Pumping station design 3rd edition

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P u m p i n g T h i r d

S t a t i o n

D e s i g n

E d i t i o n

Editor-in-Chief GARR M . JONES, PE Senior Vice President, Design Brown and Caldwell Consultants Walnut Creek, California

Co-Editors B A Y A R D E. B O S S E R M A N , I I , PE Engineering Consultant Mission Vie jo, California

R O B E R T L. S A N K S , Ph.D., PE

G E O R G E T C H O B A N O G L O U S , Ph.D., PE

Consulting Engineer and Professor Emeritus Montana State University Bozeman, Montana

Consulting Engineer and Professor Emeritus University of California at Davis Davis, California

AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEWYORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Butterworth-Heinemann is an imprint of Elsevier

ELSEVIER

for cleaning those for solids-bearing waters. The new proposed standards are in consonance with the presentations in Chapters 12, 17, 26, and 29. The research has, furthermore, led to the construction of several successful trench-type wet wells, and more are being planned or constructed.

The co-editors join me in hoping that you find the second edition even more useful than the first.

Suggestions for further improvements (other topics, elimination of errors, etc.) to make future printings or editions ever more valuable are welcome.

Robert L. Sanks Bozeman, Montana January, 1998

Preface to the Third

Edition

The third edition of this book has been revised extensively to reflect the many recent advances in equipment, design, and application of pumping systems and equipment. All chapters have been reviewed and revised as appropriate. Some material, representing equipment or technologies now obsolete has been removed and a great deal of new material added.

Among other additions, for example, is a means for ensuring the smoothest operation of rotating equipment, greatly increasing the longevity of bearings, and otherwise reducing maintenance given in Section 16-5 and Appendix C, Section 1.05B. This new edition contains many references to the Hydraulic Institute Standards, which have been improved to a point that they now are extremely valuable to engineers, owners, and to the public at large.

Two of the editors served on some of the committees that revised the standards, and the book and standards are fully compatible. The editors believe understanding and appreciating the many Hydraulic Institute's standards is helpful—almost essential—to the design and installation of pumping equipment.

To emphasize the care needed to meet the requirements of the Hydraulic Institute's Intake Design Standard, Chapter 12 has been entirely rewritten.

The latest design information for self-cleaning, trench-type wet wells, obtained by extensive model studies made by Professors Emeriti Theodore Williams and Robert Sanks (and verified by others) in the Hydraulic Laboratory of Montana State Univer-

sity is presented and discussed. Complete calculations are given for the designs of trench-type wet wells for variable speed and for constant speed pumps with computer-assisted methods for analyzing flow during the cleaning cycle. Dr. Joel Cahoon, Associate Professor, Montana State University, developed computer programs (UnifCrit2.2, Approach, and Trench2.0) that

ease the effort associated with designing self-cleaning wet wells. The use of computers for pump selection is presented and illustrated by example. A step-by-step approach to pump selection is given in which current Hydraulic Institute standards are used to aid in identifying the most suitable equipment for the most reliable performance. The chapter also includes extensive material on those installation details that extend service life and minimize maintenance.

Every effort has been made to improve this edition and to make it more user friendly. The editors welcome suggestions from readers for further improvements.

Garr M. Jones San Diego, California Bayard E. Bosserman Il Newport Beach, California Robert L. Sanks Bozeman, Montana George Tchobanoglous Davis, California December, 2004

Acknowledgments

The list of 171 contributors has increased to 183 including several author-experts, namely: Paul Cooper (Chapter 10), Alan Vause (Chapters 13 and 15), James W. Schettler (Chapter 14), Thomas M. Flegal (Chapters 16 and 28 and Appendix C), and Philip Wolstenholme (Chapter 23). The editors are grateful to these and all other contributors. Fairbanks Morse Division of Pentair Pump contributed most of the cost to build the expensive large-scale model of the revised Kirkland Pump Station for the Hydraulic Laboratory at Montana State University.

Robert Sanks contributed the rest. Yeomans Chicago Corporation contributed the recirculation pump for the model, and Mountain West Thortex.gave enough Cerami-Tech E.G. to coat the wetted surfaces of the pump for preventing corrosion. The model was constructed by Gordon Williamson and set on a cabinet built by Professor Theodore Lang. Wes Harms,

Laboratory Specialist, assisted. The Civil Engineering Department contributed space, cabinets, electricity, water, and other facilities including printing the hard copy of the manuscript for the book.

ITT Flygt contributed an engineer for several days of testing. Arnold Sdano of Fairbanks Morse spent two days helping with other tests on the model. Professor Theodore Williams worked a great many days with Robert Sanks and the model.

Arnold Sdano drew some of the more complex figures. John Clements prepared Figures 12-35 to 12-39. Many people, not always listed as contributors, have been helpful with advice and information.

Thank you all for the assistance received.

Robert L. Sanks Bozeman, Montana December, 2004

Authors and Contributors

•STEFAN M. ABELIN Systems Engineering Manager ITT Flygt Corporation Trumbull, Connecticut APPIAH AMIRTHARAJAH, Ph.D., PE Professor of Civil Engineering Georgia Institute of Technology Atlanta, Georgia •CARL N. ANDERSON, MS, PE Consultant Oakland, California THOMAS L. ANGLE, PE Director, Engineering and R&D Weir Specialty Pumps Salt Lake City, Utah RICHARD (RICK) ARBOUR Vice President, Business Consulting Practice Brown and Caldwell Saint Paul, Minnesota

•ROBERT S. BENFELL, PE (Deceased) Chief Instrumentation Engineer Brown and Caldwell Seattle, Washington HARRISON C. BICKNELL, PE Product Application Engineer General Electric Co. Schenectady, New York DONALD R. BJORK, MSEE, PE Consultant Bozeman, Montana CHARLES T. BLANCHARD CPC Corporation Sturbridge, Massachusetts KIRK BLANCHARD, PE Manager of Manufacturing Flygt Corporation Trumbull, Connecticut

NICHOLAS J. ARHONTES Collection Facilities O&M Manager County Sanitation Districts of Orange County Fountain Valley, California

•BAYARD E. BOSSERMAN II, PE Engineering Consultant Mission Viejo, California

RUSSELL H. BABCOCK, PE Consulting Engineer Westwood, Massachusetts

PAT H. BOUTHILLIER, PENG Professor of Civil Engineering University of Alberta Edmonton, Alberta, Canada

MICHAEL L. BAHM (Retired) Pump Maintenance Supervisor Department of Public Works Wastewater Treatment Division City of Baton Rouge, Louisiana VIRGILJ. BEATY (Retired) Vice President, Engineering Fairbanks Morse Pump Corp.

Kansas City, Kansas

*Asterisk denotes chapter author.

E. ROBERT BOUWKAMP, PE Formerly, Electrical Design Engineer Williams & Works, Inc. Grand Rapids, Michigan MEAD BRADNER Consultant Formerly, Applications Engineer Foxboro Company Foxboro, Massachusetts

ROBERT H. BROTHERTON, PE Director of Public Works & Utilities City of Dunedin, Florida Formerly, Associate Envirodyne Engineers Knoxville, Tennessee GEORGE R. BROWER, SCD, PE Vice President Barge, Sumner, and Cannon, Inc. Knoxville, Tennessee Formerly, Professor University of Arkansas ROLAND S. BURLINGAME, PE (Deceased) Senior Vice President Camp Dresser & McKee, Inc. Walnut Creek, California FREDRIC C. BURTON, BCE, LS, PE (Retired) Manager of International Operations Flygt Corporation Norwalk, Connecticut CASI CADRECHA Western Regional Marketing Manager Golden-Anderson Mars, Pennsylvania Formerly, Manager Valve Division Willamette Iron and Steel Co. JOEL E. CAHOON, Ph.D. Associate Professor Department of Civil Engineering Montana State University Bozeman, Montana GEOFFREYA. CARTHEW Vice President and Office Manager Brown and Caldwell Consultants Walnut Creek, California A. L. CHARBONNEAU, PENG Consulting Hydraulic Engineer Kamloops, British Columbia, Canada JOHN CLEMENTS Illustrator Brown and Caldwell Portland, Oregon *JOHN E. CONNELL, PE (Transferred) Senior Environmental Engineer Christian, Spring, Sielbach and Associates Billings, Montana *PAUL COOPER, MS, Ph.D., PE (Retired) Director, Advanced Technology, Ingersoll-Dresser Pumps, now Flowserve Corp., Phillipsberg, New Jersey HARRY E. COVEY, PE Chief Engineer The Metropolitan District Hartford, Connecticut

PATRICK J. CREEGAN, MCE, CE, SE, GE, PE Vice President-Technical Manager Water Storage and Conveyance Projects Engineering-Science, Inc. Berkeley, California ROGERJ. CRONIN, PE Partner Greeley and Han sen Engineers Richmond, Virginia ALFRED B. CUNNINGHAM, Ph.D. Professor of Civil Engineering Montana State University Bozeman, Montana RODNEY L. CUSWORTH Formerly, President Mono Group, Inc. Bensenville, Illinois ZBIGNIEWCZAMOTA Research Engineering Specialist, ITT Flygt Corporation Solna, Sweden ROBERT A. DAFFER, JR., PE Project Manager and Senior Engineer Burns and McDonnell Kansas City, Missouri THOMAS DEMLOW Principal northwest hydraulic consultants Seattle, Washington BRUCE DENSMORE Quality Control Manager Magna Drive Corporation Bellevue, Washington KUNDAN DESAI, MS Zimpro/Passavant Inc. Birmingham, Alabama MICHAELA. DEVINE Engine Division Caterpillar, Inc. Peoria, Illinois JOHANNES DE WAAL, PE Formerly, Principal Associate Clinton Bogert Associates Fort Lee, New Jersey JOHN L. DICMAS, PE (Deceased) Consulting Mechanical Engineer Arcadia, California *GARY S. DODSON, PE President G.S. Dodson & Associates Walnut Creek, California RICK A. DONALDSON District Manager Parco Engineering Corporation Medfield, Massachusetts

*JAMES C. DOWELL, PE Partner Wilson & Company, Engineers & Architects Phoenix, Arizona RONALDW. DUNCAN Senior Application Engineer MagneTek Louis Allis Drives and Systems Division of MagneTek New Berlin, Wisconsin *DAVID L. EISENHAUER, PE (Retired) Manager Engineering Standards Department Brown and Caldwell Walnut Creek, California RAYMOND L. ELLIOTT, PE (Retired) Director of Plan Review Williams & Works, Inc. Grand Rapids, Michigan EDWARDJ. ESFANDI Senior Engineer Los Angeles County Sanitation Districts Compton, California FRED A. FAIRBANKS, PE (Transferred) President Fairway Engineering San Bernardino, California *ERIK B. FISKE, MSEE, PE (Retired) Director of Engineering Byron Jackson Pump Division BW/IP International, Inc. Los Angeles, California THOMAS M. FLEGAL, MSc, PE, CDT Engineering Standards Department Manager Brown and Caldwell Eugene, Oregon MAX FREY, PE (Retired) Consultant Vice President of Engineering Cornell Pump Company Portland, Oregon *GEORGE FRYE, BS (Deceased) Chief Engineer Yeomans Brothers Company Specialist Greeley and Hansen Engineers Chicago, Illinois RAY A. GALL, MSME Senior Development Engineer Spicer Universal Joint Division Dana Corporation Toledo, Ohio PAUL R. GALLO Vice President, Engineering Rodney Hunt Company Orange, Massachusetts

*RICHARD O. GARBUS, MSME, MBA, PE (Deceased) Senior Consulting Engineer Fairbanks Morse Pump Corporation Kansas City, Kansas VICTOR G. GEREZ, Ph.D. Department of Electrical Engineering Montana State University Bozeman, Montana JAMES G. GIBBS, JR., PE Partner Wilson & Company, Engineers & Architects Albuquerque, New Mexico HAROLD D. GILMAN, BA, MA Associate Greeley and Hansen Engineers Philadelphia, Pennsylvania ROBERT C. GLOVER, PE President Fluid Kinetics Corporation Ventura, California HOWARD N. GODAT, PE President Howard Godat & Associates, Inc. Olympia, Washington *MAYO GOTTLIEBSON, BS, PE (Deceased) President Dyna Systems Company, Inc. Dublin, Ohio WILLIAM F. H. GROS President The Pitometer Associates, Inc. Chicago, Illinois L. V. GUTIERREZ, JR., DENG, PE Public Works Engineer City of Chandler, Arizona Formerly, Vice President Camp Dresser & McKee, Inc. Boston, Massachusetts *DAVIDJ. HANNA, PE Associate Professor of Construction Technology & Management Ferris State University Big Rapids, Michigan GREG HARKER Senior Applications Engineer, Flow Products Endress + Hauser Instruments Greenwood, New Jersey ROBERTJ. HART Principal Engineer, Pumps & Pumping Systems DuPont Engineering Wilmington, Delaware

GEORGE E. HECKER (Retired) President Alden Research Laboratory Holden, Massachusetts

*GARR M. JONES, BSCE, BSIE, PE Senior Vice President, Design Brown and Caldwell Walnut Creek, California

*EARL L. HECKMAN, PE (Retired) Mechanical Group Head Greeley and Hansen Engineers Chicago, Illinois

*GEORGE JORGENSEN, PE (Retired) Chief Engineer Salt Lake City Public Utilities Salt Lake City, Utah

*STANLEY S. HONGx BSEE, MSME, PE (Deceased) Associate and Chief of Electrical Design Greeley and Hansen Engineers Chicago, Illinois

WILLARD O. KEIGHTLEY, Ph.D. Professor Emeritus Montana State University Bozeman, Montana

W. ERIC HOPKINS (Retired) Project Manager Gore and Storrie Limited, Consulting Engineers Toronto, Ontario, Canada

RONALD P. KETTLE Superintendent of Desert Operations Los Angeles County Sanitation Districts Whittier, California

DAVID A. HOUSE Engineering Product Manager Dresser Pump Division Taneytown, Maryland *PHILIP A. HUFF, PE, R-M-S Consulting Electrical Engineer Acampo, California *ELIZABETH M. HUNING, PE Key Associate Wilson & Company, Engineers & Architects Phoenix, Arizona *WILLIAM A. HUNT, Ph.D., PE Consulting Engineer HKM Associates Bozeman, Montana Formerly, Professor of Civil Engineering Montana State University GARY ISAAC (Retired) Superintendent of Operations Municipality of Metropolitan Seattle (now King County Department of Metropolitan Services) Renton, Washington JOSEPH K. JACKSON Vice President, Sales Yeomans Chicago Corporation Melrose Park, Illinois

WILLIAM R. KIRKPATRICK, MSCE, PE Project Manager Engineering-Science Berkeley, California *FRANK KLEIN, BSAE, MSCE, ARCHITECT, PE (Retired) President Klein and Hoffman, Inc. Chicago, Illinois JOSEPH R. KROON, MSCE, PE Director, Liquid Services Stoner Associates, Inc. Carlisle, Pennsylvania MELVIN P. LANDIS, PE Consulting Engineer Carmichael, California LONNIE LANGE Maintenance Manager Wastewater Operations Division of Public Works and Engineering Department City of Houston Houston, Texas R. RUSSELL LANGTEAU (Retired) Pump Specialist Black & Veatch, Consulting Engineers Kansas City, Missouri

CHARLES J. JEELACK, PE Utility Engineering Administrator Department of Public Utilities City of Virginia Beach, Virginia

*PAUL C. LEACH, PE Consulting Engineer LaConner, Washington Formerly, Chief Electrical Engineer Brown and Caldwell

CASEY JONES Manager Application Engineering Square D Company Columbia, South Carolina

JOHN LEAK, BSC, ARCS Instrumentation & Automation Engineer Greeley and Hansen Engineers Philadelphia, Pennsylvania

JOSEPH E. LESCOVICH Chief Engineer GA Industries Cranberry Township, Pennsylvania "JERRY G. LILLY, MS, PE President JGL Acoustics, Inc. Bellevue, Washington RICHARD A. MALESICH Generator Sales Manager A&I Distributors Billings, Montana RALPH E. MARQUISS7 PE (Retired) Partner Rummel, Klepper & Kahl, Consulting Engineers Baltimore, Maryland *WILLIAM D. MARSCHER President Mechanical Solutions Parsippany, New Jersey COLIN MARTIN President Cham Engineering Columbia, Connecticut Consultant to ABS Pumps, Inc. Meriden, Connecticut JAMES J. MCCORMACK RHYS M. MCDONALD Senior Scientist Brown and Caldwell Walnut Creek, California.

M. STEVE MERRILL, Ph.D., PE Project Manager Brown and Caldwell Seattle, Washington WARREN H. MESLOH, PE Director Process Design & Equipment Selection Wilson & Company, Engineers & Architects Salina, Kansas J. DAVIS MILLER, PE President White Rock Engineering, Inc. Dallas, Texas STEPHEN G. MILLER (Transferred) Vice President Komline-Sanderson Peapack, New Jersey ALOYSIUS M. MOCEK, JR., PE Vice President of Engineering Parrish Power Products, Inc. Toledo, Ohio

JAMES L. MOHART, MSCE, PE, CVS Director of Administrative Services Black & Veatch, Consulting Engineers Kansas City, Missouri ARTHURMOLSEED *CHARLES D. MORRIS, Ph.D., PE Associate Professor of Civil Engineering University of Missouri Rolla, Missouri Formerly, Principal Engineer Camp Dresser & McKee, Inc. Boston, Massachusetts MICHAEL C. MULBARGER, MS, PE (Retired) Vice President Havens and Emerson, Inc. Cleveland, Ohio RICHARD L. NAILEN, PE Project Engineer Wisconsin Electric Power Company Milwaukee, Wisconsin TIMOTHY NANCE Senior Engineer Specialist Square D Company Columbia, South Carolina WILLIAM E. (ED) NELSON DENNIS R. NEUMAN Research Chemist Montana State University Bozeman, Montana *DONALD NEWTON, PE (Retired) Partner Greeley and Hansen Engineers Chicago, Illinois REYNOLD NICKEL Senior Engineer Parametrix, Inc. Sumner, Washington *ROBERT A. (RANDY) NIXON President Corrosion Probe, Inc. Centerbrook, Connecticut LORAN D. NOVACHEK Applications Engineer Waukesha Engine Division Dresser Industries, Inc. Waukesha, Wisconsin ALAN W. O'BRIEN, PE O'Brien & Associates Albuquerque, New Mexico MICHAEL R. OLSON Senior Applications Engineer Eaton Corporation, Electric Drives Division Kenosha, Wisconsin

STEPHEN H. PALAC Partner and Chief Electrical Engineer Greeley and Hansen Engineers Chicago, Illinois

JERRY P. POLLOCK Engineering Manager Johnson Power Ltd. Toledo, Ohio

CONSTANTINE PAPADAKIS, Ph.D., PE President Drexel University Philadelphia, Pennsylvania

E. O. POTTHOFF, PE (Deceased) Application Engineer General Electric Co. Schenectady, New York

*RANDALLA. PARKS Principal Integra Engineering Denver, Colorado

*MARC T. PRITCHARD (Deceased) Manager, Planning and Control Construction Management Division Brown and Caldwell Walnut Creek, California

RUSSELL L. PARR Application Engineer Cornell Pump Corporation Portland, Oregon

RICHARD E. PUSTORINO, PE President R. E. Pustonno, PC Commack, New York

EVANS VV. PASCHAL, Ph.D. Consultant Whistler Radio Services Sinclair Island Anacortes, Washington

EDGARDOQUIROZ Engineer Brown and Caldwell Consultants Walnut Creek, California

NED VV. PASCHKE Director of Engineering Madison Metropolitan Sewerage District Madison, Wisconsin

SANJAY P. REDDY Project Engineer Carollo Engineers Phoenix, Arizona

M. LEROY PATTERSON Manager Electric Transmission Operations Montana Power Co. Butte, Montana DUANE M. PETERSON Construction Engineer Archer-Western Contractors, Ltd. Phoenix, Arizona DUANE M. PETERSEN Municipal Market Manager Cornell Pump Co. Portland Oregon ALLEN VV. PETERSON, MSC, PENG Professor Emeritus Department of Civil Engineering University of Alberta Edmonton, Alberta, Canada ROBERT E. PHILLIPS, Ph. D. (Retired) Vice President of Applications and Sales Turner Designs Sunnyvale, California VVYETT C. PLAYFORD, PE (Retired) Project Engineer Williams & Works, Inc. Grand Rapids, Wisconsin

JOHN REDNER Sewerage System Superintendent Los Angeles County Sanitation Districts Whittier, California DAVID M. REESER, PE Environmental Process Manager RUST International Corp.

Portland, Oregon CARL VV. REH, PE (Deceased) Partner Greeley and Hansen Engineers Chicago, Illinois WILLIAM H. RICHARDSON, PE Partner Alvord, Burdick and Howson Chicago, Illinois *RICHARDJ. RINGWOOD, PE Consulting Engineer Walnut Creek, California Formerly, Manager of Environmental Engineering Kaiser Engineers, Inc. Oakland, California RONALD ROSIE Capital Projects Administrator Seattle Metro (now King County Department of Metropolitan Services) Seattle, Washington

•ROBERT L. SANKS, Ph.D., PE Consulting Engineer and Professor Emeritus Montana State University Bozeman, Montana

ROBERT E. STARKE Operations Engineer Aurora/Layne & Bowler North Aurora, Illinois

*PERRY L. SCHAFER Vice President Brown and Caldwell Oakland, California

OTTO STEIN, Ph.D. Associate Professor of Civil Engineering Montana State University Bozeman, Montana

*JAMESW. SCHETTLER Senior Project Manager, Mechanical Brown and Caldwell Walnut Creek, California

JOSEPH VV. STEINER Plants Superintendent Public Utilities City of Billings, Montana

*MARVIN DAN SCHMIDT, PE Principal Engineer Boyle Engineering Corporation Bakersfield, California.

DALE STILLER Director of Maintenance Madison Metro Sewerage District Madison, Wisconsin

DOUGLAS L. SCHNEIDER Senior Associate Brown and Caldwell Seattle, Washington

BRIAN G. STONE, PE Consulting Engineer Cottesloe, Australia Formerly, Vice President James M. Montgomery Consulting Engineers Pasadena, California

ARNOLD R. SDANO Director of Engineering Fairbanks Morse Pump Corporation Kansas City, Kansas DANIEL L. SHAFFER, Ph.D. Associate Professor of Chemical Engineering Montana State University Bozeman, Montana VV. STEPHEN SHENK, PE Manager of Civil Engineering Wiley and Wilson, Architects-Engineers-Planners Lynchburg, Virginia RICHARD N. SKEEHAN, PE Chief Electrical Engineer Brown and Caldwell Walnut Creek, California GARY SKIPPER President MGD Technologies Inc. San Diego, California *LOWELL G. SLOAN Chief Engineer Prosser/ENPO Industries, Inc. Piqua, Ohio *EARLE C. SMITH (Deceased) President E.C. Smith and Associates Upper Montclair, New Jersey LARRY R. SMITH, PE Civil Engineering Associate Camp Dresser & McKee, Inc. Dallas, Texas

*SAM V. SUIGUSSAAR, PE Senior Engineer Greeley and Hansen Engineers Chicago, Illinois CHARLES E. SWEENEY, PE Partner Water Resources ENSR Consulting and Engineering Redmond, Washington JAMES TAUBE Electrical Designer Florida Keys Aqueduct Authority Florida City, Florida HARVEY VV. TAYLOR, PE (Retired) Vice President CRS Engineers Portland, Oregon *LEROY R. TAYLOR, PE (Retired) Division Manager CH2M-Hill Boise, Idaho WILLIAM R. TAYLOR, Ph.D., PE Professor of Industrial and Management Engineering Montana State University Bozeman, Montana *GEORGE TCHOBANOGLOUS, Ph.D., PE Consulting Engineer and Professor Emeritus of Civil Engineering University of California, Davis Davis, California

*MICHAEL G. THALHAMER, PE Manager and Director of Water and Wastewater Engineering Psomas and Associates Sacramento, California TIMOTHY A. THOR Architect KMD Architects and Planners Portland, Oregon PATRICIA A. TRAGER, WBE, PE President TRH Engineering Chicago, Illinois JERALD D. UNDERWOOD, PE Public Utilities Director City of Billings, Montana R. DANIEL VANLUCHENE, Ph.D., PE Associate Professor of Civil Engineering Montana State University Bozeman, Montana *ALAN VAUSE Managing Engineer Brown and Caldwell Rancho Cordova, California ASHOK VARMA, MSME, PE Vice President and Office Manager Camp Dresser & McKee, Inc. Dallas, Texas JOHN VUNCANNON Sales Manager International Valve Marketing, Inc. Rockdale, Illinois LELAND J. WALKER, PE (Retired) Chairman, Board of Directors Northern Testing Laboratories, Inc. (now Maxim Technologies, Inc.) Great Falls, Montana DAVID WALRATH, PE Vice President Hazen & Sawyer, PC New York, New York THOMAS M. WALSKI, Ph.D., PE Vice President Haestad Methods, Inc. Waterbury, Connecticut HORTON WASSERMAN, PE Senior Project Engineer Malcolm Pirnie, Inc. White Plains, New York

*Asterisk denotes chapter author.

GARY Z. WATTERS, Ph.D., PE Dean, College of Engineering Computer Science and Technology California State University Chico, California JAMES C. WELL WILLIAMWHEELER Consulting Engineer Doylestown, Pennsylvania *THEODORE B. WHITON Formerly, Project Manager G.S. Dodson & Associates Walnut Creek, California THEODORE T. WILLIAMS Professor Emeritus Montana State University Bozeman, Montana THOMAS O. WILLIAMS Technical Consultant on Gas Engines and Power Generation Engine Products Division Caterpillar, Inc. Mossville, Illinois ROY E. WILSON, PE President Wilson Management Associates, Inc. Glen Head, New York ERIC L. WINCHESTER, PENG Senior Engineer ADI Limited Fredericton, New Brunswick, Canada FREDERICK R. L. WISE, Vice President Parco Engineering Medfield, Massachusetts JOHN E. WISKUS, MSSE, PE Project Manager CH2M-Hill Boise, Idaho *PHILIP WOLSTENHOLME, PE National Practice Leader for Odor Control Brown and Caldwell Seattle, Washington FRANK A. WOODBURY, PE (Retired) Senior Applications Engineer Westinghouse Electric Corporation Dallas, Texas JAMES R. WRIGHT, PE Senior Project Manager Black & Veatch Engineers-Architects Kansas City, Missouri

EUGENE K. YAREMKO, PENG Principal Northwest Hydraulic Consultants, Ltd. Edmonton, Alberta, Canada

WILLIAMYOUNG Operations Specialist Brown and Caldwell Walnut Creek, California

Contents

Special Preface to the Third Edition of Pumping Station Design ................

vi

Preface to the First Edition .........................................................................

xv

Preface to the Second Edition ....................................................................

xvii

Preface to the Third Edition ........................................................................

xix

Acknowledgments ......................................................................................

xx

Authors and Contributors ............................................................................

xxi

1.

Introduction ........................................................................................

1.1

1.1

Authors and Contributors ....................................................................

1.1

1.2

Responsibilities of Project Engineers .................................................

1.1

1.3

Units ...................................................................................................

1.2

1.4

Standards and Codes .........................................................................

1.2

1.5

Manufacturers’ Recommendations .....................................................

1.3

1.6

Safety .................................................................................................

1.3

1.7

How to Utilize This Book .....................................................................

1.3

1.8

How to Select Consulting Engineering Firms .....................................

1.4

1.9

Value Engineering ..............................................................................

1.5

1.10

Ensuring Quality and Economy ..........................................................

1.6

1.11

Avoiding Litigation ...............................................................................

1.7

1.12

Library .................................................................................................

1.8

1.13

Operator Training ................................................................................

1.8

1.14

References .........................................................................................

1.9

Nomenclature .....................................................................................

2.1

2.1

Abbreviations ......................................................................................

2.1

2.2

Definitions ...........................................................................................

2.8

2.

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vii

viii

3.

4.

5.

Contents 2.3

Symbols ..............................................................................................

2.14

2.4

Supplementary Reading .....................................................................

2.14

Flow in Conduits ................................................................................

3.1

3.1

Fundamentals of Hydraulics ...............................................................

3.1

3.2

Friction Losses in Piping .....................................................................

3.4

3.3

Pipe Tables .........................................................................................

3.9

3.4

Headlosses in Pipe Fittings ................................................................

3.11

3.5

Friction Losses in Open Channel Flow ...............................................

3.12

3.6

Energy in Pressurized Pipe Flow ........................................................

3.14

3.7

Energy in Open Channel Flow ............................................................

3.16

3.8

Unbalanced Hydraulic Forces .............................................................

3.20

3.9

Field Measurement of Pipe Diameter and Friction Coefficient ...........................................................................................

3.23

3.10

Flow of Sludges ..................................................................................

3.32

3.11

Unsteady Flow ....................................................................................

3.32

3.12

Model Studies .....................................................................................

3.33

3.13

Computational Fluid Dynamics (CFD) ................................................

3.35

3.14

References .........................................................................................

3.36

Piping ..................................................................................................

4.1

4.1

Selection of Exposed Pipe ..................................................................

4.2

4.2

Selection of Buried Piping ...................................................................

4.11

4.3

Ductile Iron Pipe (DIP) ........................................................................

4.17

4.4

Steel Pipe ...........................................................................................

4.19

4.5

Plastic Pipe .........................................................................................

4.21

4.6

Asbestos Cement Pipe (ACP) ............................................................

4.24

4.7

Reinforced Concrete Pressure Pipe (RCPP) ......................................

4.24

4.8

Design of Piping ..................................................................................

4.25

4.9

Special Piping and Plumbing ..............................................................

4.35

4.10

References .........................................................................................

4.40

4.11

Supplementary Reading .....................................................................

4.41

Valves .................................................................................................

5.1

5.1

Designing for Quality ..........................................................................

5.1

5.2

Isolation Valves ...................................................................................

5.4

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Contents

6.

7.

ix

5.3

Sluice Gates, Shear Gates, Flap Valves, and Stop Plates .................

5.14

5.4

Check Valves ......................................................................................

5.15

5.5

Control Valves ....................................................................................

5.21

5.6

Valve Actuators ...................................................................................

5.24

5.7

Air and Vacuum Valves ......................................................................

5.27

5.8

Materials of Construction ....................................................................

5.29

5.9

Installation of Valves ...........................................................................

5.30

5.10

Corrosion Protection ...........................................................................

5.31

5.11

References .........................................................................................

5.31

Fundamentals of Hydraulic Transients ............................................

6.1

6.1

Introduction .........................................................................................

6.1

6.2

Nomenclature .....................................................................................

6.2

6.3

Methods of Analysis ............................................................................

6.2

6.4

Surge Concepts in Frictionless Flow ..................................................

6.3

6.5

Slow Closure of Valves .......................................................................

6.7

6.6

Surge Concepts in Flow with Friction .................................................

6.10

6.7

Column Separation .............................................................................

6.11

6.8

Criteria for Conducting Transient Analysis .........................................

6.12

6.9

References .........................................................................................

6.13

Control of Hydraulic Transients .......................................................

7.1

7.1

Overview of Hydraulic Transient Control Strategies ...........................

7.1

7.2

Control of Pumps ................................................................................

7.8

7.3

Control Tanks .....................................................................................

7.9

7.4

Valves for Transient Control ...............................................................

7.11

7.5

Containment of Transients ..................................................................

7.13

7.6

Surge Control for Water Pumping Stations .........................................

7.15

7.7

Surge Control for Raw Wastewater Pumping Stations .......................

7.18

7.8

Pipeline Design ...................................................................................

7.19

7.9

Computer Analysis ..............................................................................

7.21

7.10

Transients in Distribution Systems .....................................................

7.23

7.11

References .........................................................................................

7.26

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x

Contents

8.

Electrical Fundamentals and Power System Principles .................

8.1

8.1

Definitions and Code References .......................................................

8.1

8.2

Electrical Fundamentals .....................................................................

8.2

8.3

Power and Control System Elements .................................................

8.9

8.4

Standby Generators and Auxiliaries ...................................................

8.26

8.5

Grounding ...........................................................................................

8.29

8.6

Lighting and Power Outlets .................................................................

8.32

8.7

Electrical Circuit Diagrams ..................................................................

8.35

8.8

Power and Control System Practices .................................................

8.37

8.9

Reference ...........................................................................................

8.41

8.10

Supplementary Readings ...................................................................

8.41

Electrical Design ................................................................................

9.1

9.1

Final Construction Drawings ...............................................................

9.1

9.2

Specifications ......................................................................................

9.3

9.3

Contacting Utilities ..............................................................................

9.4

9.4

Construction Information to Utilities ....................................................

9.5

9.5

Load Estimation ..................................................................................

9.5

9.6

Overcurrent Protection and Conductor Sizing ....................................

9.8

9.7

Lighting ...............................................................................................

9.14

9.8

Power Factor ......................................................................................

9.16

9.9

Engine Generators ..............................................................................

9.17

9.10

Short-circuit Current Calculations .......................................................

9.20

9.11

Harmonics ...........................................................................................

9.22

9.12

Construction Service ...........................................................................

9.22

9.13

References .........................................................................................

9.24

10. Performance of Centrifugal Pumps ..................................................

10.1

9.

10.1

Classification of Centrifugal Pumps ....................................................

10.1

10.2

Pump Application Terminology, Equations, and Performance Curves ................................................................................................

10.1

10.3

Pump Operating Characteristics .........................................................

10.8

10.4

Cavitation ............................................................................................ 10.16

10.5

Pump Characteristic Curves ............................................................... 10.27

10.6

Pump Operating Regions ................................................................... 10.30

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xi

10.7

Elementary Pump System Analysis .................................................... 10.32

10.8

Practical Pumping System H-Q Curve Analysis ................................. 10.37

10.9

Complex Pumping System H-Q Curves ............................................. 10.43

10.10 References ......................................................................................... 10.43

11. Types of Pumps .................................................................................

11.1

11.1

General Classifications of Pumps .......................................................

11.1

11.2

Classification of Centrifugal Pumps ....................................................

11.6

11.3

Construction of Centrifugal Pumps .....................................................

11.7

11.4

Overhung-impeller Pumps .................................................................. 11.17

11.5

Impeller-between-bearings Pumps ..................................................... 11.25

11.6

Classification of Vertical Pumps ......................................................... 11.25

11.7

Construction of Vertical Pumps .......................................................... 11.27

11.8

Types of Vertical Pumps ..................................................................... 11.31

11.9

Positive-displacement Pumps ............................................................. 11.33

11.10 Special Pumps .................................................................................... 11.35 11.11 Summary of Typical Pump Applications ............................................. 11.40 11.12 References ......................................................................................... 11.41 11.13 Supplementary Reading ..................................................................... 11.41

12. Pumps: Intake Design, Selection, and Installation .........................

12.1

12.1

Design of Pump Intakes ......................................................................

12.2

12.2

Pump Intake Design Standards ..........................................................

12.2

12.3

Types of Pump Intake Basins .............................................................

12.4

12.4

Model Study ........................................................................................ 12.11

12.5

Evolution of Trench-type Wet Wells .................................................... 12.12

12.6

Summary of Trench-type Wet Well Characteristics ............................ 12.26

12.7

Trench-type Wet Well Design ............................................................. 12.28

12.8

Wet Wells in Small Lift Stations .......................................................... 12.44

12.9

Principles of Pump Selection .............................................................. 12.47

12.10 Step-by-step Pump Selection and Installation Procedure .................. 12.54 12.11 Reducing Cost of Ownership .............................................................. 12.59 12.12 Installation Design .............................................................................. 12.61 12.13 References ......................................................................................... 12.81

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xii

Contents

13. Electric Motors ...................................................................................

13.1

13.1

General ...............................................................................................

13.1

13.2

Applications of Motors ........................................................................

13.3

13.3

Fundamentals .....................................................................................

13.6

13.4

Types of Motors for Pump Drivers ......................................................

13.9

13.5

Characteristics of Squirrel-cage Induction Motors .............................. 13.12

13.6

Motor Speed ....................................................................................... 13.12

13.7

Motor Voltage ..................................................................................... 13.13

13.8

Enclosures .......................................................................................... 13.14

13.9

Insulation ............................................................................................ 13.15

13.10 Squirrel-cage Motors .......................................................................... 13.16 13.11 Frequency of Motor Starts .................................................................. 13.20 13.12 Miscellaneous Motor Features ............................................................ 13.21 13.13 Specifying Pumping Unit Drivers ........................................................ 13.23 13.14 Definite Purpose Induction Motors ...................................................... 13.24 13.15 Design Checklist ................................................................................. 13.28 13.16 References ......................................................................................... 13.29

14. Engines ...............................................................................................

14.1

14.1

Selecting an Engine Drive ..................................................................

14.1

14.2

Duty Cycle ..........................................................................................

14.2

14.3

Fuel for Engines ..................................................................................

14.4

14.4

Aspiration ............................................................................................

14.7

14.5

Types of Engines ................................................................................

14.7

14.6

Rich-burn or Lean-burn .......................................................................

14.8

14.7

Application Criteria ..............................................................................

14.8

14.8

Starting Methods ................................................................................. 14.10

14.9

Cooling Methods ................................................................................. 14.10

14.10 Controls .............................................................................................. 14.10 14.11 Governors for Engine Control ............................................................. 14.11 14.12 Accessories for Engines ..................................................................... 14.12 14.13 Combustion Air ................................................................................... 14.15 14.14 Exhaust Silencing ............................................................................... 14.15 14.15 Pollution Control ................................................................................. 14.17 14.16 Vibration Isolation ............................................................................... 14.17 This page has been reformatted by Knovel to provide easier navigation.

Contents

xiii

14.17 Lubrication Oil Storage and Supply .................................................... 14.17 14.18 Fuel Oil Storage and Supply ............................................................... 14.18 14.19 Gaseous Fuel Storage and Supply ..................................................... 14.18 14.20 Service Piping ..................................................................................... 14.19 14.21 Building Envelope ............................................................................... 14.19 14.22 Ventilation ........................................................................................... 14.20 14.23 Maintenance ....................................................................................... 14.20

15. Variable-speed Pumping ...................................................................

15.1

15.1

Variable Speed versus Constant Speed .............................................

15.2

15.2

Design Considerations ........................................................................

15.4

15.3

Theory of Variable-speed Pumping ....................................................

15.4

15.4

Pump Selection ...................................................................................

15.9

15.5

Variable- and Constant-speed Pumps in Simultaneous Operation ............................................................................................ 15.12

15.6

Special Design Considerations ........................................................... 15.13

15.7

Analysis of Variable-speed Booster Pumping ..................................... 15.15

15.8

Minimum Flow Rate ............................................................................ 15.19

15.9

Operations in Booster Pumping .......................................................... 15.22

15.10 Simultaneous Operation of V/S and C/S Booster Pumps ................... 15.24 15.11 Adjustable- and Variable-speed Drives .............................................. 15.25 15.12 References ......................................................................................... 15.41

16. Pump-driver Specifications ..............................................................

16.1

16.1

Comparison of Two Approaches to Writing Specifications .................

16.1

16.2

Methods for Specifying Quality of Equipment .....................................

16.2

16.3

Nonrestrictive Specifications ...............................................................

16.2

16.4

Operating Conditions ..........................................................................

16.4

16.5

Mass Elastic Systems and Critical Speeds .........................................

16.4

16.6

Pump Testing ......................................................................................

16.4

16.7

Shipping Major Pumping Units ...........................................................

16.8

16.8

Submittals ...........................................................................................

16.8

16.9

Product Data .......................................................................................

16.9

16.10 Seals ...................................................................................................

16.9

16.11 Pump Shafts .......................................................................................

16.9

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xiv

Contents 16.12 Pump Shaft Bearings ..........................................................................

16.9

16.13 Vertical Drive Shafts ...........................................................................

16.9

16.14 Electric Motors ....................................................................................

16.9

16.15 Optimum Efficiency ............................................................................. 16.10 16.16 References ......................................................................................... 16.10

17. System Design for Wastewater Pumping ........................................

17.1

17.1

Organization and Control of the Process ............................................

17.1

17.2

Preliminary Engineering ......................................................................

17.2

17.3

Detailed Layout ...................................................................................

17.6

17.4

Detailed Design .................................................................................. 17.10

17.5

Examples of Large Lift Stations .......................................................... 17.11

17.6

Examples of Medium-size Lift Stations ............................................... 17.18

17.7

Examples of Small Lift Stations .......................................................... 17.25

17.8

References ......................................................................................... 17.34

18. System Design for Water Pumping ..................................................

18.1

18.1

Types of Water Pumping Stations ......................................................

18.1

18.2

Pumping Station Flow and Pressure Requirements ...........................

18.1

18.3

Raw Water Pumping from Rivers and Lakes ......................................

18.5

18.4

Raw Water Pumping from Aqueducts ................................................. 18.16

18.5

Well Pumps with Elevated Tanks ....................................................... 18.24

18.6

Booster Pumping Stations .................................................................. 18.33

18.7

Retrofitting Large Pump Basins .......................................................... 18.44

18.8

References ......................................................................................... 18.46

18.9

Suggested Reading ............................................................................ 18.46

19. System Design for Sludge Pumping ................................................

19.1

19.1

Hydraulic Design .................................................................................

19.2

19.2

Types of Pumps ..................................................................................

19.9

19.3

Pumping System Design .................................................................... 19.13

19.4

Piping System Design ......................................................................... 19.23

19.5

Long-distance Pumping ...................................................................... 19.28

19.6

References ......................................................................................... 19.28

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Contents

xv

20. Instrumentation and Control Devices ..............................................

20.1

20.1

Reliability ............................................................................................

20.1

20.2

Instrument Selection ...........................................................................

20.2

20.3

Level Measurements ..........................................................................

20.5

20.4

Pressure Measurements ..................................................................... 20.10

20.5

Flow Measurements in Pipes .............................................................. 20.13

20.6

Open Channel Flow Measurement ..................................................... 20.20

20.7

Chlorine Residual Measurement ........................................................ 20.20

20.8

Utility and Environmental Measurements ........................................... 20.20

20.9

Pumping Unit Monitors ....................................................................... 20.24

20.10 Control Equipment .............................................................................. 20.24 20.11 Control Logic ...................................................................................... 20.26 20.12 Altitude Valves .................................................................................... 20.27 20.13 Monitoring and Data Acquisition ......................................................... 20.27 20.14 Telemetry ............................................................................................ 20.29 20.15 Design Considerations ........................................................................ 20.34 20.16 References ......................................................................................... 20.35 20.17 Supplementary Reading ..................................................................... 20.35

21. Instrumentation and Control Applications ......................................

21.1

21.1

Process and Instrumentation Diagrams ..............................................

21.1

21.2

Well Pump with Hydropneumatic Tank ...............................................

21.2

21.3

Booster Stations .................................................................................

21.3

21.4

High-service Pumping Station ............................................................

21.4

21.5

Small Wastewater Lift Station .............................................................

21.5

21.6

Intermediate-sized Lift Station ............................................................

21.7

21.7

Large Wastewater Pumping Station ...................................................

21.8

22. Vibration and Noise ...........................................................................

22.1

22.1

Problems of Vibration and Noise ........................................................

22.1

22.2

Avoiding Vibration Problems ...............................................................

22.3

22.3

Troubleshooting Excessive Vibration .................................................. 22.11

22.4

Introduction to Vibration and Noise Calculations ................................ 22.19

22.5

Vibration and Noise Characteristics .................................................... 22.22

22.6

Applicable Codes ................................................................................ 22.25

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xvi

Contents 22.7

Equipment Vibration ........................................................................... 22.29

22.8

Vibration Isolation Theory ................................................................... 22.30

22.9

Vibration Isolators ............................................................................... 22.32

22.10 Piping Vibration ................................................................................... 22.35 22.11 Vibration of Drive Shafts ..................................................................... 22.46 22.12 Vibration of Structures ........................................................................ 22.50 22.13 Noise .................................................................................................. 22.52 22.14 Reducing Exterior Noise ..................................................................... 22.59 22.15 References ......................................................................................... 22.64

23. Heating, Ventilating, and Cooling .....................................................

23.1

23.1

Need for Heating, Ventilating, and Air Conditioning ...........................

23.1

23.2

HVAC Design Criteria .........................................................................

23.4

23.3

Odor Control .......................................................................................

23.6

23.4

Dry Well Design Guidelines ................................................................ 23.11

23.5

Energy Use and Conservation ............................................................ 23.13

23.6

Corrosion Protection ........................................................................... 23.15

23.7

Sequence of Design Steps ................................................................. 23.16

23.8

Ventilating System Design .................................................................. 23.18

23.9

Design of Heating Systems ................................................................ 23.25

23.10 Design of Building Cooling Systems ................................................... 23.30 23.11 Design of Refrigerated Cooling Systems ............................................ 23.32 23.12 References ......................................................................................... 23.34 23.13 Supplementary Reading ..................................................................... 23.35

24. Designing for Easy Operation and Low Maintenance ....................

24.1

24.1

Site Selection ......................................................................................

24.1

24.2

Landscaping .......................................................................................

24.2

24.3

Hydraulics ...........................................................................................

24.2

24.4

Mechanical Considerations .................................................................

24.6

24.5

Smooth-running and Reliable Pumps .................................................

24.8

24.6

Electrical Considerations .................................................................... 24.11

24.7

Architectural Considerations ............................................................... 24.13

24.8

Standby Facilities ................................................................................ 24.13

24.9

Specifications ...................................................................................... 24.14

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xvii

24.10 Operators’ Preferences ....................................................................... 24.14 24.11 Survey of Two Thousand Wastewater Pumping Stations ................... 24.24 24.12 Auxiliary Support Systems in Raw Wastewater Pumping Stations ............................................................................................... 24.32 24.13 References ......................................................................................... 24.33

25. Summary of Design Considerations ................................................

25.1

25.1

Need for Pumping Stations .................................................................

25.2

25.2

Site Selection ......................................................................................

25.3

25.3

Architectural and Environmental Considerations ................................

25.5

25.4

Future Expansion ................................................................................ 25.10

25.5

Hydraulic Constraints .......................................................................... 25.11

25.6

Types of Pumping Stations ................................................................. 25.12

25.7

Power, Drivers, and Standby .............................................................. 25.26

25.8

Application-engineered Equipment ..................................................... 25.30

25.9

Station Auxiliaries ............................................................................... 25.31

25.10 Instruments and Control ..................................................................... 25.34 25.11 Structural Design ................................................................................ 25.35 25.12 Concrete Protection: Coatings and Linings ........................................ 25.44 25.13 Corrosion of Metals ............................................................................. 25.46 25.14 Force Main Design .............................................................................. 25.51 25.15 References ......................................................................................... 25.52

26. Pumping Station Design Examples ..................................................

26.1

26.1

Redesigned Clyde Wastewater Pumping Station ...............................

26.1

26.2

Redesigned Kirkland Wastewater Pumping Station ...........................

26.8

26.3

Jameson Canyon Raw Water Pumping Station .................................. 26.15

26.4

References ......................................................................................... 26.17

27. Avoiding Blunders .............................................................................

27.1

27.1

General ...............................................................................................

27.1

27.2

Site .....................................................................................................

27.2

27.3

Environmental .....................................................................................

27.2

27.4

Safety .................................................................................................

27.2

27.5

Hydraulics ...........................................................................................

27.3

27.6

Wet Wells ............................................................................................

27.5

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xviii

Contents 27.7

Pumps ................................................................................................. 27.10

27.8

Valves ................................................................................................. 27.13

27.9

Mechanical .......................................................................................... 27.15

27.10 Electrical ............................................................................................. 27.16 27.11 Structural-architectural ........................................................................ 27.16 27.12 Specifications ...................................................................................... 27.17 27.13 Economics .......................................................................................... 27.18 27.14 The Future and Remodeling ............................................................... 27.18 27.15 Find the Blunders ................................................................................ 27.18 27.16 Design Reviews .................................................................................. 27.18 27.17 Operations .......................................................................................... 27.20 27.18 References ......................................................................................... 27.20

28. Contract Documents .........................................................................

28.1

28.1

General ...............................................................................................

28.1

28.2

Bidding and Contracting Requirements ..............................................

28.2

28.3

Technical Specifications .....................................................................

28.4

28.4

Source Material ...................................................................................

28.6

28.5

Methods of Specifying ........................................................................

28.7

28.6

Submittal Requirements .....................................................................

28.8

28.7

References .........................................................................................

28.9

29. Costs ...................................................................................................

29.1

29.1

Cost Indexes .......................................................................................

29.1

29.2

Cost Curves ........................................................................................

29.3

29.3

Maintenance and Energy ....................................................................

29.7

29.4

Interest Formulas ................................................................................

29.9

29.5

Cost Estimates .................................................................................... 29.12

29.6

References ......................................................................................... 29.28

Appendices Appendix A: Physical Data ...........................................................................

A.1

Table A.1

Base SI Units .......................................................................

A.1

Table A.2

Derived SI Units and Physical Quantities ............................

A.2

Table A.3

Physical Constants ..............................................................

A.3

Table A.4

SI Prefixes ............................................................................

A.3

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Contents

xix

Conversion Factors, U.S. Customary Units to Commonly Used SI Units .......................................................................

A.3

Table A.6

Atmospheric Pressure (SI Units) ..........................................

A.5

Table A.7

Atmospheric Pressure (U.S. Customary Units) ....................

A.5

Table A.8

Physical Properties of Water (SI Units) ................................

A.6

Table A.9

Physical Properties of Water (U.S. Customary Units) ..........

A.6

Table A.10 Physical Properties of Pipe Materials ..................................

A.7

Table A.11 Equivalent Weights and Measures ......................................

A.7

A.1

References ...........................................................................

A.9

Appendix B: Data for Flow in Pipes, Fittings, and Valves .............................

B.1

Table A.5

Table B.1

Properties of Mortar-lined Class 53 Ductile Iron Pipe, Hazen-Williams C= 120, SI Units .........................................

B.2

Properties of Mortar-lined Class 53 Ductile Iron Pipe, Hazen-Williams C= 120, U.S. Customary Units ...................

B.2

Properties of Standard Weight (ANSI B36.10) for Steel Pipe, Hazen-Williams C= 120, SI Units ................................

B.4

Properties of Standard Weight (ANSI B36.10) Steel Pipe for Hazen-Williams C= 120, U.S. Customary Units ..............

B.6

Probable Coefficients for Pipe Friction for the Design of Pipes Flowing Full for Nonaggressive Waters and Good Pipeline Maintenance ...........................................................

B.8

Moody Diagram f in the Darcy-Weisbach: a Graphical Solution of the Colebrook Equation 3-12. .............................

B.9

Headlosses for Mueller Swing Check Valves with Springloaded Levers ......................................................................

B.10

Headlosses for Mueller Swing Check Valves with Counterweighted Levers ......................................................

B.10

Recommended Energy Loss Coefficients, K, for Flanged Pipe Fittings .........................................................................

B.11

Recommended Energy Loss Coefficients, K, for Valves Open Fully ............................................................................

B.12

Geometric Properties of Partly-full Pipes and Velocity and Discharge Based on Uncorrected Manning Equation ..........

B.13

Figure B.5

Hydraulic Elements of Circular Pipes as Open Channels ....

B.14

Table B.8

Comparison of Computed Values of Velocity, Depth, Area, and Flow in Open Channels .......................................

B.15

Table B.2 Table B.3 Table B.4 Table B.5

Figure B.1 Figure B.2 Figure B.3 Table B.6 Table B.7 Figure B.4

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xx

Contents Table B.9

Velocities Required to Scour Air Pockets from Pipelines .....

B.16

Table B.10 Maximum Allowable Flow Rates in Approach Pipes. SI Units .....................................................................................

B.17

Table B.11 Maximum Allowable Flow Rates in Approach Pipes. U.S. Customary Units ..................................................................

B.18

B.1

References ...........................................................................

B.18

B.2

Supplementary Reading ......................................................

B.19

Appendix C: Typical Specifications for Pumps and Drivers ..........................

C.1

Appendix D: Common Blunders ....................................................................

D.1

D.1

Figure 27.1 ...........................................................................

D.1

D.2

Figure 27.2 ...........................................................................

D.1

D.3

References ...........................................................................

D.2

Appendix E: Checklist for Project Reviews ...................................................

E.1

E.1

Civil Design Checklist ..........................................................

E.1

E.2

Structural/Geotechnical/Architectural Design Checklist .......

E.2

E.3

Electrical Design Checklist ...................................................

E.2

E.4

Instrumentation and Control Checklist .................................

E.3

E.5

Cross-connection Control ....................................................

E.3

E.6

Mechanical Design Checklist ...............................................

E.4

E.7

References ...........................................................................

E.6

Appendix F: Start-up .....................................................................................

F.1

F.1

Pre-visit Check .....................................................................

F.2

F.2

Pre-start-up Check ...............................................................

F.2

F.3

Electrical Systems ................................................................

F.4

F.4

Simplified Operational Checks for Small Stations ................

F.9

F.5

Well Pumps ..........................................................................

F.9

F.6

Chlorination ..........................................................................

F.11

F.7

Complex Drives ....................................................................

F.12

F.8

Control Panel and Electrical Systems ..................................

F.12

F.9

Bubbler Systems ..................................................................

F.12

F.10

Vacuum Priming Systems ....................................................

F.13

F.11

Compressed Air Systems ....................................................

F.14

F.12

Hydropneumatic Tank Systems ...........................................

F.15

F.13

Main Pumps, Final Pre-start-up Checks ..............................

F.16

F.14

Wet Well and Testing of Main Pumps ..................................

F.17

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Contents

xxi

F.15

Cleaning Wet Wells ..............................................................

F.17

F.16

References ...........................................................................

F.18

Appendix G: Suction Specific Speed ............................................................

G.1

G.1

References ...........................................................................

G.2

Index ..........................................................................................................

I.1

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C h a p t e r

1

I n t r o d u c t i o n

ROBERT L. SANKS CONTRIBUTORS Roger J. Cronin Marc T. Pritchard Brian G. Stone Roy L. Wilson

This book is written for a wide variety of readers: the expert and the beginner in a design office; the project leader of a design team; the city engineer or chief engineer of a water or sewerage authority (or their subordinates) who may review plans and specifications; and manufacturers' representatives who should know how their equipment is best applied to a pumping station. Recommendations for the utilization of the book by each group of readers are given in Section 1-7.

The aim of the volume is to show how to apply the fundamentals of the various disciplines and subjects into a well-integrated pumping station—reliable, easy to operate and maintain, and free from serious design mistakes.

To facilitate the selection of good design engineers, the publisher hereby gives permission to photocopy Chapter 1 only of this book for distribution to municipalities or utilities and their representatives.

1-1. Authors and Contributors

Each author or contributor is an expert with many years of experience in the subject discussed. Furthermore, all chapters were reviewed and critiqued by four to eight other equally qualified experts, includ-

ing the editors. (Editors' names are not listed unless an editor is a principal author.)

The reviewers are listed as contributors (except, of course, for the editors), but not all contributors are reviewers. A contributor is one who has helped in any way, from writing a short segment to giving advice.

Engineers do not always agree, and the viewpoints expressed do not necessarily reflect those of each individual contributor or even of the author. Where an unresolvable conflict occurs, both viewpoints are given. No effort has been spared to make this book the most authoritative possible. In spite of these efforts, there are more differences than can be encompassed and some errors may have occurred, so read thoughtfully and with care.

1-2. Responsibilities of Project Engineers

The design of a pumping station depends on several specialties, which are listed in Table 1-1 more or less in chronological order, together with the approximate range of percentages of engineering or design costs. Not all specialties for all pumping stations are shown. For example, river engineering (not shown) might be a significant part of design costs for a raw water pumping station taking water from a river

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DANCE ON STILTS AT THE GIRLS’ UNYAGO, NIUCHI

Newala, too, suffers from the distance of its water-supply—at least the Newala of to-day does; there was once another Newala in a lovely valley at the foot of the plateau. I visited it and found scarcely a trace of houses, only a Christian cemetery, with the graves of several missionaries and their converts, remaining as a monument of its former glories. But the surroundings are wonderfully beautiful. A thick grove of splendid mango-trees closes in the weather-worn crosses and headstones; behind them, combining the useful and the agreeable, is a whole plantation of lemon-trees covered with ripe fruit; not the small African kind, but a much larger and also juicier imported variety, which drops into the hands of the passing traveller, without calling for any exertion on his part. Old Newala is now under the jurisdiction of the native pastor, Daudi, at Chingulungulu, who, as I am on very friendly terms with him, allows me, as a matter of course, the use of this lemon-grove during my stay at Newala.

FEET MUTILATED BY THE RAVAGES OF THE “JIGGER” (Sarcopsylla penetrans)

The water-supply of New Newala is in the bottom of the valley, some 1,600 feet lower down. The way is not only long and fatiguing, but the water, when we get it, is thoroughly bad. We are suffering not only from this, but from the fact that the arrangements at Newala are nothing short of luxurious. We have a separate kitchen—a hut built against the boma palisade on the right of the baraza, the interior of which is not visible from our usual position. Our two cooks were not long in finding this out, and they consequently do—or rather neglect to do—what they please. In any case they do not seem to be very particular about the boiling of our drinking-water—at least I can attribute to no other cause certain attacks of a dysenteric nature, from which both Knudsen and I have suffered for some time. If a man like Omari has to be left unwatched for a moment, he is capable of anything. Besides this complaint, we are inconvenienced by the state of our nails, which have become as hard as glass, and crack on the slightest provocation, and I have the additional infliction of pimples all over me. As if all this were not enough, we have also, for the last week been waging war against the jigger, who has found his Eldorado in the hot sand of the Makonde plateau. Our men are seen all day long—whenever their chronic colds and the dysentery likewise raging among them permit—occupied in removing this scourge of Africa from their feet and trying to prevent the disastrous consequences of its presence. It is quite common to see natives of this place with one or two toes missing; many have lost all their toes,

or even the whole front part of the foot, so that a well-formed leg ends in a shapeless stump. These ravages are caused by the female of Sarcopsylla penetrans, which bores its way under the skin and there develops an egg-sac the size of a pea. In all books on the subject, it is stated that one’s attention is called to the presence of this parasite by an intolerable itching. This agrees very well with my experience, so far as the softer parts of the sole, the spaces between and under the toes, and the side of the foot are concerned, but if the creature penetrates through the harder parts of the heel or ball of the foot, it may escape even the most careful search till it has reached maturity.

Then there is no time to be lost, if the horrible ulceration, of which we see cases by the dozen every day, is to be prevented. It is much easier, by the way, to discover the insect on the white skin of a European than on that of a native, on which the dark speck scarcely shows. The four or five jiggers which, in spite of the fact that I constantly wore high laced boots, chose my feet to settle in, were taken out for me by the all-accomplished Knudsen, after which I thought it advisable to wash out the cavities with corrosive sublimate. The natives have a different sort of disinfectant—they fill the hole with scraped roots. In a tiny Makua village on the slope of the plateau south of Newala, we saw an old woman who had filled all the spaces under her toe-nails with powdered roots by way of prophylactic treatment. What will be the result, if any, who can say?

The rest of the many trifling ills which trouble our existence are really more comic than serious. In the absence of anything else to smoke, Knudsen and I at last opened a box of cigars procured from the Indian store-keeper at Lindi, and tried them, with the most distressing results. Whether they contain opium or some other narcotic, neither of us can say, but after the tenth puff we were both “off,” three-quarters stupefied and unspeakably wretched. Slowly we recovered—and what happened next? Half-an-hour later we were once more smoking these poisonous concoctions—so insatiable is the craving for tobacco in the tropics.

Even my present attacks of fever scarcely deserve to be taken seriously. I have had no less than three here at Newala, all of which have run their course in an incredibly short time. In the early afternoon, I am busy with my old natives, asking questions and making notes. The strong midday coffee has stimulated my spirits to

an extraordinary degree, the brain is active and vigorous, and work progresses rapidly, while a pleasant warmth pervades the whole body. Suddenly this gives place to a violent chill, forcing me to put on my overcoat, though it is only half-past three and the afternoon sun is at its hottest. Now the brain no longer works with such acuteness and logical precision; more especially does it fail me in trying to establish the syntax of the difficult Makua language on which I have ventured, as if I had not enough to do without it. Under the circumstances it seems advisable to take my temperature, and I do so, to save trouble, without leaving my seat, and while going on with my work. On examination, I find it to be 101·48°. My tutors are abruptly dismissed and my bed set up in the baraza; a few minutes later I am in it and treating myself internally with hot water and lemon-juice.

Three hours later, the thermometer marks nearly 104°, and I make them carry me back into the tent, bed and all, as I am now perspiring heavily, and exposure to the cold wind just beginning to blow might mean a fatal chill. I lie still for a little while, and then find, to my great relief, that the temperature is not rising, but rather falling. This is about 7.30 p.m. At 8 p.m. I find, to my unbounded astonishment, that it has fallen below 98·6°, and I feel perfectly well. I read for an hour or two, and could very well enjoy a smoke, if I had the wherewithal—Indian cigars being out of the question.

Having no medical training, I am at a loss to account for this state of things. It is impossible that these transitory attacks of high fever should be malarial; it seems more probable that they are due to a kind of sunstroke. On consulting my note-book, I become more and more inclined to think this is the case, for these attacks regularly follow extreme fatigue and long exposure to strong sunshine. They at least have the advantage of being only short interruptions to my work, as on the following morning I am always quite fresh and fit.

My treasure of a cook is suffering from an enormous hydrocele which makes it difficult for him to get up, and Moritz is obliged to keep in the dark on account of his inflamed eyes. Knudsen’s cook, a raw boy from somewhere in the bush, knows still less of cooking than Omari; consequently Nils Knudsen himself has been promoted to the vacant post. Finding that we had come to the end of our supplies, he began by sending to Chingulungulu for the four sucking-pigs which we had

bought from Matola and temporarily left in his charge; and when they came up, neatly packed in a large crate, he callously slaughtered the biggest of them. The first joint we were thoughtless enough to entrust for roasting to Knudsen’s mshenzi cook, and it was consequently uneatable; but we made the rest of the animal into a jelly which we ate with great relish after weeks of underfeeding, consuming incredible helpings of it at both midday and evening meals. The only drawback is a certain want of variety in the tinned vegetables. Dr. Jäger, to whom the Geographical Commission entrusted the provisioning of the expeditions—mine as well as his own—because he had more time on his hands than the rest of us, seems to have laid in a huge stock of Teltow turnips,[46] an article of food which is all very well for occasional use, but which quickly palls when set before one every day; and we seem to have no other tins left. There is no help for it—we must put up with the turnips; but I am certain that, once I am home again, I shall not touch them for ten years to come.

Amid all these minor evils, which, after all, go to make up the genuine flavour of Africa, there is at least one cheering touch: Knudsen has, with the dexterity of a skilled mechanic, repaired my 9 × 12 cm. camera, at least so far that I can use it with a little care.

How, in the absence of finger-nails, he was able to accomplish such a ticklish piece of work, having no tool but a clumsy screw-driver for taking to pieces and putting together again the complicated mechanism of the instantaneous shutter, is still a mystery to me; but he did it successfully. The loss of his finger-nails shows him in a light contrasting curiously enough with the intelligence evinced by the above operation; though, after all, it is scarcely surprising after his ten years’ residence in the bush. One day, at Lindi, he had occasion to wash a dog, which must have been in need of very thorough cleansing, for the bottle handed to our friend for the purpose had an extremely strong smell. Having performed his task in the most conscientious manner, he perceived with some surprise that the dog did not appear much the better for it, and was further surprised by finding his own nails ulcerating away in the course of the next few days. “How was I to know that carbolic acid has to be diluted?” he mutters indignantly, from time to time, with a troubled gaze at his mutilated finger-tips.

Since we came to Newala we have been making excursions in all directions through the surrounding country, in accordance with old habit, and also because the akida Sefu did not get together the tribal elders from whom I wanted information so speedily as he had promised. There is, however, no harm done, as, even if seen only from the outside, the country and people are interesting enough.

The Makonde plateau is like a large rectangular table rounded off at the corners. Measured from the Indian Ocean to Newala, it is about seventy-five miles long, and between the Rovuma and the Lukuledi it averages fifty miles in breadth, so that its superficial area is about two-thirds of that of the kingdom of Saxony. The surface, however, is not level, but uniformly inclined from its south-western edge to the ocean. From the upper edge, on which Newala lies, the eye ranges for many miles east and north-east, without encountering any obstacle, over the Makonde bush. It is a green sea, from which here and there thick clouds of smoke rise, to show that it, too, is inhabited by men who carry on their tillage like so many other primitive peoples, by cutting down and burning the bush, and manuring with the ashes. Even in the radiant light of a tropical day such a fire is a grand sight.

Much less effective is the impression produced just now by the great western plain as seen from the edge of the plateau. As often as time permits, I stroll along this edge, sometimes in one direction, sometimes in another, in the hope of finding the air clear enough to let me enjoy the view; but I have always been disappointed.

Wherever one looks, clouds of smoke rise from the burning bush, and the air is full of smoke and vapour. It is a pity, for under more favourable circumstances the panorama of the whole country up to the distant Majeje hills must be truly magnificent. It is of little use taking photographs now, and an outline sketch gives a very poor idea of the scenery. In one of these excursions I went out of my way to make a personal attempt on the Makonde bush. The present edge of the plateau is the result of a far-reaching process of destruction through erosion and denudation. The Makonde strata are everywhere cut into by ravines, which, though short, are hundreds of yards in depth. In consequence of the loose stratification of these beds, not only are the walls of these ravines nearly vertical, but their upper end is closed by an equally steep escarpment, so that the

western edge of the Makonde plateau is hemmed in by a series of deep, basin-like valleys. In order to get from one side of such a ravine to the other, I cut my way through the bush with a dozen of my men.

It was a very open part, with more grass than scrub, but even so the short stretch of less than two hundred yards was very hard work; at the end of it the men’s calicoes were in rags and they themselves bleeding from hundreds of scratches, while even our strong khaki suits had not escaped scatheless.

NATIVE PATH THROUGH THE MAKONDE BUSH, NEAR MAHUTA

I see increasing reason to believe that the view formed some time back as to the origin of the Makonde bush is the correct one. I have no doubt that it is not a natural product, but the result of human occupation. Those parts of the high country where man—as a very slight amount of practice enables the eye to perceive at once—has not yet penetrated with axe and hoe, are still occupied by a splendid timber forest quite able to sustain a comparison with our mixed forests in Germany. But wherever man has once built his hut or tilled his field, this horrible bush springs up. Every phase of this process

may be seen in the course of a couple of hours’ walk along the main road. From the bush to right or left, one hears the sound of the axe— not from one spot only, but from several directions at once. A few steps further on, we can see what is taking place. The brush has been cut down and piled up in heaps to the height of a yard or more, between which the trunks of the large trees stand up like the last pillars of a magnificent ruined building. These, too, present a melancholy spectacle: the destructive Makonde have ringed them— cut a broad strip of bark all round to ensure their dying off—and also piled up pyramids of brush round them. Father and son, mother and son-in-law, are chopping away perseveringly in the background—too busy, almost, to look round at the white stranger, who usually excites so much interest. If you pass by the same place a week later, the piles of brushwood have disappeared and a thick layer of ashes has taken the place of the green forest. The large trees stretch their smouldering trunks and branches in dumb accusation to heaven—if they have not already fallen and been more or less reduced to ashes, perhaps only showing as a white stripe on the dark ground.

This work of destruction is carried out by the Makonde alike on the virgin forest and on the bush which has sprung up on sites already cultivated and deserted. In the second case they are saved the trouble of burning the large trees, these being entirely absent in the secondary bush.

After burning this piece of forest ground and loosening it with the hoe, the native sows his corn and plants his vegetables. All over the country, he goes in for bed-culture, which requires, and, in fact, receives, the most careful attention. Weeds are nowhere tolerated in the south of German East Africa. The crops may fail on the plains, where droughts are frequent, but never on the plateau with its abundant rains and heavy dews. Its fortunate inhabitants even have the satisfaction of seeing the proud Wayao and Wamakua working for them as labourers, driven by hunger to serve where they were accustomed to rule.

But the light, sandy soil is soon exhausted, and would yield no harvest the second year if cultivated twice running. This fact has been familiar to the native for ages; consequently he provides in time, and, while his crop is growing, prepares the next plot with axe and firebrand. Next year he plants this with his various crops and

lets the first piece lie fallow. For a short time it remains waste and desolate; then nature steps in to repair the destruction wrought by man; a thousand new growths spring out of the exhausted soil, and even the old stumps put forth fresh shoots. Next year the new growth is up to one’s knees, and in a few years more it is that terrible, impenetrable bush, which maintains its position till the black occupier of the land has made the round of all the available sites and come back to his starting point.

The Makonde are, body and soul, so to speak, one with this bush.

According to my Yao informants, indeed, their name means nothing else but “bush people.” Their own tradition says that they have been settled up here for a very long time, but to my surprise they laid great stress on an original immigration. Their old homes were in the south-east, near Mikindani and the mouth of the Rovuma, whence their peaceful forefathers were driven by the continual raids of the Sakalavas from Madagascar and the warlike Shirazis[47] of the coast, to take refuge on the almost inaccessible plateau. I have studied African ethnology for twenty years, but the fact that changes of population in this apparently quiet and peaceable corner of the earth could have been occasioned by outside enterprises taking place on the high seas, was completely new to me. It is, no doubt, however, correct.

The charming tribal legend of the Makonde—besides informing us of other interesting matters—explains why they have to live in the thickest of the bush and a long way from the edge of the plateau, instead of making their permanent homes beside the purling brooks and springs of the low country.

“The place where the tribe originated is Mahuta, on the southern side of the plateau towards the Rovuma, where of old time there was nothing but thick bush. Out of this bush came a man who never washed himself or shaved his head, and who ate and drank but little.

He went out and made a human figure from the wood of a tree growing in the open country, which he took home to his abode in the bush and there set it upright. In the night this image came to life and was a woman. The man and woman went down together to the Rovuma to wash themselves. Here the woman gave birth to a stillborn child. They left that place and passed over the high land into the valley of the Mbemkuru, where the woman had another child, which

was also born dead. Then they returned to the high bush country of Mahuta, where the third child was born, which lived and grew up. In course of time, the couple had many more children, and called themselves Wamatanda. These were the ancestral stock of the Makonde, also called Wamakonde,[48] i.e., aborigines. Their forefather, the man from the bush, gave his children the command to bury their dead upright, in memory of the mother of their race who was cut out of wood and awoke to life when standing upright. He also warned them against settling in the valleys and near large streams, for sickness and death dwelt there. They were to make it a rule to have their huts at least an hour’s walk from the nearest wateringplace; then their children would thrive and escape illness.”

The explanation of the name Makonde given by my informants is somewhat different from that contained in the above legend, which I extract from a little book (small, but packed with information), by Pater Adams, entitled Lindi und sein Hinterland. Otherwise, my results agree exactly with the statements of the legend. Washing?

Hapana—there is no such thing. Why should they do so? As it is, the supply of water scarcely suffices for cooking and drinking; other people do not wash, so why should the Makonde distinguish himself by such needless eccentricity? As for shaving the head, the short, woolly crop scarcely needs it,[49] so the second ancestral precept is likewise easy enough to follow. Beyond this, however, there is nothing ridiculous in the ancestor’s advice. I have obtained from various local artists a fairly large number of figures carved in wood, ranging from fifteen to twenty-three inches in height, and representing women belonging to the great group of the Mavia, Makonde, and Matambwe tribes. The carving is remarkably well done and renders the female type with great accuracy, especially the keloid ornamentation, to be described later on. As to the object and meaning of their works the sculptors either could or (more probably) would tell me nothing, and I was forced to content myself with the scanty information vouchsafed by one man, who said that the figures were merely intended to represent the nembo—the artificial deformations of pelele, ear-discs, and keloids. The legend recorded

by Pater Adams places these figures in a new light. They must surely be more than mere dolls; and we may even venture to assume that they are—though the majority of present-day Makonde are probably unaware of the fact—representations of the tribal ancestress.

The references in the legend to the descent from Mahuta to the Rovuma, and to a journey across the highlands into the Mbekuru valley, undoubtedly indicate the previous history of the tribe, the travels of the ancestral pair typifying the migrations of their descendants. The descent to the neighbouring Rovuma valley, with its extraordinary fertility and great abundance of game, is intelligible at a glance—but the crossing of the Lukuledi depression, the ascent to the Rondo Plateau and the descent to the Mbemkuru, also lie within the bounds of probability, for all these districts have exactly the same character as the extreme south. Now, however, comes a point of especial interest for our bacteriological age. The primitive Makonde did not enjoy their lives in the marshy river-valleys.

Disease raged among them, and many died. It was only after they had returned to their original home near Mahuta, that the health conditions of these people improved. We are very apt to think of the African as a stupid person whose ignorance of nature is only equalled by his fear of it, and who looks on all mishaps as caused by evil spirits and malignant natural powers. It is much more correct to assume in this case that the people very early learnt to distinguish districts infested with malaria from those where it is absent.

This knowledge is crystallized in the ancestral warning against settling in the valleys and near the great waters, the dwelling-places of disease and death. At the same time, for security against the hostile Mavia south of the Rovuma, it was enacted that every settlement must be not less than a certain distance from the southern edge of the plateau. Such in fact is their mode of life at the present day. It is not such a bad one, and certainly they are both safer and more comfortable than the Makua, the recent intruders from the south, who have made USUAL METHOD OF good their footing on the western edge of the CLOSING HUT-DOOR plateau, extending over a fairly wide belt of country. Neither Makua nor Makonde show in their dwellings anything of the size and comeliness of the Yao houses in the plain, especially at Masasi, Chingulungulu and Zuza’s. Jumbe Chauro, a Makonde hamlet not far from Newala, on the road to Mahuta, is the

most important settlement of the tribe I have yet seen, and has fairly spacious huts. But how slovenly is their construction compared with the palatial residences of the elephant-hunters living in the plain.

The roofs are still more untidy than in the general run of huts during the dry season, the walls show here and there the scanty beginnings or the lamentable remains of the mud plastering, and the interior is a veritable dog-kennel; dirt, dust and disorder everywhere. A few huts only show any attempt at division into rooms, and this consists merely of very roughly-made bamboo partitions. In one point alone have I noticed any indication of progress—in the method of fastening the door. Houses all over the south are secured in a simple but ingenious manner. The door consists of a set of stout pieces of wood or bamboo, tied with bark-string to two cross-pieces, and moving in two grooves round one of the door-posts, so as to open inwards. If the owner wishes to leave home, he takes two logs as thick as a man’s upper arm and about a yard long. One of these is placed obliquely against the middle of the door from the inside, so as to form an angle of from 60° to 75° with the ground. He then places the second piece horizontally across the first, pressing it downward with all his might.

It is kept in place by two strong posts planted in the ground a few inches inside the door. This fastening is absolutely safe, but of course cannot be applied to both doors at once, otherwise how could the owner leave or enter his house? I have not yet succeeded in finding out how the back door is fastened.

MAKONDE LOCK AND KEY AT JUMBE CHAURO

This is the general way of closing a house. The Makonde at Jumbe Chauro, however, have a much more complicated, solid and original one. Here, too, the door is as already described, except that there is only one post on the inside, standing by itself about six inches from one side of the doorway. Opposite this post is a hole in the wall just large enough to admit a man’s arm. The door is closed inside by a large wooden bolt passing through a hole in this post and pressing with its free end against the door. The other end has three holes into which fit three pegs running in vertical grooves inside the post. The door is opened with a wooden key about a foot long, somewhat curved and sloped off at the butt; the other end has three pegs corresponding to the holes, in the bolt, so that, when it is thrust through the hole in the wall and inserted into the rectangular opening in the post, the pegs can be lifted and the bolt drawn out.[50]

MODE OF INSERTING THE KEY

With no small pride first one householder and then a second showed me on the spot the action of this greatest invention of the Makonde Highlands. To both with an admiring exclamation of “Vizuri sana!” (“Very fine!”). I expressed the wish to take back these marvels with me to Ulaya, to show the Wazungu what clever fellows the Makonde are. Scarcely five minutes after my return to camp at Newala, the two men came up sweating under the weight of two heavy logs which they laid down at my feet, handing over at the same time the keys of the fallen fortress. Arguing, logically enough, that if the key was wanted, the lock would be wanted with it, they had taken their axes and chopped down the posts—as it never occurred to them to dig them out of the ground and so bring them intact. Thus I have

two badly damaged specimens, and the owners, instead of praise, come in for a blowing-up.

The Makua huts in the environs of Newala are especially miserable; their more than slovenly construction reminds one of the temporary erections of the Makua at Hatia’s, though the people here have not been concerned in a war. It must therefore be due to congenital idleness, or else to the absence of a powerful chief. Even the baraza at Mlipa’s, a short hour’s walk south-east of Newala, shares in this general neglect. While public buildings in this country are usually looked after more or less carefully, this is in evident danger of being blown over by the first strong easterly gale. The only attractive object in this whole district is the grave of the late chief Mlipa. I visited it in the morning, while the sun was still trying with partial success to break through the rolling mists, and the circular grove of tall euphorbias, which, with a broken pot, is all that marks the old king’s resting-place, impressed one with a touch of pathos.

Even my very materially-minded carriers seemed to feel something of the sort, for instead of their usual ribald songs, they chanted solemnly, as we marched on through the dense green of the Makonde bush:—