDF (Electricité de France) to carry out a test series to optimize the La Coche Power plant. The data extracted from this work have been used in the frame of a research project.

A first experiment, performed on a large jet impacting the free surface of an open channel, has confirmed that physical phenomena concerning the behavior of large scale plunging jets are still not well understoodThe main parameters that have been measured are: the penetration depth, the entrained …

Hydraulics Of Submerged Offset-Jets, Galla Ravi Kishore, Subhasish Dey

International Symposium on Hydraulic Structures

This study presents an experimental investigation of hydraulic characteristics of submerged offset jets. The instantaneous velocity was captured by an acoustic Doppler velocimeter (ADV). A total of 20 runs were carried out by varying different parameters: Reynolds number (28475−80730), offset ratio (3.16−6.2), jet Froude number (1.9−3), submergence parameter (0.65−2.82) and sluice gate openings (3, 3.5, 4, 4.5 and 5 cm). It is observed that the length of the reattachment depends on the relative offset height and the tail water depth. A mathematical formulation is developed for the submerged offset jet assuming a submerged jump in a drop structure to find …

Confined Disposal Facility Improved Weir Designs, C. K. Maglio, B. M. Scully

International Symposium on Hydraulic Structures

One of the initial constraints of any dredging project is deciding where to place dredged material. When placed upland, materials can be used beneficially, as beach nourishment or for habitat restoration, or can be placed in an upland confined disposal facility (CDF). Several times the solids volume in water is required to fluidized and hydraulically pump the materials. Once in the CDF, materials settle out of suspension, with clarified water decanted. This paper describes in general a current weir design used by the U.S. Army Corps of Engineers (USACE) and illustrates the innovations of the new Jacksonville District standard weir. …

Training Of A Few River Mouths Of Kerala Coast In India, V. Sundar, S. A. Sannasiraj

International Symposium on Hydraulic Structures

The coastal regions of Kerala are mostly dynamic in nature and is accentuated as the result of various developmental activities taking place along the coastline. Choking of river mouths and sand bar formation is a persistent perennial problem occurring in the tropical states of the Indian sub-continent during non-monsoon seasons. Predominant sediment transport is attributed as a major reason for this occurrence. Critical locations along the Kerala coast were identified to be Cheruvathur, Korapuzha and Chettuvai. Training of river mouths was identified as the long term solution for the aforementioned problem, and hence the same were proposed for construction after …

Piano Key Weir For Enlargement Of The West Fork Of Eno River Reservoir, B. M. Crookston, Loring Crowley, Michael Pfister

International Symposium on Hydraulic Structures

The West Fork of Eno River Reservoir Dam is located near Hillsborough, North Carolina, USA. The earthen embankment dam provides an impoundment used by the town for water supply. The project was originally completed in 2000 with forethought by the owner for an expansion, which was anticipated in the original design. Currently, the design of that expansion to raise the reservoir level for increased water supply is underway. Following a detailed analysis of viable upgrades, a piano key (PK) weir (anticipated as the first to be constructed in the USA) was selected by the owner due to its effectiveness in …

Numerical Modeling Of The Spillways For The Dam Raise At Isabella Dam, Laurie L. Ebner, S K. Askelson, E A. Thompson, Nathan C. Cox

International Symposium on Hydraulic Structures

The Sacramento District Corps of Engineers is designing modifications to the Isabella Dam located on the KernRiver in the Tulare Lake Basin in the southern portion of the San Joaquin Basin, in Kern County, California. These modifications include: raising the elevation of two high head dams (185 ft and 100 ft respectively) by 16 ft;modifying a service spillway to better suit the needs of flood capacity, and creating a new labyrinth weir emergency spillway. To aid in the design of both spillways, a series of three-dimensional (3D) computational fluid dynamics(CFD) models of the Isabella Reservoir and outlet works were developed. …

Sensitivity Analysis For Discharge Coefficients Of Piano Key Weirs, M. Oertel

International Symposium on Hydraulic Structures

Piano Key Weirs are relatively new weir structures which can be used as flood release structure at the top of a dam or as regular weir structure within a river system. The benefit of a PKW is an increased discharge capacity, and hence lower free surface heads at the upstream reservoir. During the last years several experimental and numerical research investigations were carried out to analyze discharge coefficients for various PKW types. Therefore, numerical 3D CFD codes and small-scaled experimental models were used. To identify discharge coefficients the Poleni formula can be used. By measuring the total discharge and the …

The Hydraulic Design Of An Arced Labyrinth Weir At Isabella Dam, E. A. Thompson, N. C. Cox, Laurie Ebner, Blake Tullis

International Symposium on Hydraulic Structures

The Sacramento District Corps of Engineers is designing modifications to the Isabella Dam located in Kern County, California. These modifications include creating a new arced labyrinth weir emergency spillway in order to safely pass the probable maximum flood (PMF).

The rating curve for the arced labyrinth weir was based upon information published in a PhD dissertation (Crookston, 2010), and a Master’s Thesis (Christensen, 2012) from Utah State University and a subsequent journal article (Crookston and Tullis 2012). The proposed prototype weir geometry was a 12-cycle arced labyrinth weir with a 16º sidewall angle. As the published hydraulic performance data were …

Towards A New Design Equation For Piano Key Weirs Discharge Capacity, H. Bashiri, B. Dewals, M. Pirotton, P. Archambeau, S. Erpicum

International Symposium on Hydraulic Structures

No abstract provided.

Influence Of Some Geometrical Parameters On Piano Key Weir Discharge Efficiency, G. M. Cicero

International Symposium on Hydraulic Structures

The Piano Key Weir (PKW) is a type of labyrinth weir with efficient hydraulic performance especially at low heads.Since the primary parameters were extensively studied, Electricité De France (EDF) launched a new experimental program to improve the knowledge of some secondary parameters such as the overhangs, the crest shape and the dam height. This program included the testing of a trapezoidal shape and of PKWs under submerged conditions.The data measured under free-flow conditions were also used to validate empirical correlations and numerical models Wolf 1D PKW and Flow 3D. This article gives an overview of the program and highlights the …

Mouth Of The Columbia River North Jetty Erosion Stabilization, C. C. Humphrey, B. J. Abel, H. R. Moritz

International Symposium on Hydraulic Structures

The mouth of the Columbia River (MCR), located at the river’s confluence with the Pacific Ocean between Oregon and Washington, is a critical regional and national gateway for trade and commerce. The MCR is protected and stabilized by three rubble-mound jetties, all of which are in need of major rehabilitation. In 2014 rehabilitation starting with construction of the North Jetty Lagoon Fill project.

Soon after construction of the North Jetty in 1917, deposition of sand caused the formation of a wide beach along the north side of the jetty, which helped protect much of the north side of the jetty …