THE BALKANS-THE MOST EROSIVE PART OF EUROPE ?

Soil erosion has been occurring over the geological time. Inappropriate human activities accelerate this process. Soil erosion by water is a widespread problem throughout Europe. The South and Southeast regions of Europe are significantly prone to water erosion. In parts of the region, erosion has reached a stage of irreversibility and in some places erosion has practically ceased because there is no soil left. Scientists from the Balkan countries faced with the erosion problem for years, paid significant attention to solving problems with erosion. The aim of this study is to compare the results of water erosion intensity in the Balkan countries with other European countries. The basic methodological approach in this paper is an analysis of secondary data, using the method of “content analyses” of various data sources. Inductive and deductive qualitative analysis was used and finally the method of “comparative analysis” is applied too. Through the analysis of national researches, it was estimated that erosion intensity in Balkan countries is 548 m3km-2 (similar to 5.48 tha-1) and the total amount of annual produced erosive material is 419.9*106 m3. The mean European average annual erosion intensity is 3.13tha-1. The most erosive countries in Europe are the Balkan countries, Albania and Montenegro where the mean annual intensity of erosion is > 10 tha-1. Кључне речи: erosion intensity, soil loss, Balkan


INTRODUCTION
Soil erosion is considered one of the major threats to European soils, particularly in the Mediterranean areas (Communication on Soil Protection -"Towards a Thematic Strategy for Soil Protection", CEC, 2002).In order to effectively formulate mitigation strategies and implement conservation measures to counteract soil erosion, it is essential to objectively identify and quantify areas at risk (Gobin et al., 2002).Erosion is understood to be a physical phenomenon that results in the displacement of soil and rock particles by water, wind, ice and gravity.Numerous aspects and processes contribute to erosion, of which the most direct and generally acknowledged are: land cover/use changes, soil characteristics, rock formation, topography including hydrography and climate.The amount of edaphic material available for transport (potentially erodible) is depending on soil erodibility, stone content and characteristics.The transport capacity, i.e. the amount of energy available in the form of rain splash or runoff (volume and velocity) is determined by climatic factors and establishes whether and at what rate erosion can take place (Morgan and Quinton, 2001).The transport capacity is also influenced by topography, soil characteristics determining hydraulic processes in the soil (e.g.permeability and soil depth) and vegetation cover.
Various methods, models and approaches to erosion risk assessment are used by various countries in Europe.There is a significant difference within the scientific community in several erosion related issues, including the definition and acceptance of erosion, erosion intensity measurement, erosion intensity modeling, and they particularly depend on a scientist's provenience (various schools, various professions etc.).At the European level, there is no unified classification of erosion or a unified model for erosion intensity and risk.In the oldest reports about water erosion at the world or European levels there are data about the Balkan countries.
In the recent period several models and approaches in a GIS environment have been developed using the available database for erosion factors at the European level.In most of the recent scientific projects launched by JRC (Joint research center of Europe) and other scientific institutions in Europe, research was focused on EU countries and data about water erosion especially in the Western Balkan countries are missing.Within the EEA (European Environment Agency) reports could be found data about water erosion in almost all European countries.
Scientists in the Balkan countries faced with the erosion problem for years, developed their own models or prepared various erosion risk maps using national databases.There is a significant difference in the results obtained using various models or results obtained on wider especially European level and the national level.Those were reasons for launching this study.

THEORETICAL BACKGROUND
Various terms denote erosion vulnerability (susceptibility to physical damages), erosion risk (a probability or threat of damages and losses caused by external or internal vulnerability), soil erodibility (resistance to two energy sources: the impact of raindrops on the soil surface, and the shearing action of runoff between clods in grooves or rills.)and erosion intensity (magnitude of the damages).Various authors use various terms and data in this study will be presented as erosion intensity regardless of being vulnerability or risk.`Annual erosion intensity (eroded or deposed material) in various studies/reposts is expressed as -volume measure -(m3km-2) or weight measure -(tha-1).Conversion of data into various measurement units is very complex.For this study it was accepted to be 1:1 (equal) although it is not exactly correct.According to Roose E., (2002), each erosion type corresponds to an annual soil loss intensity that varies from 1 to 15 tha-1 for inter-rill erosion, 10 to 150 tha-1 for linear erosion, 20 to 500 t ha-1 for mass movements.
A wide variety of models are used for assessing soil erosion risk.USLE (Universal Soil Loss Equation) is the most used method in the world and the following are its variants.It should be stressed that a lot of models as SWAT or STREAM are in fact complex computerized models that encompass several topics related to soil and water, but in the part of erosion the USLE method is involved in the models.In the territory of former Yugoslavia, the Erosion Potential Model (EPM) was established by Gavrilović.Although USLE is the most widely used method, it is limited only to rill and inter-rill erosion.(Blinkov I., 2014)

AIMS, MATERIALS AND METHODLOGY
The aim of this study is to compare the results of water erosion intensity performed by national researches in the Balkan countries with those in European countries done using the models on wider scale (European maps).The objectives of this study are as follow: analysis of results of erosion intensity at the European level; analysis of results of erosion intensity at the national level of Balkan countries; and comparison of the results.
The Balkan Peninsula, the most southeastern peninsula of Europe is surrounded by the Black Sea, the Sea of Marmara, the Aegean Sea, the Mediterranean Sea, the Ionian Sea, and the Adriatic Sea.Although there is no sharp physiographic separation between the peninsula and Central Europe, the line of the Sava and Danube rivers is commonly considered as the region's northern limit.The Balkan Peninsula therefore includes most of Slovenia, Croatia, Serbia, Bosnia and Herzegovina, Montenegro, Albania, Macedonia, continental Greece (including the Peloponnesus), Bulgaria, European Turkey, and SE Romania.
The research methodology was adapted to the objective needs.The basic methodological approach in this paper is an analysis of secondary data, using the method of "content analysis" of various data sources.This method is used for the research of written documents.Before starting the analysis was the sample for analysis was determined, and the sample can be a word, sen-tence, data, map or other item that corresponds to the survey.Inductive and deductive qualitative analysis was used during the first 2 objectives and the step model by Mayring.The method of "comparative analysis" used for the 3rd objective is applied to each of them and comparing similar phenomena, classification and categorization, which are related to the subject of the research.This method is used to determine the difference that needs to be addressed.
The complexity of the process of erosion, as well as modeling, requires a comprehensive analysis of a number of secondary data sources, which are analyzed documents goals and dedicated special emphasis on the situation of erosion, in the sense: Which model is used?;What is the applicability of the model to define various processes of erosion?What factors/data used by the model and that is their precision?What are the results?What are the differences between the results?What's the reason for difference?
The following 3 criteria for analysis were used: the erosion intensity expression (t/ha or m 3 /km 2 ), working (map) scale and used methodology.

Erosion data at the European level
The recent projects (PESERA, MESALES etc) focused on modelling erosion in the EU countries.On the other hand, data about erosion factors were investigated for the whole continent.
According to the slopes classified in 7 categories, some Balkan countries (Slovenia, Bosnia, Albania, Macedonia, Greece) are almost on the whole highly susceptible to erosion.According to the soil types, the highest susceptibility areas can be found in Croatia and Greece.Because of its mountainous character, almost the whole region (excluding Slavonia, Vojvodina, Trakia and parts of Romania) belong to the highly susceptible area.According to the rainfall erodibility class, Slovenia, Croatia, Montenegro, Albania and Greece are the most susceptible If we compare the above factors with other regions of Europe, a high susceptibility to water erosion processes in the Balkan countries can be observed.
Knijf et al. ( 2000) calculated K-soil erodibility factor by USLE, that depends on soil texture, soil structure and soil organic matter.High values of K-factor were found for areas mostly in Albania and Serbia and in small areas in Macedonia, Bosnia and Bulgaria.
Besides the above mentioned projects, data about erosion in the whole of Europe can be found.Within EEA (European Environment Agency) annual or periodical reports about the state of the environment data can be found on water erosion in Europe at various scales.
The first report where there are data about water erosion at the European level is "Europe- an Environment -The Dobris Assessment" from 1993.This publication summarizes a major report on the European environment which has been prepared by the EC Task Force for the European Environmental Agency in cooperation with the UNECE, UNEP, OECD, the Council of Europe, WHO, IUCN and Eurostat, together with the individual countries of Europe.Under title Europe's Environment: The Dobris Assessment, the report covers the state of the environment in Europe, including nearly 50 States.This map was produced using the GLASOD approach on a 1:30 000 000 scale.
Later, in 2012 scientists from JRC of Europe calculated soil losses using RUSLE.While the overall patterns of erosion are generally sound, the validation of erosion data can be challenging.The data presented are currently being validated through comparisons with national datasets and expert judgment.In this sense, zooming in on a specific locality can give the impression of a situation that differs from reality.In addition, the model used in this exercise does not consider localized intense precipitation (http://www.eea.europa.eu/data-and-maps/figures/estimated-soil-erosion-by-water).
According to the Dobrisz Assessment report (1994) soil erosion in Europe affects 115 million ha causing loss of fertility and water pollution.Balkan countries represent "the red zone" of water erosion intensity in Europe.According to the JRC map that used RUSLE (this method estimate only rill and inter-rill erosion), Albania and Slovenia are the most erosive countries in the region.
The article "EC -Eurostat -Agri-environmental indicator -soil erosion -2013, provides a fact sheet of the European Union (EU) agri-environmental indicator soil erosion.It consists of an overview of recent data, complemented by all information on definitions, measurement methods and context needed to interpret them correctly.

The Balkan Countries -national researches
Generally, official data about erosion intensity of the WB countries was developed in the 80's and 90's of the XX century.The common characteristics of former SFRJ countries is that erosion maps were created using the EPM -Erosion Potential Method.All maps were created using expert judgment approach through direct on-field mapping of erosion processes on a scale of 1:50 000.These data were later digitized (scanned, georeferenced and vectorized) in a GIS environment.In the last 15 years there are a lot of studies where erosion intensity was calculated using modelling in a GIS environment, but those studies were launched only for some parts of the country and not for the whole country.The erosion maps of Albania and Bulgaria were prepared using the modelling approach in a GIS environment, although there are also data from past erosion mapping.

Albania
Several papers edited in various journals or proceedings were analyzed for this purpose.According to Zdruly et al. (2001) the estimated soil erosion values vary from 32 to 185 tha -1 .Grazhdani (2006) stated that the maximum erosion intensity in Albania reaches 510 t/ha y in Gjirokaster.The most comprehensive research about water erosion was done by Grazhdani et al through a NATO project in 2006.Water erosion intensity was measured using new specific modelling in a GIS environment.A one-dimensional hydrology, vegetation and erosion model (RDI/CSEP) is used to calculate accumulative soil erosion.This model provides an integration of the climatic, topography and associated vegetation components into soil erosion modelling.The forecast runoff, accumulated across the frequency distribution of storms, is used to give a climatic potential, which is then appropriately combined with the measures of topography and soil erodibility to estimate the expected rate of soil erosion at a resolution of 1 km.The approach for evaluation and mapping of soil erosion by water uses the existing soil maps, land use maps, a digital elevation model (1km), and interpolated climate data.There are three areas where the annual erosion rate is more than 100tha -1 y -1 (two in Gjirokastër and one in Sarandë).Erosion rates are the highest in October, November, February and December and the lowest in June and July (<tha -1 y -1 ).These rates show that erosion in most cases is not well controlled and the most appropriate soil management practices are not being applied (Grazhdani et al, 2006).

Bulgaria
According to the National Long-term Erosion Control Programme (NLECP) estimations were made using the RUSLE method.Marinov (2013) cited Biolchev that the average annual soil losses at end of 70th of the last century were 136 Mt.It would take into account that 68% of which was formed on the croplands, which represents 34.6% of the agricultural lands of Bulgaria in this period.The last study shows that the territory of Bulgaria represents 2.5% of the EU 27 countries area and contributes with 3.8% of the total soil erosion losses, estimated for those countries (Rousseva 2008).For the forestry fund the whole classified area at the end of 2004, according to the degree of erosion, was about 292000 ha which is 7.2% of the whole forest area (Marinov, 2005).It was found that the most widely affected by erosion were territories of the Regional Forestry Boards (RFB) -Blagoevgrad, Kardjali, Kiustendil, Sofia and Smolian.These areas vary between 30000 and 60000 ha.The average annual sediment load in main rivers in Bulgaria ranges from 0.1 t/ha (Maritza et Pazardjik) to 13.2 th -1 for Arda at Dzebel (Ruseva et al., 2006).

Bosnia and Herzegovina
Designing of the Erosion Map of SR Bosnia and Herzegovina began in 1979.Its intense design lasted for 7 years, and was completed in 1985.The Erosion Map was created in accordance with the methodology of Ph.D Slobodan Gavrilović, and it was amended and modified by the new method of determining the coefficients of erosion by Radenko Lazarević.The Map was designed on a topographic map scale of 1:25000 and had a total of 432 sheets (sections), which covered the entire territory of SR BiH.The Erosion Map was made in two copies.During the War (1992War ( -1995) ) both copies were destroyed.The total average amount of sediment, created on the territory of SR BiH per year is 16.518,031 m³, or 323 m³km-².The severest erosion affected the Krka river basin (Butišnica), the Kupa river and the Ukrina river.The lowest erosion was recorded in the immediate catchment area of the Sava river basin and the Adriatic sea.According to the SR BiH Erosion Map the total sediment production of permanently lost or transported sediment every year is 8805286 m³y -1 or 193 m³km-²/y -1 in SR BiH (Lazic Z., 2012).
Up to now, the erosion map only for Republika Srpska has been produced using 2 methodologies: USLE -useful only for agricultural land by Predić and using the EPM -on a watershed level by Toshic.Even in the newest documents (National Action Plan to Combat Land degradation and desertification in BIH -working version) there is no new erosion map, which means that it is still being prepared.Old existing data from the erosion map of BiH prepared in 1985 will be used for later comparisons.

Croatia
Erosion data for Croatia were not available enough.There are old data for the territory of the Sava river basin that belongs to Croatia.These data were produced using the EPM methodology.
On the other hand, there is a map of erosion using RUSLE produced by JRC.
According to the old data about the Sava river basin (Bekic et al), total mean annual production of erosive material (erosion production by Gavrilović) is W = 9 085 179 m 3 or Wsp = 352 m 3 km -2 y -1 .The mean annual transported sediment quantity is G= 3361784 m 3 or Gsp = 130 km -2 .
The Sava river basin in Croatia covers 25770 km 2 that is 45.5% of the whole territory.
Using the CORINE approach, Husnjak et al ( 2008) estimated the soil erosion risk in the territory of the Republic of Croatia at a scale of 1:300.000.The author developed a map of actual and potential erosion risk.

Greece
According to Kosmas et al. (2007), annual erosion rates measured in agricultural land IN hilly areas located in central northern Greece ranged from 0-52 tkm -2 , erosion rates on perennial crops in vineyards in the Attica region vary from 15 -252 tkm -2 , The result of destruction of forests is the intense erosion of Greek soils.It has been estimated that about 750 m 3 km -2 y -1 , of sediments are produced in Greece.This means that in the entire mountainous Greek area are produced almost 86.000.000m 3 sediments annually, which along with rain waters are driven into the lowland or the sea.By this erosion process it is estimated that nearly 30% of country's land is one step close to desertification (Hatzistathis, 2003).

Macedonia
The erosion map of the Republic of Macedonia was developed by scientists from the WDI -Water Development Institute of RM, using the EPM -Gavrilović methodology through direct onfield mapping of erosion intensity in the period of the 80's of the XX century by Gorgević et al.A synthetic report was launched in 1993.Later, the working maps were scanned, georeferenced and vectorized.According to the Erosion map of Macedonia (Water Development Institute, 1993), an area of 9423 km 2 or 36.65% of the total state area is in the highest categories (I-III).The total annual erosion for Macedonia is about 17*10 6 m 3 y -1 or 685 m 3 km -2 y -1 , with about 7.5*10 6 m 3 y -1 or 303m 3 km -2 y -1 of sediment are moved away from the site where it is eroded.(Blinkov et al., 2006).A significant part of these deposits within Macedonia, about 3*10 6 m 3 y -1 , is not carried through the downstream sections of the rivers to the exit of the state territory, but are deposited in natural lakes and reservoirs.For example, the rates of annual sediment yield to the biggest reservoirs in Macedonia are: Tikveš (1.3* 10 6 m 3 or 497 m 3/ km -2 ), Kalimanci (0.42*10 6 m 3 or 970 m 3/ km -2 ).-Blinkov (2005,2013).In the recent period several projects were realized, modelling the erosion intensity in a GIS environment using EPM or USLE on a defined region in Macedonia by various scientists.Kostadinov et al. (2006) cited significant data for erosion in Montenegro.Excessive erosion in Montenegro occurs mostly in the Ibar river basin, coastal catchments and in smaller river catchments in the river Piva basin.Total annual production (soil losses) in Montenegro amount to 17.3*10 6 m 3 or 1253 m 3 km -2 .Annual sediment transport is calculated as 4.86* 10 6 m 3 or 351.7 m 3 km -2 .According to Spalević et al. (2014), real annual soil loss for Železnica (coastal region) are 1899 m 3 km -2 , for Biogradska Rijeka (central part) -282 m 3 km -2 , and for Đurička reka (northern part) -645 m 3 km -2 .

Serbia
Data about erosion intensity in the above countries was provided by Kostadinov et al. (2005 and2006).The Erosion map of Serbia (including Kosovo) was made in 1973 using the EPM methodology.This map shows that, of the total area of Serbia, 86.00% is endangered by erosion processes of various intensities, Vojvodina 72.29%, Kosovo and Metohija 94.82%.A new map of erosion was produced in 1984, but there were no essential differences compared to the map in 1973.Total average annual gross erosion in Serbia amounts to 37,249,975.0 m 3 y -1 , specific annual gross erosion amounts to 421.57m 3 ×km -2 y -1 , annual sediment transport is 9,350,765.0m 3 y -1 and the specific annual sediment transport is 105.80 m 3 ×km -2 y -1 .The permanent soil loss in Serbia is 487.86 m 3 ×km -2 y -1 and in Kosovo and Metohija 248.98 m 3 ×km -2 y -1 .In normal erosion, which is a positive process, soil loss is 0.1 mm, i.e. up to 100 m 3 ×km -2 y -1 .The most endangered region in Serbia is Southeast part of the country closed to the borders with Macedonia and Bulgaria.

Slovenia
According to Hrvatin et al. (2006), the total area affected by erosion processes is between 42-44% of the territory.Torrent erosion is a problem for 1/5 of the territory of this country.In Slovenia there are 370 erosion hot-spots and 700 major torrents.In those areas annual erosion intensity is >10 th -1 .In the most erosive areas, the intensity is 45 th -1 (Western Karavanki Mountains) and 50 th -1 (Socha basin -Julian Alps).Hrvatin cited various data about erosion intensity as follows: 15 th -1 material deposed in stream beds (Socha basin), 6.2 th -1 (Sava basin); 5.7 th -1 (Drava basin) 2.6 th -1 (Kolpa basin).About 6.4 th -1 is the value of mean annual deposition in all rivers and streams.Annual soil loss at the country level was assessed using the EPM method by Gavrilović adapted to Slovenian conditions, and it varies between 5-6 th -1 (5.2 -5.2 *10 6 m 3 ).According to the model developed by JRC and data by EFTA, the mean erosion intensity in Slovenia is 8 th -1

A comparison of erosion intensity between the EU and Balkan countries
Data for erosion intensity expressed in t/ha for the EU countries were taken from the EU-27 EFTA report (2006).For Bosnia and Herzegovina, Serbia, Montenegro, Kosovo and Macedonia, the data used were from erosion mapping in the 80's.Data from Croatia (obtained by Husnjak et al.) were converted to be comparable with other data using the mean values of all categories.For Albania we used data by Grazhdani S. (2006) on sediment yield, but although these results cover only 64% of the territory, they were converted for the whole territory.For other non-EU countries data were taken from various national reports.There are 42 European states with a total area of 5969289 km 2 .Transcontinental states as follows: Russia, Turkey, Kazakhstan, Azerbaijan, Armenia, Georgia, Cypress are not considered in this research.Out of 42 European states, this research encompasses 36 that cover 98.25% of the whole European area.Data were missing for 6 states; Iceland, Malta, Lichtenstein, Andorra, Monaco and Vatican, all together 103510 km 2 .Iceland is characterized by a specific relief conditions and significant erosion processes, but there are no exact data about erosion intensity and these countries are not taken in consideration.
The mean annual erosion intensity of European states is calculated as 3.18 th -1 , and the total soil losses (produced sediments) are 1973*10 6 tonnes.The Balkan countries (Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Macedonia, Montenegro, Romania, Serbia and Slovenia) cover 765891 km 2 or 12.85% of the territory of European states.The mean annual erosion intensity in the Balkans is 5.48 th -1 and varies from 2.3 (Bulgaria) up to 18.7 th -1 (Albania).The total annual soil losses are 419.9*10 6tonnes.It means that 21.28% of the total annual soil losses in Europe originate from the Balkan countries.
According to the erosion intensity, countries in Europe could be classified in 6 groups.The most endangered countries (>10 th -1 ) are Albania and Montenegro.In the second group (5-10 th -1 ) are Italy, Portugal, Slovenia, Macedonia and Romania.It should be stressed that erosion intensity for the EU countries was determined using the RUSLE method that shows lower results in the countries dominated by hilly-mountainous and mountainous areas.

Figure 3 .
Figure 3. Water erosion in Europe

Figure 4 .Figure 5 .Figure 6 .
Figure 4. Erosion intensity in the European countries Eurostat) and the reports from several projects in the latest period were realized by JRC -Joint Research centre of Europe or other scientific institution.Various data were found.Somewhere there were data on erosion intensity at the European level, somewhere only at the EU level, and data about erosion factors were found for all European countries.Several maps were found as follow: EEA -The Dobris Assessment, 1993, SERA (Soil erosion risk assessment) in Europe -Knijf et al 2000, MESALES (Modèle d'Evaluation Spatiale de l'ALéa Erosion des Sols -Regional Modelling of Soil Erosion Risk) project, PESERA project (2003), EEA report -data and maps -2012, EC -Eurostat -Agri-environmental indicator -soil erosion -2013.Soil erosion in Europe, book, Willy&Sons, Editor(s): John Boardman, Jean Poesen, 2006.Balkan countries national reports, database and maps prepared by various scientists: Albania

Table 1 .
A review of erosion intensity in the Balkan countries

] Annual Erosion intensity Erosion Absolute Specific map scale Methodology Source m 3 t *10 6 m 3 km -2 tha -1
*original data were converted with the aim to be comparable