DUMPING SITES IN THE LJUBLJANSKO POLJE WATER PROTECTION AREA, THE PRIMARY SOURCE OF LJUBLJANA'S DRINKING WATER ODLAGALIŠČA ODPADKOV NA VODOVARSTVENEM OBMOČJU LJUBLJANSKEGA POLJA, GLAVNEM VIRU OSKRBE LJUBLJANE S PITNO VODO Mateja Breg, Drago Kladnik, Aleš Smrekar Underground water is most threatened by illegal dumping sites in gravel pits. Podzemno vodo najbolj ogrožajo divja odlagališča v gramoznicah. Dumping sites in the Ljubljansko polje water protection area, the primary source of Ljubljana's drinking water UDC: 911.3:628.472.2(497.4Ljubljansko polje) 628.472.2:504.5(497.4Ljubljansko polje) COBISS: 1.01 ABSTRACT: Ljubljansko polje is a gravel plain lying along the Sava River north of Ljubljana. Although built-up areas are steadily expanding, the water protection area has helped preserve the character of relatively intensely cultivated agricultural land at least in its central part. However, illegal dumping sites pose a threat to the groundwater in the gravel aquifer. In the narrowest and narrow water protection areas of Ljubljansko polje, we have found, registered, and studied 1,445 illegal dumping sites with a total surface area amounting to 120,816 m2 and a total volume of 209,422 m3. A good seventh (13.5%) of the total waste is hazardous. In the area surveyed, we also registered 86 gravel pits, 47 information and warning signs, and 57 road barriers on access roads. In time, it will be necessary to rehabilitate all the illegal dumping sites; however, due to the large quantity of waste it is unrealistic to expect this to happen in one go, and we have therefore established a priority schedule for the rehabilitation. KEYWORDS: geography, environmental protection, illegal dumping site, water protection area, Ljubljana, groundwater, rehabilitation The article was submitted for publication on February 28, 2007. ADDRESSES: Mateja Breg, B. Sc. Anton Melik Geographical Institute Scientific Research Center of the Slovenian Academy of Sciences and Arts Gosposka ulica 13, SI - 1000 Ljubljana, Slovenia E-mail: mateja.breg@zrc-sazu.si Drago Kladnik, Ph.D. Anton Melik Geographical Institute Scientific Research Center of the Slovenian Academy of Sciences and Arts Gosposka ulica 13, SI - 1000 Ljubljana, Slovenia E-mail: drago.kladnik@zrc-sazu.si Ale{ Smrekar, Ph. D. Anton Melik Geographical Institute Scientific Research Center of the Slovenian Academy of Sciences and Arts Gosposka ulica 13, SI - 1000 Ljubljana, Slovenia E-mail: ales.smrekar@zrc-sazu.si Contents 1 Introduction 2 Outline of studied area 3 Legislative provisions 4 Work methods 5 Basic features of illegal dumping sites 5.1 Size parameters of illegal dumping sites 5.2 Composition of waste 5.3 Environmental parameters of dumping sites 6 Priority rehabilitation of dumping sites 7 Conclusions 8 References 75 75 77 78 80 80 82 84 88 88 91 1 Introduction On one hand, in the irregular relief of Slovenia, gravel plains with aquifers are the most important source of drinking water, supplying water to more than 90% of the population, and on the other, they comprise the economic, traffic, and settling core of the country (Kladnik et al. 2002). In the last few decades, these areas have been distinctly subject to urban activities that have almost supplanted agriculture, which relative to surface area still remains its biggest user. In spite of numerous restrictions in the water protection areas, the cities have expanded onto these areas as well, especially on the areas of zones with less strict protection regimes (Bra~i~ @eleznik et al. 2005; Rejec Brancelj 2001), which we can now consider urban areas. Modern cities in economically developed countries deviate substantially from the concepts of sustainable development because their activities and populations need very extensive areas of agriculturally productive land to meet their material and energy demands and for dumping various emissions and wastes (Hille 1994, Hille 1997; cited in Plut 2003). The degradation of the urban landscape originates in the incompleteness of the material circles (e. g. waste) and the use of non-renewable energy resources (e. g. gravel), which results in burdening of the landscape and changes in landscape structure and the dynamics of cities and their surroundings (Breg, Urbanc 2005; Urbanc, Breg 2005). The land on riverine gravel plains in many places is out of sight and therefore has always been exposed to illegal encroachments by the urban population, resulting in ever increasing degradation. In many cases, the riverine landscape has not found its proper place in the value system of the population, who consider it only as a natural resource and a place for illegal encroachments. Gravel pits and illegal dumping sites are a good example. The number of illegal dumping sites and their negative impact are greater than we are willing to admit to ourselves, which reduces the possibilities for the rapid and comprehensive regulation of the problem. In Slovenia, such dumping sites are a relatively new, undesirable, and disturbing part of the landscape. Due to the various negative impacts of illegal dumping sites, the authorities are trying to systematically prevent the occurrence of new illegal dumping sites and the accumulation of additional waste on already existing illegal dumping sites. The fundamental principles of waste management are: • solving the waste problem at the source (reduction of volume), • prevention, • separate collection of waste material, • recycling of organic waste, • rational and gradual establishment of a network of facilities for waste management, • rational use of space, • protection of natural and cultural values, and • rehabilitation of illegal dumping sites. One of the main measures for the promotion of long-term principles of waste managing is education, training, and providing information. Public opposition to appropriate waste management appears particularly on the local, implementation level, while individuals in the wider community have a more positive attitude. However, waste is a reality and we must face its negative impacts and solve them as effectively as possible. 2 Outline of studied area The quantity of groundwater contained in the aquiferous gravel-sand and conglomerate layers that fill the Ljubljansko polje depression is estimated at up to 100 million m3. This is one of the largest reservoirs of undergorund water in Slovenia, a natural resource of regional importance (Bra~i~ @eleznik et al. 2005a). The depth to the groundwater depends on its water table and the altitude of the terrain. On a high terrace near Vižmarje, the groundwater is found at a depth of more than thirty meters, and between Ježica and Zadobrova, at depths of only five to ten meters. The annual regime of water table changes in the 1987-2005 period indicates considerable annual oscillation. In the Brod area, the oscillation spans 4 to 6 meters, around the Kleče pumping station 5 to 6 meters, and around the Hrastje pumping station 1.5 to 2 meters. In general, the groundwater flows from the northwest to the southeast or east. In the western part of the aquifer, its velocity is between 5 and 10 meters per day, and in the eastern part, mostly between 10 and 20 meters per day (Auersperger et al. 2005). JARSKI PROD water protection area 0 / vodovarstveno območje 0 water protection area I / vodovarstveno območje I water protection area 11A / vodovarstveno območje IIA water protection area IIB / vodovarstveno območje IIB m 0 500 1000 2000 3000 4000 Authors / Avtorja vsebine: Mateja Breg in Aleš Smrekar Cartography / Avtorji zemljevida: Jerneja Fridl, Mateja Breg in Peter Pehani (IAPŠ) Source / Vir: Digitalni ortofoto posnetki 1 : 5000, 2005, © Geodetska uprava RS © Geografski inštitut Antona Melika ZRC SAZU, 2006 HRASTJE K b •< Figure 1: The narrowest and narrow water protection areas on Ljubljansko polje. The primary source for the charging of the Ljubljansko polje aquifer is the Sava River, and the secondary source is the infiltration of precipitation water, which in places is considerably reduced due to urban land use (Smrekar 2004). In its upper part, the Sava charges the aquifer while in its lower part, the groundwater flows back into the river (Auersperger et al. 2005). The second largest surface watercourse on Ljubljansko polje is the Ljubljanica River. However, its flow is slow and its silty bottom greatly limits the transfer of water between the river and the aquifer. The City Municipality of Ljubljana supplies its population and industry from a number ofwater sources. The most extensive pumping sites of drinking water for the supply of Ljubljana are situated on Ljubljansko polje, and its pumping stations are incorporated in the central water system. According to the Decree on the Water Protection Zone for the Aquifer of Ljubljansko polje (Official Gazette of the RS No. 120/2004), an area of 42.98 km2 lies within the narrowest (0, I) and narrow (IIA, IIB) water protection areas. Water started to flow in the first 606 of Ljubljana's houses on May 17,1890, and the Kleče pumping station remains the heart of Ljubljana's water system. The Hrastje pumping station was opened in 1953, the Šentvid pumping station in 1955, and the Jarški prod pumping station in 1982 (Bračič Železnik, Jamnik 2005). Underground water is closely connected with natural conditions and human activities. Its vulnerability depends on the hydrogeological, hydrological, and pedological conditions. Various construction works and excavations such as the excavation of gravel also have an impact on it. There are illegal gravel pits outside the consolidated urban area, especially on the lower terraces beside the Sava River. Four large legal gravel pits are located in Stanežiče, in the Dovjež area, southwest of the expressway intersection in Tomačevo, and in Obrije. They are all in the rehabilitation phase. Fortunately, the abandoned gravel pits were not filled with large quantities of waste since after 1924 when organized waste collection started, waste was transported mainly to southern parts of Ljubljana (Orožen Adamič, Pleskovič 1975). The cleansing capability of gravel and sand cover layers is effective with biological contamination but less so with chemical contamination. In general, the concentration of contaminatants decreases with the distance they travel through the ground. Soluble wastes, including fertilizers and certain industrial waste materials, cannot be removed by filtration, and metallic solutions are not susceptible to biological processes. We can conclude from the analysis of changing land use (Frantar et al. 2005) that urbanization is the most important cause of groundwater pollution. Urbanization has caused the amount of farm land to shrink, although agricultural land use has increasingly spread closer to the Sava River (Kladnik et al. 2004). Allotment gardeners, as a group with a large number of users of agricultural land, are having an increasing impact with their unique cultivation and other activities. 3 Legislative provisions For a long time, standard-setting regulation of waste management has been one of the most problematic fields of environmental protection in Slovenia. The main reasons are the previous social indifference to waste and waste management, the lack of vertical and horizontal administrative and professional coordination and organization, economic measures, and the natural characteristics of the Slovene environment (Viler Kovačič 2001). Before the implementation of the Environmental Protection Act in 1993, the entire system of waste management was regulated by the Waste Management Act (OG SRS 8/1978). It introduced the commitment that the creation of waste should be prevented and limited, that the waste should be recycled, and that waste should be managed in a wise, safe, and environmentally friendly fashion. The implementation of the Environmental Protection Act (OG RS 32/1993 with amendments) introduced a new approach to solving environmental protection issues in general, including the solution of the waste management problem, which had become ever more pressing. The amended Environmental Protection Act (OG RS 41/2004 with amendments) follows similar guidelines. Increased progress in the standard-setting regulation of waste management actually only began in 1998 with the adoption of the Regulations for the Management of Waste (OG RS 84/1998 with amendments) as the basis for waste management. These regulations are also called the »general regulations on waste« since they define obligatory ways of waste management and other conditions for the collection, transportation, processing, and removal of waste. It is also important because it introduced the European classification list of all types of waste, among which hazardous waste is specially defined. The regulations emphasize that collection, storage, transportation, processing, and removal of waste must be done in a manner that does not present a threat to human health and without the use of procedures and methods that would present an excess burden on the environment. Since 2000, the obligatory waste management and other conditions for its disposal and dumping site activities have been defined by the Regulations on the Landfill of Waste (OG RS 5/2000 with amendments), which was followed in 2006 by the Decree on the Landfill of Waste (OG RS 32/2006) that specifically emphasized that waste must only be dumped at authorized dumping sites. Thus it is forbidden to dump waste in places and areas that are not defined as authorized dumping sites. The Decree also states that dumping sites are not permitted in water protection areas. The Regulation on Soil Pollution Caused by Waste Deposits (OG RS 3/2003) defines obligatory actions in the planning and implementation of excavations or artificial landfill for the improvement of the ecological condition of the ground, which is important for the rehabilitation of gravel pits whether empty or filled with waste. Given that waste management falls under competence of the Ministry for the Environment and Spatial Planning, the greatest authority is given to the Inspectorate of the Republic of Slovenia for the Environment and Spatial Planning, a body of this ministry. Certain regulations in this field are also monitored by the market, health, and veterinary inspectors and inspectors for nuclear safety and energy production as well as by city inspectors. Water protection is regulated and directed by the Framework Directive on Water adopted in 2000 by the European Parliament and the EU Council of Ministers. It is based on comprehensive and sustainable water management, where the quantity and the quality of different types of water, including underground water, are equally important (Lanz, Scheuer 2001). The umbrella law in the field of water in Slovenia is the Waters Act (OG RS 67/2002), which is of course in line with the European directive. Drinking water protection zones or water protection areas, as they are more recently labelled, have a long tradition on Ljubljansko polje. First designated in 1955, they were decisive for the protection of the water source because they limited the spread of the city in the vicinity of water pumping stations (Breznik 1988). In 1977 and 1988, they were followed by two updated decrees. The latest Decree on the Water Protection Zone for the Aquifer of Ljubljansko polje (UL RS 120/2004) is based on extensive research work. This is the first decree originating in the Regulations on Criteria for the Designation of a Water Protection Zone (OG RS 64/2004). The terms and methods for the supply of Ljubljana with drinking water are regulated by the Decree on the Supply of Drinking Water (OG RS 17/2006). The Regulations on Drinking Water (OG RS 19/2004 with amendments) specify requirements for the uniformity and health suitability of drinking water and prescribe conditions for ensuring healthy drinking water. The Decree on Quality Standards for Groundwater (UL RS 100/2005) states the standards for determining its chemical condition, for the evaluation of long-term trends of its contamination and their changes, the state of the pollution of the water body, when measures for the prevention and limitation of the input of contaminants into the groundwater should begin, and for determining when to stop rehabilitation activities. 4 Work methods An inventory of illegal dumping sites, an analysis of their condition, and the preparation of proposals for their rehabilitation was undertaken from March to September 2006 in several work phases (Smrekar et al. 2006): • preparation work: analysis of literature and secondary sources, examination of legislative instruments, collection of accessible existing databases; • field work: mapping and survey of illegal dumping sites, data acquisition using PDA's; • computer processing of data: data entry and organization of spatial data in databases, statistical processing, spatial analyses; • chemical analysis of samples: preparation and analysis of representative samples; • graphical presentation: presentation of the results of actual situation on maps and graphs • rehabilitation program: proposal of most urgent rehabilitation interventions. Figure 2: Field inventory of illegal dumping sites. from 31 to 100% ILLEGAL DUMPING SITE from 15 to 50% from 13 to 30% from 1 to 15% from 2 to 5% CATEGORY 1 VULNERABILITY OF THE DUMPING SITE AREA 5,8,11,14,17 or 20% DISTANCE FROM THE NEAREST WATER PROTECTION AREA 5,8,11,14,17 or 20% AVERAGE DEPTH OF GROUNDWATER 5 or 10% LOCATION OF THE DUMPING SITE CATEGORY 2 LEVEL OF CONTAMINATION 2,4,6,8 or 10% TOTAL QUANTITY OF WASTE 10,11,13,15 or 17% QUANTITY OF HAZARDOUS WASTE 1 or 3% SUSPICION OF WASTE DEPOSITS UNDER THE SURFACE CATEGORY 3 ESTHETIC APPEARANCE 1,2,3,5 or 10% CURRENT ACTIVITY AT THE DUMPING SITE 0.3 or 5% VISIBILITY OF THE DUMPING SITE CATEGORY 4 FIELD ASSESSMENT FOR THE REHABILITATION 2.4 or 5% METHOD OF RECOMMENDED REHABILITATION Figure 3: Classification and evaluation of indicators for establishing priority rehabilitation of illegal dumping sites. Establishing priority for the rehabilitation of illegal dumping sites was done on the basis of indicators of key importance from the viewpoint of environmental issues (Breg et al. 2005). We considered the landscape and ecological characteristics of the area from the viewpoint of the contamination of the water source and several surveyed characteristics of the dumping sites. We combined the selected indicators into four categories according to their assumed significance from the viewpoint of establishing priority rehabilitation and determined appropriate weights for each. The Slovene version of this article uses the term »divje odlagališče odpadkov« for »illegal dumping sites,« but other synonymous terms such as »nedovoljen odlagališče odpadkov,« »neurejen odlagališče odpadkov,« črno odlagališče odpadkov,» and «nelegalno odlagališče odpadkov» also exist in the literature (Kladnik et al. 2005). 5 Basic features of illegal dumping sites Previous cadastres of dumping sites exist. In September 1996, the Oikos company surveyed the entire area of the City Municipality of Ljubljana (Kobal et al. 1996) and registered 457 dumping sites with a total volume of 32,782 m3. The Bion company also performed a study at the level of the entire municipality (Berden et al. 2004), in which the data was processed according to district communities. The study registered 278 illegal dumping sites with an estimated total volume of 100,000 m3. In both studies, the border value for a registered dumping site was one cubic meter of waste. It is interesting and curious that according to the cited data the number of dumping sites supposedly decreased by almost 40% between 1996 and 2004 while the quantity of waste supposedly increased by more than three times. The first thorough study of illegal dumping sites in Slovenia was performed a good decade ago (Šebenik 1994). Compared with earlier studies, an important innovation in Šebenik's approach was the quite accurate treatment of the volume parameters of the dumping sites. Šebenik analyzed 3,501 sample dumping sites with volumes from one cubic meter to 10,000 m3. The average dumping site measured 135 m2 and contained 47 m3 of waste material. Dumping sites with volumes up to 1,000 m3 contained 39% of the waste, indicating that smaller dumping sites are important from the viewpoint of the quantity of waste material and not just for their number. We found, registered, and studied 1,445 illegal dumping sites in the studied area on Ljubljansko polje with a total surface area of 120,816 m2, which means that waste covers 0.28% of the entire area and makes this one of the most waste-polluted areas in Slovenia. The total volume of waste is 209,422 m3. The average dumping site measures 83.6 m2 and contains 145.5 m3 of waste material. We also registered 86 dung pits, 47 information and warning signs, and 57 road barriers on access roads. At the request of the inspection authorities, the Snaga company, which is responsible for the disposal of communal waste in Ljubljana, has removed a total of 36,499 m3 of communal waste from all the illegal dumping sites in the City Municipality of Ljubljana in the last six years (2000-2005). 5.1 Size parameters of illegal dumping sites Among the 1,445 surveyed illegal dumping sites, small dumping sites dominate. Some 550 or a good third of the dumping sites do not exceed 10 m2, and most (696 or 48.1%) are in the 11 m2 to 100 m2 size class. Only 199 dumping sites measure more than 100 m2, and while only 24 dumping sites exceed 1,000 m2, all together they occupy 7.3% of the total surface area of dumping sites. The surface area of the largest dumping site is estimated to be 6,000 m2. As the surface area covered by the dumping sites increases, their thickness also typically increases. Although the thickness of 802 dumping sites does not exceed one meter deep (360 dumping sites do not exceed 0.5 m), the waste on more than one hundred dumping sites has accumulated to at least two meters thick, and the thickest dumping site in one of the abandoned gravel pits reaches a depth of 11 meters. Some 757 or more than half (52.4%) of the dumping sites do not exceed a volume of 10 m3, but in spite of their number they contain only a small percentage (1.3%) of the total quantity of identified waste. On the other hand, there are 36 dumping sites with a volume of 1,000 m3 and more where almost three Figure 4: Registered dumping sites. P Figure 5: Illegal dumping sites according to land ownership. 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 public/javno private/zasebno □ area/povrsina (m2) □ volume/prostornina (m3) quarters (72.5%) of the waste is accumulated. The largest dumping site contains about 42,000 m3 or almost a fifth of the identified waste. While much of the waste is found on privately-owned land, well over half is found on »public asset« category land or land owned by companies. The latter land covers 54.0% of the surface area and accounts for 61.3% of the volume of the registered waste. This reveals a lack of supervision of the public sector land, although the private owners are also obviously helpless against illegal dumping. Some 16.5% of the illegal dumping sites are on municipality land and account for more than a quarter (25.8%) of all such occupied surfaces and more than one third (37.8%) of the total quantity of recorded waste. 5.2 Composition of waste Illegally dumped waste is rarely homogenous. In most cases, it is a mix of waste of local origin (construction, industrial, communal, primary sector waste, tailings). The location of dumping sites is often detrimental from the viewpoint of both groundwater contamination and their unsightly appearance, which has an impact on the quality of the living environment and the tourist and recreational attractiveness of the landscape. In our research, we classified waste into the following groups: • primary sector waste; • industrial waste; • construction waste; • medical and veterinary waste; • communal waste; • other waste. A more detailed classification according to the types of waste revealed that two thirds (67.3%) of the waste comes from construction operations (demolition waste material, surplus dirt from the excavation of new building sites), followed by waste from the primary sector (17.8%). Communal waste comprises 10.2%, industrial waste 1.4%, and medical and veterinary waste 1.1%. In general, the impact of construction waste material on the environment is negligible, but only if the wastes do not contain elements that could chemically contaminate the environment. Common household waste usually contains hazardous chemical substances such as motor oil, detergents, sprays, and the like (Šebenik 1994). To prevent the dangerous contamination of groundwater, these wastes must have priority in the envisaged rehabilitation of dumping sites. Hazardous waste is composed mostly of abandoned vehicles, barrels with unknown contents (empty metal barrels are classified as bulky waste), and containers for paints, lacquers, motor oil, and agrochemical substances. Communal waste is mostly solid, composed of heterogeneous household and similar wastes Figure 6: Composition and volume of waste at illegal dumping sites. P generated by production and service activities in the living environment and in areas and buildings in public use. Due to its diverse and variable composition, it is technologically difficult to separate communal waste into its components. The quantity of communal waste found at illegal dumping sites is somewhat surprising since according to the data from the Snaga company, 99% of the households in Ljubljana have organized waste collection. The volume of hazardous waste is 28,749 m3, 13.7% of the total volume. The main hazardous construction wastes include asbestos panels, asphalt, impregnated glass wool, tar paper, and unemptied containers. Hazardous industrial waste includes parts of machinery and equipment, the remains of refrigerators, industrial adhesives, paint and solvent containers, paint in plastic bottles, motor oil, and various types of metal barrels with unknown contents. Hazardous communal waste includes the remains of household appliances and other appliances containing parts with environmentally-hazardous substances. 5.3 Environmental parameters of dumping sites Waste is scattered everywhere except in the fenced catchment areas (water protection area 0). The largest number of dumping sites (760 or 52.6% of all sites with a total surface area of 57,340 m2 or 47.5%, and a volume of 118,975 m3 or 56.8%) are located in the narrow areas with a strict water protection regime (IIA). Of course, dumping sites located closer to the pumping stations (water protection area I) are potentially more hazardous, but the quantity of waste here is substantially smaller. Fortunately, there are only 71 such dumping sites with a total area of 8,589 m2 (7.2%) and a volume of10,249m3 (4.9%). The remaining 831 dumping sites are located in the narrow areas with less strict regime (water protection area IIB). Most of the illegal dumping sites are located in overgrown areas and hidden from view. More than half of the dumping sites (covering 46.0% of the surface area and containing 39.6% of the volume) are located in bushes and thin or dense forests. Barren areas »only« host 216 illegal dumping sites, and some Figure 7: Depth of groundwater under illegal dumping sites. P Figure 8: Illegal dumping site in a gravel pit near a garden allotment area. Figure 9: Activity of illegal dumping sites. P waste is also found on recent unovergrown gravel pits. We even registered 79 illegal dumping sites with a total volume of 1,092 m3 or 0.5% of all waste on built-up land. There are 126 illegal dumping sites in gravel pits, where some 61.2% of the registered waste with a volume of 128,150 m3 is found, covering 55,873 m2 or 46.2% of total surface area of the dumping sites. On Ljubljansko polje, we registered 87 gravel pits, and only 15 of them were free of waste. Gravel pits began to appear to a greater extent after 1958 (Smrekar et al. 2005). Relative to the quantity of waste, inactive dumping sites lead with more than half (51.4%), while fully active dumping sites contribute just under a third (30.9%). There is a reasonable suspicion that additional quantities of past waste are hidden below 359 dumping sites (24.8%). Unfortunately, this suspicion applies in particular at the larger dumping sites where we registered 87,009 m3 or 41.5% of the total quantity of waste. Illegal dumping sites are mostly found at locations remote from settlements and major roads. One of the most important factors for their existence is the accessibility of the location where waste can be dumped. Access is usually easy on a gravel plain, so it is not surprising that more than two thirds (67.5%) of illegal dumping sites are located less than five meters from access roads. Various routes lead to illegal dumping sites and the various types of barriers set up on asphalt and dirt roads as well as on wagon tracks and footpaths should be the greatest hindrance to the unobstructed delivery of waste material. Unfortunately, it is possible to get around them in many cases. An interesting fact is that 222 dumping sites with 42.9% of the total surface area and 55.0% of the total volume are only accessible by passing road barriers, which indicates that the competent authorities are trying to limit illegal dumping. Unfortunately, however, new piles of waste have started to accumulate before the barriers. The majority of the 57 recorded barriers are concentrated along the banks of the Sava River, especially downstream from Brod on the right bank and from Črnuče on the left bank of the river. The most frequently employed barriers are gates and embankments. 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