NOT FOR QUOTATION WITHOUT PERMISSION OF THE AUTHOR AUSTRIAN LAKE ECOSYSTEMS CASE STUDY: Achievements, Problems, and Outlook After the First Year of Research Kurt Fedra December 1 9 80 CP-80-4 1 CoZZaborative Papers report work which has not been performed solely at the International Institute for Applied Systems Analysis and which has received only limited review. Views or opinions expressed herein do not necessarily represent those of the Institute, its National Member Organizations, or other organi- zations supporting the work. INTERNATIONAL INSTITUTE FOR APPLIED SYSTEMS ANALYSIS A-2361 Laxenburq, Austria This paper was originally prepared under the title "Modelling for Management" for presentation at a Nater Research Centre (U.K. ) Conference on "River Pollution Control", Oxford, 9-11 Asril, 1979. PREFACE Among the various fields of research at the Resources and En- vironment Area of the International Institute for Applied Sys- tems Analysis (IIASA), environmental systems have played a sig- nificant role ever since the establishment of the Institute. In 1977, as a result of an IIASA workshop on Water Quality Model- ing, it was decided to focus particular attention on the water quality problems of natural lakes and man-made impoundments (storage reservoirs). It was felt that IIASA could make an im- portant contribution to the use of models for water quality con- trol and management purposes by attempting to bridge the gap between the natural sciences and policy-oriented disciplines. Accordingiy, two specialized workshops were convened. The first of these was the workshop on Geophysical and Ecological Modeling -of Deep Lakes and Reservoirs (1977) and the second one was the workshop on Hydrological and Ecological Models -of Shal- low Lakes and Reservoirs (1978). Based on the discussions at these workshops, the needs for methodological developments and for comparative studies involving lake ecosystems in IIASAts Na- tional Member Countries were identified. In 1979 a case study on Lake Balaton was initiated as a comparative venture between IIA- SA and several Hungarian organizations, led by the Hungarian Academy of Sciences. In 1980 the set of IIASA1s lake-related case studies was enriched by the initiation of a study on lake ecosystems in Austria. This work was started with the generous support of the Austrian "Fonds zur Fbrderung der wissenschaftli- chen Forschung" and was conducted in close collaboration with several Austrian organizations led by the Institute of Limnology of the Austrian Academy of Sciences. In this paper, Dr. Kurt Fedra, Principal Investigator for the Austrian Lake Ecosystems Case Study, reports on the project achievements, problems, and plans for further research a seen after the first year of the study. It contains a thorough description of the lake ecosystems studied as well as a discus- sion of methodological achievements and problems. IIASA1s studies on lake ecosystems are designed to enhance understanding, to extend and develop new methods of analysis, and to assist analysts and decision-makers concerned with the utilization of these systems and the preservation of their na- tural values. The implementation of these goals obviously calls for establishment of direct contacts, not only with the research community, but also with decision- makers interested in using the results of our analytical work. And this is why particular stress is laid in this paper on expanding collaborative ties with representatives of various scientific' disciplines and decision-making organizations. For the successful continuation of the Austrian Lake Ecosystems Case Study it is essential that we draw upon their joint knowledge. Dr. Janusz Kindler Chairman Resources and Environment Area ACKNOWLEDGEMENTS The Austrian Lake Ecosystems Case Study is supported by the Austrian Research Foundation "Fonds zur Fbrderung der Wissen- sckaftlichen Forschung" with the reserach grant No.3905. The au- thor most gratefully acknowledges the valuable support by the official leaders of the project, Prof.Oleg Vasiliev, former chairman of the Resources and Environment Area at IIASA, and Prof. Heinz Lbffler, Director, Institute for Limnology of the Austrian Academy of Sciences, and by Dr.Janusz Kindler, Chairman of the Resources and Environment Area at IIASA. The author wants to express his gratitude towards many Aus- trian colleagues, as well zs to various institutions and author- ities, for their continuing collaboration in this study. I feel especially indebted towards Drs. O.Moog, A.Jagsch, F.Neuhuber, M.Dokuli1, and B.Schulz, as well as the Meteorological Service and the Hydrographical Service in Vienna, fcr their generous support with largely unpublished data and information. I also want to thank K.Moniruzaman and M.Rodriguez for their help and contributions to the study. This study would not have been possible without the stimulat- ing, critical as well as encouraging environment at the REN area at IIASA, for which I want to thank all my colleagues who con- tributed to it. --LIST OF FIGURES 1: 'dater quality in a socio-economic and political f rzmework 2: Water quality in a watershed framework 6 3: A generalized structure for environmental management problems 4: Lake Neusiedl in its watershed 18 5: Development of tourism around lake Neusiedl and the annual means of available phosphorus in the lake 19 6: Basic processes in the nutrient system of lake Neusiedl 22 7: System of coupled models for the description of lake Neusiedl 25 6: Available phosphorus (P-PO4, 1975 - 1977) in lake Neusiedl 9: Catchment area of the river Ager 32 10: Development of tourism in the Attersee region 34 11: The Attersee system: a minimum-structure for the watershed system 12: The Attersee system: a system of 19 subwatersheds 13: The Attersee and its main tributaries 40 14: Total phosphorus content of the Attersee for the years 1975 to 1979 15: Phosphorus export from the Attersee 42 16: Attersee Water Quality Model: graphic output 43 17: Mondsee Lake Chemistry: temperature and dissolved oxygen 18: Mondsee Lake Chemistry: soluble phosphorus and nitrate 19: Lake Water Quality simulation for the Mondsee 48 20: Oxygen concentrations at the end of the summer stagnation in Lake Fuschl 21: Oxygen concentration of the Irrse for 1979 22: The nutrient diversion- and treatment systems in the Ager catchment basin 23: The structure of the Attersee simulation system 24: The development of tourism, water quality, and sanitation effort for the Wbrthersee 25: Water quality and sanitation effort for Millstattersee and Gssiachersee 26: Oxygen and total phosphorus concentrations in the Wbrthersee 1978 27: Oxygen and total phosphorus concentrations in the Millstattersee 1978 28: Oxygen and total phosphorus concentrations for the Ossiachersee 1978 29: Yearly patterns of oxygen distribution for the Ossiachersee, 1975 and 1977 30: The surfacewater systems of the Untere Lobau 31: Nutrient dynamics of the Untere Lobau system for 1980 32: Community adaptation model output 33: Alternative model structures of increasing complexity for the description of a pelagic food web Pelagic foodweb model version model output 35: Total phosphorus in the Attersee, average yearly pattern of the depth distribution 36: Set diagram of the relationships between input- and output-space of a simulation model 37: Model response-hyperspace projections 38: Model character-vectorspace projection 39: Probability distributions for a model output variable 40: Ensemble of behavior-runs for the Attersee model 41: Prediction with ensembles 42: A representation of prediction uncertainty versus input change and time TABLE OF CONTENTS Preface iii Acknowledgements v List of Figures vii INTRODUCTION TO THE PROJECT: Defining the general problem The structure of the approach SELECTED LAKE ECOSYSTEMS: Specific problems: water quality and eutrophication Lake Neusiedl: Eutrophication, tourism, and agriculture The Salzkammergut lakes: Lake water quality in a watershed framework Attersee Mondsee Fuschlsee, Irrsee The coupled lake system The Carinthian lake district: Case histories of lake sanitation Wbrthersee Millstattersee Ossiachersee Some more lake systems METHODOLOGICAL RESEARCH Ecological complexity: Adaptation and selforganization Issues of uncertainty: Hypothesis testing- under uncertainty Parameter uncertainty and prediction accuracy OPEN PROBLEMS AND FUTURE DIRECTIONS APPENDIX: A) Collaborating institutions and individuals B) Publications (incl. abstracts) and publication projects c j Bibliography INTRODUCTION --TO THE PROJECT: The Austrian Lake Ecosystems Case Study is carried out at the Resources and Environment Area, within the frame of Task 2: 'Fodels for Environmental Quality Control and Management'. Of- ficially started in January 1980, the study is supported by external funding from the Austrian Research Foundation "Fonds zur Fbrderung der wissenchaftlichen Forschung". The research program was drafted by the author under the original title "Ap- plication of Systems Analysis to Lake Ecosystems", and the final proposal for the research grant was a joint effort of Prof. Oleg Vasiliev, former Chairman of the Eesources and Environment Area at IIASA, and Prof.Heinz Lbffler, Director, Institute for Limnology of the Austrian Academy of Sciences. The study is a cooperative research effort, where the Resources and Environment area at IIASA provides a broad spectrum of systems analytical techniques and expertise to complement lake research in Austria. Much of this largely limnologically oriented research in Austria was carried