Presentation on theme: "Sustainable Hydropower In Alpine Rivers Ecosystems Philippe Belleudy, Hernàn Alcayaga – PP9 Laboratoire d’Étude des Transferts en Hydrologie et Environnement."— Presentation transcript:
Sustainable Hydropower In Alpine Rivers Ecosystems Philippe Belleudy, Hernàn Alcayaga – PP9 Laboratoire d’Étude des Transferts en Hydrologie et Environnement Université Joseph Fourier – Grenoble 1 GESTRANS – 22 novembre 2012
page 2 Morphodynamics and their large scale/slow working impacts 1.SHARE Objectives, partnership, work packages Results 2.Integration of morphodynamics within SHARE method : why and how 3.Modelling morphodynamics at basin scale The idea The test case After SHARE
page 3 1. SHARE objectives Balancing river ecosystems and hydropower requirements River users and defenders face a daily contradiction, notably in implementing both the Directive on Electricity Production from Renewable Energy Sources and the Water Framework Directive. The purpose of SHARE is to develop, test and promote a decision support system (DSS) to merge, on an unprejudiced base, both river ecosystems and hydropower requirements. Arc River (upstream) Barrage de la Girotte (doc.M.Pila)
page 4 1. SHARE partnership 13 partners Universities, local authorities, NGOs, hydropower companies Leaded by ARPA Valle d’Aosta 5 countries different domain of expertise River morphology from LTHE
page 5 1. SHARE results Deliverables A method / a tool / a handbook / databases A set of generally applicable and comparable indicators & monitoring standards Regional cooperation Pilot case studies ► A strong limitation for an efficient development For us End user justification of our basic research Partnership €€
page 6 2. MORPHODYNAMICS : why ? Source:WFD guidance doc #10 WFD and morphodynamics 1.Good ecological status may be reached even with bad morphological conditions!
page 7 2. MORPHODYNAMICS : why ? WFD and morphodynamics 1.Good ecological status may be reached even with bad morphological conditions! 2.Simplistic, it hardly takes into account the transformations at long time scale Drac River (upstream)
page 8 limits of the active bed before HP equipment 2.Simplistic, it hardly takes into account the transformations at long time scale Drac River (downstream)
page 9 limits of the active braided bed before HP equipment 2.Simplistic, it hardly takes into account the transformations at long time scale Drac River (downstream)
page MORPHODYNAMICS : how ? A pre-processor has been developed for the assessment of morphological changes Integration within SHARE method Alt. 1 Alternatives Alt. 2 Alt. n :::: Production d’électricité Apport a la matrice des énergies renouvelables Qualité Biologique Qualité Physique - Chimique Qualité Hydro - morphologique Sub-criteria Qualité de milieu aquatique Energie Criteria rate ! Rating AGREGATION Indice d’altération de débit Indice de poisson Condition de nutriments Indice de continuité de la rivière Quantité de l’électricité générée par année Indice de diatomées Indice d’efficience de production d’électricité Condition d’oxygène SESAMO indicators Condition de température erosion/deposition wider/narrower finer/coarser
page Modelling morphodynamics at basin scale 3.1The idea 3.2The method 3.3Explained thru the Isère test case 3.4After SHARE Alcayaga H., Belleudy, Ph, Jourdain, C. - Morphological modeling of river perturbations due to hydroelectric structures at watershed scale – RiverFlow 2012
page The idea (1/2) river conditions are made by upstream driving factors 1.flow regime 2.sediment sources from upstream reaches and lateral watersheds Schematization of the trajectories from state A to state C or C’ in response to two permanent disturbances of the control factors with different magnitudes (adapted from Werritty, 1997). The modeling is based of the alteration of an existing dynamical equilibrium controlled by the u/s driving factors : hydrology + sediment input conditioned by local physical characteristics
page The idea (2/2) upstream perturbations of the driving factors propagate downstream concerning bed-load and bed transformation : it needs time ! The Ubaye R. sweeps down solid material deposited at the outlet of its tributaries a conceptual modeling at basin scale [ km²] at “engineering” time scale [ ² yr] based on expert knowledge Supported by a GIS description of the watershed
page The method (1/4) Index for alteration of the hydrological regime From flow duration curves Using a reference morphological discharge
page The method (2/4) Index for alteration of the sediment sources Sediment supply index (9 classes) Alteration of the sediment continuity Pente du terrain (0X0)  Couverture végétale (00X)  Combinaison et reclassement (XXX) classes qui sont reclassées dans 9 catégories. Type de roche (X00) [3 ] = Q in, pre SS in, pre Q out, pre SS out, pre Q in, post SS in, post Q out, post SS out, post
page 16 Morphodynamics and their large scale/ slow working impacts 3.2. The method (3/4) : integration of expert knowledge decreased cross-section area increased/decreased w increased/decreased d increased bed level (aggradation) disappearance terrace deposition in pools deposition in riffles channel instability incision wider and deeper channel increased w increased d increased/decreased s increased/decreased d50 increased/decreased w/d increased the wavelength of the meander increased/decreased %silt and clay increased the cross-section area increased/decreased w increased/decreased d bed level: aggradation disappearance of terrace deposition in riffles erosion/deposition in pools Channel aggradation vegetation encroachment Textural shifts at confluences Island and bar construction diminution the cross-section area increased/decreased w increased/decreased d aggradation formation of terrace erosion/deposition of riffles deposition in pools deposition decreased channel capacity (w*d) decreased channel width (w) deposition decreased channel capacity (w*d) decreased channel width (w) diminution du profil en travers diminution/augmentation de w diminution/augmentation de d pas de changement en le niveau du lit A/D ou faible de dégradation formation de terrasse érosion de rapides érosion/dépôt en mouilles decreased the cross-section area decreased w decreased d Not changes in the bed level (A/D) formation of terrace erosion de riffles deposition in pools bed scour armored channel bar and island erosion channel degradation, narrowing increased the cross-section area increased/decreased w increased/decreased d degradation disappearance terrace erosion/deposition in riffles erosion pools aggradation decreased w decreased d increased s decreased d50 decreased /increased w/d decreased the wavelength of the meander decreased sinuosity increased %silt and clay channel instability narower and deeper channel Processes decreased in intensity decreased w increased/decreased d decreased s increased/decreased d50 increased/decreased w/d decreased wavelength of the meander increased sinuosity decreased %silt and clay accommodation not changes in channel capacity (w*d=cte) redistribution decreased the channel capacity (w*d) decreased channel width (w) channel instability incision deeper, wider? channel increased w increased d decreased s increased d50 decreased/increased w/d increased the wavelength of the meander increased sinuosity decreased %silt and clay increased the cross-section area increased w increased d no changes in bed level A/D disappearance of terrace deposition into the riffles erosion of pools processes increased in intensity Grant, 2003 and 2012 Schumm, 1969 and 1977 Petts, 1980 Kellerhals & Church, 1989 Brandt, 2000 Lane, 1955 Williams & Wolman, 1984 Dust & Wohl, 2012 channel instability aggradation wider and shallower channel increased w decreased d increased/decreased d50 increased/decreased w/d decreased sinuosity decreased %silt and clay
D: degradation; A: aggradation; =: invariable; +: increased; -:decreased; +/-: increased or decreased; Y: occurrence of phenomena; N: non occurrence of phenomena; Y/N: occurrence or non occurrence of phenomena * * according to Schumm (1969) and Huang and Nanson (2002) * 3.2. The method (4/4) A vector : direction + amplitude 10 morphological indicators Aggradation / Slope / width / depth / d50…
page Pilot Case Study : a proxy of Arc-Isère basin 5500 km² “HP stuffed” Calculation of the morphological impact of HP equipment Assuming a «pristine » equilibrium just after WW2 Unvalidated and simplifed data
page Pilot Case Study : Arc-Isère basin 25 sub basins and reaches river typology watershed sediment production nodes : tributaries, plants and dams
page Pilot Case Study : Arc-Isère basin alteration the flow regime FQ
page Pilot Case Study : Arc-Isère basin alteration the sediment sources AS
page Pilot Case Study : Arc-Isère basin FQ and AS for 25 sub-basins and reaches
page Pilot Case Study : Arc-Isère basin FQ and AS for 25 sub-basins and reaches (1) (3) (2)
page Pilot Case Study : Arc-Isère basin … closer for 3 examples-reaches 45° FQ (1) 135° 225° AS 180° (2) (3) 270° Trends 1.Aggradation, steeper slope, decrease of w, d, C, probable siltation and colonisation of the vegetation on bars. 2.Chanel erosion, milder slope, 3.Xxx
page Pilot Case Study : Arc-Isère basin - validation Peiry et al., L’incision des rivières dans les Alpes françaises du nord : état de la question. Coherent ! Bed degradation [1950_1980] Combined effect of gravel mining d/s
page After-SHARE (1) discussion « Isere-like » No contract / no data / no details Designed to cost « Validation » Calculation of sediment supply A rough schematization of transport and morphological processes Suspended load Vegetation …
page After-SHARE (1) discussion 1.« Isere-like » 2.Designed to cost 3.At basin scale : not for detailled assessment 4.A rough schematization of transport and morphological processes 5.The diversity
page After-SHARE (2) next to come ! 6.Transient effects and superposition of perturbations Gregory 2006, adapted from Graf (1977) and Schumm (1979).
page After-SHARE (2) next to come ! 6.Transient effects and superposition of perturbations Pente final Pente initial V(t=1) V(t=2) V(t=n) t=1t=2 … t=n temps volume (v) volume charrié (m3)
page After-SHARE (2) next to come ! 7.Adapted to other impacts Gravel mining Climate change Available for…
page 31 Summary 1.SHARE A good idea Mitigated in term of scientific results 2.morphodynamics and must be considered when assessing the ecological status of rivers 3.modelling morphodynamics at basin scale An opportunity A method which has been validated The after-SHARE is focussed on dynamics Philippe BELLEUDY Laboratoire d’Étude des Transferts en Hydrologie et Environnement vielen Dank für Ihre Aufmerksamkeit !
page 32 1.Morphodynamics are important issues for river ecology, for HP production 2.A slow working process, at basin scale morpho assessment may be complex 3.Integration of morphodynamics within SHARE method 4.Pilot Case Study : Arc-Isère testing morphodynamics SHARE potential at basin scale Zusammenfassung Philippe BELLEUDY Laboratoire d’Étude des Transferts en Hydrologie et Environnement vielen Dank für Ihre Aufmerksamkeit !