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Sustainable Hydropower In Alpine Rivers Ecosystems

This presentation discusses the integration of morphodynamics within the SHARE method to balance river ecosystems and hydropower requirements in alpine rivers. The presentation covers the objectives, partnership, work packages, and results of the SHARE project.

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Sustainable Hydropower In Alpine Rivers Ecosystems

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  1. 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

  2. Morphodynamics and their large scale/slow working impacts • SHARE Objectives, partnership, work packages Results • Integration of morphodynamics within SHARE method : why and how • Modelling morphodynamics at basin scale The idea The test case After SHARE

  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. Arc River (upstream) • 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. Barrage de la Girotte (doc.M.Pila)

  4. 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

  5. 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 € http://www.share-alpinerivers.eu

  6. page 6 2. MORPHODYNAMICS : why ? • WFD and morphodynamics • Good ecological status may be reached even with bad morphological conditions! Source:WFD guidance doc #10

  7. page 7 2. MORPHODYNAMICS : why ? WFD and morphodynamics Good ecological status may be reached even with bad morphological conditions! Simplistic, it hardly takes into account the transformations at long time scale Drac River (upstream)

  8. page 8 limits of the active bed before HP equipment • Simplistic, it hardly takes into account the transformations at long time scale Drac River (downstream)

  9. Simplistic, it hardly takes into account the transformations at long time scale page 9 Drac River (downstream) limits of the active braided bed before HP equipment

  10. page 10 2. MORPHODYNAMICS : how ? A pre-processor has been developed for the assessment of morphological changes Quantité de l’électricité générée par année AGREGATION Indice d’efficience de production d’électricité Alt. 1 Indice d’altération de débit Alt. 2 Indice de continuité de la rivière rate ! Indice de diatomées : : Indice de poisson erosion/deposition wider/narrower finer/coarser Condition de nutriments Condition d’oxygène Condition de température Alt. n SESAMO indicators Criteria Rating Alternatives Sub-criteria Production d’électricité Apport a la matrice des énergies renouvelables Energie Qualité Hydro -morphologique Qualité de milieu aquatique Qualité Biologique Qualité Physique - Chimique • Integration within SHARE method

  11. page 11 3. Modelling morphodynamics at basin scale 3.1 The idea 3.2 The method 3.3 Explained thru the Isère test case 3.4 After SHARE Alcayaga H., Belleudy, Ph, Jourdain, C. - Morphological modeling of river perturbations due to hydroelectric structures at watershed scale – RiverFlow 2012

  12. page 12 3.1. The idea (1/2) river conditions are made by upstream driving factors flow regime sediment sources from upstream reaches and lateral watersheds • 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 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).

  13. page 13 3.1. The idea (2/2) upstream perturbations of the driving factors propagate downstream concerning bed-load and bed transformation : it needs time ! • a conceptual modeling • at basin scale [1000-30000 km²] • at “engineering” time scale [10-1-10² yr] • based on expert knowledge • Supported by a GIS description of the watershed The Ubaye R. sweeps down solid material deposited at the outlet of its tributaries

  14. page 14 3.2. The method (1/4) Index for alteration of the hydrological regime From flow duration curves Using a reference morphological discharge

  15. page 15 3.2. The method (2/4) Index for alteration of the sediment sources Sediment supply index (9 classes) Alteration of the sediment continuity Type de roche (X00) [3] Pente du terrain (0X0) [5] Couverture végétale (00X) [5] = Combinaison et reclassement (XXX) classes qui sont reclassées dans 9 catégories. Qout, pre SSout, pre Qout, post SSout, post Qin, post SSin, post Qin, pre SSin, pre

  16. page 16 3.2. The method (3/4) : integration of expert knowledge increased the cross-section area increased/decreased w increased/decreased d bed level: aggradation disappearance of terrace deposition in riffles erosion/deposition in pools aggradation channel instability aggradation wider and shallower channel decreased w decreased d increased s decreased d50 decreased /increased w/d decreased the wavelength of the meander decreased sinuosity increased %silt and clay processes increased in intensity increased w decreased d increased/decreased d50 increased/decreased w/d decreased sinuosity decreased %silt and clay 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 decreased cross-section area increased/decreased w increased/decreased d increased bed level (aggradation) disappearance terrace deposition in pools deposition in riffles Channel aggradation vegetation encroachment Textural shifts at confluences Island and bar construction 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 diminution the cross-section area increased/decreased w increased/decreased d aggradation formation of terrace erosion/deposition of riffles deposition in pools augmentation des flux sans variation de style tendance au dépôt channel instability narower and deeper channel channel instability incision wider and deeper channel deposition decreased channel capacity (w*d) decreased channel width (w) increased the cross-section area increased/decreased w increased/decreased d degradation disappearance terrace erosion/deposition in riffles erosion pools tendance à l'érosion deposition decreased channel capacity (w*d) decreased channel width (w) diminution des flux sans variation de style channel instability incision deeper, wider? channel Processes decreased in intensity Schumm, 1969 and 1977 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 increased w increasedd decreased s increased d50 decreased/increased w/d increased the wavelength of the meander increased sinuosity decreased %silt and clay Petts,1980 Kellerhals & Church,1989 Brandt, 2000 redistribution decreased the channel capacity (w*d) decreased channel width (w) Grant, 2003 and 2012 accommodation not changes in channel capacity (w*d=cte) 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 bed scour armored channel bar and island erosion channel degradation, narrowing 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 Lane, 1955 Williams & Wolman,1984 Dust & Wohl, 2012 Morphodynamics and their large scale/ slow working impacts

  17. 3.2. The method (4/4) • A vector : direction + amplitude • 10 morphological indicators • Aggradation / Slope / width / depth / d50… * 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)

  18. page 18 3.3. 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

  19. page 19 3.3. Pilot Case Study : Arc-Isère basin 25 sub basins and reaches river typology watershed sediment production nodes : tributaries, plants and dams

  20. page 20 3.3. Pilot Case Study : Arc-Isère basin alteration the flow regime FQ

  21. page 21 3.3. Pilot Case Study : Arc-Isère basin alteration the sediment sources AS

  22. page 22 3.3. Pilot Case Study : Arc-Isère basin FQ and AS for 25 sub-basins and reaches

  23. page 23 3.3. Pilot Case Study : Arc-Isère basin FQ and AS for 25 sub-basins and reaches (1) (3) (2)

  24. page 24 3.3. Pilot Case Study : Arc-Isère basin … closer for 3 examples-reaches AS 0.4 45° 135° processes increased in intensity deposition and aggradation trend 0.2 0.05 FQ 180° (3) (1) (2) processes decreased in intensity erosion and degradation trend 225° 270° • Trends • Aggradation, steeper slope, decrease of w, d, C, probable siltation and colonisation of the vegetation on bars. • Chanel erosion, milder slope, • Xxx

  25. page 25 3.3. Pilot Case Study : Arc-Isère basin - validation Coherent ! Bed degradation [1950_1980] Combined effect of gravel mining d/s Peiry et al., 1994. L’incision des rivières dans les Alpes françaises du nord : état de la question.

  26. page 26 3.5 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 • …

  27. page 27 3.5 After-SHARE (1) discussion • « Isere-like » • Designed to cost • At basin scale : not for detailled assessment • A rough schematization of transport and morphological processes • The diversity

  28. page 28 3.5 After-SHARE (2) next to come ! Transient effects and superposition of perturbations Gregory 2006, adapted from Graf (1977) and Schumm (1979).

  29. page 29 3.5 After-SHARE (2) next to come ! 500 volume 460 charrié 420 (m3) 380 340 300 volume (v) 260 220 180 140 100 60 20 t=1 t=2 … t=n temps - 10 000 20 000 30 000 40 000 50 000 Transient effects and superposition of perturbations V(t=n) Pente final V(t=2) V(t=1) Pente initial

  30. page 30 3.5 After-SHARE (2) next to come ! • Adapted to other impacts • Gravel mining • Climate change • Available for…

  31. page 31 Summary SHARE A good idea Mitigated in term of scientific results morphodynamics and must be considered when assessing the ecological status of rivers modelling morphodynamics at basin scale An opportunity A method which has been validated The after-SHARE is focussed on dynamics vielen Dank für Ihre Aufmerksamkeit! Philippe BELLEUDY Laboratoire d’Étude des Transferts en Hydrologie et Environnement philippe.belleudy@ujf-grenoble.fr| +33 476.635.662

  32. Zusammenfassung • Morphodynamics are important issues for river ecology, for HP production • A slow working process, at basin scale morpho assessment may be complex • Integration of morphodynamics within SHARE method • Pilot Case Study : Arc-Isère testing morphodynamics SHARE potential at basin scale vielen Dank für Ihre Aufmerksamkeit! Philippe BELLEUDY Laboratoire d’Étude des Transferts en Hydrologie et Environnement philippe.belleudy@ujf-grenoble.fr| +33 476.635.662

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