Engineering Commons^™

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 …

Assessment Of Equilibrium Scour By A Submerged Circular Turbulent Impinging Jet In Cohesive Soils, Mahmud Rashedul Amin, Kerry Mazurek

International Symposium on Hydraulic Structures

In this paper, results from a study where detailed measurements of the time development of the scour holes produced by a submerged circular vertical impinging jet in cohesive soils from long-term scour tests are presented. This type of jet is the one used in the ASTM standard Jet Erodiblity Test, which relies on measurements of the time development of scour for prediction of soil erodibility parameters. In the experiments, measurements of the entire scour hole were taken on a 2 mm grid using a computer-controlled laser displacement meter after scouring times of 5 min, 10 min, 15 min, 20 min, …

Articulating Concrete Blocks: The Long And Winding Road, J. A. Nadeau

International Symposium on Hydraulic Structures

This paper will provide an overview of Articulating Concrete Blocks (ACB’s) from three perspectives: 1. the Manufacturer, 2. The Engineer and 3. The Researcher and how these independent entities interact with each other and the regulatory community to further the scientific understanding and use of ACB systems. ACB’s, since their development in the late 1970’s, represent a growing choice of design engineers in economically solving their critical erosion prevention problems as well as a variety of other non-hydraulic applications. Typical applications of ACB’s are found in protecting channels and canals, dam spillways and embankments, bridge piers and abutments, river bank …

Scouring Processes Downstream A Crossbar Block Ramp, M. Oertel, Daniel Bung

International Symposium on Hydraulic Structures

Crossbar block ramps are hydraulic structures to conquer large river bottom steps via several pool-step-systems. Due to reduced velocities and increased flow depths, fish climb capability can be given. Several authors investigated crossbar block ramp variations to determine flow resistance, energy dissipation and bed stability features on the structure. But also the downstream end of the structure must be taken into account concerning scouring processes to guarantee the structure’s stability and to reduce damage during flood events. The present paper presents a comprehensive experimental investigation program dealing with scouring processes downstream a crossbar block ramp. Influences by ramp slope, discharge …

Visual And Photogrammetric Observations Of An Internal Erosion Failure, T. L. Wahl, R. V. Rinehart, M. J. Klein, J. B. Rittgers

International Symposium on Hydraulic Structures

A 0.91-m (3-ft) high, homogeneous, silty clay embankment was tested to investigate erosion processes occurring during failure by internal erosion. The embankment was constructed in a 3.79-m (12.44-ft) wide test flume equipped with a clear acrylic viewing window at the abutment where failure was initiated. Failure was initiated at mid-height when an embedded 12-mm (½-inch) diameter rebar was removed from the embankment. The test lasted approximately 48 minutes, and during that time the erosion pipe enlarged dramatically. The test was stopped just before the collapse of the soil bridge over the enlarged pipe.

Erosion was visually monitored during the test …

Shear Stress Distribution Prediction In Circular Channels Using Tsallis Entropy, H. Bonakdari, Z. Sheikh Khozani

International Symposium on Hydraulic Structures

Detailed knowledge of flow and shear stress distribution in channels is essential in accurately calculating the rates of sediment transport and deposition for geomorphic adjustment. Circular cross sections are usual in sewer channels and the sedimentation of suspended material is a significant matter in such sections. In this study, an analytical model is extended to predict the shear stress distribution in circular channels based Tsallis entropy concept. A new formula for estimating shear stress distribution in circular channels is derived by maximizing the Tsallis entropy subject to mass conservation. The distribution derived from the Tsallis entropy is examined using experimental …

Folsom Dam Auxiliary Spillway – Design Innovations And Construction Lessons Learned, C. Y. Wan, C. M. Nolan

International Symposium on Hydraulic Structures

The new Folsom Dam Auxiliary Spillway gated Control Structure, part of the overarching Joint Federal Project, was recently completed. To make operation and maintenance activities for this activity more user-friendly, this project implemented innovative designs, and a select few related to the tainter gate (seals, dogging system, and anchor inspection access) are presented in this paper. This project also provided additional monitoring capacity to the trunnion anchors, both during and post-construction, both physical and data, with great results. Further, this paper discusses some lessons learned on tainter gate specifications during gate construction and installation. Building and bridge construction specifications were …

Discharge Correlations For Spillways With Radial Gates, Gerald A. Schohl

International Symposium on Hydraulic Structures

Equations used at the Tennessee Valley Authority (TVA) to compute free and gated (orifice) discharges through spillways with radial gates are presented along with correlations based on TVA model test data for discharge coefficients and submergence factors. The correlations and data may be applicable for estimating discharges through gated spillways that are similar to those at TVA and for which specific model test data are unavailable. Included in this paper, perhaps for the first time in the literature, are correlations and data indicating for given gate opening the headwater at which flow begins the transition from free discharge to gated …

State-Of-The-Practice Review Of Maintenance Closure Structures For Large Spillway Gates, C. M. Johnson, R. T. Indri, F. G. Snider, S. M. Planck, K. F. De Lapp

International Symposium on Hydraulic Structures

Maintenance, remediation, and inspection of large spillway gates are best performed in a dry, dewatered state due to reduced overall cost, worker safety, and improved work quality. Provision for gate dewatering has become a key design consideration for new spillways. Unfortunately, many existing spillways were not originally constructed with gate dewatering capabilities. Therefore, maintenance and inspection work has often been scheduled during planned drawdowns or seasonally low reservoir levels. However, for operators of hydroelectric, flood control, water supply, and multi-purpose dams, artificial drawdowns can significantly impact operations, flood protection, downstream habitat, and revenue generation. Aging gates deteriorate and require significant …

Advanced Gate Operation Strategies In Hec-Ras 5.0, C. R. Goodell

International Symposium on Hydraulic Structures

The Hydrologic Engineering Center’s River Analysis System (HEC-RAS) is designed for computing water surface profiles and inundation maps, but it is also able to handle flow through gated structures using a variety of equation sand techniques. HEC-RAS has a small selection of built-in gate types, representing some of the more common gates that are used for controlling flow at dams and canal structures. Each gate type in HEC-RAS has a set of empirical equations that are used to compute head loss through the structure for a given flow. There are also two operational schemes that can be chosen for gates: …

Designing A Steel Gate Dam Across An Ephemeral River – Tempe Town Lake Dam Design, Stewart S. Vaghti, Dean B. Durkee, Andrew J. Lynch

International Symposium on Hydraulic Structures

After the existing Tempe Town Lake downstream dam failed unexpectedly in 2010, the City of Tempe, AZ, USA was tasked with designing and constructing a replacement dam to maintain their lake, pass flows in the ephemeral Salt River, and deliberately lower to avert flooding. Through an alternatives evaluation process, a hydraulically operated steel gate system was selected from a field of twenty studied alternative configurations to replace the existing rubber bladder system.

The gate design produced eight 32.3 meter (106 foot) long, 6.4 meter (21 foot) tall, and 118,000 kilogram (260,000 pound) steel gates operated by single-acting hydraulic cylinders and …

Usace Portland District Spillway Gate Rehabilitation Program, Laurie Ebner, William Fortuny, David Hamernik, Matthew Hess, Mark Sawka

International Symposium on Hydraulic Structures

The U.S. Army Corps of Engineers (USACE) Portland District has 90 spillway radial Tainter gates. There are 42 gates at the 11 Willamette Valley Basin projects, 5 gates at the two Rogue Basin projects and 43 gates at the two Columbia River projects. Since 2001 there have been various studies, inspections and incidents that have prompted the Portland District to become concerned about the structural integrity and mechanical and electrical reliability of these gates. In 2008, load induced buckling was observed on three of the four Tainter gate end frames at Foster Dam which led to emergency repairs. Additional observations …

Hydraulic Structures-The Future Of Design, Thomas North

International Symposium on Hydraulic Structures

The state of the art of design of hydraulic structures is changing rapidly. Although hydraulic structures include a broad spectrum of applications, there is an increasing need for specialization in planning, design, materials, construction, risk and hazard assessment, aging infrastructure, and lifecycle maintenance.

Today’s role of hydraulic structures involves improving water management practices, water quality, and environmental restoration and protection. Hydraulic design has expanded to include water planning as well as improvements in the design, construction, operation, and maintenance of locks, dams, spillways, and outlet works. The challenges affecting planning and design involve understanding the role of government policies, economics, …