ECOLOGICAL RESPONSE OF A MULTI-PURPOSE RIVER DEVELOPMENT PROJECT USING MACRO-INVERTEBRATES RICHNESS AND FISH HABITAT VALUE THÈSE NO 3807 (2006) PRÉSENTÉE LE 23 MAI 2007 À LA FACULTÉ DE L'ENVIRONNEMENT NATUREL, ARCHITECTURAL ET CONSTRUIT LABORATOIRE DES SYSTÈMES ÉCOLOGIQUES PROGRAMME DOCTORAL EN ENVIRONNEMENT ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE POUR L'OBTENTION DU GRADE DE DOCTEUR ÈS SCIENCES PAR Marc PELLAUD diplôme en sciences naturelles de l'environnement, Université de Genève de nationalité suisse et originaire de Genève (GE) acceptée sur proposition du jury: Prof. J.-L. Scartezzini, président du jury Prof. R. Schlaepfer, Prof. A. Buttler, directeurs de thèse Dr E. Castella, rapporteur Prof. B. Oertli, rapporteur Prof. A. Schleiss, rapporteur Suisse 2007 2 Acknowledgments Funds were generously provided by La Comission suisse pour la Technologie et l’Innovation (CTI project no 6794.1 FHS – IW), in partnership with Les Forces Motrices Valaisannes (FMV), Le Service des forces Hydrauliques du Valais (SFH – VS) and the Office F´ed´eral de L’EnVironnement (OFEV). Rodolphe Schlaepfer, I wish to thank you, first for the confidence you expressed by accepting me as one of your PhD student and second for the liberty you granted me in as how to conduct this thesis. Your pragmatism, your scientific rigor, your availability and your humanity made you the most valuable asset for the accomplishment of this work. Be assured that it is of great honor to be the last PhD student of your GECOS laboratory. Alexandre Buttler, you are as equally important, since you not only welcome me in your laboratory when times were uncertain but accepted to be my thesis co-director, so a sincere thank you! Philippe Heller, for the challenges of inter-disciplinary cooperation and his openness and tolerance for my discipline and my way of working, and I can pretend knowing an hydraulic engineer! My gratitude also goes to Dr. Ion Iorgulescu, who guided my first steps in the world of Fuzzy Logic and their great potential in environmental sciences. To the members of my jury: Prof. Anton Schleiss, for his interest in ecology and his impeccable conduct of the SYNERGIE project. Dr. Em- manuel Castella for the availability of his immense knowledge of hydrosys- tems, but also for leading my first steps in the world of rhodanien freshwater ecology. Prof. Beat Oertli, for your availability as a jury of this work. I wish to thank you all. To all my colleagues with whom I shared office space, a special thanks for you guys to withstand me, my mess and my dog (Attila)! The golden globe probably goes to my friend Dr. Thibault Lachat,withwhomIshared space for the longest. Mounir Krichane, Anna Klingmann, Dr. Vincent Luyet, Damien Pasche and Junior Tremblay cheers to you all! 3 4 The various affiliates to the GECOS and ECOS/WSL laboratories, since I was fortunate enough to be part of two/three structures during my work. I will start chronologically with the GECOS people, and the two super sec- retaries, Jacqueline and V´eronique (souvent imit´ees, jamais ´egal´ees!) and Bruno (on se voit `a 1130 pour aller manger au Vinci?), but also Christian, Flavio and Rita. Now the ECOS/WSL people, Brigitte (she runs the place!), Restituta, Jean, the two Francois, Claire, Jed, Edward, Isabelle, Martine, Michael, Elena, S´everine, Daniel, Alexia, Thierry, Valentine, Andy, Aur´elie, Nicolas, Florian, Enrique and those who I may have forgotten to mention. The many people who helped me during this work, Dr. Romaine Per- raudin, Dr. Jean-Marie Furbringer, Dr. Marc Bernard, Alex Hoffmann and others. My lovely wife, Nazlee, who supported me throughout this and without whom I could not have done this. When the alarm rang in the morning, it was your presence that fed my motivation to get up and do this thing! I love you baby! My parents, Olinka and Christian and Eric my brother, for your life-long support! Hey guess what, I’m thirty and should be finished with school (for a while)! My in-laws, for their support and understanding. Yan, my little sister, for coming to visit and reviewing my writing! Thanks! Friends, family, train co-seaters and brother in arms, Francois Hubert & Estefania and the Faro people (Adrien malouco, Dona Manuela, Bruno, and others..), Vadym Lupo and the full contact team, Dominique, Wael, Wim le belge, Carlos, Sophie, and the others, Urko, Andri & Andrea, Ricardo (go cardiac!), M. Carrupt (tu rame`nes le dessert?), Manu Chao, Marie-jo & Fabienne, Alex, Edouard & Christina, Julien & Luly, Kenneth, Alicia, Fr´edo Menu, Reda Mounes, Manu l’Africain & Martha, Xema, Cristina, Vera, Alex (le Russe), Anouar, Sacha L´echot and Jamal Sehir (Checkport, International Airport of Geneva) for their tolerance in my working hours and the cheap tickets, Bajan friends (Alice, Mike, Edgehills, Moorjanis, banks!), Chuck, Pat, Anda & others in New Hampshire, Naoko and Ayumi and our Japanese connexion, the fat Finlays’ (Nat & Grant) in London (we’ll snowboard more next year!). Attila, for the ever-inspiring midnight winter walks. Thank you so much for making these years a lot easier! Summary It has been acknowledged that river morphology and hydrology have been inten- sively altered due to the anthropic demands in floodplain land use and manage- ment, flood protection, promotion of navigability or energy production. Rivers were transformed in water highways, having lost contact with their surrounding floodplain as well as the plethora of ecological processes and occupants once thriv- ing in these ecotonal zones. The identification of this emerging threat of morpho- logical and hydrological alteration on ecological integrity adds further complexity in the exploitation of hydrosystem resources. These resources are heavily coveted and guarded by different lobbies each having strategic views on future project development. Stakeholders may want to promote hydro-electricity, ecologists a natural reserve, communes may wish to have an increased flood protection and leisure promoters a nautical center. As a result, the proposition of a river de- velopment project is certain to face opposition of one party or the other. The motivations of this dissertation are anchored in this context, where various and sometimes conflicting potentials for hydrosystem exploitation remain. This works aims at contributing scientifically to an innovative approach at the conception phase of a multi-purpose river development project by developing the ecological module to be implemented in the general project’s optimizer. The SYNERGIE project hypothesis is that it should be possible to identify a synergetic pattern joining the interests of ecological integrity, flood safety, energy production and leisure development. Such a multi-objective river development project would stand more chance of acceptance. This dissertation focuses on the ecological as- pects of such a river development project and an application on the regulated Swiss Upper Rhone River. Is expected an ecological answer to a river develop- ment project design / management which has to be compatible with Heller’s Heller (2007) general SYNERGIE project optimizer taking into account all the project poles. The system of interest is composed of a buffering reservoir of ca. 1 km2, a run-of- the-river dam, a hydro power-plant, and an artificial river ensuring longitudinal continuum. The primary part of the work consisted in an extensive literature review on system understanding, anthropic alterations and quality assessment / prediction tool available. The approach consisted of two levels (1) the general ecological con- siderations to be followed at the project reservoir scale and (2) the measure of the 5 6 downstream ecological response through modeling. General ecological considera- tions at the reservoir scale were the implementation of an artificial river ensuring longitudinal connectivity, implementation of artificial ecotonal boosters and the al- location of a sanctuary zone with limited public access. The downstream measure of ecological integrity was based on the choice of three taxonomic groups of macro- invertebrates and four ecological guilds (groups) of fish. Mayflies (Ephemeroptera), stoneflies (Plecoptera) and caddisflies (Trichoptera) richness were predicted using simple hydrological and morphological covariates (i.e. substrate, current speed,...) coupled to system specific faunistic surveys. Bank, riffle, pool and midstream fish guilds habitat values were determined using existing methods. By using the simulation results of river development project scenarios as inputs, the ecolog- ical response (i.e. the measure of ecological integrity) was computed following the assumptions that high predicted macro-invertebrate richness and high guilds habitat values were linked to a high ecological integrity. An emphasis on the hydropeaking effect in relation with river morphology was performed on macro- invertebrates. They were found to respond well to hydrological and morphological changes induced by river development projects while the approach by fish habitat value encountered limitations in its applicability. Four multi-objective project scenarios were analyzed, (1) the actual state of the Swiss Upper Rhone River at the Riddes site (VS), (2) a hypothetical hydropeaking mitigation project, (3) a hypothetical bed widening project and (4) a hypotheti- cal bed widening coupled to hydropeakaing mitigation project. The actual state resulted in the worst measure of ecological integrity, with comparable results for hydropeaking mitigation project or the bed widening project. The highest measure