2009/1 PAGES 16 – 21 RECEIVED 13. 10. 2008 ACCEPTED 10. 11. 2008

M. ANDO, V. MACURA, A. ŠKRINÁR, Marek Ando Department of Land and Water Resources Management, [email protected] T. ZAČKA Prof. Viliam Macura, PhD. Department of Land and Water Resources Management, [email protected] Andrej Škrinár Department of Land and Water Resources Management, EVALUATION OF SOME [email protected] Tomáš Začka Department of Land and Water Resources ECOLOGICAL ASPECTS OF Management Faculty of Civil Engineering Slovak University of Technology, Radlinského 11 THE DRIETOMICA BROOK BY 813 68 Bratislava, Tel: +421 (2) 5927 4498

DECISION-MAKING Research field: river modification, river restoration, interaction between biotic and abiotic characteristics in aquatic zone of streams, low-flow analysis

ABSTRACT KEY WORDS

During the years 1995-2006, research on the impact of river regulation on the aquatic • IFIM, habitat, zone of the Drietomica brook was implemented. Drietomica is a typical representative of • abundance, streams in the Slovak flysch area, and it is located in north-western Slovakia in the region • ichthyomass, of White Carpathians. In this article the results of modeling a microhabitat by means of • weighted usable area. Instream Flow Incremental Methodology (IFIM) are presented. For the 1-dimensional modeling, the River Habitat Simulation System (RHABSIM) and for the 2-dimensional modeling, River2D software, both of which are used to analyze the interaction between a water flow, the morphology of a riverbed and the biological components of the environment, were used. After a hydraulic calibration was performed, the available habitat in the shape of a weighted usable area was simulated using both models. The current stage of the research represents the testing of the differences between the various types of models and a comparison of the impact of the non-biotic parameters on the development of the suitability curves, which define fish hiding-places as a microhabitat of a stream.

1 INTRODUCTION other uses, such as when a wetland is filled or a prairie is covered by housing developments. Habitat degradation occurs when the The ecological state of a stream is affected by many factors, the most habitat is so diminished in quality that species are no longer able important of which is the habitat of fauna and flora in the aquatic to survive. Water development projects include dams, dredging, part of the stream. The configuration of a habitat significantly stream channelization, flood control structures, and canals. These affects the organization and structure of a biological community projects adversely affect species in a number of ways. The natural (Maddock, 1999). Understanding the impact of human activity on flow of rivers and streams may be disrupted. Riparian (stream bank) a habitat’s structure remains one of the most neglected research habitat may be destroyed, fragmented, or degraded (Richmond, fields in water management. The loss of dead arms and reduction 2003). Some examples of improper engineering in the Pilica River of the inundation area and natural riverbed segmentation are the in Vistula drainage basin in are shown by Penczak (1996, primary reasons for negative changes in the aquatic part of a stream 2001). Engineering, which consists here in protecting eroded banks (Hesse & Sheets, 1993). Many biologists consider habitat loss, by reveting them with fascine or limestone boulders, is unfavorable habitat degradation, and habitat fragmentation the primary threats for fish mainly in the initial phase and more in small than in large to species survival. Habitat loss occurs when habitat is converted to rivers (Penczak, 1996).

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The entry of Slovakia into the European Union (EU) determined its assessing the quality of the habitat for various fish species orientation concerning standard techniques used within the borders (determination of the suitability curves). of the EU. It is necessary to achieve compatible results which are • Processing data that characterizes individual types of habitat usable during the process of the transposition, implementation and and suitability curves, and the quantification of the hydraulic legal application of European frameworks in water management. and morphological characteristics of the stream using the fish as Within the bounds of monitoring and assessing the ecological quality a bioindicator. of water, the European framework directive 2000/60/EC requires The ichthyologic measurements were implemented in cooperation a determination of the characteristic parameters of unaffected water with the Zoological Institute of the Slovak Academy of Science in bodies which correspond to a very good ecological quality. These Bratislava and the Department of Poultry Farming and Small Farm conditions have been declared reference conditions for a given type of the Slovak Agricultural University in Nitra. The of water body. If a stream lacks unaffected sections, modeling of were caught with electrofishing technique (direct pulse current the biological conditions in the stream is required. “Type-specific 230–400 V, 2.8–5.2 A) by using a back electric fishing device type biological reference conditions based on modelling may be derived ELT 60 II GI (Hans Grassl, ), in an upstream direction by using either predictive models or hindcasting methods. The methods wadding in the water with three catches. Each fish was measured shall use historical, palaeological and other available data and shall (SL–standard length to the nearest mm) using a measuring tape and provide a sufficient level of confidence about the values for the weighted (digital balance to the nearest gram). After processing reference conditions to ensure that the conditions so derived are all fishes were returned live to the water. The abundance and the consistent and valid for each surface water body type.” (European biomass of fish communities were estimated according to (Laslie Framework Directive 2000/60/EC) and Davis, 1939). The characterization of the reference sections: The first reference section with a length of 100 m lies in the village 2 MATERIALS AND METHODS of Drietoma, which is located in the north-western Slovakia in the region of White Carpathians. The riverbed has been modified into The hydroecological quality of the three reference sections of a simple trapezoid-shaped profile with slopes of 1:1.5. The slopes the Drietomica brook was evaluated using the RHABSIM 1- are stabilized by concrete feet and prefabricated components. dimensional model (Payne, 1998). One of those sections was also The bottom of the riverbed is flat with an average width of 12 evaluated using the River2D 2-dimensional model (Steffler & m. Riverbank vegetation is occasionally present. According to

Blackburn, 2002). a granulometric analysis, the mean grain gauge is d50 =17.5 mm. Assessment of the habitat quality of the aquatic part of the The second section, which has a length of 119 m, lies above the Drietomica stream: village of Drietoma and is 1800 m away from the first section. The models that we used in this study work according to the The character of the riverbed is natural with a segmented bottom. principle of the IFIM method (Bovee et al., 1998; Macura, Čistý, The riverbanks are stabilized by a root system of willow and alder 2001; Macura, Škrinár, 2004; Macura, Škrinár, Začka, 2004a; vegetation, the crowns of which shade most of the stream. The Macura, Škrinár, Začka, 2004b). It is an interdisciplinary decision- average width of the riverbed is 7 m with 1.2 m deep local potholes.

making system, which has arisen as a result of the knowledge that The mean grain gauge is d50 =26 mm. most fish species prefer certain combinations of water depths, The third section, which was modeled using both the 1D and 2D flow velocities, hiding places and materials of a riverbed. If these models, is 240 m long. It has a natural character and is connected values are known in a given stream reference section, it is possible to the second section upstream. That section was chosen because it to forecast the impact of changes to the biological environment of incorporates various types of habitat including fish covers. a stream. The water of the Drietomica falls into the I. class of cleanness The following procedure was used for modeling the quality of the according to the oxygen regime factor; according to other factors, it Drietomica habitat: falls into the II. class. • Delineation of certain stream reference sections. Ichthyologic characteristics of the reference sections: • Measurements of the topographical parameters of the reference There is a significantly higher abundance of fish in the lower stream sections. section than in the upper stream section. The seasonal changes in • Hydrometric measurements during 3 various water levels of each the abundance are related to fluctuations in biodiversity as a result reference section. of migration during the time of reproduction and increases in the • Conducting an ichthyological and hydraulic survey aimed at frequency of growth. Regarding the ichthyomass, the changes in

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Tab. 1. The diversity of species of the ichthyofauna in the reference the first and second sections are tiny and statistically inconclusive. sections of Drietomica Under normal conditions the ichthyomass of the lower section Natural River should also be significantly higher. The cause of a contrary state is Family – Species stream regulation the river regulation of a certain section and, as a consequence, the CYPRINIDAE lack of suitable life conditions for some fish species. The diversity of species of the ichthyofauna in the Drietomica brook Common minnow – Phoxinus phoxinus + + is listed in Table 1; the basic data for abundance and ichthyomass Gudgeon – Gobio gobio - + are given in Table 2. Dace – Leuciscus leuciscus - + Chub – Leuciscus cephalus - + BALITORIDAE 3 RESULTS Stone loach – Barbatula barbatula + + SALMONIDAE The quantification of the quality of a habitat in the IFIM methodology Rainbow trout – Oncorhynchus mykiss + - is represented by the weighted usable area (WUA), which is a direct Brown trout – Salmo labrax m. fario + + function of the discharges and represents the suitability of the entire Brook trout – Salvelinus fontinalis + - modeled section; which is divided into microhabitat levels. These THYMALLIDAE outcomes are the proper basis for future decision-making and water- management planning. Grayling – Thymallus thymallus + + After the hydraulic calibration of both models, we simulated a suitable habitat in the form of a WUA during various discharges Bullhead – gobio + + (Fig. 2). There is an obvious difference between the results obtained Alpine bullhead – Cottus poecilopus + + by the 1-D and 2-D models (Tab. 3 and Fig. 1), which is due to the Hybrid (Cottus gobio x Cottus + - greater degree of accuracy and larger detail of the 2-dimensional poecilopus) hydraulic module of River2D following from the 2D modeling Number of species (not considering the 8 9 principle. Unlike 1-D modeling it also considers the spatial hybrid) direction of a stream (a certain model can simulate flow intensity

Tab. 2. Basic data of the abundance (pcs.ha-1) and ichthyomass (kg.ha-1) in the reference sections of Drietomica during the years 1995 – 2006. The italicized data are from fishing out in the summer. Abundance (pcs.ha-1) Ichthyomass (kg.ha-1) Natural stream – reference Regulated stream Natural stream – reference Regulated stream Year section 2 – reference section 1 section 2 – reference section 1 spring (1a) autumn (1b) spring (2a) autumn (2b) spring (1a) autumn (1b) spring (2a) autumn (2b) 1995 - 2606 - 17425 - 64.1 - 152.3 1996 993 1374 1975 4258 16.1 35.8 31.9 51.3 1997 - 4822 - 6625 - 111.5 - 88.2 1998 1333 3097 5433 6398 32.3 42.4 79.1 71.6 1999 ------2000 5987 6391 3292 8300 191.9 123.2 39.9 46 2001 - 10582 - 7144 - 100 - 41.7 2002 7148 9837 8098 26749 108.6 92.6 81.7 287.7 2003 6361 - 22253 - 203.5 - 278.6 - 2004 - 2507 - 34017 - 54.5 - 271.6 2005 4886 - 14036 - 55.3 - 149.3 - 2006 - 3704 - 10915 - 84.2 - 131.4

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Tab. 3 and Fig. 1: Comparison of the weighted usable area (WUA) share on the total water surface area in the natural part of Drietomica during various discharges simulated by the 1-D and 2-D models, considering and not considering the fish cover places in the determination of the suitability curves (WCFC - without considering fish covers, CFC - considering fish covers). model River2D RHABSIM – 1D Bioindicator Total surface Total surface Q [m3/s] method WUA [m2] % WUA [m2] % (Latin name) area [m2] area [m2] Alpine bullhead WCFC 289 1235 23.40 263 1118 23.52 (Cottus gobio) CFC 181 1235 14.66 0.3 Brown trout WCFC 194 1235 15.71 166 1118 14.85 (Salmo trutta m. fario) CFC 124 1235 10.04 Alpine bullhead WCFC 348 1385 25.13 449 1271 35.32 (Cottus gobio) CFC 218 1385 15.74 0.55 Brown trout WCFC 287 1385 20.72 334 1271 26.27 (Salmo trutta m. fario) CFC 184 1385 13.29 Alpine bullhead WCFC 390 1520 25.66 665 1380 48.19 (Cottus gobio) CFC 233 1520 15.33 0.95 Brown trout WCFC 379 1520 24.93 587 1380 42.54 (Salmo trutta m. fario) CFC 236 1520 15.53 Alpine bullhead WCFC 318 1605 19.81 717 1446 49.59 (Cottus gobio) CFC 186 1605 11.59 1.4 Brown trout WCFC 364 1605 22.68 762 1446 52.70 (Salmo trutta m. fario) CFC 225 1605 14.02

in various directions), and the input topography of the riverbed is more detailed in the 2-D model. The effect of the implementation of the cover suitability curves on the model is also obvious from the table, which provides a comparison of the WUA share on the total water surface area. However, the decrease in this share as a result of the implementation of the cover suitability curves is a logical consequence of the embedment of the other parameter (cover) into the model, which follows from the WUA calculation method (a multiple reduction of the WUA by the mutual multiplication of the suitability rate of the individual parameters).

4 CONCLUSION

From the existing results of our research on stream habitat modeling (Macura, Čistý, 2001; Macura, Škrinár, 2004; Macura, Škrinár, Fig. 1 Začka, 2004a; Macura, Škrinár, Začka, 2004b), it follows that the relationship between a fish population and the characteristics of its habitat as modeled by the IFIM methodology gives a true picture of the changes evoked by discharges and riverbed topography interference (for example, river regulation). A lot of various

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Combined Suitability Qin = 0.550 0.65 0.58 0.52 0.45 0.39 0.32 0.26 0.19 0.13 0.06 0.00 Distance 10.0 m

Fig. 2: Progress of combined suitability for Brown trout considering fish-covers in the natural section of Drietomica during a 0.55 m3/s discharge.

habitat models exist that are related to the stream biota, but their also fulfils all the conditions for standardizing the determination outcomes are incompatible. A greater uniformity aimed at a better of the unaffected natural state of a stream by modeling, which compatibility of individual results would be more useful. is directly required by the European Water Framework Directive In future developments in modeling stream biological conditions 2000/60/EC. in Slovakia, attention should be directed to models using the IFIM methodology; considering the greater accuracy of the 2-D Acknowledgements: We thank agencies for supporting the projects models, their use is especially recommended. The initiated method No. 1/0585/08 and No. AV 4/0110/06.

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REFERENCES

• Bovee, K.D. - Lamb, B.L. - Bartholow, J.M. - Stalnaker, EÚ o vode. (Modeling stream biological conditions according C.B. - Taylor, J. - Henriksen, J. (1998) Stream habitat to the EU Water Framework Directive). Integrovaný manažment analysis using the instream flow incremental methodology. U.S. povodí a implementácia Rámcovej smernice EÚ o vode. Geological Survey, Biological Resources Division Information (Watershed Integrated Management and EU Water Framework Technology Report USGS/BRD-1998-0004. 139 p. Directive Implementation.) Bratislava, April 2004, ISBN80- • Hesse, L.W. - Sheets, W. (1993) The Missouri River 969136-0-3, pp. 98-103. hydrosystem. Fisheries 18(5), pp. 5-14. • Maddock, I. (1999) The importance of physical habitat • Laslie, P. H. - Davis D. H. S. (1939) An attempt to determine assessment for evaluating river health. Freshwater Biology 41, the absolute numbers of rats on a given area. J. Anim. Ecol. 8, pp. 373-391. pp.94–113. • Payne, T.R. (1998) RHABSIM 2.1 for DOS and Windows • Macura, V. - Čistý, M. (2001) Návrh optimálnych parametrov user’s manual. California, USA. habitatu revitalizovaného toku. (Proposal for restored stream • Penczak, T. (1996) Natural regenerations of endangered fish optimal parameters). Acta Horticulturae et regiotecturae 4, populations in the Pilica drainage basin after reducing human 2001, pp. 43 - 46. impacts. Conservation of endangered freshwater fish in Europe. • Macura, V. - Škrinár, A. (2004) Vplyv minimálnych prietokov Birkhäuser Verlag Basel, Switzerland, pp. 121-133. na biologické prostredie akvatickej oblasti toku. (Impact of • Penczak, T. (2001) Population of fish in relation to riparian ecological discharges on the biological environment of the ecotone development in the Narew river catchment. Ecology & aquatic part of a stream). Acta Horticulturae et regiotecturae 2, Hydrobiology 1-2, vol. 1, pp. 163-176. 2004, pp. 271 - 275. • Richmond, E. (2003) Fisheries, Fresh-Water. In: Water: Science • Macura, V. - Škrinár, A. - Začka, T. (2004a) Zovšeobecnenie and Issues. Ed. E. Julius Dasch. Vol. 2. New York: Macmillan vhodnostných kriviek rýb flyšových tokov na Slovensku a ich Reference USA. pp. 56-61. 4 vols. aplikácia pri modelovaní neovplyvnených úsekov tokov v súlade • Steffler, P.M - Blackburn, J. (2002) River2D, Two-Dimensional s rámcovou smernicou EU. (Generalization of fish suitability Depth Averaged Model of River Hydrodynamics and Fish curves from Slovak flysch streams and their application during Habitat, Introduction to Depth Averaged Modeling and User’s the modeling of unaffected stream parts according to the EU Manual. University of Alberta, Canada. Framework Directive). Vodní toky. H. Králové, September • DIRECTIVE 2000/60/EC OF THE EUROPEAN PARLIAMENT 2004. ISBN 80-86386-55-4. AND OF THE COUNCIL of 23 October 2000. Establishing • Macura, V. - Škrinár, A. - Začka, T. (2004b) Modelovanie a framework for Community action in the field of water biologických podmienok toku v súlade s rámcovou smernicou policy.

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