Lymington Coastal Flood Defence Sea dikes design.docx
- 文档编号:8669251
- 上传时间:2023-02-01
- 格式:DOCX
- 页数:25
- 大小:2.33MB
Lymington Coastal Flood Defence Sea dikes design.docx
《Lymington Coastal Flood Defence Sea dikes design.docx》由会员分享,可在线阅读,更多相关《Lymington Coastal Flood Defence Sea dikes design.docx(25页珍藏版)》请在冰豆网上搜索。
LymingtonCoastalFloodDefenceSeadikesdesign
Name:
YanbingWang
26133172
Course:
MScCivilEngineering
EngineeringandtheEnvironment
CENV6123CoastalFloodDefence:
Assignment2
Deadline:
Tuesday06May2014.
Introduction
Lymington isaportonthewestbankofthe LymingtonRiver onthe Solent,inthe NewForestdistrict of Hampshire,England.Itistotheeastofthe SouthEastDorsetconurbation,andfaces Yarmouth onthe IsleofWight whichisconnectedtoitbyacarferry,operatedby Wightlink.Thetownhasalargetouristindustry,basedonproximitytothe NewForest andtheharbour.Itisamajor yachting centrewiththree marinas.Accordingtothe2011censustheLymingtonurbanareahadapopulationof15,407.IfyouweretoalsoincludethenearbyparishofBoldrewhichincludesWalhampton,normallyconsideredpartofLymington,thenthepopulationin2011was17,410.(Wikipedia2014)
SinceLymingtonissuchaplacewithlargepopulationanditstouristindustryrelatingtoitseconomy,anditsdangerouslocationwhichmaysufferingfromflood,itisnecessarytopreventLymingtonfromflooding.ThelocationofLymingtonisshowninFigure1.
Figure1.ThelocationofLymington(Googlemaps2014)
Thebackgroundinformationontheriver/seafloodeventatLyimingtoninDecember1999isfrom“Lymingtoninformationv3.ppt”.Flooddefensesin1999canbeseeninFigure2,andFigure3showsthemeasuredriverandsealevelsforDecember1999.
UseHEC-RAStoanswerthequestionsbelow.
KeyQuestion1:
whatsizegateswilldrainthesysteminaspringtidewitha1in50yearflood?
KeyQuestion2:
WillthesegatesworkOKinaneaptide?
KeyQuestion3:
Ifweexpectsealevelrisetoadd50cmtothemeansealevel,willthegatesworkadequately?
IftheydonotworkOK,whatdoyourecommendwedo?
Figure2.Flooddefensesin1999(Clarkeetal2013)
Figure3.MeasuredRiverandsealevels:
December1999(Clarkeetal2013)
Theroaddecklevelisassumedtobe+2.0mOD,andtheflooddefensesattherailwaylineisassumedtoberaisedto+2.5mOD.Themainaimistostoptheupstreampondlevelrisingabovetheroaddecklevel.
Methodology
Thereisnewmoonon31st,March,2014,andspringtidecanbeobserved.Aweeklateron7th,April,2014,andneaptidecanbeobserved.ThetidedataisshowninTable1.
Time
SpringTide(m)(31/03/2014)
NeapTide(m)(07/04/2014)
+(m)
SpringTide+0.5(m)
NeapTide+0.5(m)
00:
00
1.12
-0.11
0.5
1.62
0.39
01:
00
1.11
0.03
0.5
1.61
0.53
02:
00
0.63
0.3
0.5
1.13
0.8
03:
00
-0.64
0.64
0.5
-0.14
1.14
04:
00
-1.55
0.74
0.5
-1.05
1.24
05:
00
-1.37
0.76
0.5
-0.87
1.26
06:
00
-0.65
0.65
0.5
-0.15
1.15
07:
00
-0.12
0.28
0.5
0.38
0.78
08:
00
0.14
-0.17
0.5
0.64
0.33
09:
00
0.44
-0.38
0.5
0.94
0.12
10:
00
0.97
-0.33
0.5
1.47
0.17
11:
00
1.21
-0.18
0.5
1.71
0.32
12:
00
0.98
-0.04
0.5
1.48
0.46
13:
00
1.04
0.05
0.5
1.54
0.55
14:
00
0.86
0.28
0.5
1.36
0.78
15:
00
-0.2
0.6
0.5
0.3
1.1
16:
00
-1.38
0.88
0.5
-0.88
1.38
17:
00
-1.58
0.99
0.5
-1.08
1.49
18:
00
-0.96
0.98
0.5
-0.46
1.48
19:
00
-0.34
0.7
0.5
0.16
1.2
20:
00
0
0.19
0.5
0.5
0.69
21:
00
0.23
-0.15
0.5
0.73
0.35
22:
00
0.69
-0.24
0.5
1.19
0.26
23:
00
1.23
-0.15
0.5
1.73
0.35
00:
00
1.12
-0.11
0.5
1.62
0.39
Table1.Tidedataforspringtideandneaptidein24hrs(ChannelCoastalObservatory2014)
TheordnancedatumchartforspringtideandneaptidechartsareshowninFigure4andFigure5separately.
Figure4.Ordnancedatumchartforspringtideon
31/03/2014(ChannelCoastalObservatory2014)
Figure5.Ordnancedatumchartforspringtideon
07/04/2014(ChannelCoastalObservatory2014)
For1999modelling,theunsteadyflowdataisshowninFigure3above.ThefigureshowsthattheHWstageis2.2m,sowhendoingthe1999modeltogetthegatesize,greateffortshouldbeusedtomakethemodelgetHWstagecloserenoughto2.2m.
Figure6.RealHydrographsfortheRiverLymington
RiverflowdatacanbeseeninTable2.RiverflowdatacanbereadfromFigure6.
Non-steadyflowanalysis(1999model)
Figure7.InlineStructureWeirStationElevationFigure8.InlineGate
Gatesize:
Height:
2.5m
Width:
5.5m
Invert:
-0.22m
Figure9.GeometryGraph
TheflowhydrographandstagehydrographareshowninFigure10andFigure11.Riverflowis5-50m3/sec(Clarkeetal2013).
Figure10.FlowHydrograph
Figure11.StageHydrograph
Figure12.ElevationControlledGates
Figure13.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure13.ThemaximumHWStageis2.22m,whichisveryclosetotherealHWstage2.2m.Themaximumflowis41.34m3/sec,whichisclosetothemaximumrealriverflow35m3/sec.InordertoadjustthemaximumHWstageto2.2m,gatesize,gateopeningandclosingrateareadjusted.Whenincreasethewidthofthegate,HWstagegetssmaller.Also,increasingthegateopeningandclosingratecanmaketheHWstagesmaller.
KeyQuestion1:
Non-steadyflowanalysis(springtidewitha1in50yearflood,data:
31/03/2014)
Gatesize:
Height:
2.5m
Width:
5.5m
Invert:
-0.22m
InlineStructureandgateforspringtidecaseisthesameas1999case.Howevertheflowhydrographandstagehydrographarenotthesameas1999case,whichcanbeseeninFigure15andFigure16respectively.
Figure14.FlowHydrographDataInput
Figure15.Flowhydrograph
Figure16.unsteadystagehydrographdatainput
Figure17.Stagehydrograph
Figure18.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure18.ThemaximumHWStageis1.80m,whichislowerthantheroaddecklevelof2.0mOD.Themaximumflowis27.12m3/s,reflectsthatthemaximumflowislessthanthemaximumflow(29.5m3/s)witha1in50yearfloodinFigure6.Sothecurrentgatewilldrainthesysteminaspringtidewitha1in50yearflood.
KeyQuestion2:
Non-steadyflowanalysis(neaptide,data:
07/04/2014)
KeeptheInlineStructureandGeometrythesameasthe31/03/2014model.
Gatesizekeepsthesameasfollows:
Height:
2.5m
Width:
5.5m
Invert:
-0.22m
Changethestagehydrographasfollows.
Figure19.unsteadystagehydrographdatainput
Figure20.Stagehydrograph
Figure21.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure21.ThemaximumHWStageis1.80m,whichislowerthantheroaddecklevelof2.0mOD.Themaximumflowis27.09m3/s,reflectsthatthemaximumflowislessthanthemaximumflow(29.5m3/s)witha1in50yearfloodinFigure6.Sothecurrentgatewilldrainthesysteminaneaptidewitha1in50yearflood.
KeyQuestion3:
Non-steadyflowanalysis(adding50cmtothemeansealevel)
Changetheriverflowto120%oftheriverflowusedintheformercasesbecauseoftheeffectofclimatechange.The20%wasreportedinPPS25.KeeptheInlineStructureandGeometrythesameasthe31/03/2014model.
Gatesizekeepsthesameasfollows:
Height:
2.5m
Width:
5.5m
Invert:
-0.22m
Springtide(adding50cmtothemeansealevel)
Changetheflowhydrographandstagehydrographasfollows.
Figure22.unsteadyflowhydrographdatainput
Figure23.FlowHydrograph
Figure24.unsteadystagehydrographdatainput
Figure25.Stagehydrograph
Figure26.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure26.ThemaximumHWStageis2.01m,whichishigherthantheroaddecklevelof2.0mOD.Themaximumflowis36.55m3/s,reflectsthatthemaximumflowisbiggerthanthemaximumflow(35.4m3/s)witha1in50yearfloodinFigure6.Sothecurrentgatecannotdrainthesysteminaneaptidewitha1in50yearflood.
Improvingmethod:
Method1:
Inordertokeepthegatedrainthesysteminaneaptidewitha1in50yearflood,thegatesizehavetobechanged.
Gatesize:
Height:
2.5m
Width:
8m
Invert:
-0.22m
Figure27.InlineGate
Figure28.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure28.ThemaximumHWStageis1.69m,whichislowerthantheroaddecklevelof2.0mOD.Themaximumflowis32.88m3/s,reflectsthatthemaximumflowissmallerthanthemaximumflow(35.4m3/s)witha1in50yearfloodinFigure13.Sothecurrentgatewilldrainthesysteminaneaptidewitha1in50yearflood.
Method2:
Inordertokeepthegatedrainthesysteminaneaptidewitha1in50yearflood,addonemoregateatstation200m.Keepotherfactorsconstantsuchasgateopeningandclosingrate,maximumgateopening,andetc..
Gatesizeisstillthesameasthe1999gate:
Height:
2.5m
Width:
5.5m
Invert:
-0.22m
Figure29.InlineGate
Figure30.GeometryGraph
Figure31.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure31.ThemaximumHWStageis1.90m,whichislowerthantheroaddecklevelof2.0mOD.Sothecurrentgatewilldrainthesysteminaneaptidewitha1in50yearflood.
Neaptide(adding50cmtothemeansealevel)
Changetheflowhydrographandstagehydrographasfollows.Theflowhydrographisthesameasthespringtide(adding50cmtothemeansealevel)case.
Figure32.unsteadystagehydrographdatainput
Figure33.Stagehydrograph
Figure33.StageandFlowHydrographs
GetthefinalstageandflowhydrographsasshowninFigure33.ThemaximumHWStageis2.0m,whichishigherthantheroaddecklevelof2.0mOD.Sothecurrentgatecannotdrainthesysteminaneaptidewitha1in50yearflood.
Improvingmethod:
Sinceneaptideislowerthanthespringtide,ifthegatesizeisOKforthespringtidecase,itshouldbeOKforthenea
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- Lymington Coastal Flood Defence Sea dikes design
链接地址:https://www.bdocx.com/doc/8669251.html