1 / 45

Lectu r e 3 : Flood Routing

Lectu r e 3 : Flood Routing CEM 0 01 H y dra u l i c S t ructu r es, C o a s t a l a n d River Engineer i ng. Dr Md R o w shon Kamal. r o w shon@legendag r oup.ed u .my. H / P: 0126627589. 1 S c hool of Com p u t ing, Information T ec hnology & Engin ee ring.

cedric
Télécharger la présentation

Lectu r e 3 : Flood Routing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture 3:Flood Routing CEM001HydraulicStructures,CoastalandRiverEngineering DrMd RowshonKamal rowshon@legendagroup.edu.my H/P:0126627589 1 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  2. HydrologicRouting:Application Analysetheeffectsofconduitmodifications • • • • • • • • Stormwaterdetention Floodmitigation Reservoirstorage Spillwaysizing Pumpingstations pond storage Changesinlanduse and Overtoppingofhighwayembankments 2 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  3. HydrologicalFlood Routing Themovementoffloodwavedowntoachannel orthroughareservoirandassociatedchangein timingorattenuation ofthewaveconstitutean importanttopicin floodplainhydrology. Itisessentialtounderstand thetheoreticaland practicalaspects offloodroutingtopredictthe temporal andspatialvariationsofafloodwave throughariverreachand/orreservoir. Floodroutingisalsousedtopredicttheoutflow • • • hydrograph from a watershed subjected to a knownamountofrainfall. 3 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  4. Routing Simulatethemovementofwaterthroughphysical componentsofwatershed(e.g.,channels) • • Commonly used to predict the magnitudes, volumes, and temporal patterns of flow (often a floodwave)asit moves downachannel • Physical/Hydraulic: momentum Conservation of mass and • Conceptual/Hydrologic: (continuity),butinexact Some representations physics 4 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  5. RoutingandTypes Routing is the process of predicting temporal and spatial variation of a flood wave as it or travels through a river (or channel reach reservoir. Twotypesofroutingcanbeperformed: •HydraulicRouting •HydrologicRouting 5 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  6. HydraulicRouting Hydraulicroutingmethod combinesthe continuity equation with a morerealisticrelationshipdescribing the actualphysicsof the movementof the water The equation usedresultsfrom conservationof momentum,assuming • • – – – In uniformvelocitydistribution(depth averaged) hydrostaticpressure smallbottom slope • hydraulic routing analysis, itis intended that the dynamicsofthewater accuratelydescribed orfloodwavemovementbemore 6 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  7. Useof Manning Equation • Stage isalsorelated to the outflowvia a relationship such as Manning's equation Q1.49AR2 S1 3 2 h f n 7 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  8. Hydrologic Routing Hydrologicrouting techniquesinvolvethe balancing of of inflow, outflow andvolume of storage through use the continuity equation. Application: Floodpredictions Evaluationofflood controlmeasures Assessmentofeffectsofurbanization Floodwarning Reservoirdesignand operation Spillway designfordams 8 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  9. Bukit MerahReservoir,Malaysia 9 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  10. Lake Livingston, USA 10 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  11. Lake Conroe,USA 11 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  12. Detention Ponds Detentionponds store and treat urbanrunoff andalso provide floodcontrol for the overalldevelopment. Pondsconstructedas amenitiesfor thegolfcourse and other community centers that were built up aroundthem. School ofCivilEngineering/Linton 12 School ofComputing,InformationTechnology& Engineering

  13. DetentionPond,AUSTIN,TX 13 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  14. Hydrologic Routing IOS Continuity Where Equation: t I =Inflow O=Outflow S/t=Rate ofchange ofstorage Problem: You You Need: haveahydrographatonelocation(I) haverivercharacteristics(S=f(I,O)) Ahydrographatdifferentlocation(O) 14 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  15. Hydrologic Routing HydrographatpointA HydrographatpointB The hydrograph at B is attenuated due to storagecharacteristicsofthestreamreach. Assumption:noseepage,leakage,evaporation, orinflowfromthesides. 15 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  16. River Reach Comparisons: River vs. Reservoir Routing Level pool reservoir 16 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  17. HydrologicalRouting Combinethecontinuityequationwithsome • relationship betweenstorage, outflow, and possiblyinflow • These relationships are usually nature assumed, empirical,oranalyticalin Anofexampleofsucha • relationship might be a stage-dischargerelationship 17 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  18. Inflow Characteristics 18 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  19. Inflow-Storage-Outflow Characteristics 19 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  20. Inflow-Storage-Outflow Characteristics 20 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  21. Inflow-Outflow Characteristics 21 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  22. Storage-Water Level Characteristics 22 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  23. Outflow Determination 23 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  24. HydrologicalRouting RiverorChannelRouting –Muskingummethod –Muskingum-CungeMethod ReservoirRouting • • – Inflow-Storage-DischargeCurve (Puls Method) Storage-IndicationMethod (ModifiedPuls Method) Method – 24 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  25. Reservoir Routing 25 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  26. RequiredInformation • • • Inflowhydrograph Outflowhydrograph Surcharge Storage vs Water Level graph 26 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  27. Inflow-Storage-Discharge(ISD) Step1:Atfirst,asuitabletimeintervaltischosenanda betweenelevationasOrdinateand[2S/t Thetimeintervalisusuallytakenas0.20 timeoftheriseoftheinflowhydrograph. curveisprepared +O]asabscissa. to0.40timesthe From the same plot, a curve between outflow rates and elevationcanbedrawn. Step2:Atthestartoftherouting,thetermsontheL.H.S. Eq.(3)areknownand[2S2/t+O2]iscomputed. of of[2S2/t+O2]computedinStep Step3:Forthevalue 2, vs [2S/t the value ofelevation isdeterminedfrom + O] ElevationcurveandO2 fromOutflowvsElevationcurve. 27 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  28. 28 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  29. Inflow-Storage-Discharge(ISD) Step 4:Step3:Forthevalueof[2S2/t+O2]computedin Step2,thevalueofelevation isdeterminedfrom[2S/t+ O] vs Elevationcurveand O2fromOutflow vs Elevationcurve. Step 5:Thenthevalue of[2S2/t+ O2] bydeducting2O2is determinedfrom [2S2/t +O2] (I2 + I3) + [2S2/t- O2] = [2S3/t +O3] Step6:Theaboveproceduresarerepeated inflowhydrographisrouted. tilltheentire Step7:Finally,themaximumwaterleveland outflowratearedetermined.Alsotheoutflow drawn. themaximum hydrographis 29 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  30. Modified Puls • The Modified Puls routing method is most oftenappliedtoreservoirrouting –storagerelatedtooutflow • The method may also be applied to river routingforcertainchannelsituations TheModifiedPulsmethodisalsoreferredto astheStorage-Indicationmethod • • As a hydrologic method, the Modified Puls the equation is described by considering discrete continuityequation... 30 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  31. Storage Indication orModified Method Puls Sn In  Qn  Sn1 In1 Qn1   t 2 2 Re-writing (substitutingO forQto followconvention) 2Sn 2Sn1   I  O   I On1     n1 n n t t The solution to the Modified Puls method is accomplishedbydevelopingagraph(ortable)ofOvs [2S/Δt + O]. In order to do this, a stage-discharge- storagerelationshipmustbeknown (outlet works). (rules)orderived 31 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  32. Modified PulsExample and 2S/t Given curve, the following inflow hydrograph + O find the outflow hydrograph for the reservoir assuming storm. it to be completely full at the beginning of the HydrographForModifiedPulsExample 180 150 120 90 60 30 0 0 2 4 6 8 10 Time(hr) Discharge(cfs) 32 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  33. Storage Indication or Modified Puls Method t altischosenanda abletimeinter v Step1:Atfirst,asui curve is prepared between Elevation as Ordinate and [2S/t+O]asAbscissa.Thetimeintervalisusually taken as 0.20to 0.40timesthetime oftheriseoftheinflow hydrograph.Fromthesameplot,acurvebetweenoutflow rates and elevationcan be drawn. Step2:Atthestartoftherouting,thetermsontheL.H.S. ofEq.(3)are knownand[2S2/t+ O2]iscomputed. Step3:Forthevalueof[2S2/t+O2]iscomputedinStep 2,thevalueofElevationisdeterminedfrom[2S/t+O] vs Elevation curve and O2 from Outflow vs Elevation curve. 33 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  34. ModifiedPuls Method Step4:Thenthevalueof[2S2/t+O2]bydeducting2O2 is determined from[2S2/t- O2] Step5:Then,thevalueof[2S3/t+O3]iscomputedfrom the valuesof[2S2/t- O2]and (I2+ (I2+ I3)+[2S2/t- O2]=[2S3/t+ I3),thus O3] Step6:Theaboveproceduresare inflowhydrographis routed. repeated tilltheentire Step 7: Finally, the maximum water level and the maximumoutflowratearedetermined.Alsotheoutflow hydrographisdrawn. 34 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  35. Modified Puls Example • 2S/t+ Ocurve: 35 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  36. ModifiedPulsExample •Atablemay be createdasfollows: Time In In+In+1 2Sn/t-On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 1 2 3 4 5 6 7 8 9 10 11 12 36 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  37. ModifiedPulsExample •Next, usingthehydrographandinterpolation, inflow (discharge)values. insert the •For example at 1 hour, the inflow is 30 cfs. Time In In+In+1 2Sn/t- On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) HydrographForModifiedPulsExample 180 150 120 90 60 30 0 0 2 4 6 8 10 Time(hr) 0 0 1 30 2 60 3 90 4 120 Discharge(cfs) 5 150 6 180 7 135 8 90 9 45 10 0 11 0 12 0 37 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  38. Modified Puls Example •Thenextstep isto addtheinflowtotheinflowinthe next timestep. •For thefirst blanktheinflow at0 is added to the inflow at 1 hour to obtain a value of 30. Time In In+In+1 2Sn/t- On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 0 30 1 30 2 60 3 90 4 120 5 150 6 180 7 135 8 90 9 45 10 0 11 0 12 0 38 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  39. ModifiedPulsExample •Thisis thenrepeatedfortherestof thevaluesinthecolumn. Time In In+In+1 2Sn/t-On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 0 30 1 30 90 2 60 150 3 90 210 4 120 270 5 150 330 6 180 315 7 135 225 8 90 135 9 45 45 10 0 0 11 0 0 12 0 0 39 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  40. Modified Puls Example 2Sn 2Sn1   I  O   I On1     n1 n n t t •The 2Sn/t+ equation: On+1 columncanthen be calculatedusingthefollowing I+I +2S1-O=2S2+O     1 2 1 2 t t Notethat2Sn/t- Onand On+1 aresettozero. Time In In+In+1 2Sn/ (hr) (cfs) (cfs) (c t-On 2Sn/t+On+1 On+1 fs) (cfs) (cfs) 0 0 30 0 0 1 30 90 30 2 60 150 3 90 210 30+ 0 =2Sn/t+ On+1 4 120 270 5 150 330 6 180 315 7 135 225 8 90 135 9 45 45 10 0 0 11 0 0 12 0 0 40 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  41. ModifiedPulsExample •Thenusingthecurveprovidedoutflowcan bedetermined. • Inthiscase,since2Sn/t+ provide(darnhardtosee!) On+1 =30,outflow=5 basedonthegraph Time In In+In+1 2Sn/t-On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 0 30 0 0 1 30 90 30 5 2 60 150 3 90 210 4 120 270 5 150 330 6 180 315 7 135 225 8 90 135 9 45 45 10 0 0 11 0 0 12 0 0 41 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  42. ModifiedPulsExample •To obtainthefinalcolumn,2Sn/t- On,twotimes theoutflowis subtractedfrom2Sn/t+ On+1. • Inthisexample30 - 2*5= 20 Time In In+In+1 2Sn/t-On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 0 30 0 0 1 30 90 20 30 5 2 60 150 3 90 210 4 120 270 5 150 330 6 180 315 7 135 225 8 90 135 9 45 45 10 0 0 11 0 0 12 0 0 42 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  43. Modified Puls Example 2Sn 2Sn1   I  O   I On1   n1 n n t t   •The same stepsarerepeatedfor • First90 +20 =110. thenextline. • Fromthegraph,110equalsan • Finally110- 2*18=74 outflowvalueof18. Time In In+In+1 2Sn/t-On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 0 30 0 0 1 30 90 20 30 5 2 60 150 74 110 18 3 90 210 4 120 270 5 150 330 6 180 315 7 135 225 8 90 135 9 45 45 10 0 0 11 0 0 12 0 0 43 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  44. ModifiedPulsExample •Thisprocesscanthenbe repeatedfortherestofthecolumns. •Now alistoftheoutflowvalueshavebeen problemiscomplete. calculatedand the Time In In+In+1 2Sn/t-On 2Sn/t+On+1 On+1 (hr) (cfs) (cfs) (cfs) (cfs) (cfs) 0 0 30 0 0 1 30 90 20 30 5 2 60 150 74 110 18 3 90 210 160 224 32 4 120 270 284 370 43 5 150 330 450 554 52 6 180 315 664 780 58 7 135 225 853 979 63 8 90 135 948 1078 65 9 45 45 953 1085 65 10 0 0 870 998 64 11 0 0 746 870 62 12 0 0 630 746 58 44 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

  45. End 45 School ofComputing,InformationTechnology& Engineering School ofCivilEngineering/Linton

More Related