Small Dams: Planning, Construction and Maintenance

212 Pages·2013·21.409 MB·English

by  Barry Lewis

Lewis Barry Lewis
Small Dams
Small Dams: Planning, Construction and Maintenance has been written to provide a S Planning, Construction and Maintenance
practical approach and guide to determining catchment yield and the amount of water m
required in a dam, advising on selecting and working with engineers and contractors, as
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well as outlining the cause of dam failures and how to remedy problems quickly. It also
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covers relevant legislation, environmental and ecological issues. l

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Employing the principles in this book, in conjunction with heeding the advice of suitably
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experienced and qualifi ed engineers and contractors, will reduce the risk of failure and
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help to ensure the long term success of any small dam in question. Small Dams will be
an invaluable resource for anyone who owns a dam, and a useful reference for agencies,
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contractors and engineers.
The author, Barry Lewis, has over forty years of experience as an engineer and has
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written extensively on farm dams, soil conservation, catchment management and the la
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environmental impact of dams both on and off streams. He was also directly involved in n
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the licensing and regulating of small dams in Australia. n
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Small Dams
TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk
Small Dams
Planning, Construction and Maintenance
Barry Lewis
Dam Consultant,Melbourne, Australia
CRCPress/BalkemaisanimprintoftheTaylor&FrancisGroup,aninformabusiness
©2014Taylor&FrancisGroup,London,UK
TypesetbyMPSLimited,Chennai,India
PrintedandBoundbyCPIGroup(UK)Ltd,Croydon,CR04YY.
Allrightsreserved.Nopartofthispublicationortheinformationcontained
hereinmaybereproduced,storedinaretrievalsystem,ortransmittedinany
formorbyanymeans,electronic,mechanical,byphotocopying,recordingor
otherwise,withoutwrittenpriorpermissionfromthepublishers.
Althoughallcareistakentoensureintegrityandthequalityofthispublication
andtheinformationherein,noresponsibilityisassumedbythepublishersnor
theauthorforanydamagetothepropertyorpersonsasaresultofoperation
oruseofthispublicationand/ortheinformationcontainedherein.
LibraryofCongressCataloging-in-PublicationData
Lewis,Barry,1942–
SmallDams:Planning,ConstructionandMaintenance/BarryLewis,DamConsultant,
Melbourne,Australia.
pagescm
Includesbibliographicalreferencesandindex.
ISBN978-0-415-62111-3(hardback)
1. Reservoirs—Designandconstruction. 2.Water-supply,Agricultural. I.Title.
TC540.L55 2013
627’.8—dc23
2013022561
Publishedby: CRCPress/Balkema
P.O.Box11320,2301EH,Leiden,TheNetherlands
e-mail:[email protected]
www.crcpress.com–www.taylorandfrancis.com
ISBN:978-0-415-62111-3(Hbk)
ISBN:978-1-315-85774-9(eBookPDF)
Disclaimer
This book is intended for use as a guide to owners and operators of small dams. It
suggestsprudentapproachestonormalsurveillanceandmaintenancepracticewitha
viewtoenhancingthelong-termsafetyandsurvivalofsmalldams. Itisnotintended
as a source of detailed information to cover all possible eventualities. In the event of
anysuspectedimminentorpotentialfailurecondition,expertadviceshouldbesought
immediately.
TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk
Table of contents
Preface xiii
Acknowledgments xv
Introduction xvii
Section1 Planning 1
1.1 Assessingwaterneeds 1
1.1.1 Planningwatersupplies 1
1.1.2 Waterquality 2
1.2 Assessmentofcatchmentyield 3
1.2.1 Factorscontrollingcatchmentyield 3
1.2.2 Methodsofestimatingcatchmentyield 4
1.2.3 Howtreesaffectyield 8
1.2.4 Artificialcatchments 8
1.3 Damsiteselection 9
1.3.1 Choosingadamsite 10
1.4 Typesoffarmstorages 12
1.4.1 Gullydams 14
1.4.2 Hillsidedams 14
1.4.3 Ringtanks 15
1.4.4 Turkey’snesttanks 17
1.4.5 Excavatedtanks 18
1.4.6 Weirs 20
1.4.7 Off-waterwaystorages 20
1.5 Damstoragesize 20
1.5.1 Evaporationlosses 21
1.5.2 Waysofcontrollingevaporation 22
1.5.3 Seepagelosses 22
1.5.4 Averagewaterconsumption 22
1.6 Usingadamindrought 25
1.7 Firefighting 28
1.8 Smalldamsandtrees 29
1.9 Damcostjustification 30
viii Table of contents
Section2 Investigation 33
2.1 Soiltesting 33
2.1.1 Foundation 33
2.1.2 Borrowpitforembankmentmaterial 34
2.1.3 Spillwaysite 34
2.2 Siteselectioncriteria 34
2.2.1 Seepagelosses 34
2.2.2 Stabilityofdamsides 36
2.2.3 Sedimentationindams 36
2.3 Foundationmaterials 36
2.4 Embankmentmaterials 37
2.5 Siteinvestigationofmaterials 38
2.5.1 Soiltexturetests 38
2.5.2 Unifiedsoilclassification 38
2.6 Analysisofsoil 41
2.6.1 Coretrench 41
2.6.2 Embankmentsoil 42
2.7 Locationofsoil 42
2.8 Unsuitablematerial 43
Section3 Design 45
3.1 Itemsthatneedtobeconsidered 45
3.1.1 Embankmenttypes 46
3.1.2 Coretrench 48
3.1.3 Embankmentbatterslope 48
3.1.4 Crestwidth 50
3.1.5 Freeboard 51
3.1.6 Alternativewaysofbatterprotection 52
3.1.7 Topsoilcover 54
3.1.8 Fencing 55
3.2 Floodflowestimation 55
3.2.1 Peakflowestimation 56
3.3 Outletstructures 56
3.3.1 Earthspillways 57
3.3.2 Designspillwaycapacity 58
3.3.3 Selectingspillwaydimensions 58
3.3.4 Chutespillways 60
3.4 Pipelinesthroughembankments 61
3.4.1 Tricklepipes 64
3.4.2 Dropinletstructures 64
3.4.3 Cut-offcollars 65
3.5 Earthandwatercomputations 65
3.5.1 Embankmentmaterial 65
3.5.2 Floorslope 68
3.5.3 Areabeneathembankment 68
3.5.4 Excavatedtanks 69
Table of contents ix
3.5.5 Waterstoragecapacitycomputations 69
3.5.6 Storageexcavationratio 72
3.6 Estimateofcosts 72
3.6.1 Economics 72
3.6.2 Damqualitypaysovertime 74
Section4 Documentation 75
4.1 Collationofplansandspecification 75
4.2 Collectingbasicdesigndata 76
4.2.1 Catchmentmap 76
4.2.2 Location(topographical)map 77
4.2.3 Profilesandcross-sections 77
4.2.4 Soils 77
4.3 Assemblyofdata 78
4.3.1 Analysisofdata 78
4.3.2 Design 78
4.4 Constructiondocumentsanddrawings 79
4.4.1 Specifications 79
4.4.2 Checklist 80
4.5 Finalreviewandapproval 80
4.5.1 Records 80
Section5 Construction 81
5.1 Approvalfordambuilding 81
5.1.1 Detailsthatmayneedtobesubmitted 81
5.1.2 Referraldams 82
5.2 Selectingyourdambuilders 83
5.2.1 Selectinganengineer 83
5.2.2 Detailsthatanengineercanprovide 84
5.3 Howtobuildadam 85
5.4 Stepsinconstructingadam 85
5.4.1 Settingout 85
5.4.2 Diversionofwater 87
5.4.3 Clearingandgrubbing 87
5.4.4 Strippingtopsoil 87
5.4.5 Coretrench 88
5.4.6 Borrowpitmaterial 88
5.4.7 Selectionandplacingofmaterial 88
5.4.8 Spillwayandoutletstructures 88
5.4.9 Battersandtopsoil 89
5.5 Compaction 89
5.5.1 Compactionwhenconstructingadam 90
5.5.2 Recommendationsforcompaction 90
5.6 Soilmoisture 91
5.6.1 Adjustingsoilmoisture 91
5.7 Allowanceforsettlement 92