construction and refurbishment of earthen irrigation channel banks

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GroupSymbolsSuitability for Earthen IrrigationChannelsRemediation Techniques CommentsImpermeability ErosionResistanceDispersionResistanceGW Not suitable 2 1 (best) Mix clay with gravel to form aGW-GC material.GP Not suitable 3 1 (best)Line the channel with a clay orgeomembrane linerMix clay with gravel to formGC materialLine the channel with a clay orgeomembrane linerGM 6 5 3 May require clay orgeomembrane liner to improveimpermeabilityGC 2 4 2 NO TREATMENT REQUIREDGW-GC 1 (best) 1 (best) 2 NO TREATMENT REQUIREDSW Not suitable 8 1 (best) Mix clay with sand to form aSW-SC material.SP Not suitable 9coarse1 (best)Line the channel with a clay orgeomembrane linerMix clay with sand to form SCmaterial.Line the channel with a clay orSM 7 10coarseErosionCriticalgeomembrane liner3 May require clay orgeomembrane liner to improveimpermeability.SC 4 7 2 NO TREATMENT REQUIREDSW-SC 3 6 2 NO TREATMENT REQUIREDML 8 ErosionCriticalVariable.Must beWill probably be highlydispersive. Treat as pertestedCL 5 11 Variable.Must betestedCI 7 12 Variable.Must betestedSection 15.9.3.Requires protective cover overbatter and crest.Test for dispersion.Requires protective cover overbatter and crest to protect bankfrom moderate shrinkage.Test for dispersion.OL 9 ErosionCritical- Not suitable due to thedecay of organic matterMH Not suitable Not suitable Variable.Must betestedWill have a high shrinkage %and probably be highlydispersive.Treat as per Section 15.9.2and15.9.3.This material is notsuitable without a largeamount of treatment.CH10 (worst)Volume changecritical13 (worst) Variable.Must betestedWill have a high shrinkage %.Treat as per section 15.9.2.Test for dispersion.OH Not suitable Not suitable Not suitable Not suitable due to thedecay of organic matterTable 15-8 Remediation Techniques for Low Quality Channel Bank MaterialsConstruction and Refurbishment of Earthen Channel Banks
15.9.2 ShrinkageFat clays (expansive clays) are generally not suitable for channel banks which aresubject to wetting and drying, because of swelling and shrinking properties that canlead to cracking. Materials of very high shrinkage (Pat Test > 7%) are unsuitablefor channel bank construction unless they are carefully treated by placing a blanketof sand or gravel over the bank or the bank material is chemically treated. Threepossible treatment methods are outlined below:1. Sand or Gravel CoverA minimum of 150mm of well-graded sand (SW) or well-graded gravel (GW)with less than 5% fines is required over the crest and outside batter to preventdrying of the compacted bank.Where the exposed bank is higher than 1.5 metres or the bank is in a more aridenvironment the thickness of sand or gravel should be increased to about 300mm.With very high shrinkage material, a cover of topsoil and vegetation will not beadequate to protect the bank from cracking.Refer to Section 17 Protective Cover.2. Chemical treatmentChemical treatment of bank material with relatively small quantities of substancessuch as lime, gypsum or other suitable chemicals can reduce the plasticity,shrinkage and expansion properties of soils generally in proportion to the amountof chemical used. Laboratory testing and expert advice should be sought todetermine the best type and quantity of chemical required for a particular bankmaterial to raise the shrinkage limit of the soil to the point that drying crackscannot develop. The laboratory quantities are generally increased to account forthe poorer mixing and proportioning in a field situation. The cost of the chemical,its transportation and application is also likely to be significant.A typical treatment sequence would consist of:1. The required quantity of chemical is uniformly spread over the surface area ofa 100-150mm thick layer of soil to be treated.2. The chemical is thoroughly mixed at a specified moisture content into thelayer of soil using a rotary type mixer.3. The layer is compacted to the specified density.4. The process is repeated for successive 100 to 150mm thick layers of the bank.Alternatively the treatment can be applied as a 200 to 300mm blanket over theouter surface of the bank, thereby reducing the expense of treating the entire bank.It is best mixed in two stages – the first with soil to a depth of 100-150mm overthe surface of the bank and then compacted, followed by a second mixing of soiland gypsum say in the borrow pit, which is then spread in a 100-150mm layer andcompacted over the surface of the bank. This procedure is used because it is notpossible to adequately compact a single 300mm layer of soil.Construction and Refurbishment of Earthen Channel Banks
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Your comments on the format and con
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During the course of this project,
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AcknowledgmentsThese Guidelines rep
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FundingFunding of this project was
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Table of ContentsBook 1SubjectPage
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1. Introduction1.1 GeneralGood asse
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(iv) provide proven practice approa
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3. Research Procedure3.1 Terms of R
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4. How to use these Guidelines4.1 W
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6. Units of MeasurementQuantity Uni
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8. Earthen Irrigation Channels8.1 D
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8.3 ReferencesAustralian National C
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9.1 IntroductionA key input to adva
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Data from Goulburn-Murray Water’s
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General 1 2 3 4 5 6DescriptionRisk
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Channel BankSequential Deterioratio
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9.2 ReferencesGutteridge Haskins &
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10.2.3.1 Dispersive layer of materi
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Causes ofSpecific factorDeteriorati
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10.1.2.5 BendsA bend in the channel
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10.1.4.1 Construction techniqueIrri
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10.1.5.4 Overtopping of banksIn ade
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In the past maintenance techniques
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Maintenance is a continuing require
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10.1.7.4 Yabbies/fresh water crayfi
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Direct removal ofmaterial by entrai
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Figure 10.10 shows longitudinal cra
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10.2.3.3 Irregular compaction - bri
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10.3 ReferencesEmerson W (1996), pe
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11.1 GeneralThe Investigation and P
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iv) Available fill materials and, w
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12.15 Radius of Bends .............
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There are several ways a channel ca
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• Land acquisition extent and typ
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The investigation should generally
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• Backfill: 10% compaction factor
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1. Flow Area, A, is the cross-secti
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after ageing and weed growth. If an
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elationships may be the controlling
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These maximum velocities should be
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Thus channels are usually designed
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Some of the design issues that shou
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12.12.1.3 Best PracticeEither of th
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12.13.2 Channel MaintenanceIncrease
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along a channel. The depth of the w
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12.13.4.7 Change of AlignmentThe in
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12.15 Radius of Bends12.15.1 Flow A
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12.16 Channel Cross SectionThe cros
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Some irrigation authorities use one
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12.16.2 BanksChannel cross sections
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Unless the bank is very high, the s
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The stability of channel batters ca
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drop bars become difficult and time
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Both the height above the bed and t
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• enable maintenance of the chann
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- Access agreementsA description of
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13/08/02 19:2012.20 Channel Tenure
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13/08/02 19:20As with the damage to
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13/08/02 19:20Advantages of Protect
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- gates provide a better deterrent
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13/08/02 19:20When considering expo
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13/08/02 19:20A typical design draw
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13/08/02 19:20Sinclair Knight Merz
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13.1 IntroductionIn many irrigation
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For example, the initial constructi
Page 134 and 135: 13.2.6 When to use Life Cycle Analy
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Page 138 and 139: • assess cost of collecting missi
Page 140 and 141: Microsoft Excel has quite a good pr
Page 142 and 143: The costs used in these methods sho
Page 144 and 145: Life CyclePhaseInvestigationDesignC
Page 146 and 147: Life CyclePhaseMaintenanceRehabilit
Page 148 and 149: ReplacementProject managementInvest
Page 150 and 151: Residual valueLegal feesInsuranceAd
Page 152 and 153: 13.4.6.2 Recurring CostsChannel con
Page 154 and 155: $1.00.80Percent ofValue of$1.00.60.
Page 156 and 157: 13.4.11 Evaluate ResultsThe results
Page 158 and 159: 13.6 Tipsthe way open to incur sign
Page 160 and 161: 14. Risk AnalysisTable of ContentsS
Page 162 and 163: Consequences for irrigation authori
Page 164 and 165: 15. Material Selection and TestingT
Page 166 and 167: c) Shrinkage - will the bank crack
Page 168 and 169: depth. For this reason, the soils o
Page 170 and 171: Natural moisture content should als
Page 172 and 173: The study identified some confusion
Page 174 and 175: 15.4.2 Determination of the plastic
Page 176 and 177: 1. Preparation of PatTake approxima
Page 178 and 179: EmersonClass No.Degree ofDispersion
Page 180 and 181: 15.7.1 Coarse grained soilsIn this
Page 182 and 183: sufficient gravel for erosion resis
Page 186 and 187: The uniform application and thoroug
Page 188 and 189: essential that the chemical is thor
Page 190 and 191: Where laboratory testing facilities
Page 192 and 193: Clays are the plastic fines. They c
Page 194 and 195: etween the soil sample and the wate
Page 196 and 197: 16. Compaction ControlTable of Cont
Page 198 and 199: 16.1 PurposeDuring this research pr
Page 200 and 201: All compaction equipment utilises s
Page 202 and 203: The soil density required for a cha
Page 204 and 205: In the past, a method specification
Page 206 and 207: Low permeability and high stability
Page 208 and 209: 16.10.1.1 Tamping Foot RollerTampin
Page 210 and 211: 16.10.1.5 Non-Circular Impact Rolle
Page 212 and 213: 16.10.3 Compactor OperationsAfter t
Page 214 and 215: 16.11.4 Moisture Content ControlBef
Page 216 and 217: 16.12 Density Control Tests and Pro
Page 218 and 219: Correlation with local materials an
Page 220 and 221: The main advantages of the Nuclear
Page 222 and 223: Figure 16.4Hilf Density Ratio Repor
Page 224 and 225: The location and test results for e
Page 226 and 227: 16.14.3 Reporting and RecordsTest r
Page 228 and 229: 16.16 Tests for small projectsThe s
Page 230 and 231: The advantages of the Drop Test are
Page 232 and 233: AS1289.6.3.2-1997AS1289.6.3.3-1997A
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17. Protective CoverTable of Conten
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The bank dries and cracks from the
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17.5 Specifications17.5.1 GravelPar
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17.6 Establish Vegetation CoverTops
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Species Growing Conditions Establis
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17.7.2 Rope Wick ApplicationMuch of
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There are a number of fibre mats or
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17.10 Australian StandardsAS1289.3.
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18.1 IntroductionFor many earthen c
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When re-shaping the batters of exis
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LifeCrestOld bank lineBattered bank
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Photos\inside batter\CG7channel2arm
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4. To help place the rock material
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False ToeFigure 18.8Protective laye
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The confinement system would be adv
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• Able to survive during non-oper
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18.6 ReferencesHutchison D & Locke
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19.20 Guidelines on Field Quality C
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Construction and Refurbishment of E
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• Figure 19.2)3. Temporary Bench
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The capabilities and limitations of
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19.3.1 Construction EquipmentThe ba
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construction. The aim of scarifying
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Whether or not a front-end loader o
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The thickness of each layer will va
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distribution. The use of alternativ
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19.8 Construction RecordsAdequate r
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19.12 Protective Cover on Crest and
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19.21 Australian StandardsAS 1726-1
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20.1 ScopeAustralia’s earthen irr
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Bank re-construction normally requi
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•meter outlet locations and type
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In the case of channel bank refurbi
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20.4.1.1 StrippingWith outside bank
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All public roads to be used by truc
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5. Material is delivered by trucks
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Need to drain and de-waterEBM befor
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significantly and a more conservati
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Aim for crest width ofabout 2 metre
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Refer to Section 18, Inside Batter
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21.8.10 Re-alignment ..............
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Seepage is a complex hydrologic phe
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2. Seepage losses increase as the d
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Refer also to the following section
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21.4 Channel Seepage ConsequencesSe
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Channel seepage is one of the sever
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Seepage is proportional to soil per
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Methods based on vertical flow meas
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ainfallPumpingevapotranspirationIrr
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Flow NetsA flow net is a system of
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Data from indirect measurement proc
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(ii) EM SurveyElectro-magnetic (EM)
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The volume of waterloss from the dr
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21.7.3.2 Inflow-Outflow Method (Dyn
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Imperfect seal will cause the meter
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The groundwater level can then be d
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Stable IsotopesThe basis of testing
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To be most successful, there needs
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21.8.6 Surface interception drainag
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KeyWatertable before tree plantingW
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• The preparation of a best pract
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21.11 ReferencesAustralian National
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22. Channel LiningTable of Contents
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22.1 IntroductionThe conservation o
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The different types of channel lini
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Table 22-1Unlined Earthen Channels
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Lining of channels will not elimina
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To supply a given discharge, the cr
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22.4.5 Structural SafetyThe stabili
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soil pressures and under-drainage i
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Concrete linings are suitable for b
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22.5.12 Availability of Constructio
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esistance to erosion. To improve th
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Construction and Refurbishment of E
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22.7.1.2 General Design Considerati
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22.7.1.4 Lining ThicknessThe thickn
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particular problems, but in smaller
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Where the earth lining finishes abo
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control where the channel material
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sand requires about 5% cement by we
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22.7.6 Soil SealantsSoil sealants a
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22.7.7 Cost of Earth LiningsThe cap
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Although they can assist with shear
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22.8.2 Membrane Liner TypesGeomembr
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Polyethylene has also appeared in m
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FPP resistance to common chemical e
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The base coat and seal coat rates m
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A common and misleading argument is
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These thermal expansion and contrac
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Another factor is the ability to ha
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Some lining methods expand and cont
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22.8.9.1 Geomembrane ThicknessThe t
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Cover typeThickness ofEarth fill(m)
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22.8.9.5 Cover MaterialGeomembranes
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As well, velocities which are permi
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22.8.11 FencingWhen livestock, part
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22.10 ReferencesAlther GR (1987), T
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23. Measures to Reduce the Rate ofD
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Channel DesignBank MaterialDeterior
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Stock and VerminAdjacentlandholders
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To ensure that a channel bank has a
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Advantages of Draining• Allows fo
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To efficiently maintain a channel,
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Compared with other countries where
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23.4.7 LeaksTransverse cracks are t
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23.5 Reduction of Deterioration due
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Photo 23-1Channel bed showing mumbl
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Thus, control of carp by draining c
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The disadvantages of a biological c
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Carp have been blamed for erosion o
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Management Groups gives guidelines
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Organisation Contact Details Aims/A
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Chemical treatment is often recomme
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23.7 Reduction of Deterioration due
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Grey Parrot Pea - Dillaynia cineres
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Lodge G (1998), Review on Fish Barr
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cation exchange capacity (CEC) a me
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fetch the distance over which the w
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plant term used for construction eq
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supply level the supply level is a
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