Hydraulic Engineering Commons^™

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 …