Robinwood Project ==================================================================
Component 2: Hydrogeology Report for Eastern Slovakia
August 2006
Peter Bajtoš1, Soňa Cicmanová1, Zoltán Németh2, Silvester Pramuka1 and Ľubica Záhorová1
State Geological Institute of Dionýz Štúr 1Regional Centre Spišská Nová Ves 2Regional Centre Košice
Content
1 Hydrological ecosystems 3 1.1 Kinds of hydrological ecosystems in Eastern Slovakia 3 1.2 Areal spread of hydrological ecosystems 3 1.3 Hydrological ecosystems in determined protection territories 4 1.4 Legislative protection of hydrological ecosystems 20 1.5 Relation of hydrological ecosystems to forest management 23 1.6 Range of artificial draining systems 24 1.7 Floods and system of their regulation 25 2 GIS 27 3 Past, recent and future demands of water 27 3.1 Supplying and consumption of water 27 3.2 Changes of population and migration influencing the water use 29 3.3 Studies focussed on future water supply 30 3.4 Conditions of hydrogeological collectors 30 4 Modelling of rainfall-outflow processes in relation to forest crops 32 5 Load of territory by stress factors 35 5.1 Geodynamic phenomena 35 5.2 Soil erosion and soil weathering 38 5.3 Floods 39 5.4 Acidification and contamination of water 41 5.5 Contamination of underground water 48 5.6 Decrease of level of underground water 50 6 Conclusions 52 7 Suggestions for further works 55 8 References 59
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Introduction The report reviews the recent hydrogeological situation in the region of Eastern Slovakia for the
purpose of the project ROBINWOOD – component 2 Hydrogeology. Special attention is devoted to the level of knowledge about the importance of forest crops at forming of underground water reserves in floods and forming of rainfall-outflow processes, as well as the characteristics of activities negatively influencing the hydrogeological systems and the role of legislative instruments at protection of hydrological ecosystems and hydrosphere. 1 Hydrological ecosystems 1.1 Kinds of hydrological ecosystems in Eastern Slovakia
The following hydrogeological ecosystems are present in the territory of Eastern Slovakia:
• superficial water flows
• lakes
• swamps
• near-river flood areas
• moorlands and wet meadows
• upland moors (mosses) Water biotopes, connected with the rivers in Eastern Slovakia (Bodrog, Ondava, Hornád,
Torysa, Poprad, Slaná) and their tributaries as well as drainage areas, represent the large-scale hydrological ecosystem. 1.2 Areal spread of hydrological ecosystems
The most extended type of hydrological ecosystems is represented by the superficial water flows, forming the river network of the area. Its average density reaches approximately 1.1 km/km2, though the areal variability in relation to geological underlier from 0.1 km/km2 in karst plains to 3.4 km/km2 in Paleogene rocks was found. In the area of the East Slovakian Lowland the Latorica river is accompanied by remnants of near-river floodplain forests. These in comparison with the former extent of their spread do not cover the large areas. The decrease of their areal extent was caused mainly by the expansion of agricultural use of the territory and dewatering of the territory by drainage systems. Rivers and streams in the lowland and hollow basin areas are mostly regulated and accompanied by riverside tree and bush inbarks. Though, locally in the river flood-plains, the moorlands and wet meadows occur in the vicinity of water flows. In the morphologically rugged areas the superficial flows are regulated only
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in the internal parts of settlements. Locally there are present the high moors (mosses), moorlands and wet meadows.
In 1991-2000, the experts from the Centre of mapping of wet-areas of the Slovak Union of the Nature and Country Protectors in Prievidza performed the inventory control of wet lands in the territory of Slovak Republic. In Eastern Slovakia 270 wet lands of national of regional importance were documented with cumulative area 15.54 km2. From the total areal extent of Eastern Slovakia 15,746 km2 it represents the ratio 0.01 %. Besides these localities, there were documented 1,050 wet lands of local importance and next 500 non-classified wet lands (documented geographically, without fauna and flora characterization). Two Ramsar localities – wet lands of international importance were acclaimed (Latorica with extent 4,405 ha, Senné – fishponds: 425 ha). Next 5 localities were suggested. The National list of suggested areas SPA contents 11 territories situated in Eastern Slovakia which overlap with two Ramsar localities.
1.3 Hydrological ecosystems in determined protection territories
Regarding to its exceptional position in the nature, the hydrological ecosystems are usually a part of important broad-cast protected territories. In the frame of national system of nature protection in the Slovak Republic as well as by the act declaration in the territory of Prešov and Košice self-governing districts the following large-area protected territories are present: Prešov self-governing district: Košice self-governing district: High Tatras national park (eastern part) National park Slovak Paradise National park Poloniny National park Slovak Karst National park Pieniny Protected country area Vihorlat Protected country area Eastern Carpathians Protected country area Latorica In the frame of each large-area protected territory there simultaneously exist the small-scale protected areas (natural and cultural) of several categories (national natural reservations, natural reservations, national natural landmarks, natural landmarks, protected areas, etc.). Despite, the small-scale protected areas occur also away of boundaries of the broad-scale protected areas, which in several cases concerns exactly the hydrological ecosystems. These, regarding their character, are exceptional, but usually do not have larger areal extent. The reason of this is in variegated natural conditions, characteristic for the region of Eastern Slovakia, as well as the whole Slovakia. The protected country area Latorica is an exception, because the hydrological ecosystems dominate here and have the full-area protection. 4
Exactly this fact is focussed in European system of natural protection NATURA 2000, built by the member states of European Union independently on national systems of protected areas. The main elements of ecologic net of European important protected areas are the natural biotope, feral animals and plants. The important – if not the most important – role is played by the hydrological ecosystems, which in biggest range are united by both European particularly protected territorial types – according to Directive about biotopes (SACs) and Directive about birds (SPAs). In the frame of whole territory of Eastern Slovakia, the sphere of action of executive agencies of the State natural protection is divided among Administrations of individual large-territory protected areas, during which time the central part of the territory, where the large-territory protected areas - national parks (NP) and protected country areas (CHKO) are not present, belongs under the Regional Administration of Protection of Nature and Country with the seat in the town Prešov (RSOPK). 1.4 Legislative protection of hydrological ecosystems
The state obligation of careful use of the natural sources and taking care on ecological balance
is embodied directly into the article 44 of the Constitution of Slovak Republic. The legislative environment and juridical conditions of protection of evaluated ecosystems are secured by mutual interconnection of several juridical norms. All these norms regulate the scope of executive administrations and villages, as well as the rights and duties of juristic and natural persons at particular activities directly related to protection of nature and the country. As principal laws there can be identified:
• Law No. 17/1992 Collection of Laws about living environment – as amended by the law of National assembly No. 127/1994 Coll. of Laws and No. 287/1994 Coll. of Laws.
• Law No. 543/2002 Coll. of Laws about the nature and country protection.
• Law No. 184/2002 Coll. of Laws about water and about the change and completing of some laws (water law) as amended of later regulations.
• Law No. 61/1977 Coll. of Laws about forests as amended by the Law No. 229/1991 Coll. of Laws and the Law of National Council of Slovak Republic No. 183/1993 Coll. of Laws (full version No. 14/1994 Coll. of Laws – before the Law No. 166/1960 Coll. of Laws about forests and forest management /Forest Law).
• Law No. 100/1977 Coll. of Laws about management in forests and state administration of the forest management as amended by the following regulations (full version No. 15/1994 Coll. of Laws).
• Law No. 307/1992 Coll. of Laws about the protection of agricultural soil fund.
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• Law No. 127/1997 Coll. of Laws about appraisal of influence on living environment (EIA) – actualized to 24.2.2005. The above listed laws have available also corresponding executive regulations.
The main guarantee of protection of all constituents of living environment is the Ministry of Environment of Slovak Republic. The requests on general water protection, achievement of environmental targets, forming of conditions for sustainable use of water sources are determined by the Law of National Assembly of Slovak Republic No. 364/2004 Coll. of Laws about water (Water Law). From the viewpoint of complex water evaluation, including also social-economic relations there is very important the Law No. 127/1997 Coll. of Laws about appraisal of influence on living environment (EIA). In supplement to this law (including the restatements of this law) are defined all activities, which underlie to declaratory procedure or obligatory appreciation. Both aspects of the water protection – qualitative and quantitative – are roofed mainly in the important areas for water management by the system of so-called areal protection of water, consisting from three protection kinds:
• general, resulting from the water law
• wider regional protection – protected water-managing areas
• special, so-called tighter protection, relating mainly the water sources used for drinking purposes – zones of hygienic protection (PHO).
The special category is represented by the protection of natural healing sources and mineral water, resulting from the law about the health maintenance. According to the Water Law the general protection of water and water sources refers in the full range for the whole territory of Slovak Republic without exception. According to the Water Law, everybody performing activity which could negatively influence the superficial water, underground water and water conditions, is responsible for their preservation and protection (so-called the common protection of water). Owners of agricultural and forest soil are responsible for preservation of good water conditions, as well as for precaution before the harmful changes of vent conditions, soil erosion and improvement of conditions for retention of water in the area.
The regional (wider) protection of water uses the form of the protected water-resources areas (CHVO), as well as the form of important water-resources areas. It means that in the particular areas, important for water supply, the water-resources management authorities can regulate or restrict activities, which would threaten the water-resources management interests. This protection results from the §31 of the Water Law. In the territory of Eastern Slovakia four protected water-resources areas
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(CHVO) are proclaimed: Vihorlat, Slovak Karst – Plešivec Plain, Slovak Karst – Horný vrch Plain, Upper drainage basin of the Hnilec river.
More rigorous special protection is realized by the proclamation of the zones of hygienic protection PHO in terms of § 32 of Water Law and Regulation of Ministry of Environment of Slovak Republic No. 398/2002 about details of determination of protected zones of water sources and remedies for the water protection.
Next kind of special protection is the demarcation of water flows and their drainage areas, specially determined for collective supplying of inhabitants by drinking water. According to §44 of the Water Law the water-courses from the viewpoint of their importance are divided into important ones for the water-supplying and small water-courses. By their use they are divided to waterworks flows and further water flows. Recently the regulation No. 56/2001 Coll. of Laws is approved, determining the waterworks flows and their drainage areas as well as the list of important flows from the viewpoint of water-resources. In the drainage areas of water-resources important flows the stiffened up protection is valid. Any activity there requires the agreement of relevant waterworks authorities. This remedy has secured that any activity will be performed without negative consequences for the quality and quantity of water in water supplying flows and their drainage areas.
In the frame of Water Law in relation to protection of hydrological ecosystems there can be mentioned mainly the Statute of the Government of Slovak Republic No. 617/2004, which determines the sensible areas and woundable areas. These areas are represented mainly by the water systems in agricultural land in particular cadastral areas of villages. With the problematics of ecosystems protection tightly relates also the question of their threatening through the non-permissible quality of superficial water. In these cases for the state executive agencies there is obligatory the Direction of Government No. 491/2002 Coll. of Laws, determining the qualitative aims of superficial water and limit values of indicators of pollution of sewage water. Decree by the Ministry of Agriculture of Slovak Republic No. 531/1994 – 540 about the highest allowed values of harmful substances in the soil and about determining of institutions licensed to detect real values of these substances, legislatively states also the valuation of contamination of the soil fund as well as the soil as in the wide meaning. Besides government regulation and executive announcements to particular laws in its sphere of activity, the Ministry of Environment of Slovak Republic issued several Methodical guidelines for solving particular questions. The quality of superficial water consequently interferes also the quality of river, resp. the lake sediments. These sediments reflect not immediate but long-time quality of superficial water in particular area. The risk evaluation from the polluted sediments of water flows and water reservoirs is
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regulated by the methodical guideline of Ministry of Environment of Slovak Republic No. 549/98 – 2, aiming to unify individual steps during the risk evaluation from contamination (Risk Assessment). In direct relation to protection of all sorts of ecosystems is the Methodical guideline of Ministry of Environment of Slovak Republic No. P-2/93 (dated 23. 3.1993) for elaboration of documents of territorial system of ecological stability. The methodic direction assures the pursuance of decision of the Government of Slovak Republic to Conception of territorial system of economic stability and to General over-region territorial system of ecological stability of Slovak Republic (NÚSES). The aim of the Territorial system of ecological stability (ÚSES) is to form and retain the stability of biotic and abiotic systems of the country, retain the variability of conditions for biodiversity and genetic resources of flora and fauna. Documents are elaborated in various levels – from the General scheme for the whole Slovak Republic (NÚSES), through regions (RÚSES) down to towns and villages (MÚSES) in the most-detail scales 1 : 5 000 or 1:10 000. They contain complex (text and map) valuation of biogeographic division of the country, its ecosystems and their ecostabilization functions. All documents tightly relate to areal-planning documentation in these levels, they are in disposal at its provider, or for territory of particular Offices of living environment and in the departments of the state protection of the nature. 1.5 Relation of hydrological ecosystems to forest management
The state administration of the forest management and the huntsmanship is performed by the Ministry of Agriculture of Slovak Republic. It concerns with questions of strategy and politics of the forest development, legislative conditions as well as cooperation with further economic branches. Through regional and district forest offices they supervise on conformity of activities with legislative delimitations, they agree the forest-management plans; declare the protected forests and forests of the special determination. Forest offices are obligatory to inspect all activities practised in forests, license and agree realized works as well as render decrees, allowances and follow selected economic information. The forests can be under the patronage of state subjects in the sphere of authority of MP SR, MO SR and MŠ and non-governmental subjects (forests of various communities, churches, agricultural cooperatives, municipal, and private).
The preservation, development and protection of forests as a part of living environment and natural resources of the country for fulfilling of their irrecoverable functions, forming of economic conditions for persisting maintable management in forests represent the declared scope of the Law No. 326/2005 Coll. of Laws about forests. As a by-production of forests the ecological function are defined as soil-protective, water-work and climatic function as well as societal one, among which is the natural-protective and water-protective function. Due to the guarding of specific requirements of society the forests of particular determination are acclaimed in which the way of management significantly changes 8
in comparison with the common management. As the forests of particular determination the forests in the protection zones of water supplying sources of the I. and II. degree can be declared as well as the forests in protection zones in natural healing sources and sources of mineral water in protected areas and on forest land with an exception of biotope occurrences of the European importance or protected kinds. The executor of exploitation is obliged to perform exploitation by the way minimizing the negative impacts on soil and after termination of exploitation he is obliged the handle with disrupted land by the way to protect further damage. During yarding, transport and storing of wood the maintaining person is obliged to restrain excessive abuse of soil and water flows. It is restricted to route the roads, incline as well as approaching paths by the water-courses. In forest land is beside other things forbidden to invade the soil cover, convey the forest soil or scrabble soil, to disturb the water regime mainly by dewatering of land and modification of water flows. The tool of the state, owner and administrator of the forest for sustainable management in forests is the forest economic plan. According to §26 of this law mainly as the tasks of the forest economic plan or as remedies of relevant executive agency the forest-technical melioration must be done. They represent the antierosion protection of forest land; improving the quality of forest soil, mainly the renewal of their chemical composition and water regime; foundation of forest crops to improve the antierosion, antilandslide, water-supplying and water-protection forest function. The forest law also defines the “damping the streams in forests” as the file of biological, technical and administrative remedies in drainage areas of fine water flows aimed for protection against floods, moderation of erosion processes and accumulation of water mainly for the reasons of protection against fires, which in the public interest is guaranteed by the administrator of the water flow (§48 to 51 of the Law No. 364/2004 Coll. of Laws).
The Slovak Republic (SR) belongs among the European states with the highest areal ratio of forests. The ratio of the gross domestic product made by the forest economics in the whole gross domestic product of Slovak Republic constantly decreases and remains below the level of 1%. The important constituent of reforms after 1989 was also the transformation of proprietorship relations to forests, consisting on returning of property to former owners. Recently the state owns 42.2 % of the forest soil fund (LPF) and in use of non-state sector is 38.5 % of LPF SR. The measure of forest land in the Košice District is 13 %, in the Prešov District 22 %. Above 28 % of the land area of forest overgrowth can be designated as natural; as ecologically stable can be evaluated 20 % and as prevailingly ecologically stable 48 % of forest ecosystems. The signs of damage, prevailingly by imissions, were found on 31 % of trees. After 1990 the demand of full-valued use of public-use forest functions has increased as well as the securing the forest maintenance according to principles of sustainable growth of economy. In concern for increasing of biodiversity of forest ecosystems, which increases the ecological stability of the forests, the raising ratio of broad-leaved trees at the expense of coniferous is expected. Realizing the remedies of the silvicultural conception of Slovak Republic in the 9
agreement with EU strategy assumes the beginning of the sustainable economics in the forests, strengthening of ecologization of the forest ecosystems management, increase of biodiversity in forests, reforestation of non-used agricultural soil and full strengthening of public services of forests. It is necessary to determine the limit, under which level the use of forest machinery will not threaten the forest survival. Between the management of forests and the nature protection, represented by the state executive agency of natural protection on one side and the non-governmental organizations (VLK, Sosna) on the other, recently occurred common conflicts, relating the different opinions on suitable way of management in forests (mainly on the range, concept and intensity of wood exploitation) in relation to sustainable growth of country management. 1.6 Range of artificial drainaging systems
As states the Report about water economy in Slovak Republic (2002), in administration of
water-resources management in SR are adapted water flows in the length 7,907 km (app. 20 % from the total administered length), built protected embankments in the length 2,770 km (7 %), the regulation of dewatering from the territory is allowed by 235 dams and 54 large water reservoirs (from this number 47 are of multipurpose use and 7 represent large water supply reservoirs). In the management of forest economics approximately 780 km of adopted small water flows, from which to 80 % is located in internal parts of villages. The Ministry of Soil Economics of SR performs statistic detection aiming to obtain information about the main melioration facilities. Dewatering was realized by dewatering channels, trenches and drainage systems. Recently the passportization of dewatering facilities is done and many of them will be after the evaluation suggested for abolition. Though, problems concern those facilities, having justification, but regarding the shortcoming of financial sources their service is not realized sufficiently, which negatively influences the agricultural soils.
The irrigation systems were built prevailingly as supplementary, which main aim was, regarding to irregular distribution of rains in vegetation period, to fill up the moisture deficit. Sporadically there were built the liquid manure irrigations. In larger scale there were built the special irrigations (drop and point systems) mainly for irrigation of fruit plantations and vineyards.
Regarding to shortness of financial sources in agricultural subjects, the irrigations recently are used in lower scale (app. 20 %). Critical is also the situation in the maintenance of the main irritation facilities, but also in irritation technique because of their considerably old age. There is the ambition to make active the irritation systems in the most productive areas (East Slovakian Lowland) in relation to supposed climatic changes (Plan of development of rural agglomerations of SR).
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Tab. 1: Main melioration facilities in the Eastern Slovakia (ha) District Built irritation Built dewatering
Prešov District 5 093 75 530
Košice District 26 968 125 615
Together 32 061 201 145
Source: Slovak Water-managing Enterprise, 2002
Extended drainage systems are present mainly in the territory of East Slovakian Lowland (Fig.
1) and the Košice Basin. Though their intensive spread is concentrated to alluvial plains of the next important rivers of the Eastern Slovakia. Their drainage function is manifested mainly in the springtime after the snow melting and during the rain reach periods. The stable drainage function plays the systems in the vicinity of rivers and in morphological depressions with the fixed level of ground water.
From the hydrological viewpoint there is interesting the impact of men activities in the drainage basin of Bodrog river, targeted to protection against floods, as well as the assurance of the water supply in the optimal time. In period before the water-resources management modification the water at floods swelled from the river channels and flooded large territory. The concentration of water into embanked areas, shortening of water flows and increase of inclination caused that the dewatering became faster and culmination flowage was increased. The rise of maximum levels proves e.g. also the comparison of maximum levels in the town Streda nad Bodrogom from 1924, when at flowage 1,160 m3.s-1 the water level was in the altitude 99.60 m a.s.l., and recently it is 101.24 m n. m. (Šútor et al., 1975). This level change at the same water flowage is not only the result of embanking of river system, but also of swelling from the water-work Tiszalök and the lowering of the flowage capacity of the Bodrog river.
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Fig. 1: Range of dewatering of ground by systematic drainage in the territory of East Slovakian Lowland (Collective of authors, 1991). 1.7 Floods and system of their regulation
The flood-protection system in SR is constituted by the Law of National Assembly of SR No. 666/2004 Coll. of Laws about protection against floods. The Law about protection against floods is systematically included as constituent part and simultaneously as assumption of complexity of juridical adjusting of the Law about water and in the wider context is included into protection of living environment, where directly interlocks on rights declared by the Constitution of Slovak Republic. By the same way as the Law about water alone, being elaborated in intentions of the directive No. 2000/60/ES of European Parliament and the Council from 23.10.2000 determining the frame of the scope of Community in the area of water politics, and which contains the principal regulations and principles guarantying after its active implementation the gradual compatibility of the law of SR with regulations of European Community, so also this law above requests in its modification accepts and transfers into the
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practice (Kadubec, 2005). The law constitutes the scope and tasks of organs of the state administration, villages, flood committees and rescue components in the field of protection against floods and rights as well as duties of juridical persons and physical persons allowed to carry business as well as further physical persons during coordination of activities related to serving help in the protection against floods.
The department of the Ministry of Environment of SR covers tasks in flood-protection preferably by the state enterprise in its sphere of authority – the Slovak Water-managing Enterprise, state enterprise, Banská Štiavnica. The significant constituent of flood-protection remedies is the water-courses adjustment, building water reservoirs, flood-protection breakwaters, pumping stations and dewatering channels. The particular tasks at weakening of impacts of flood waves in Eastern Slovakia have the dams Veľká Domaša and Vihorlat (Zemplínska Šírava), Starina and the dry polder Beša. The constituent of flood-protection remedies is also the insuring the coordinated practice in flood-protection with neighbouring states in the case of the water flows crossing frontiers. This co-operation takes place in the frame of signed agreements between state governments and in the sense of protocols of individual settling for state boundary water. After considering of consequences of repeated extreme floods in Tisa river, which drainage basin spreads in the territory of five states, was in 25. 5. 2001 by the ministers of all touched states signed the Budapest Declaration. On the base of this declaration the Forum of the Tisa drainage basin against floods was formed. Its aim is common elaboration and coordination in fulfilling the Concept of flood-protection in the Tisa drainage basin. In Slovak territory the collaboration concerns the drainage basins of the rivers Tisa, Bodrog, Uh, Latorica, Hornád, Bodva and Slaná.
The state administration of flood-protection is represented by the ministry, district offices of living environment and villages. The Government of the Slovak Republic and executive agencies of the flood-protection form the Flood commissions, represented by the Central Flood Commission, District Flood Commissions, Local Flood Commissions and the Village Flood Commissions. The Ministry of Environment and Department of Interior (in the case of need also other central state executive agencies) constitute the operation groups for completing tasks for protection against floods. The operation group directly executes the service during floods and holds the floods diary according to working regulation of the operation group, which is issued by the decree of minister of appropriate central agency of state administration. For guarding and coordination of tasks in flood-protection the flood dispatching centre is established in the ministry as well as the Central Flood Commission with adequate technical and material facilities. The Slovak Water-managing Enterprise (SVP), state enterprise, as an administrator of important as well as small water flows, from the viewpoint of water-management guaranties the complex of tasks of protection against floods, being organized on the base of hydrological floods. Four branches of this enterprise SVP – OZ Bratislava, OZ Piešťany, OZ Banská Bystrica and OZ Košice administer and administrate the integrated hydrological entities through their 13
lower organization constituents – enterprises. This way of managing allows during flood activity quickly concentrate and relocate capacities for providing works in the most afflicted areas. The unified controller system in particular enterprise with central working place of flow and emergency service is established in enterprise headquarters of SVP in Banská Štiavnica, control centres are also in all branches and enterprises of drainage areas. During the food activity these working places verge into the regime of flood control centres with uninterrupted operation. The unified control centre of SVP, state enterprise, mainly during the more extended flood situation guarantees the coordinated realization of safeguarding works in the range of whole Slovak Republic and tightly coordinates with flood authorities. It renders actual information, suggests and submits remedies for agencies of flood protection.
Regarding to ratio of flood damages and their outcomes the flood situation was considered by the National Assembly of the Slovak Republic and the Government of the Slovak Republic, which with their decree No. 31 from 19. 1. 2000 agreed the “Program of the flood-protection of Slovak Republic to 2010”. This decree contains the whole complex of short-term, medium-term and long-term flood-protection remedies, including the set of scientific-technical projects and improvement of flood warning and prediction system of SR (POVAPSYS). The aims of the “Program...” for the area of water management are:
• Lowering of flood flowage increasing the retention in drainage area
• Retention of peak flood waves in retention spaces of water reservoirs and polders as well as by reactivation of flooding surfaces
• Insuring the required flowage capacity of the channel and where possible also increasing the retention space of the reservoir
• Lowering of discharge velocity by renaturization of former channels
• Building of protection dams
• Early warning and prediction service. The SVP, state enterprise, fulfils the “Program...” mainly by building of water-management
buildings, solving the emergency and unfavourable situations in the most-exposed areas of SR, including the East Slovakian Lowland. From the evaluation of realized remedies (Abaffy, 2003, 2004) there followed, that available financial sources from the state budget are not sufficient for realization of activities included in the “Program...” From the recent state of guarantying of flood protection there follows, that this area is solved and guaranteed only according to acuteness of problems in individual drainage areas and flow segments. It is not solved conceptionally with taking into account all aspects influencing on flood in particular drainage area, despite many suggested and realized remedies would go out from the results of solved research works – VTP. In the frame of the “Program...” the solution of
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the set of VTPs was supposed. Because the financial sources for their solution were not guaranteed, in 2000 there was elaborated only the Report for introductory appraisal with division.
2 GIS
As a part of databases of Information system about living environment of SR (ISŽP), which operation is guaranteed by institutions of the department of Ministry of Environment of SR, the information is presented in Information system about territory (ISÚ) and its practical outputs in the form of Central Geographic System (CGS) in the web site http://isu.enviroportal.sk. The main constituent of the project is represented by the systematic forming, exchange, use and offering of digital information processed in the environment of geographic information system (GIS). This information is necessary for the requirements of tasks, projects, materials supporting the areal planning, support of emergency management, development of territory as well as tasks as for example the Integrated management of the drainage areas (IMP), Integrated management of the country (IMK), etc. The geospatial data rendered using ISÚ serve information from various areas. In the frame of recent situation and availability of geospatial data as the basic scale level for the reasons of ISÚ was selected the scale 1 : 50 000 with covering of the area of whole Slovak Republic. The list of disposable datasets CGS/IMK contains 144 thematic layers related to digital model of relief, climatic, hydrologic, geologic conditions of the area, chemical composition of water and soil, country cover, adaptation of superficial flows, water-supplying objects, protected areas and protected zones and others. The approach to geospatial data is divided according to users into 2 principal groups: 1.) Users from the department of MŽP SR; 2.) Further users. In the near future there is planned the putting into service the support of technology WFS, which will allow users the approach to “sharp” vector geospatial data. These data are used in the frame of activities of Slovak Agency for Living Environment as well as further organizations of the department of MŽP SR with a perspective on interdepartmental collaboration.
In the Slovak Water-management Enterprise, state enterprise, the system of maps of areas threatened by floods was elaborated, which comes out from the valid legislative of SR and fulfils the obligatory map types by kinds allowing to improve all system of management of flood risks. This suggested system contains following kinds of maps: map of inundation area, map of potential zones of inundation area, map of flood risk, map of the course of flood of inundation territory, map of risk and potential outcomes of floods, map of historical flood and map of breakthrough wave.
The metainformation system of the department of agriculture contains also the geographic information system of the main melioration facilities (objects built by HMZ, dewatering channels, small water flows, dewatering and drainage systems, irrigation systems), elaborated and actualized by the state enterprise Hydromeliorácie ( http://mis.mpsr.sk). 15
The State Geological Institute of Dionýz Štúr (ŠGÚDŠ) recently forms in the frame of geological task “Compiling of geological maps for the use of Integrated Management of the Country” GIS, consisting from information layers representing the geomorphological conditions (digital model of the relief), hydrogeological conditions, pedological characteristics and occurrence of geodynamic phenomena, covering whole area of Slovakia in the scale 1 : 50 000.
3 Past, recent and future demands of water 3.1 Supplying and consumption of water Because of irregular distribution of sources of underground water in Slovakia, only 17 % from the total amount is present in the Eastern Slovakia. Nearly all districts of Eastern Slovakia are supposed to be deficient from the viewpoint of demands for requested amount of good quality drink water. The development of water consumption from underground sources indicates from 1991 the gradual decrease (in the period 1989-2000 depletion by 36 % in the frame of Slovakia) in consequence of transformation of central controlled state economics to market economics (decrease of production, growth of prices for water consumption). The decrease of consumption was documented also in the case of water from superficial sources (in period 1989-2000 decrease by 57 % in the frame of Slovakia). From the viewpoint of more important forming and protection of sources of underground water in the region there is present the protected water-supplying area (CHVO) Vihorlat and from the western part into it reach the CHVO Slovak Karts (Plešivec Plain and Horný vrch Plain) and CHVO Upper flow of the Hnilec river (substantial part of the Slovak Paradise). In these areas there are formed the natural accumulations of underground water and waterworks use there have the important sources of underground water (springs, exsurgences). Though the dominant part of the region lies in the waterworks distinctly deficient territory and for water supply there is used water from alluvial sediments of flows, resp. superficial water from the waterworks flows and from water reservoirs. In the territory of the Prešov District 44 water-supplying flows were determined, being already used as the water sources or they can be used in the future. In the Košice District 31 water-supplying flows were determined using 6 flows. Regarding to unsuitable hydrogeological conditions (flysch beds) for occurrence of larger accumulations of underground water is, not only for supplying by water, but also for adjusting of dewatering conditions, the waterworks reservoirs are built. The favourable conditions for their building are in northern part of the region (PSK) in upper segments of Topľa, Ondava and Laborec rivers flows, where recently for waterworks purposes are used 3 water reservoirs - Veľká Domaša, Malá Domaša and Starina. In Košice District for the water supplying of the Košice town the Bukovec reservoir is used. The disadvantage of waterworks use of water reservoirs is necessity of more-degree water elaboration 16
for drinking water, which requires remarkable economic load and in the final consequence it reflects in the prices of the water for consumers. From the viewpoint of recent state of drink water supplying the eastern parts of the region (Snina, Michalovce, Trebišov) dispose the important capacities of water sources (water reservoir Starina and underground sources of water Slovenské Nové Mesto, Boťany, Lastomír, Popričný a.o.) and built intake with the reach to six counties. The central areas of the region (Košice, Prešov) are characterized by the biggest needs. These areas are tied with the main intake from the water reservoir Starina and by this way they are supplied approximately until 2007-2010. In sub-Tatras area (counties Poprad, Kežmarok) for supplying there are used mainly the sources of underground water at Liptovská Teplička, from Spišská Teplica, from Tatranská Kotlina and others. The water reserves in these areas are sufficient also for the future. The water supplying in the counties Spišská Nová Ves and Levoča is from the balance viewpoint passive, therefore water is conveyed into this area from the Poprad grouped water-conduit. The Rožňava area (including the Revúca town from the Banská Bystrica district) is from the viewpoint of water sources highly active also for the perspective safe supplying. 3.2 Changes of population and migration influencing the water use During the last years the long-lasting population growth has stopped. The new phenomenon appearing in Slovakia is the migration for work. Differing from the sizeable migration before 1960, when people abandoned only rural areas, recently at the expense of large towns the settlements in their neighbourhood are preferably inhabited. The rural settlement of more distant areas – mainly in attractive mountain environment – increasingly reaches the recreation nature (huts, cottages). With this change there is related also endeavour about more intensive tourist–recreational, resp. agrotourist use of the territory. In the region the water-supplying use have mainly the superficial water and shallow underground water, being very vulnerable and threatened by discharging of polluted waste water. Significant there is that after incorporation of Slovakia into EU, for particular villages distinctly increased the possibility of financial sources of EU use for building the water-conduits, sewerages and sewage tanks. For development of East Slovakian region recently there are very actual the ambitions about the building of industrial zones and industrial parks for application of various investment intents. It is obvious, that in the cases of successful starting of production activities the next requests for use of drinking and technological water will appear. 17
3.3 Studies focussed on future water supply The area of Eastern Slovakia is supposed as deficit one from the viewpoint of requests for water supplying. Important is that from the viewpoint of regional planning there has the remarkable importance the protection of interest areas mainly for the construction of perspective waterworks. Regarding the protection, but also effective use of the territory until the realization time are in the Prešov District for water reservoirs selected three localities - Tichý potok, Jakubany and Lukov. For the need of these reservoirs numerous controversial opinions exist, mainly regarding the protection of surrounding natural environment. From this reason, more studies were elaborated. From this number important was for example the study of Ministry of Environment of SR about the state of use of recent water sources regarding to development of water consumption in the future. All used water sources of the region were subjected to complex hydrogeological and balance evaluation. Besides other things the study showed sizeable reserves and shortcomings in rational and effective recent practice of waterworks companies. 3.4 Conditions of hydrogeological collectors
Occurrence and spatial spread of hydrogeological collectors in the territory of Eastern Slovakia
reflects mainly the geological setting of the territory. The main rock types, building this territory are the Quaternary sediments, Neogene sediments, neovolcanic rocks, Paleogene sediments, Mesozoic sediments, Paleozoic metamorphites and metamorphites of crystalline basement.
The measure of ability of rock environment to accumulate the underground water and make possible its flowing is evaluated through flow capacity of rocks. The degree of flow capacity can be quantified by parameter – coefficient of flow capacity T, expressing the volume flowage of water through the watered collector of unit width and watered thickness at unit hydraulic gradient. In large scales we can express the flow capacity in four degrees:
low T < 1.10-4 m2.s-1
moderate T = 1.10-4 – 1.10-3 m2.s-1
high T = 1.10-3 – 1.10-2 m2.s-1
very high T = > 1.10-2 m2.s-1. The hydrogeological scheme of the territory of East Slovakian District is graphically shown in
Fig. 2. In the map the individual lithological types are differentiated by hatching and the degree of their flow capacity by differing colour.
The most important hydrogeological collectors, locally reaching very high flow capacity, though in dominion with high flow capacity, are Quaternary fluvial sediments – gravel and sand. They are 18
characteristic with intergranular type of permeability. Their most common occurrence is the territory of the East Slovakian Lowland, the important accumulations their form in lower segments of biggest rivers of this territory. They represent very productive hydrogeological collectors allowing the use of water by concentrated intake of regional importance (collective water-conduits).
Very important hydrogeological collectors are represented also by the limestones and dolomites of Mesozoic age, forming known karst areas (Slovak Karst, Slovak Paradise, Belianske Tatry Mts., Galmus Mts., Branisko Mts., Muránska planina plain...). They are characteristic with karst-fracture type of permeability and with prevalent high degree of flow capacity. They are dewatered in important scale by known karst springs of high efficiency. Many of them are caught and used for collective water-conduits.
Moderate to high degree of flow capacity is characteristic for Neogene clay with intercalations of gravel and sand as well as Paleogene sandstones. The beds of gravel and sand form the hydrogeological collectors in non-permeable clay beds. They are characterized with intergranular type of permeability. The important spread they have mainly in the Košice Basin and East Slovakian Lowland. Using drills the underground water can by withdrawn in amounts of several l/s for one drill. Paleogene sandstones are spread mainly in the Levoča hills, where reach moderate flow capacity and in the Ondavská vrchovina Upland with high flow capacity. They are characterized with fracture type of permeability, capture of springs. Using drills their production can reach several l/s of underground water.
The moderate flow capacity is reached by neovolcanic rocks (building the mountain ranges Slanské vrchy and Vihorlat), Paleogene flysch formed by alternation of sandstone and claystone beds, conglomerates of Paleogene as well as Paleozoic age, variegated Mesozoic limestones and quartzstones. In listed lithological types the fracture type of permeability prevails. Only in the case of neovolcanic rocks there is important representation of intergranular type of permeability tied with volcanosedimentary rocks. The caught sources reach capacity in tenths to first l/s and only rarely above 5 l/s, which allows prevailingly the local, eventually individual supplying.
Low to moderate flow capacity was found in the case of Paleogene claystones and Mesozoic and Paleozoic schists, all with fracture type of permeability. Low flow capacity and fracture type of permeability characterize the Mesozoic marlstones and marl limestones, as well as Paleozoic intrusions (mainly granitoids, granites, and granodiorites) and metamorphites. They have low importance from the water-supplying viewpoint; the caught sources reach efficiency in tenths l/s, which allow prevailingly only individual supply.
The state water resources management balance (ŠVHB) evaluates in its chapter titled the Underground water the relation among the potential possibilities of underground water exploitation and their waterworks, industrial and agricultural use. The main valuation unit is the hydrogeological region.
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Recently in all hydrogeological regions of Eastern Slovakia is observed a good balance state. In 2001-2002 the significant lowering of offtaken water amount was registered in some localities. 4 Modelling of rainfall-outflow processes in relation to forest crops
The influence of forest on hydrological regime of water flows is a topic of investigation from the end of the last century. The sizeable number of until done experiments allowed some degree of generalization of knowledge of relation of forest and outflow. Generally it was declared that forests have (Mráček and Krečmer, 1975):
• Remarkable ability to suppress the rain water in outflow, that means the retention ability
• To cumulate the rain water on extended surface of wood, in soil cover and in the soil alone, i.e. accumulation ability
• The ability of slowing the water outflow by the change of superficial outflow to underground outflow, i.e. the retardation function.
During last years in international scientific community there was emphasized the need of better understanding of hydrological processes. The preferred areas encompassed the study of hydrological processes in various time and space scales, interactions surface - atmosphere, understanding of influence of climatic changes on hydrological cycle and water resources, etc. One as the main assumptions of development in this area was the international and interdisciplinary cooperation. The main Slovak investigation programs in hydrology from 1999 till 2002 are focussed on interactions soil-water-vegetation-atmosphere, processes regulating outflow, the water quality and influence of use of the country for outflow, morphology of rivers and the sediments transport, flow of underground water and their regime, regionalization and mapping, extreme events, influence of climatic changes for hydrological processes and management of water sources (Szolgay, 2003). The investigation of the transport of water, ions and energy in the system soil-water-plants-atmosphere was partially focussed on quantification of components of water balance in unsaturated zone of lowland forest ecosystem (Šútor et al., 2002).
The change of the relation of society to living environment and need of integrated management of drainage areas have compelled the support of process oriented investigation in hydrology, which allowed significantly extend the knowledge about the outflow forming in slopes in small drainage areas during the last decades. The mathematic modelling of outflow inclined to spatially differentiated simulation of processes of water transport in drainage area. The theoretical and experimental hydrological outputs are integrated as well as the results of further disciplines like hydrometeorology, hydrology, hydrogeology and geoinformatics into comprehensive mathematic models of processes in the drainage area. These models, named also as models with spatially divided parameters, are based
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on solution of partial differential equations (Hlavčová et al., 2001). In these models the spatial variability of physical-geographical characteristics of drainage area is expresses using small homogenous spatial units – grids and in their net the differential equations are solved by numerical methods. The practical use of such models is sometimes limited by insufficient quality of input data, incommensurate equations for various conditions of the outflow forming and with problems with stability and convergence of numeric schemes. As compromise the models with so-called halfly-dismembered parameters are implemented, simplifying representation of spatial variability of environment by concentrating on dominant mechanisms of outflow generation and using bigger homogenous spatial units.
The determining factors of the final outflow amount from the drainage area and its time changes
are mainly (Minďáš et al., 1998):
• Geomorphological characteristic of relief
• Hydrogeological conditions of drainage area
• Meteorological conditions
• Water balance of forest cover
• Total forest coverage of drainage area and structure of the country without forest. The decisive processes, determining in the final consequence the role of forest in hydrological
regime of the country, are chiefly the evapotranspiration and infiltration of the rain water. The evapotranspiration of the forest ecosystems includes three important components: interception evaporation (evaporation of caught rain water on the surface of plants), evaporation from soil and transpiration (water release by plants prevailingly through the pores of leaves and needles). Interception so-called non-productive evaporation has different course in various altitudes and has similar character as evaporation from open water surface. It is determined by outer meteorological factors, but also by the character of tree-tops of the forest cover resp. forest cover as a whole. The important element is for example also the seeping of rain water on the trees trunk, when for beech Kantor (1981) states the value of the seeping on tree trunk in the vegetation area 19.9 % from the rains of free area, but for the spruce only 1.4 %. The transpiration of forest covers represents in vegetation period the principal part of the whole evapotranspiration. According to data about transpiration of covers of European wood species summarized by Brechtel and Lenhardt (in Kantor, 1989) the annual transpiration values in beech overgrowths range in 290-497 mm (in average it is 313 mm per year) and in the spruce forests 100-516 mm (in average 286 mm per year). In the base of measured values of transpiration flow in locality Poľana-Hukavský grúň the actual transpiration of beech forest cover is 285 mm per vegetation period at rain total amount 735 mm, which represents 35 % from the rain total amount (Střelcová and Minďáš, 2000). The infiltration of the rain water into the forest soil is influenced
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by intensity and length of rain lasting, as well as the character of soil environment, mainly by grain-size composition of the soil and actual moisture factor. Because the permeability of soil changes in relation to its actual moisture saturation, also experimental measured values also in one measuring point show marked spread. According to measurement results by Kantor (1984) from the period 1977-1981 the values of vertical water percolation in the depth 70 cm varied in the range 22.9-51.6 % of rains from the outer free plane for spruce forest cover and 33.9-65 % of rains from the outer free plane for beech forest cover. For intensity of superficial outflow in forest there influences also the total amount as well as intensity of rains, inclination and exposition of slope, wood composition, age and structure of the forest cover as well as the type of herb layer, thickness and form of superimposed as well as soil mould, but also permeability of soil and degree of its freezing, which determine the infiltration (Midriak, 1992). In forest covers of coniferous pulp in Slovakia (spruce, fir, pine, larch) represent superficial outflow from 22 up to 782 (in average 255) l.ha-1 per day, representing 0.07-2.52 % (in average 0.99 %) from the rainfall on the area without forest cover. In the forest cover from broadleaved species (beech, oak, hornbeam) in Slovakia the total amount 34-1080 (in average 323) l.ha-1.day-1 superficially outflows that means 0.14-5.03 % (in average 1.52 %) from the rain in free area (Midriak, 1992). In middle mountain altitude locality Poľana-Hukavský grúň the summary ratio of superficial and underground outflow in total rain drop 930 mm = 100 % for beech forest 363 mm = 39 % and for spruce forest 316 mm = 34 %.
At the base of long time rows of experimental observations in the Orlické hory Mts. and in Beskydy Mts. (Czech Republic) and by analysis of many foreign studies there is possible with the high probability to suppose as confirmed the principal knowledge about the role of forests in forming the outflow from the rain (Kantor and Šach, 2002):
• Superficial outflow and following soil erosion are in the forest covers fully negligible. This statement is valid not only for natural forests, but also for forest commercial. Even in the case of assart exploitation there are no erosion processes (with exception of boulder-type localities) resulting on the lumbering of trees, but are always the demonstrations of wrong organized load and movement of heavy mechanization equipments and further activities of a man. The absence of superficial outflow in the forest (which here, besides the high percolaton ability of soil substratum is eliminated also by the system of water ways formed in the forest soil by the tree roots, animals etc.), despite its often occurrence on agriculturally managed land, it is so the first and very important assumption of absorption of floods in the country.
• Regarding the ecological stability as well as steadiness and safeness of production it is one of indubitable priorities of forest management the transformation of spruce monocultures on mixed forests. Though the investigation results fully unambiguously showed that the increasing ratio of broad-leaved trees does not lower the danger of floods. The broad-leaved wood species are
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namely regarding to leafless state apart from vegetation seasons and less biomass of assimilation organs able to suppress and withdraw less rain water than coniferous wood species (mainly spruce).
• The upland and mountain forests (in difference to all non-forest ecosystems) absorb very easily the storm rainfall about the vigorousness up to 50 mm. The continual rainfalls about the intensity up to 100 mm will manifest in the total highness of outfall of the water from the forest, but from the viewpoint of water resources management efficiency they are still feasible. As a critical boundary for effective absorbing the floods by the forest there can be supposed the boundary of 150 to 200 mm of continual rainfalls. At this total amount the forest land is always fully saturated by the water including the infilling of the depressions as the soil surface, so in the rock underground. Then the non-controlled and spontaneous outflow of the water starts through the whole soil profile, ascending often on the soil surface, namely without regard on species composition or ways of maintenance. Using other words, also the body of forest soil has similarly as the technical facilities – fagot dams, its capacity abilities, which cannot be overstepped.
From the viewpoint of evaluation of the influence of forests on evapotranspiration and water balance in the drainage area there was alleged (Novák, 2001), that the total amounts of evapotranspiration of the forest, being about 10-15 % higher as from the forests from low vegetation, are caused prevailingly by evaporation of caught water by interceptions. As a result of high forests interception the amount of water inputted into soil is lowered. Part of rainfalls, striking on the surface of the soil layer, has formed favourable conditions for infiltration owing to suitable soil structure.
From the appraisal of forest response for transformation of rainfalls into the superficial outflow, there is necessary to distinguish two cases (Minďáš et al., 2001): 1) evaluation of the forest influence on total aquosity of superficial flows, 2) evaluation of the forest influence from the viewpoint of its antifloods efficiency. Despite numerous and often conflicting results of the studies of the forest influence on water outflow there is undisputable, that despite forests do not fully restrain flood waves, they can by significant way reduced their course (Minďáš et al., 2001). The extreme water state in torrent with forest drainage area, probable occurring once per 100 years, can be expected in drainage area without forests each 16 years (Mráček and Krečmer, 1975). From generalized knowledge about the influence of total forest coverage of drainage area (Valtýni, 1986) there results, that the maximum specific outflow in the flysch areas is the most distinctive influenced, where even small regress of forest coverage will reflects in the distinctive increase of maximum outflow amounts and their unstableness. Outflow is the least influenced by the change of forest coverage in the drainage areas with carbonate rocks, where the influence of the change of forest coverage on outflow is approximately half than that in the flysch. The
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influence of the forest for water capacity of superficial flows in the periods of low and medium states is not investigated.
The total retention capacity of the drainage areas with the forest cover in Slovakia is estimated on 45-70 mm, in the case of 100 % forest coverage. The decrease of the retention capacity with decreasing percentage of forest coverage lowers initially slower; beneath the boundary 50-60 % of the forest coverage it is much distinctive.
The preliminary research analysis (graph 2) of average month flowage recorded in stream-gauging station in 2003 indicates the sizeable influence of hydrogeological conditions of drainage areas for stability of regime of superficial outflow, when the highest ratio of unstableness of outflow expressed by the ratio of maximum and minimum monthly average during year is expressed by the drainage areas built by flysch rocks (Paleogene claystones and sandstones), moderately lower level of unstableness is expressed by the drainage areas built with Neogene volcanites (Graph 1). In graphs the data from the drainage areas built by Neogene sediments are not depicted, reaching the extreme values Qmax/Qmin around 500. The considerably more stable is the outflow from the drainage areas built by metamorphic and karst rocks. The important factor determining the aquosity of drainage areas is the rainfall total amount and the level of evapotranspiration, which are indirectly reflected by the highness of drainage areas. The values of minimum average month flowages in 2003 are depicted in the regression graph towards the altitudes of the terminal profile of drainage areas and towards estimates percentages of the forest coverage of drainage areas indicate, that despite the rainfall-climatic conditions are the determining at the forming outflow regime in drainage areas, also the degree of forestation resp. country use type can play an important role here. The drainage areas, built by flysch Paleogene sediments and Neogene rocks are simultaneously characteristic also by increased amount of landslides.
43.2
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Graph 1: Ratio of maximum and minimum mouthy flowages in 2003 in superficial flows in Eastern
Slovakia according to geological characteristic of the drainage areas.
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Graph 2: Minimum monthly flowage and ratio of maximum and minimum monthly flowages in 2003 in superficial flows of the Eastern Slovakia according to geological characteristics of drainage areas vs. altitude of termination of drainage areas and estimated percentage forest coverage of drainage areas. The resolution of drainage areas geology: triangle – metamorphic rocks, square – karst, circle – flysch, plus sign – neovolcanites. 5 Load of territory by stress factors 5.1 Geodynamic phenomena
Geodynamic phenomena in the interest area are manifested by specific way in high-mountain area, in the area of flysch zone, in the foothill of neovolcanic mountains and in Inner-Carpathian hollow basins.
In the mountainous region in high core mountains (High Tatra Mts.) belong among the most often geodynamic processes the weathering, erosion and various sorts of slope processes (debris avalanches, rocky and avalanche flows, rock collapsing and slides). In core uplands (Slovak Ore Mts.) the tectonic uplifts and depth erosion of the flows is not so intensive; therefore the slope gravitation movements are not developed in such scale as in the high mountains. Usually there occur movements
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of slope coverage and weathering underground. The particular type of slope deformations is common at the margins of limestone planes (Muránska planina and Plešivecká planina karst planes). Besides the slope movements in the core uplands the karst phenomena and slope erosion have the biggest importance. The washout erosion is not a typical phenomenon of the core uplands.
In the region of Carpathian flysch in area of flysch highland from geodynamic phenomena the most important is the deep weathering, slope erosion and slope movements. In area of flysch highlands the areal slope erosion is widely spread, which together with abrupt changes of saturation by water causes the intensive development of areal and flow landslides. The small permeability of rock footwall causes that majority of rainfall water quickly runs away when the originally continual forest coverage was disturbed. The most intensive development of washouts in deforested and agricultural used uplands and in lowered foothills of highlands, where the very favourable conditions for it are formed by slope clay of big thicknesses and eluvia located on prevailingly clay-marl complexes of badly permeable underground, as well as intensive rainfalls and dynamic superficial outflow at melting of snow cover. Despite, the slope movements are the most typical process in this area. In the area of flysch highlands the majority of registered slope deformations are concentrated, because of the complex of optimal conditions for application of landslide-forming factors (rock properties, relief, arrangement of river net, and intensive rainfall activity). The very important and as a rule permanently affecting factor at the origin of landslides is the water flows erosion, lateral scouring of slopes and washout erosion. Besides the natural factors, the important role at lowering of stability has in these conditions also the man activity, mainly the unsuitable interventions during the communications building.
In the area built by volcanic rocks from the more important geodynamic processes the gravitation slope movements and deformations of miscellaneous types – deep as well as superficial creeping, rock breakdowns, areal as well as flow landslides, as well as running-down of soil and stony flows. In the central part of neovolcanic rocks the deformations are infrequent. The main part of the landslides is tied to margins of volcanic mountain hills (Slanské vrchy Mts., Vihorlat Mts.), where volcanic rocks rest on Paleogene schistose formations or Neogene weakly consolidated formations.
The majority of geodynamic phenomena are concentrated into the inner-mountainous valleys with morphology of middle and higher uplands. The landslides are formed on slopes mainly owing to intensive deep and lateral erosion of water flows. The very suitable conditions for origin of landslides are here prevailingly at boundary of complexes with various physical-mechanical properties. The prevailing type of slope movements in innermontane hollow basins are the areal and flow landslides on slopes of uplands, eventually deeper landslides on rotation slide planes (in molasse Neogene sediments), activated by the lateral river erosion. The very typical sign for coverage formations in hollow basins the accumulation of solifluction deluvia predisposed for landsliding. Very often are the landslides artificially
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activated by undercutting of slopes and scouring of water reservoirs. The intensive slope erosion affects the hollow basin uplands.
In lowland areas among the most common geodynamic process belong the washout erosion, lateral flow erosion and transposition of their water-courses, streaming of sands, suffosion, volume changes of clay soil. In plain areas of Inner Carpathian lowlands the more intensive development of washout erosion is restricted mainly by flat relief, but in plain uplands it is relatively strongly developed. In the measures against washout erosion are necessarily focuses on concentrated superficial slope outflow (restoring of vegetation cover, liquidation of erosion as well as artificial furrows already in the beginning stadium, repairing of field roads, technical adaptation and hatching to restrain the deep and lateral erosion etc.). The disturbing accumulation activity of wind is relatively common. The processes of sand vanning by unconsidered agrotechnical and building activities are underestimated. The deforestation and removal of vegetation cover, as well as deep ploughing of shallow soil on eolian sand can initiate the process of deflation and drifting in of fertile fields (East Slovakian Lowland).
The slope movements are the most important geodynamic phenomena influencing the optimal use of the area and operation of technical works. There originate or are activated by spontaneous way (usually at rainy accumulations) or as a consequence of technical activity of the man. For obtaining of the complex information about the occurrence of landslides in the Geofond basis there are registered the slope movements and the data are still renewed. Recently also the whole area monitoring of landslides is solved in selected localities and the Atlas of slope stability maps in the scale 1 : 50 000 was compiled. The landslide areas in the territory of interest are mainly in the flysch hollow basins, in intermontane depressions and at the margins of neovolcanic mountain ranges (Fig. 3), which represents the substantial part of the Eastern Slovakia. The landslides in these areas disturb the forest coverage, agricultural soil, meadows and pastures; threaten railways and roads, as well as development of some towns and villages. The slope stability is the limiting factor of the optimal use of the country. The measure of the knowledge of occurrence and regularities of origin of the landslides allow their prognoses, because 90 % of landslides recently originate by reactivation of old, potential landslides as a consequence of negative anthropogenic activities, which are invoked directly by technical works and engineering workings but also the following factors among which belong the changes of regime of underground and superficial water, deforestation of the area, making worse of outflow conditions of superficial and underground water, etc.
The presence and activity of underground water on rock environment has substantial influence on origin, properties and stability of landslides. The importance of hydrogeological conditions in investigation and survey of landslides in the frame of the monitoring of landslides of Slovak Republic has been treated by the workers of ŠGÚDŠ (Scherer, 1999, 2000). The investigation of landslides has 27
confirmed, that at the base of making clearer of the circulation and regime of underground water there is better understandable the influence of the underground water on engineering-geological properties of the landslide area, following to suggest the way of following of monitoring of the landslide stability and in the case of need to suggest the optimal way of remedy. From these reasons there would be necessary already during surveying, resp. remediation of the each landslide to know their largeness, dip and shape of infiltration area, which underlie the behaviour of landsliding process.
As the relevant factors reflecting the favourable conditions for the origin of landslides there can be possible on the base of until obtained knowledge about given problematics to suppose the geological setting (lithology, seismic-tectonic and structural conditions), geomorphological conditions and character of georelief (morphometric characteristics, mainly of the slope dip), hydrological-climatic and with them related hydrogeological conditions of the territory as well as anthropogenetic factors being represented by the country structure and the recent country use. The density of registered landslides in the drainage basins built by flysch rocks reaches the average 0.28 landslides/km2, in drainage areas built by Neogene sediments and neovolcanites 0.33 landslides/km2, while in the environment of metamorphic rocks only 0.06 landslides/km2 and in karst areas 0.003 landslides/km2. From the total amount 3,982 landslides registered in the territory of East Slovakian District only 16.5 % is localized in forest coverage and 10 % at the forest boundary, though the forest coverage represents app. 45 % of the territory area.
It is generally known, that very important (if not the most important) factor influencing the landslides activation is represented by heavy rains underlying the quick saturation of slope sediments by water. Therefore as a stabilization factor in areas with natural potential for the origin of landslides will be affected such type of the country use, which to some extent will absorb the quantity of infiltrated rain water in the year periods rich in rainfalls. From this view the forestation of the territory can by an important stabilization element.
Each year the spring floods and summer cloud-bursts cause tens of landslides, directly harming
the communications and in some cases threatening also the built-up areas, or line buildings. In 2006 the landslides in the Ždiar village were registered above the state road, being located in the immediate neighbourhood of the family houses. The landslide on local communication was registered also in villages Vlková and Vrbov. The intensive rainfalls caused the landslides and roadways also in the route from Herľany to Banské towns, where nearly 10 metres long segment decreased about 1 m. The rainfalls caused the slide of the roadway into the Hnilec river flow in the segment of the road in direction Gelnica – Prakovce and in Parchovany village, where in immediate vicinity of the road the slope has slid in the length 50 metres. In direction between Vyšný Slavkov and Spišské Podhradie village the landslide threatened road. The Slovak road board recently has to salvage the landslides in the state roads I/50 Dargov, I/18 Bertotovce, I/67 Tatranská Kotlina – Ždiar, I/73 Kuková, I/77 Podolinec. 28
Liquidation of the landslides requires sizeable financial sources also from the state reserves. The financial expenditures for correction of individual slides vary in the range 25–250 thousand EUR.
Marginally to these facts we have to emphasize, that in practice we very often meet the correction of damaged housing, being in flooded areas, where usually after floods the expensive water courses regulation and building of new dwellings, being repeatedly situated into relatively suitable or even to unsuitable area for building-up area.
Similarly it is also at new individual building-up, for which already now the territories usually conditionally unsuitable to unsuitable for building are taken from the soil fond of the territory (sloppy, sliding, with low bearing capacity etc.) without precise determining of conditions of building-up.
5.2 Soil erosion and weathering of soil
The soil erosion or removal of soil by the rain water or wind is allowed if soil remains uncovered, exposed to direct effect of rain resp. wind, or if in the soil is lowered content of organic matter. Therefore the agriculture and deforestation represent the activities the most negatively influencing the soil fond. The ratio of erosion induced by cultivation of soil (mainly ploughing) as well as induced by building of forest roads in the system of relief-forming and soil-degradation processes are in Slovakia very important.
The soil erosion represents the removal of soil matter and from this process resulting lowering of the thickness of superficial soil layers, mainly by the influence of water and wind. There are distinguished four main types of water erosion: superficial (activated by outflow of rainfall in small planes), areal (concerning the larger soil units with more distinct influence), washout type (strongly damaging the soil surface), combined (consisting from several kinds of erosion). The most serious problem of agricultural soil in SR is the water erosion. It threatens app. 1,360,000 hectares (app. 55 %) of agricultural soil (Jambor and Ilavská, 1998).
Potential of water erosion we can evaluate according to degrees of erosion endangering. According to evaluation we can state, that the localities the most threatened by erosion are located in climatically drier regions of East Slovakian Lowland. The agricultural soil of these districts localized on moderate slopes has middle level of endangering by water erosion. Strongly threatened areas of agricultural soils, present on slopes in climatically colder and wetter regions. The extreme threaten of soil by water erosion is represented by soil on distinct slopes, in cold and wet climatic regions.
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Tab. 2: Endangering of agricultural soil in SR by water erosion
Intensity of erosion threat Area in ha % from PPF
Neither or weak erosionMedium erosionStrong erosionExtreme strong erosion
1 065 420 473 520 426 170 402 490
45,0 20,0 18,0 17,0
Source: MP SR The wind erosion does not represent the more serious problem in SR. It afflicts app. 6.5 % from
the area of agricultural soil in SR, mainly in the areas with lighter soils. Such areas are present in East Slovakian Lowland (VÚPOP, 2000).
Tab. 3: Endangering of agricultural soil in SR by wind erosion
Intensity of erosion threat Area v ha % from PPF
Without threat to moderately threatened by wind erosionModerately threatened by with erosionStrongly threatened by with erosionExtremely threatened by wind erosion
2 213 700 113 650
9 470 30 780
93,5 4,8 0,4 1,3
Source: MP SR The changes of soil erosions during the course of years are not observed and processed in full
area of Slovakia. The potential soil threat against erosion would by anticipated by the right principles of maintenance of agricultural soil. For protection of soil against erosion there is dedicated also the financial support in the frame of antierosion remedies of the Plan of rural development 2004–2006. In this plan the support of disadvantageous areas as well as implementation of agroenvironmental remedies would lead to lowering of the risk of erosion in the future, mainly in the areas strongly threatened by the erosion, in areas located on the slopes of climatically colder and wetter regions. 5.3 Floods
The superficial water outflow regime in the territory of Eastern Slovakia shows the altitude
zonality that means with increasing altitude the average amount of superficial outflow increases, ratio of snow falls increases, the occurrence of highest average monthly flowages pushes from March to May-June and the lowermost from September to January-February. The floods have in the territory of
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Eastern Slovakia the variegated course, which is caused by their differing physical and geographical conditions. In mountainous areas they have quick running which reflects into the smaller number of days of flood activity. In lowlands their onset is lower, last longer; therefore the number of days of flood activity is higher. In period 1990-2002, day of declared flood activity occurred in all months, though mainly in March and April, next in July and August. In the first case, the most common occurrence of flood activity reflects on snow melting. In July and August the increased floods occurrence is tied with distinct rainfall events (several days lasting rains) connected with the low atmospheric pressure. Following the valuation of hydroprognostic stations of Slovak Hydrometeorological Institute (SHMÚ) in 1990-2002 we can state, that number of days of flood activity during the last 6 years of listed time period moderately increased.
It is without doubts, that also in distant past the territory of Eastern Slovakia was the often place of flood disasters. From preserved records as such the century water in the drainage area of Bodrog and Tisa rivers in 1888 can be supposed. The occurrence of extended floods was in this territory often also in 20th century. From the biggest floods there can be mentioned the hundred year water in drainage area of Bodrog and Tisa in 1924, in Tisa also in 1932. The extended floods occurred also in 1967, 1974, 1979 or 1980. The whole drainage area of the Hornád river was caught by the disastrous flood in 1958, along Torysa river the flood catastrophe occurred in 1952. The end of 2nd and beginning of 3rd millennium brought for region of Eastern Slovakia in short time span many extended floods with disastrous consequences. These events were individually examined and reconstructed there were the conditions of forming of flood waves in drainage areas. The valuation of historical floods in rivers in drainage area of Bodrog was done (Halmová, 2001). The analysis if existing data has showed the growing extremeness of regime in drainage areas along the Uh river (Pekárová and Miklánek, 2001).
In July 1997 the flood waves hit firstly the torrent flows in Šariš area and in water flows of Torysa (mainly in village Tichý potok), Malý Lipník and Dunajec 3rd degree of flood activity was declared. First flood situation in 1998 originated in spring time, when as a result of intensive rainfalls in Eastern Carpathians (away of the territory of SR) rapidly increased the levels of Latorica, Bodrog and Tisa water flows. Next rain activity caused the areal flooding of the fields of East Slovakian Lowland. Next flood activity originated in the summer period and had several phases, caused by local storms and heavy rains. In 20. 7. 1998 the storms of unprecedented intensity hit the southeast of the Levočské vrchy Mts. From the cloud-burst (storm rainfall) has rained in the upper water drainage area of the Malá Svinka stream during one hour more than 100 mm of rainfalls. The originated torrent wave reached the highness up to 4 m, flooded the village Jarovnice and 50 persons lost their lives. Seriously injured were also the villages Renčišov, Uzovské Pekľany, Dubovica and furthers. The flood damages along the flows in the administration of the Slovak water-management enterprise were calculated to 996 million of SKK and expenses on safeguarding works reached the level 20.3 million SKK. In October 31
1998 the dramatic situation occurred mainly along the Uh river in Lekárovce village, where during 18 hours the water level increased by 8 m and due to the protection of village the embankment was disconnected by the blast. In the spring 1999 the rivers in the East Slovakian Lowland swelled and the situation enforced to charge for the fourth time during its history from 1965 the polder Beša, which during 17.5 hour caught 28 million m3 of the flood water. In 2000 the East Slovakian Lowland was again afflicted and the Tisa river reached 100-year flowage. The flood situation along Tisa, Bodrog and Latorica rivers lasted from the first half of February till the second half of May. During this time the reservoirs in the Bodrog drainage area caught altogether 220.4 million m3 of the water, from this number in Zemplínska šírava 117 million m3, in Veľká Domaša 51 million m3, in Starina 11 million m3 and in polder Beša 41.4 m3. The expenses on safeguarding works hold in 2000 in Eastern Slovakia represented the sum 46.2 million Sk. In 2001 the summer rainstorms with cloud-bursts of various intensity occurred daily, each time in different area and locally struck individual villages in small flows, mainly in the Prešov district in the upper segments of the drainage areas of Poprad, Hornád, Ondava, Topľa, Laborec and Torysa rivers. During expansive flood in March 2002 the 2nd degree flood activity was alerted in the Bodrog, Torysa, and Topľa and Latorica rivers. The summer storms in months May-August caused in numerous water flows of Eastern Slovakia local floods, during which some villages in the Bardejov county (Cígeľka, Sveržov, Gaboltov, Kurov, Petrová, Frička) as well as in the counties Spišská Nová Ves and Levoča were flooded. In July the similar situation repeated in these same counties. In August the storm rainfalls struck villages Matejovce, Betlanovce, Janík and Poprad (Abaffy, 2003). As a result of heavy rainfall dated between 27. 7. 2004 and 30. 7. 2004 in the territories of the Košice and Prešov self-governing regions (VUC) occurred common flood of water flows. As a result of this there originated the increased flood flowages, which in the Haniska village led to flooding of large part of the village by the water from Torysa river, in the Kapušany village the small river Sekčov flooded 80 houses as well as industrial facilities of Slovnaft, Radoma and Aque Exotic. In 31. 7. 2004 the protection embankment of Ondava river was overflowed and consequently ruptured, which caused flooding and threatening several settlements. The emergency situation originated in November 2004 in several water flows in the area of High Tatras as a consequence of windstorm, during which several forest creeks were blocked by broken and sawyer trees. Un 2005 the complications appeared because of ice effects during the outflow of spring water, causing floods in the Hornád river in the Spišská Nová Ves, Krompachy and Betlanovce. The local storms, causing the flood situations were in 5.-6. May in drainage area of Poprad and 3. May along the Topla river. The most serious situation was in the drainage basin of Trnávka water flow in villages Parchovany, Vojčice and Trebišov-Pačižov, where the disruption of embankments of the streams Bačkovský potok and Trnávka. The embankment was artificially disconnected and water directed away of internal parts of the villages. The counterflood
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activity was intensive also in the period July – September 2005, with origin of flood situation in drainage basins of Topľa, Torysa and Hornád rivers.
5.4 Acidification and contamination of water
After 1989 the new economic conditions caused the deterioration of situation in the state of acidification of agricultural soil. The agricultural facilities stopped the practical application of calcareous matter as well as industrial fertilizers into the soil. This caused the gradual increase of acidification of soil, which has demonstrated by the increase of acidification of soil as a result of abandoned liming of the soil, as well as subsiding of the influence of application of industrial fertilizers in the past, but also by the influence of atmospheric pollutants penetrating into soil. The lowered concentrations of acid atmospheric pollutants after 1989 related with attenuation of the Slovak industry, increase by the extended traffic, which is reflected mainly by NOx. In the second half of the 1990s the situation in soil acidification has stabilized and even moderately improved. It is the result of particular stabilization of inner soil chemistry, and lowered application of physiologically acid-actuating fertilizers as well as lowered inputs of atmospheric pollutants.
In the territory of Eastern Slovakia the lower values of pH were observed in the area of the Spiš-Gemer Ore Mts. (counties Gelnica, Spišská Nová Ves and Rožňava) and in marginal parts of region built by crystalline basement (Poprad, Kežmarok), as well as rocks by the outer flysch zone (Bardejov, Svidník, Stropkov, Snina, Humenné, Medzilaborce) and Central Carpathian Paleogene (Levoča hills –county Kežmarok). In these areas the soil is characterizes as strongly acid to extremely acid (pH/H2O in interval 3.5–5.5). For the remnant part of the region territory the weakly to medium acid soils are characteristic, small part has soils characterized as a neutral (pH/H2O > 6.5). 5.5 Contamination of underground water Character of geogenetic pollution, resp. geogenetic ratio in pollution of underground water of the region is represented by often increased levels of iron (Fe) and manganese (Mn). Both elements are characteristic for underground water of flysch Paleogene sedimentary complexes, building the whole northern half of the region and dominating in the territory of the Prešov District. The excess limit contents of these metals occur in numerous springs in whole flysch area. Consequently they concentrate in water of superficial flows outflowing into the southern part of the region (Košice district). Both metals determine prevailingly the bad sensor properties of water (taste, smell). In recently occurring contents are not toxic.
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The natural acidification of underground water manifests in the area of neovolcanites and in the area of the Spiš-Gemer Ore Mts. In the area of the Spiš-Gemer Ore Mts. as well as in the wider surroundings of the town Košice to this former acidification there can be associated also the acidification effect caused by metallization influences of exhalation from former large mining and dressing (Rudňany, Rožňava) as well as processing enterprises (VSŽ). The alkalization influences (pH above 8.5) occur in underground waters of the region only very sporadically. The main reason can be with the biggest probability in strong pollution of municipal character. The anthropogenic pollution, which means the polluting of underground water in the evaluated region, represents serious fact, because regarding the hydrogeological conditions of the territory the more important sources of the underground water occur here in very woundable collectors as alluvial deposits and karst planes. In these rock environments the underground water is nearly often in direct hydraulic connection with superficial flows and quality of their water determines also the quality of underground water. From the viewpoint of pollution character and its potential sources the economic use of the territory is determining, for distribution of contamination the determining are its geomorphological and hydrological conditions. As the widest-spread contaminants of underground water can be in evaluated region designate prevailingly (NO2) nitrites, (NO3) nitrates, (NH4) ammonium ions, being the products mainly of agricultural production, use of fertilizers (PO4 phosphates), resp. together with (Cl) chlorides and (SO4) disulphates also of communal pollution in surrounding of settlements. The excess limit contents of NO3 in underground water (springs, drills, wells) are unambiguously concentrated into areas with intensive agricultural use (ploughland) – East Slovakian Lowland, Turňa, Košice and Hornád basin mainly in the surrounding of bigger towns (Bardejov, Svidník, Stropkov, Stará Ľubovňa, Strážske, Humenné, Vranov nad Topľou a.o.). The threat of lowered quality of underground water relates with pollution of superficial water by communal and industrial waste water and imissions. The increased contents of iron, manganese, oil substances and locally also specific organic materials reach the underground water for example of alluvial deposits of rivers Poprad, Cirocha from Snina down to aperture, Laborec from Humenné and Ondava from Domaša. Besides off-shore zones there is problematic the underground water quality mainly in the areas along Bodrog river and in surrounding of Michalovce and Trebišov. The trend of deep oxidation-reduction zonality manifests here, which results in increased contents of nitrites, ammonium ions, iron and manganese. The specific case is the water sources of near-shore zone of Uh river in Lekárovce village, which are threatened by oil emergencies in Ukraine. The underground water of deposits of the Hornád river used mainly in the segment below the water reservoir Ružín (Družstevná pri Hornáde village), are connected with risk regarding to frequent increase of contents of toxic metals (As, Hg, Pb, Cd). In substantially lower scale is this character demonstrated in northern part of the territory, where it is concentrated mainly into alluviums of superficial flows used by agriculture and into the surrounding of settlement agglomerations. 34
The specific element from the viewpoint of anthropogenic as well as geogenic character of contamination of underground water is the toxic (As) arsenic. From the geogenic viewpoint it is present in rock environment, where accompanies mainly the occurrences of sulphidic and siderite mineralization, but at the same time it is a constituent of emissions, imissions and released waste water at anthropogenic industrial activity. In evaluated region its excess limits (Fig. 9) in underground, resp. mining water are concentrated mainly in its southern part – into areas with historical mining and dressing activities at exploitation of siderite and sulphidic ore (the Spiš-Gemer Ore Mts.), but also to the Slanské vrchy Mts. and into the wider surrounding of the town Košice (the industrial plant of former East Slovakian Iron and Steel Works - VSŽ – recently US STEEL). 5.6 Decrease of level of underground water
The permanent decrease of the underground water level as an unfavourable result of excessively high exploitation is not registered in the territory of Eastern Slovakia. Only in the eastern part of Medzibodrožie are the former character of streaming of underground water of watered fluvial sediments is distinctly modified by hydraulic interventions. The negative phenomena of exploitation of underground water were locally identified also in the Central area of the Slovak Karst, where the exploitation of karts-fracture water by the deep drills has manifested by the lowering of efficiency by considerable distant springs. 6 Results
The territory of Eastern Slovakia is rich in occurrences of hydrological ecosystems. Their widest-spread type is represented by superficial flows, forming the dense river net. Areally irregular and local is the occurrence of moorland, wet meadows and upland moors (mosses). Two Ramsar localities were declared here – the wet land of international importance (Latorica, Senné - fishponds) and suggested there are next five localities. The near-river wet areas of Latorica are spatially the most extended and specific type of hydrological ecosystem, recently representing only the fragment of former area of floodplain forests of East Slovakian Lowland. The recent river net is markedly modified by the water supply adaptations of the water flows, mainly in their lower segments. The recent legislative forms conditions for effective protection of hydrological ecosystems, though the risk element is represented by the spread of country management under administration of several government departments and their branches with potentially discordant preferred interests. The originating conflicts of various lobbyist groups and non-governmental organization for optimal management of particular area can, besides the
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contradictory target interests cause also contradictory professional interests. Next risk factor is the effective inspection of observance of legislatively determined protection conditions.
The most important hydrogeological collector in the territory of Eastern Slovakia is from the qualitative viewpoint the Quaternary fluvial sediments accumulated mainly in the East Slovakian Lowland, the Košice Basin, but also in next hollow basins and valleys of important superficial flows. Despite, their water-supply use is in numerous localities restrained by wrong qualitative state of underground water, which is a result of anthropogenic activity, mainly of agriculture. Therefore there is needful to increase the effort for improving of qualitative state of underground water of Quaternary fluvial collectors by identification and gradual elimination of the pollution sources.
The next important hydrogeological collector is represented by the karst areas, being recently secured by the high degree of legislative protection (national parks NP, protected country areas CHKO, water-supply areas). The risk factor, mainly from the viewpoint of the water quality, is the asseting the legislative in practice, mainly in recreation-tourist areas and in localities with illegal waste deposits. The special attention there is necessary to focus to prevention of excessive offtaken of underground water by deep drills in the central area of the Slovak Karst.
Until realized studies of the forest role at forming of outflow from rainfalls have showed that:
• Superficial outflow and following soil erosion are in forest overgrowths fully negligible.
• The totals from evapotranspiration from the forest are about 10-75 % higher than from lowland vegetation.
• The influence from generic, age composition and structure of forest coverage for interception, transpiration and evaporation.
• At rainfall-outflow and erosion processes the forest roads represent the important elements.
• The infiltration amount into geological underlier is influenced by the type of soil use.
• Suitable methods of forestry and forest curing can to some extent regulate the water regime of the whole country and lower the intensity of flood waves (lower the number of floods).
• Integrated planning of the country use can solve the tendency of some areas of the territory for erosion and landslides forming.
• The flood-plain forests increase the hydraulic “roughness” of flood area, lower the advance of the flood wave and their appropriate spacing in the river net can desynchronize the flood wave.
The above stated results show the important role of forests as the stabilization element in the
country. The role of forests as an important factor influencing the outflow relationships in the territory is in the Eastern Slovakia highlighted by the fact, that forests cover the areas with higher altitudes, resp.
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upper parts of drainage areas with the highest total amount of rainfall and therefore they indirectly influence by its impact also the hydrological situation of lower parts of drainage areas. Similarly there is necessary to emphasize, that accumulation, retention and soil-protection function of forests is significantly influenced by the way of practice of economic activity and therefore the forest management is an important tool of influencing the ecological situation of the whole drainage area.
The most important stress factors charging the territory of Eastern Slovakia are floods, soil erosion and landslides. All these phenomena are tied with the rainfall-outflow process of the territory, being determined by the natural conditions, though often significantly modified by anthropogenic influence. For understanding of the influence of anthropogenic activities for intensity of improvement of mentioned stress factors the interdisciplinary approach is necessary, integrating the knowledge by hydrology, hydrogeology, geology, pedology and climatology, with taking into account all economic and social questions. The obtained knowledge would following reflect into practical integrated management of drainage area resp. of the country in the sense of the Dublin principles (Technical Advisory Committee, 2000). The recent state in Slovakia has in this view considerable reserves, when scientific investigation of this problematics is deficiently covered by funds and the country management lacks the effective mutual communication between appropriate state authorities as well as further concerned subjects. The change of until unfavourable state in this course is indicated by the establishing and activity of the Council for integrated management of drainage areas as advisory body of the minister of environment.
The protection system against floods is guaranteed by special law (No. 666/2004 Coll. of Laws), which activities towards the flood-protection prevention focuses nearly exclusively to technical adjustments of water courses. It does not pay attention to character of country use in drainage basins in relation to influencing of retention function of the country during rainfall period as a whole. The financing of activities of the “Program of flood protection till 2010” is deficient and the risk of growth of damages caused by floods increases. The completion of this program in original financial–time frame is already unrealistic and there is necessary to revaluate and actualize it for the period till 2015. 7 Suggestions for further works
Next interdisciplinary investigation would be focussed on development of methods for suggesting suitable structure of the country in drainage basins, which would allow the country use when preservation of suitable outflow relationships and minimization of the risk of origin of soil erosion and landslides. The key stabilizing elements in the structure of the country would be the properly arranged tree coverage and tree alleys. The attention would by focussed mainly on areas of large-scale managed soil, where there would be investigated the abilities of lowering of the risk of soil erosion and improvement of outflow conditions and water quality by more appropriate ways of soil treatment and 37
keeping of properly localized and shaped areas with cover from bushes and trees. Simultaneously there is necessary to verify the possibilities of afforestation of non-used agricultural soil and make prognoses of impacts of these activities. In managed planes of forest crops the study of influence of age, sort and structure of composition of plant coverage on outflow condition and focus attention on unsuitable influence of the net of traffic and approaching roads and the movement of heavy machinery on outflow-erosion conditions of the localities. The important condition of sustainable country management is the accentuation of ecological and country-forming aspect of agricultural and forest-managing activities, including the forming of legislative frame and economic motivation for ecologically suitable behaviour of operating subjects.
Because in the conditions of Slovakia until it is not demonstrated that forest ecosystems have higher retardation ability (increasing of underground outflow) as other drainage areas without forests, there is necessary to obtain quantitative data about the influence of the country type for the ratio of underground and superficial outflow from the total amount of rainfall in the drainage area. The scientifically founded data will allow to be used at argumentation of the meaningfulness and needfulness of possible forestification in some drainage areas, against state administration and public. Simultaneously there will be possible to quantify the influence of the country type for steadiness of the superficial outflow in drainage area and for activation of negative manifestations of erosion and landslides. The study of rainfall-outflow processes would lead in selected drainage areas to forming of numerical models of the outflow with spatially dismembered parameters. Because the most expressive negative influences caused by unfavourable outflow conditions are indicated in drainage areas built by flysch and molasse sediments, it is necessary to concentrate the attention on these sediments, that means on the upper drainage areas of the Torysa, Topľa, Ondava and Laborec rivers as well as on foothills of the slopes of the Slanské vrchy hills mainly in the Košická kotlina. For analyses of the influence of the past and recent country use for rainfall-outflow conditions in drainage areas it is suitable to use the data continually obtained in observational objects of superficial water, underground water and climatic data from basic net of Slovak Hydrometeorological Institute (SHMÚ). The comparison of outflow regime of selected superficial water, taking into account the influence of geomorphological, climatic and hydrogeological characteristics of drainage areas, with the use of statistic methods and modelling techniques, it is possible to quantify the influence of the country type on outflow regime in the drainage areas of the Eastern Slovakia.
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Šútor, J. - Štekauerová, V. - Majerčák, J. 2002: Water balance of the atmosphere- pant canopy - soil aeration zone - groundwater system in a lowland forest ecosystem. In.: Holko, L. - Miklánek, P. - Parajka, J. - Kostka, Z., Eds.:ERB and NEFRIEND Proj. 5 Conf.Interdisciplinary Approaches in Small Catchment Hydrology: Monitoring and Research, Bratislava, IHP UNESCO/IH SAS.
Fig.2: Hydrogeological conditions of the Eastern Slovakia
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Fig.3: Landslides occurence in the Eastern Slovakia
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