Code H Al -Tpl/L Ecostream, a Response Model For
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PROVINCIE NOORD-BRABANT AFDELING WATER no. / oc code HAl -tPl/l Ecostream,a Response Modelfo rAquati c Ecosystems in Lowland Streams DEMONSTRATION PROJECT FORTH E DEVELOPMENT OF INTEGRATED MANAGEMENT PLANS FORCATCHMEN TAREA S OF SMALL TRANS-BORDER LOWLAND RIVERS: THE RIVER DOMMEL 6. Ecostream, aRespons e Model forAquati c Ecosystems in Lowland Streams H. Olde Venterink N. M. Pieterse M.J. Wassen A.W.M. Verkroost Demonstration project forthe Development ofIntegrated Management Plans forCatchment Areas of Small Trans-BorderLowland Rivers: the RiverDommel Administrativeproject leader: Ir. A. Span (Province ofNorth Brabant, NL) Scientificproject leader: Dr. A.W.M. Verkroost(Utrecht University, NL) Copyright© 1998Faculty ofGeographical Sciences, Utrecht University POBox 80115 3508 TC Utrecht. The Netherlands Nopart of this publication maybe reproduced ortransmitted in any form orby any means, electronic or mechanicalincluding photocopying, recording, orany information storage andretrieval system without permission inwriting from thefaculty ofgeographical sciences, Utrecht University ISBN 90-73083-20-6 Contents Preface Summary Samenvatting 1. Introduction 13 1.1 Physical-chemical characteristics of lowland streams 13 1.1.1 Natural lowlandstreams 13 1.1.2 Lowlandstreams in TheNetherlands and Flanders at theend of the 20h century 13 1.2 Aquatic invertebratesand vegetation of lowland streams 14 1.2.1 Natural lowlandstreams 14 1.1.2 Lowlandstreams in TheNetherlands and Flanders at theend of the 2Cfh century 17 1.3In Searchfor differentiating environmental variables between aquatic ecosystems 17 1.4Towards an ecological prediction model forlowland streams 17 2. ECOSTREAM 19 2.1 Themodel concept 19 2.2Stream dimensions 21 2.3Permanency 22 2.4 Current velocity 22 2.5Saprobic state 23 3. Application ofECOSTREAM in the River Dommel Catchment 25 3.1 Upper-, middle,and lower courses 25 3.2 Permanent- andsummer-dry stream segments 25 3.3 Current velocity 25 3.4 Saprobic state 25 3.5Simulated distribution of aquatic ecotope types 30 3.6 Observeddistribution of aquatic ecosystems 35 3.7Comparison of ECOSTREAM simulations with field observations 35 Conclusionsand Discussion 38 Acknowledgments 32 References 33 Append/'ces / List ofaquatic ecotopetypes and characteristic aquatic invertebrate-, macrophyteand fish species 42 // Mapwith names of streams in the Dommelcatchment 52 Preface This publication is part of a series of technical reports concerning the EU-LIFE Dommel demonstration projectfo rth e development ofintegrate d management planso fsmal l trans-border lowland rivers. Forthi s project an integrated model was developed. The structure of this model is shown inth e nextfigure . Forfurthe r information about the project is referred toth e first report inthi sseries : Ecohydrological Modelling and Integrated Management Planning inth e Catchment Area of the River Dommel. The project was supervised by a committee inwhic h the following persons participated: A.S.W. Span (chaiwoman) Province of North Brabant, The Netherlands J.S. ten Veldhuis (secretary) Province of North Brabant, The Netherlands A.W.M. Mol Province of North Brabant, The Netherlands J. Hemelraad Water board the Dommel, The Netherlands Y. Ronse Flemish Environmental Company (VMM), Belgium M. Lambrichts Administration for Environment, Nature and Land Use (AMINAL), Belgium G. Lambrechts Administration for Environment, Nature and Land Use (AMINAL), Belgium G. Vanderwaeren Administration for Environment, Nature and Land Use (AMINAL), Belgium H. Awouters Province of Limburg, Belgium J. van Rijen Ministry ofAgriculture , Nature Conservation and Fisheries (LNV), The Netherlands Summary Inthi srepor tth e model ECOSTREAM ispresented . ECOSTREAMwa sconstructe d with the aim to develop an instrument bywhic h interventions inth e landscape and changes inwate r quality can beassesse d on aquatic ecosystems in lowland streams. The Aquatic Ecotope system Types (AET), as developed at the DLO-lnstitute for Forestry and Nature Management (IBN-DLO) and the Centre for Environmental Science (CML) University of Leiden, servea s basicentitie sfo r ECOSTREAM. The construction of ECOSTREAM is primary basedo naquati c invertebrates of lowland streams.Th e model concept of ECOSTREAM is based on decision rules and classification. Froma literature study major differentiating environmental variables for aquatic invertebrates in lowland streamswer e distinguished. These major variables are: stream dimensions (position in thecatchment , and whether or not dry periods in summer), current velocity, and saprobic state ofth esurfac ewater . The aquatic ecotope typeswer e ordered ina 3D -matri xwit hthes e variables along the axes. The decision rules of ECOSTREAM are focused on these environmental variables. The model ECOSTREAM isdevelope d incooperatio nwit hth e model STREAMFLOW, which simulates the environmental variables. ECOSTREAM simulations are carried out for streams of the river Dommel catchment and are comparedwit hth edistributio n of a measured biotic index inthi s catchment. This biotic index is determined by means of the indication value of aquatic invertebrates for especially organic pollution ofth e surfacewater . Itca ntherefor e beuse da sa bioti c reference for the saprobic state simulation. Becauseth e simulated ecotope types correspond well with the observed distribution of the biotic index in the field, it is concluded that the saprobic state part of ECOSTREAM functions appropriately. For a complete validation of ECOSTREAM, simulated ecotope types should be compared with observed ecotope types in the field. The necessary data for this purpose, however, are not available for the Dommel catchment. Samenvatting In dit rapport wordt het model ECOSTREAM beproken. Het ontwikkelen van dit model had tot doel een instrument te verkrijgen waarmee de effecten van ingrepen in het landschap kunnen worden ingeschat op aquatische ecosystemen in laaglandbeken. Als basis-eenheden voor ECOSTREAM dienen de Aquatische Ecotoop systeem Typen (AET), die zijn ontwikkeld bij het IBN-DLO en het CML. De ontwikkeling van ECOSTREAM is primair gebaseerd op macrofauna gemeenschappen in laaglandbeken. Het model concept van ECOSTREAM is gebaseerd op beslisregels en classificatie. Op basis van een literatuurstudie zijn de belangrijkste differentiërende milieu-variabelen voor macrofauna in laaglandbeken onderscheiden. Deze hoofdvariabelen zijn: beekdimensies (positie in hetstroomgebied , ena l dan niet droogvallen in dezomer) , stroomsnelheid en saprobiegraad van hetoppervlaktewater . DeAE Twerde n geordend inee n 3D-matrix met deze hoofdvariabelen opd eassen . Beslisregels in ECOSTREAM zijn ook gericht opdez e milieu-variabelen. Het model ECOSTREAM is ontwikkeld in samenhang met het model STREAMFLOW dat de voorspelling van de milieu-variabelen verzorgt. ECOSTREAM simulaties werden uitgevoerd voor beken in het stroomgebied van de Dommel. De simulaties werden vergeleken met de verspreiding van een gemeten biotische index in het stroomgebied. Deze biotische index wordt bepaald op basis van de indicatie waarde van macrofauna voor vooral de organische belasting van het oppervlaktewater. Het is daarom geschikt als biotische referentie voor de saprobie-graad simulatie. Omdat de gesimuleerde verspreiding van ecotoop typen goed overeenkomt met de waargenomen verspreiding van de biotische index in hetveld , isgeconcludeer d dat het saprobie gedeelte van ECOSTREAM goed functioneert. Voor eenvolledig e validatie van ECOSTREAM moeten gesimuleerde ecotoop typen worden vergeleken metveldwaarneminge n van ecotoop typen. De hiervoor benodigde data zijn echter niet beschikbaar voor het stroomgebied van de Dommel. 1. Introduction 1.1 Physical-chemical characteristic oflowland streams 1.1.1 Natural lowlandstreams Lowland streams areth etypica l type of runningwater s inTh e Netherlands (Higler &Verdonschot , 1993) and large parts of Flanders (e.g. Bervoets & Scheiders, 1990). Discharge of lowland streams fluctuates strongly because they are fed dominantly by precipitation and superficial groundwater flow (Moller Pillot, 1971;Gardeniers , 1981;Verdonschot , 1990a; Pieterse et al, 1998). Upper courses ofth ethes e streams can even fall dry in summer. The velocity of running water in the stream influences the size and distribution of substrate particles. Substrates in lowland streams rangefro mgrave l to siltan ddetritu s in more quiet places, forming a continually changing mosaic pattern of micro habitats (Tolkamp, 1980; Gardeniers, 1981; Verdonschot, 1990a; Higler & Verdonschot, 1993). The longitudinal profile of a natural lowland stream meanders. Thestreambe di sasymmetrical , differing from sandy shallows to strongly overhanging hollow banks. This complex of hydrological and morphological characteristics is called the 'stream-character' (Gardeniers, 1981; Verdonschot, 1990a). The upper courses of natural streams are mostly shaded bythei r riparianvegetatio n (Gardeniers, 1981; Higle r & Verdonschot, 1993). In general in natural lowland streams more or less gradual changes are found in physical variables from upper courses towards the lower course. Discharge, width, and depth increases towards the lower course because the catchment area increases; current velocity decreases becauseth eslop edecrease s (e.g.Pieters e etal , 1998). Inaddition , in general gradual chemical changes of the water are found as well. For instance a gradual change can be found from oligotrophic conditions inth e upper courses towards mesotrophic and in some cases