DOCSLIB.ORG

Flow Rate Equation for Suppressed and Submerged Sluice Gates ITRC Report No

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Flow Rate Equation for Suppressed and Submerged Sluice Gates ITRC Report No Flow Rate Equation for Suppressed and Submerged Sluice Gates www.itrc.org/reports/sluicegate.htm ITRC Report No. R 20-001 Flow Rate Equation for Suppressed and Submerged Sluice Gates Prepared by Charles M. Burt Albert J. Clemmens Kyle Feist May 2020 IRRIGATION TRAINING & RESEARCH CENTER California Polytechnic State University San Luis Obispo, CA 93407-0730 Office Phone: (805) 756-2434 FAX: (805) 756-2433 www.itrc.org Reference to any specific process, product or service by manufacturer, trade name, trademark or otherwise does not necessarily imply endorsement or recommendation of use by either California Polytechnic State University, the Irrigation Training & Research Center, or any other party mentioned in this document. No party makes any warranty, express or implied and assumes no legal liability or responsibility for the accuracy or completeness of any apparatus, product, process or data described. This report was prepared by ITRC as an account of work done to date. All designs and cost estimates are subject to final confirmation. Flow Rate Equation for Suppressed and Submerged Sluice Gates www.itrc.org/reports/sluicegate.htm ITRC Report No. R 20-001 Acknowledgements This work was funded by the California Dept. of Water Resources (Agreement No. 4600011908) and the USBR Mid-Pacific Region. Notation The following symbols are used in this report: a = relative gate opening; B = horizontal dimension of the rectangular sluice gate opening; Cc = a dimensionless contraction coefficient equaling the ratio of the area of the vena contracta to the area of the gate opening; Cd = discharge coefficient; CdBos = Bos (1989) adjusted Cd; Cdcomb = Cd combining concepts in Bos (1989) and Belaud et al (2009); Cdadj = adjusted Cd; CP = contracted portion; Cv = a dimensionless coefficient, accounting for the velocity head of approach; Cva = a dimensionless coefficient, accounting for the water head only but does not fully account for the velocity head of approach; Cvf = a dimensionless correction factor for the velocity distribution and friction losses; g = gravitation acceleration constant; H = head, or water depth above the horizontal floor; Q = flow rate; R = a dimensionless ratio related to the suppressed versus contracted perimeter; W = vertical dimension of the rectangular sluice gate opening; Y = water depth; Y1 = water depth measured approximately 2.2 m upstream of the gate; Y1A = water depth immediately upstream of the sluice gate; Y2freeflow = shallowest water depth downstream of the gate in a free-flow condition; Y2submerged = shallowest depth for a submerged condition; Y3 = Water depth downstream of the gate, beyond any turbulence Z = a “best fit” factor in a discharge equation by Bos (1989). Irrigation Training & Research Center i Flow Rate Equation for Suppressed and Submerged Sluice Gates www.itrc.org/reports/sluicegate.htm ITRC Report No. R 20-001 Table of Contents Introduction ............................................................................................................................ 1 Theory ...................................................................................................................................................... 2 Experiment .............................................................................................................................. 5 Test Conditions ........................................................................................................................................ 5 Data Analysis ............................................................................................................................................ 7 Submerged Discharge Coefficient Determination ................................................................................. 10 Conclusions ........................................................................................................................... 14 References............................................................................................................................. 15 List of Figures Figure 1. Profile view of a sluice gate – horizontal floor .............................................................................. 2 Figure 2. Contraction coefficient as a function of relative gate opening. Submerged sluice gate ............. 4 Figure 3. Plan view of 374 mm wide sluice gate dimensions. All dimensions are mm. Flow is from left to right. ................................................................................................................................. 5 Figure 4. Side view of 374 mm wide sluice gate dimensions. All dimensions are mm. .............................. 5 0.5 Figure 5. Cd for submerged conditions where Q = Cd A (2gΔH) .............................................................. 10 Figure 6. Predicted flow rates versus measured (actual), using CdBos ........................................................ 11 Figure 7. Cdadj versus a for submerged sluice gates, where Cdadj = Cd /(1 + .9 B/(B+W)) ............................ 12 Figure 8. Predicted flow rates versus actual, using the new Cdcomb ........................................................... 13 Figure 9. Comparison of predicted versus measured submerged sluice gate flows using three techniques for estimating a discharge coefficient ................................................................... 13 List of Tables Table 1. Data from submerged sluice gates .................................................................................................. 8 Irrigation Training & Research Center ii Flow Rate Equation for Suppressed and Submerged Sluice Gates www.itrc.org/reports/sluicegate.htm ITRC Report No. R 20-001 Flow Rate Equation for Suppressed and Submerged Sluice Gates Introduction In irrigation projects, the control and measurement of flow rates at key bifurcation points is essential. Flumes in canals can be excellent measurement devices, but in some cases, they can be expensive and can have maintenance issues. A key limitation is that they require enough head (difference in water level across the flume) for accuracy. Acoustic Doppler flow meters and other similar devices can have problems including high cost, the need for excellent calibration, the need to average data for at least 30 minutes, and early failures. Sluice gates are often used at the heads of canals and at turnouts (offtakes) in irrigation districts to control flows, and sometimes to estimate flow rates. They are also increasingly used as combination flow control and flow measurement structures, for which programmable logic controllers (PLCs) measure upstream and downstream water levels and gate openings, and automatically adjust gate openings to maintain a constant target flow rate. Using sluice gates for accurate flow measurement has proven to be problematic because of the uncertainty regarding what discharge coefficient to use in the flow rate equation. There are numerous entrance and exit conditions of sluice gates in the field, including how far side gate frames extend into the flow path, floor steps (either up or down), length of upstream walls, orientation of the gates to the main canal flow, and exit conditions. Upstream and downstream water levels are measured in a wide variety of locations; some automated gate manufacturers attach upstream and downstream water level sensors to the gate frame itself, while other engineers specify water level sensors completely upstream and/or downstream of gate entrance sections. The differences result in theoretical and practical differences between the constants that must be used in any flow rate equation. Furthermore, there are submerged, free flow, and “uncertain” or “transition” hydraulic conditions as related to downstream water levels. Belaud et al (2009) noted that there can be large deviations between models and discharge measurements. Although a wide range of entrance and exit conditions can exist in the field, the specific condition of rectangular sluice gates with suppressed sides and bottom is of interest because ITRC frequently designs gates with those configurations and has felt that existing formulas were inadequate based on occasional comparisons with current meters and various acoustic doppler flow meters. Furthermore, there are many large-scale installations, such as in Sindh Province of Pakistan that have suppressed sluice gates already installed. An empirical understanding of what conditions gave predictable results was pursued. This empirical approach, obtained without a complete organization of the theory behind the answers, has provided long-standing hydraulics solutions using dimensionless variables such as the Moody diagram, which describes (but does not explain) pipe friction. Irrigation Training & Research Center 1 Flow Rate Equation for Suppressed and Submerged Sluice Gates www.itrc.org/reports/sluicegate.htm ITRC Report No. R 20-001 Theory Pertinent hydraulic variables for submerged and free flow conditions are frequently illustrated as in Figure 1. Figure 1. Profile view of a sluice gate – horizontal floor Y2freeflow is defined as the shallowest water depth downstream of the gate for a free-flow condition. Y2submerged is defined as the shallowest depth downstream of the gate for a submerged condition. The head (H) in a flat channel for any section is defined as the water depth above the floor. The difference in head, used in various discharge equations, is defined as: ΔH = Y1 – Y3 (Eq. 1) The general equation to compute the flow rate through a sluice gate
Load more

Recommended publications
  • Development of the Canal Lock
    Notes on the early technical development of European canal locks Mike Clarke 8 Green Bank Barnoldswick BB18 6HX [email protected] 2011 1 Stockholm Edinburgh Belfast Newry Canal Dublin Liverpool Rivers Kennet Alster Navigation and Hamburg Thames Amsterdam River Havel Stecknitz Berlin Warsaw Canal River Spree London See inset Bruxelles Prague Paris Canal de Briare Strasbourg Spaarndam Amsterdam Montreuil-Bellay Vienna Gouda Tienhoven Munich Brielle BudapestVreeswijk Canal du Nivernais Damme Willebroeke Brugge Bruxelles Naviglio Grande Milan Venice Canal de Bereguard Governolo Belgrade 250 Km 250 Mi. Location of places mentioned in the text A view of a navigable staunch in East Anglia, England, showing a typical vertical lifting gateof a type which has been in use from the earliest days of navigable passages in river weirs and flood prevention embankments. Front cover: The lock at Montreuil-Bellay on the River Thouet in France has been converted from a flash lock into a chamber lock by the addition of side walls and a lower gate. 2 The Early Technical Development of European Canal Locks In Europe from the tenth century, lock construction On his flood protection embankments, sluices developed from two types of usage. The first was were used to control the passage of water from one land drainage associated with tidal and river flood side of the embankment to the other. They quickly defense. The earliest examples were built in the Low developed from simple lifting gates, or a flat valve in a Countries, especially in the area between Brussels tunnel to the gates controlling a passage wide enough and Amsterdam.
    [Show full text]
  • C. Rynne Waterpower and Sustainable Energy in 19 Th -Century 147 Europe and the USA
    european journal of ppostclascsicalarchaaeologies volume 10/2020 SAP Società Archeologica s.r.l. Mantova 2020 pca EDITORS EDITORIAL BOARD Gian Pietro Brogiolo (chief editor) Paul Arthur (Università del Salento) Alexandra Chavarría (executive editor) Margarita Díaz-Andreu (ICREA - Universitat de Barcelona) José M. Martín Civantos (Universidad de Granada) ADVISORY BOARD Girolamo Fiorentino (Università del Salento) Martin Carver (University of York) Caterina Giostra (Università Cattolica del Sacro Cuore di Milano) Matthew H. Johnson (Northwestern University of Chicago) Susanne Hakenbeck (University of Cambridge) Giuliano Volpe (Università degli Studi di Foggia) Vasco La Salvia (Università degli Studi G. D’Annunzio di Chieti e Pescara) Marco Valenti (Università degli Studi di Siena) Bastien Lefebvre (Université Toulouse - Jean Jaurès) Alberto León (Universidad de Córdoba) ASSISTANT EDITOR Tamara Lewit (University of Melbourne) Federico Marazzi (Università degli Studi Suor Orsola Benincasa di Napoli) Francesca Benetti Dieter Quast (Römisch-Germanisches Zentralmuseum Mainz) Andrew Reynolds (University College London) Mauro Rottoli (Laboratorio di archeobiologia dei Musei Civici di Como) Colin Rynne (University College Cork) Post-Classical Archaeologies (PCA) is an independent, international, peer-reviewed journal devoted to the communication of post-classical research. PCA publishes a variety of manuscript types, including original research, discussions and review ar - ticles. Topics of interest include all subjects that relate to the science and practice of archaeology, particularly multidiscipli - nary research which use specialist methodologies, such as zooarchaeology, paleobotany, archaeometallurgy, archaeome - try, spatial analysis, as well as other experimental methodologies applied to the archaeology of post-classical Europe. Submission of a manuscript implies that the work has not been published before, that it is not under consideration for publication elsewhere and that it has been approved by all co-authors.
    [Show full text]
  • CLAVERTON PUMPING STATION David Rivers
    BIAS JOURNAL No 6 1973 Page No. 13 BIAS JOURNAL No 6 1973 CLAVERTON PUMPING STATION David Rivers History The waterwheel-powered water-pumping station at being adopted for the replacement segments manu- Claverton, near Bath, is an important industrial monu- factured by the G.W.R. The original type of junction ment not only because it is now a unique example of can be seen on the two old segments. During the this application for a waterwheel, but it is also period when shut down for this repair, the main shaft an essential feature in the operation of the Kennet and journals on the water wheel were machined and new Avon Canal in the Limpley Stoke valley. brasses fitted. The eastern journal was supported on pads and the shaft turned using water power. The pumping station was built between 1809 and 1813 to supply water to the Nine Mile Pound which extends Following this, the pumping station gave its regular from the top of the Widcombe flight of seven locks in service, operating for 24 hours per day through 9 Bath to the next lock at Bradford on Avon. The canal months of the year; until in 1952, due to lack of has been hampered ever since its construction by leak- maintenance about 50 of the wooden gear teeth were age on the short section from Limpley Stoke road sheared off the pit wheel. These wooden teeth were bridge to Avoncliffe aqueduct, and the flow from higher almost certainly those fitted when the new rim was up the canal was not considered adequate to compen- fitted and had thus given over 20 years service.
    [Show full text]
  • Scouring Downstream of Sluice Gate
    Conference Paper, Published Version Lim, Siow-Yong; Yu, Guoliang Scouring Downstream of Sluice Gate Verfügbar unter/Available at: https://hdl.handle.net/20.500.11970/100350 Vorgeschlagene Zitierweise/Suggested citation: Lim, Siow-Yong; Yu, Guoliang (2002): Scouring Downstream of Sluice Gate. In: Chen, Hamn- Ching; Briaud, Jean-Louis (Hg.): First International Conference on Scour of Foundations. November 17-20, 2002, College Station, USA. College Station, Texas: Texas Transportation Inst., Publications Dept.. S. 395-409. Standardnutzungsbedingungen/Terms of Use: Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichenden Nutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, die Weiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung der Namensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license is applicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the material of the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms of the restrictive license will be binding. First International Conference on Scour of Foundations, ICSF-1 Texas A&M University, College Station, Texas, USA November 17-20, 2002 SCOURING DOWNSTREAM OF SLUICE GATE Scouring Downstream of Sluice Gate By Siow-Yong Lim1 and Guoliang Yu2 ABSTRACT This paper presents the results of an extensive experimental study on local scour caused by high velocity jets issuing from submerged sluice gates or 2-D jet outlets.
    [Show full text]
  • Part 1 - River Brue and Tidal Sections of the Rivers Parrett and Tone
    Opportunities for further dredging in Somerset Part 1 - River Brue and tidal sections of the Rivers Parrett and Tone MCR5576-RT001-R03-00 October 2016 Opportunities for further dredging in Somerset Part 1 - River Brue and tidal sections of the Rivers Parrett and Tone Document information Document permissions Confidential - client Project number MCR5576 Project name Opportunities for further dredging in Somerset Report title Part 1 - River Brue and tidal sections of the Rivers Parrett and Tone Report number RT001 Release number R03-00 Report date October 2016 Client Somerset Rivers Authority (SRA) Client representative Iain Sturdy and Nick Stevens Project manager David Ramsbottom Project director Mark Lee Document history Date Release Prepared Approved Authorised Notes 27 Oct 2016 03-00 DMR DSM DMR Addition of changes requested by the SRA 07 Jul 2016 02-00 DMR MWL DMR Final version taking account of comments from the SRA 06 May 2016 01-00 DSM DMR DMR Document authorisation Prepared Approved Authorised © HR Wallingford Ltd This report has been prepared for HR Wallingford’s client and not for any other person. Only our client should rely upon the contents of this report and any methods or results which are contained within it and then only for the purposes for which the report was originally prepared. We accept no liability for any loss or damage suffered by any person who has relied on the contents of this report, other than our client. This report may contain material or information obtained from other people. We accept no liability for any loss or damage suffered by any person, including our client, as a result of any error or inaccuracy in third party material or information which is included within this report.
    [Show full text]
  • Teachers Notes About the Project
    Page 43 PCP Teachers Notes 1—About The Parrett Catchment Project The Parrett Catchment Project (PCP) is a partnership, established in 2000, whose long term goal is to reduce the frequent and severe flooding in the lower river Parrett basin. The partnership can do this by developing a way to manage the use of land and water which can easily be continued but with mini- mal long term effects on the environment (i.e. is sustainable). The partnership’s way of managing land and water will also need to try and benefit the economic, social and cultural life of the River Parrett catchment and protect and improve the environment for future generations. The Parrett catchment covers half of Somerset, incorporating 180 parish councils and approximately 138,000 households. The major towns in the catchment are Bridgwater, Taunton, and Yeovil. The catchment covers lots of different scenery from the arable uplands around Sherborne to the wet grass- lands of the Somerset Levels and Moors. Twenty seven stakeholder organisations now form the PCP partnership. The project is paid for by a group of nine organisations, including Somerset County Council and the Environment Agency. In 2002 the PCP also won lots of financial support and recognition as part of the European ‘Joint Approach for Managing Flooding’ (JAF) project. The JAF project also gets money from the Environment Agency. The money from the JAF project has enabled the PCP to deliver its innovative ‘Farming Water’ pro- gramme, which is made up of a number of demonstration and awareness raising projects: · Flood retention schemes · Flood storage schemes · Woodland development · Arable reversion to grassland · Soil management · Monitoring The JAF project also encourages co-operative working with partner organisations in Germany and The Netherlands, where there are lots of existing programmes already that provide ‘Farming Water’ schemes.
    [Show full text]
  • Alaskan Placer Mining School of Mineral Engineering and Alaska Miners Association
    MIRL Report Number 69 Sixth Annual Conference on Alaskan Placer Mining School of Mineral Engineering and Alaska Miners Association March 28 - 29, 1984 Fine Arts Concert Hall University of Alaska Fairbanks, Alaska An abridged format of papers, presentations and addresses given during the 1984 conference compiled and edited by: Daniel E. Walsh, M. Susan Wray ACKNOWLEDGEMENTS This report is an abridged transcription of the papers and presentations given at the Sixth Annual Conference on Alaskan Placer Mining, held on March 28-29, 1984, and co-sponsored by the School of Mineral Engineering, University of Alaska, Fairbanks, and the Alaska Miners Association. The editors wish to thank those speakers who submitted a manuscript, or pro- vided photos and illustrations to accompany their paper, greatly contributing to the accuracy and value of these proceedings. Published by Mineral Industry Research Laboratory School of Mineral Engineering University of Alaska, Fairbanks Fairbanks, Alaska 9 Printet %Ragor Less P.O. Box 298, Delta Juncaon,Alaska 99737 Conference Committee James Madonna School of Mineral Engineering, Mining Extension Leah Madonna Alaska Miners Association Del Ackels Resident, Circle Mining District Jeff Burton School of Mineral Engineering David Maneval School of Mineral Engineering Rose Rybachek Alaska Women in Mining John Sims Office of Mineral Development, ADCED Don Stein Alaska Miners Association Dan Walsh School of Mineral Engineering, MIRL iii Table of Contents Page Acknowledgements ........................................................................................i
    [Show full text]
  • Design of Locks Part 1
    DESIGNDESIGN OFOF LOCKSLOCKS 1 Ministry of Transport, Public Works and Water Management Civil Engineering Division Directorate-General Public Works and Water Management Design of locks Part 1 Table of contents part 1: Foreword 1. Introduction 1-1 1.1 Locks in the Netherlands 1-1 1.2 Objective 1-2 1.3 Overview of content 1-2 1.4 Justification 1-3 2. Program of Requirements 2-1 2.1 Introduction 2-1 2.2 Preconditions 2-2 2.2.1 Topography 2-2 2.2.2 Existing lock (locks) 2-2 2.2.3 Water levels (approx.) 2-2 2.2.4 Wind 2-3 2.2.5 Morphology 2-3 2.2.6 Soil characteristics 2-3 2.3 Functional requirements 2-4 2.3.1 Functional requirements regarding navigation 2-4 2.3.1.1 General 2-4 2.3.1.2 Lock approaches 2-5 2.3.1.3 Leading jetties 2-6 2.3.1.4 Chamber and heads 2-6 2.3.2 Functional requirements regarding the water retaining (structure) 2-7 2.3.3 Functional requirements regarding water management 2-8 2.3.3.1 General 2-8 2.3.3.2 Limiting water loss 2-8 2.3.3.3 Separation of salt and fresh water or clean and polluted water 2-9 2.3.3.4 Water intake and discharge 2-9 2.3.4 Functional requirements regarding the crossing, dry infrastructure 2-10 2.3.4.1 Roads 2-10 2.3.4.2 Cables and mains 2-11 2.4 User requirements 2-13 2.4.1 Levels 2-13 2.4.1.1 Locking levels 2-13 2.4.1.2 Design levels 2-14 2.4.2 Possible preference for separating different kinds of vessels 2-15 2.4.2.1 Separation in using line-up area, waiting area and chamber 2-15 2.4.2.2 Separation for use of the leading jetty 2-16 2.4.3 Mooring facilities in chamber and lock approach 2-17 2.4.3.1
    [Show full text]
  • A Nineteenth Century Watermill in Central Florida
    University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2017 Against the Flow: A Nineteenth Century Watermill in Central Florida Elizabeth Chance Campbell University of Central Florida Part of the Anthropology Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Masters Thesis (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Chance Campbell, Elizabeth, "Against the Flow: A Nineteenth Century Watermill in Central Florida" (2017). Electronic Theses and Dissertations, 2004-2019. 5350. https://stars.library.ucf.edu/etd/5350 AGAINST THE FLOW: A NINETEENTH CENTURY WATERMILL IN CENTRAL FLORIDA by ELIZABETH GAYL CHANCE CAMPBELL B.A. University of Central Florida, 2009 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Anthropology in the College of Sciences at the University of Central Florida Orlando, FL Spring Term 2017 ABSTRACT Small community watermills in Central Florida have gone virtually undocumented archaeologically and little is known about them except for written historical accounts. In an effort to determine how a settler in 1866 Florida would have used prior technological knowledge to design, build, and use a watermill I used a GIS predictive model to locate a previously undocumented watermill built in what is now Seminole County Florida. After the mill was located, excavations were conducted to determine the size of the mill structures, the industrial capacity of the mill, and determine the construction methods employed to build the mill.
    [Show full text]
  • Watermill at No Mill Could Have Been Created Without the Millwright, and No Historical Background Complete Without His Mention
    H.H.L Carpenter Liverpool College of Higher Education The Watermill at No mill could have been created without the millwright, and no historical background complete without his mention. Millwrighting was a craft which grew up with the invention of the water and windmills. It was a completely adaptable craft, for Bunbury no two mills were ever the same. It had no previous technologies to guide it, except for the construction that now remains of the 1960 complex, which of the wheel itself and the construction of the comprised the mill itself, stables and an engine shed. building. Both of these crafts came together under The miller still occupies the mill house which stands the jurisdiction of the one man who had to adapt 100 m. away. them to his needs. The wheel needed modifying The present structure is a three storied brick to take the strains imposed upon it and, more building on a sandstone foundation which is built importantly, for cogs or paddles to be fitted. into the damside. It houses the water-wheel and all The buildings, and here I include the ancillary the gearing and machinery of the mill. The dam constructions to direct the water onto the wheel, which creates the millpond has a sluice on one side had to be custom made to suit the millwright, of the mill and a culvert to direct the water onto the for this later became the task of the mason. wheel in the mill at first floor level. It also affords This idea helps to distinguish the character of access to the top floor for the off-loading and the millwright.
    [Show full text]
  • “Eureka!” – the Evolution of Gold Mining John Sowinski, G188 Abstract the Geological Processes That Shaped California Over
    1 “Eureka!” – The Evolution of Gold Mining John Sowinski, G188 Abstract The geological processes that shaped California over hundreds of millions of years had a significant role in American history. Hydrothermal ore deposits, specifically gold, formed by steam saturated with valuable minerals that were precipitated out as the steam cooled were mined extensively throughout the 19th and 20th centuries. Terranes that were accreted by the west coast of the North American continent added more hydrothermally generated gold especially around the Mother Lode region in Northern California. Placer mining sprung up in the late 1840’s after James Marshall discovered yellow, metallic flakes in a river near a saw mill he was building for John Sutter. Technological advances in mining allowed for harder-to-reach deposits to be mined out of source rock using high-powered jets of water. In the late 1890’s, dredges were used to extract gold from riverbeds in the Central Valley and enormous profits were generated. Open pit mining used today has allowed companies to extract very low-grade ore deposits from the earth with environmental consequences. Mercury contamination is a significant problem in Californian watersheds and around abandoned mines. Cyanide leaks have caused drastic environmental damage to rivers and streams. However, even with its disadvantages, the Gold Rush had significant positive effects and propelled California into the modern age. 2 Introduction In the late 1840s, the entire nation was swept into a gold frenzy [PBS The Gold Rush]. Newspapers across the country were reporting mass migrations of self-proclaimed miners to California in search of easy money.
    [Show full text]
  • Lecture Notes on Locks; It Took the Time That Was Needed, Too Long for the Impatient Mind, but It Was Done with Pleasure
    CIE3330 Hydraulic Structures Locks version March 2011 W.F. Molenaar e.a. Cover photo and artist impression: IJmuiden lock complex – the Netherlands Courtesy Rijkswaterstaat Delft University of Technology Artikelnummer 06917290042 CT 3330 Hydraulic Structures Locks © Hydraulic Engineering Faculty of Civil Engineering LL 3/3/2011 Delft University of Technology CT 3330 Hydraulic Structures Locks TABLE OF CONTENTS PREFACE......................................................................................................................................................1 READER TO THESE LECTURE NOTES .....................................................................................................1 1. Introduction to sluices, locks, especially navigation locks ................................................................3 1.1 Dewatering gate (uitwateringssluis) .....................................................................................................3 1.2 Stop lock (spuisluis) .............................................................................................................................5 1.3 Guard Lock (keersluis) / Storm Surge Barrier.....................................................................................6 1.4 Navigation Locks..................................................................................................................................8 2. Navigation lock design .........................................................................................................................14
    [Show full text]