WuhanUniversityofTechnologyDepartmentofSpatial InformationandPlanningSchoolofResourcesandEnvironmentEngineeringSedimentconnectivity withinriverside-morphologicalprocesses coupling framework foridentifying finesedimentsourceswithinJiuRiverBasin(Romania)GabrielaAdinaMOROSANU-MITOSERIUInstituteofGeographyoftheRomanianAcademy,Romaniagabriela.adina.m@gmail.com
1 Sediment connectivity within riverside - morphological processes coupling framework for identifying fine sediment sources within Jiu River Basin (Romania) Gabriela Adina MOROȘANU-MITOȘERIU Institute of Geography of the Romanian Academy, Romania gabriela.adina.m@gmail.com Wuhan University of Technology Department of Spatial Information and Planning School of Resources and Environment Engineering
Sediment connectivitywithinriverside-morphologicalprocesses coupling framework for identifying fine sediment sourceswithin Jiu River Basin(RomaniaOUTLINEIntroduction:Context,Objective.Studyarea:MethodologyResultsanddiscussion:Conclusion
Sediment connectivity within riverside - morphological processes coupling framework for identifying fine sediment sources within Jiu River Basin (Romania) OUTLINE • Introduction: Context, Objective • Study area • Methodology • Results and discussion • Conclusion
IntroductionGeneralcontextIdentifyingandquantifyingthesourcesoffinesedimentsinariverbasiniskey tothe efficient management of hydro-sedimentaryresources.!Slope(upstream)&Riverbank/FloodplainRiverchannelsConveyorbeltmodel(downstream)connectivity degree is a key and difficult(Ferguson, 1981)factor to quantify in sediment yield studies at river basinscales.ObjectiveTo evaluate the actual potential of a watershed system for sediment production and transfer,taking into accountvarious categories of geomorphic processes and anthropogenic factors,that escape the initial analysis ontopographiccriteria,basedonwhichthedegreeofsourcetosinksedimentconnectivityoftenresults.3
Slope (upstream) & Riverbank/ Floodplain River channels (downstream) connectivity degree is a key and difficult factor to quantify in sediment yield studies at river basin scales. 3 Objective To evaluate the actual potential of a watershed system for sediment production and transfer, taking into account various categories of geomorphic processes and anthropogenic factors, that escape the initial analysis on topographic criteria, based on which the degree of source to sink sediment connectivity often results. ! Identifying and quantifying the sources of fine sediments in a river basin is key to the efficient management of hydro-sedimentary resources. Introduction General context Conveyor belt model (Ferguson, 1981)
Study areaRep.otdoldovaMaVadeni-Tg.JiuSerbiaReservoirsAhtirudes(m)M4Budga050100200KmJiu River Basin:-SWRomaniaDanubetributary,CarpathianwatershedLegend-Area~10,080km2MainRivers-ComplexnaturalCoal extraction areasElevations (m)and(geomorphologyHigh:2519&geomorphicfactors)(coalLow : 23anthropogenicmining,reservoirs&dams)sediment051020Kmyield drivers
4 Study area Coal extraction areas Jiu River Basin: SW Romania Danube tributary, Carpathian watershed Area ~10,080 km2 Complex natural (geomorphology and geomorphic factors) & anthropogenic (coal mining, reservoirs & dams) sediment yield drivers
CernaP>Anthropicpression:BistritnMotruNReservoirsRValea lui:Jalesijalovan2km35V50Sohodo460ClocotiseueusMotruPn75+R.VateaRHMareR3KR.lismanaMotrusorP425OrleaVb-R5BrebinaLegendRiversC) Biu River Basin10ReservoirsRivers12Elevation (m)Hydropowerplants2519-23Dams-Jiu11R.WaterdiversionsDaXO15rivet41Hydrometric Stations
Anthropic pression: Reservoirs Vija Clocoti ş Motru Tismana Valea lui Iovan R. Tismana R. Brebina R. Motru R. Jaleş (Sohodol) 1 3 2 4 5 6 7 8 9 10 11 12 13 14 15 475 650 425 460 535 a b Rivers Reservoirs Hydropowerplants Dams Water diversions Hydrometric Stations 2km
1716Bumbesti Jiu>Anthropicpression:usitReservoirsP2kmC.Valea SaduluiCurtisoaraH.C.Turcinesti18H.C.VadeniRamaradiapitrgAlready built reservoirsTgJiuReservoirs for planningNon-permanentLH.C.TgJiuaccumulationRRiversLegendDamsJiuRiverBasinHydropowerplantsRiversCitiesElevation (m)10251916 Hydrometric stations23Danube980mrivet15
Anthropic pression: Reservoirs 2km Tg Jiu Bumbesti Jiu H.C. Vădeni H.C. Tg Jiu H.C. Turcinesti H.C. Curtisoara H.C. Valea Sadului Already built reservoirs Reservoirs for planning Non-permanent accumulation Rivers Dams Hydropower plants Cities Hydrometric stations 16 17 18 19 15
MethodologyA,W,STwostepsworkflow:1)theidentificationoftheupstreamUpslopecomponent(Dup)sedimentgeneratingareaswhich areDup=WSVAgeomorphicallymostconnectedtotheRIW=I-deliveryldownstreamstoragel225 (x - xm)2accumulation areas (river mouth),bydalsinkRIapplyingthe connectivityindex (IC)IC=logio(proposed by Cavalli et al. (2013);DonReferencecellHEd.DdnW.SVadeniTg.JiuReservoirsConnectivitytargetDanubeConceptual schemeoftheIndexofConnectivity(IC)(afterCremaetal.,2015modifiedafterBorsellietal.,2008)S-the avg.slope gradient of the upslope contributing area, A-the upslope contributing area (pixels)W-Weightfactor(impedancetorunoff)oftheupslopecontributingarea,Ri-roughnessindexd,-thelengthoftheflowpathalongtheithcell accordingtothesteepestdownslopedirectionx,-value of one specific cell of the residual topographywithin the moving window
Methodology 7 Two steps workflow: 1) the identification of the upstream sediment generating areas which are geomorphically most connected to the downstream delivery/ storage/ accumulation areas (river mouth), by applying the connectivity index (IC) proposed by Cavalli et al. (2013); Conceptual scheme of the Index of Connectivity (IC) (after Crema et al., 2015 modified after Borselli et al., 2008) Upslope component (Dup) Reference cell Connectivity target A, W, S S - the avg. slope gradient of the upslope contributing area, A - the upslope contributing area (pixels) W – Weight factor (impedance to runoff) of the upslope contributing area, RI – roughness index di - the length of the flow path along the i th cell according to the steepest downslope direction xi - value of one specific cell of the residual topography within the moving window i-1 i 1
SedimentConnectivityWorkflowCorrectingtheDigital ElevationComputingtheDigital TerrainModelEUDEMfor2017Modelfortheyears'80(Romanian+ALOSPALSAR12.5mresolutionTopographicalmap1:25,000)DEMfor JiltRiver(notusedfortheICcomputation)Drainage networkderivation by TauDEMfunctions (Tarboton etal.,2015)bytheanalysisofhydrologicinformation二fromDTM/DEM山门Setting+targets (outlet/rivernetwork)Weighting factors1ORManning'sn(FAODigitalSoilMapoftheWorld(DSMW>WeightFactorW（Cavalli&Marchi,2008Notarget1IC(25x25m)--SedlnConnec
8 Sediment Connectivity Workflow Computing the Digital Terrain Model for the years ’80 (Romanian Topographical map 1:25,000) Correcting the Digital Elevation Model EUDEM for 2017 Drainage network derivation by TauDEM functions (Tarboton et al., 2015) by the analysis of hydrologic information from DTM/ DEM Weighting factors Manning’s n (FAO Digital Soil Map of the World (DSMW) Weight Factor W (Cavalli & Marchi, 2008) Setting ≠ targets (outlet/ river network) OR No target IC (25x25 m) + ALOS PALSAR 12.5 m resolution DEM for Jilt River (not used for the IC computation)
MethodologyReservoirs(upstream-downstream)A, W, Sregional disconnectivity(LateralRiverembankmentsUpslopecomponent (Dup)barriers)sandDup=WSVAFloodplainmining(accelerators of erosion and sedimentmobilisation)andfinesediment sheets(RI)W=I-(sedimentblankets)華225 (x -m)2Coalmining,with open pit minesRI(localsinks),steriledumps(unstableLocal shReference cesedimentdeposits)eIC=logio()(localIn-riveraccumulationssedimentsuppliers)Legend2(sedimentGeomorphicprocessesDdnsourcesandtransportpaths)Nadeni-Tg.Jiu2)ThereconsiderationofthepotentialReservoirsConnectivitytarsource-sink sedimentconnectivity,byDDanubemeansofadditionalcouplingordecouplingfeatures:ConceptualschemeoftheIndexofConnectivity(IC)(afterCremaetal.,2015modifiedafterBorsellietal.,2008)2
Methodology 9 - Reservoirs (upstream – downstream) regional disconnectivity - River embankments (Lateral barriers) - Floodplain sand mining (accelerators of erosion and sediment mobilisation) and fine sediment sheets (sediment blankets) - Coal mining, with open pit mines (local sinks), sterile dumps (unstable sediment deposits) - In-river accumulations (local sediment suppliers) - Geomorphic processes (sediment sources and transport paths) Conceptual scheme of the Index of Connectivity (IC) (after Crema et al., 2015 modified after Borselli et al., 2008) Upslope component (Dup) Reference cell Connectivity target A, W, S i-1 i 2 2) The reconsideration of the potential source – sink sediment connectivity, by means of additional coupling or decoupling features:
MethodologyConceptual modelforquantifyingthefactorsforchangingthe intrinsicpotentialof sedimentaryconnectivityGeomorphicprocessesclassificationaccordingto:Changing the connectivitycategories from the initialonetoTableI.NominalclassificationofgeomorphiccouplingLandslidesthose considered moreappropriateinterfacesbetweenlandslidesandchannel(afterKorup,2005)Gulliesforthetypes ofgeomorphicGeomorphicCharacteristicsprocesses (thecategoriesrespectFallscouplinginterfaceMassmovement>10kmextendsoverthe statistical division of the initialEarthflowsinterfluves ordrainagedivides,and/orconnectivitymapinto4:low,lowobliteratesvalleyfloor(e.g.mountainrangeRiverbankaccumulations/erosioncollapse, lateral spreading,sackung,deepmedium, medium-high,highAreaseatedgravitational slope defomation)sedimentconnectivity)Morethan half of landsliderunoutTable ll.Nominal classification of landslides impact uponaccommodatedalongdrainage line(e.griverchannels (afterKorup,2005)channelized rockfall,long run-outrocavalanches,landslides transforming into+GeomorphicDiagnostic landform assemblagedebris flows afterentraining water-impactclassCoal mining areas:Linearsaturatedchannelfill)BufferedNo discemiblephysical contactbetweenEmplacementof landslidedeposit atalandslide toe and river channel.Openpitmines(Low-Mediumc.)normalornear-nomal planformangletochannel.2RiparianLandslide slightly protruding or impinging on riverSterileDumps(Medium-Highc.channel:concavelandsidetoe:cleardominancePointoffluvialerosion.Sedimentbarriers:Landslidedropsintowaterbody(e.g.fjordReservoirs(lowconnectivity)moraine or landslide-dammed, or floodplain3OcclusionDiversionofriverchainnelaroundconvexlake).landslidetoe(orbreachedlandslidedam)Dams(noconnectivity)comparedtochannelcourseup-andIndirectdownstream.of the contactzone.LandslideisgeomorphicallydecouplecSandmines (medium-highc.)4BlockageOccurrence of a landslide-dammed lake.(Harvey,2002);no physicalcontactcausing riverlateralerosion andbetween deposittoeand channel.ObliterationComplete burial of valley floor; landslide pondsNh Landslide suspended on hillslopesediment uptakeordammedlakes,streampiracy.(colluvial storage)10reversal, or chaotic drainage.NvLandslides buffered on valley fllNilNi Landsliderunoutoniceorsnow
Conceptual model for quantifying the factors for changing the intrinsic potential of sedimentary connectivity 10 Methodology Geomorphic processes classification according to: Sand mines (medium – high c.), causing river lateral erosion and sediment uptake Coal mining areas: • Open pit mines (Low-Medium c.) • Sterile Dumps (Medium – High c.) Sediment barriers: • Reservoirs (low connectivity) • Dams (no connectivity) 2 • Landslides • Gullies • Falls • Earthflows • Riverbank accumulations/ erosion Changing the connectivity categories from the initial one to those considered more appropriate for the types of geomorphic processes (the categories respect the statistical division of the initial connectivity map into 4: low, lowmedium, medium-high, high sediment connectivity) +