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Nishava flood risk_project_results_publication_en


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Nishava flood risk_project_results_publication_en

  1. 1. Програма за ТГС по ИПП България – Сърбия FLOOD RISK IN NISHAVA RIVER BASIN Nishava river basin is a transboundary river basin, located in the Republic ofBulgaria and Serbia with an area 4113 km 2 /26.9% of this area is located within theRepublic of Bulgaria/. Nišava river is a right tributary and also the longest and deepest one of SouthMorava (Bulgarian Morava) River. The river 248 km long, of which 40 km are onBulgarian territory and 208 km on Serbian territory. Nišava river rises east of thepeak Kom in Stara Planina. In its upper course it is called Ginska river so often(mainly in Serbia) is believed that Nishava originated after a merger with GinskaRiver on Serbian territory, near the village Sukova. Before the village of GintsiNishava flows in a deep valley, and then passes through Godech Valley. AfterRazboishte village and before the village of Kalotina it forms a beautiful gorge. Westfrom Kalotina Nishava leaves the territory of Bulgaria and passes through Caribrodand Pirot in a field where it flows into the river Temska. After the region of BelaPalanka Town it form the impressive Sichevska gorge. In Serbia Nishava passesthrough the cities of Caribrod, Pirot, Bela Palanka, Nishka Banya and Nis.The main factors that generally intensify the torrential processes are changes in landuse, soil sealing, urbanization and transport infrastructure.Changes in land useLand use in Nishava river basin is presented in Appendix 8 of CORINE - 2006database. Data analysis shows that more than half of the size of the basin /54.7% oftotal area/ is occupied by forests. Mixed forests /5.4% of forest area/, followed bydeciduous forests /3.5% of forest area/. The second largest area is occupied byarable land, including rainfed and irrigated fields. In total they comprise of 1214.0km2 /Fig.4/. Woodland and arable land are widely presented in the river basin. Aconsiderable area is occupied by natural grasslands and pastures /524.5 km 2/,which, like forests and farmland, are ubiquitous throughout the basin. Land use in Nishava river basin /CORINE 2006/ EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  2. 2. Програма за ТГС по ИПП България – СърбияUrban land /incl. settlements, industrial sites and road infrastructure, etc./, ponds andareas occupied by bare rock, sand, and areas with sparse vegetation cover an arealess than one percent of the territory.Changes in land use in Nishava river basin /CORINE 2000 and 2006/ 2006, 2000, Difference,Category of land use km2 km2 km2Urban area 101,29 90,6 + 10,69 542,7 466,6Natural and artificial grass area + 76,10Arable land 1214,02 1236,7 -22,68 2207,5Forests 2271,1 -63,60Coast areas, bare rocks and areas of sparse 37,24 39,6vegetation -2,36 10,96Aquatic area 9,1 1,86 4 113,7Total area of the basin 4 113,71 1Changes in land use are determined on the basis of data on land cover, according toCorine – 2000. Analysis of the data in the table shows that changes in the main land EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  3. 3. Програма за ТГС по ИПП България – Сърбияuse categories compared to the same categories in 2000 were negligible. Increasedarea is in urbanized territory with 11 km2. Some increase was been observed in thepasture and grassland /natural and man-made/, which in 2006 increased by 76 km2.In terms of flood formation, forests play a very important water regulating role. Datafrom CORINE show that total forest land in 2006 decreased by about 64 km2.Changes in the area of all forest types, however, is minor.Categories of land use in river basin Nishava on CORINE 2000 and 2006 Category 2000 - % of 2006 - % of Difference in % total area total area1. Settlements with 0,030663 0,029575 -0,001087821 dense urbanization2 Settlements with less 1,724978 1,942239 0,21726071 dense urbanization3 Industrial ot 0,193782 0,205482 0,011699849 commercial objects4 Transport infrastructure and 0,016126 0,016126 1,96021E-07 related land5 Airports 0,053472 0,055091 0,0016189786 Quarries and opencast 0,17452 0,203593 0,02907369 mining7 Green area in 0,032554 0,019134 -0,013419653 settlements8 Area for sports and 0,010272 0,010226 -4,64341E-05 tourism9 Unirrigated arable area 6,599017 6,526317 -0,07269951410 Vineyards 0,060472 0,037202 -0,02327016711 Fruit trees and berries 0,01774312 Pasture 2,820408 2,669824 -0,15058414913 Complexes of fragmented agricultural 10,9228 10,61248 -0,310325963 land14 Agricultural land with 12,48132 12,31762 -0,163698457 EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  4. 4. Програма за ТГС по ИПП България – Сърбия significant areas of natural vegetation15 Deciduous forests 33,62288 33,7931 0,17021970416 Coniferous forests 1,730484 1,864477 0,13399303617 Mixed forests 2,695711 2,913147 0,21743601418 Natural grass area 8,489909 10,50342 2,01350969619 Transitional tree-shrub 17,15798 15,09172 -2,066263929 vegetation20 Beaches, dunes, sand 0,017651 0,011399 -0,00625188121 Bare rocks 0,135157 0,160906 0,02574913822 Areas with sparse 0,809093 0,732839 -0,07625432 vegetation23 Inland moors 0,047042 0,089926 0,04288387624 Rivers 0,006745 0,006745 5,34698E-0825 Aquatic area 0,16696 0,169674 0,002714237At the same time, changes associated with deterioration of the structure,completeness and productivity of intact natural communities should be taken intoconsideration.As a result of these changes, flood retention and bioecological functions of forestshave weakened and the destructive activity of the torrential erosion hasstrenghtened.Soil sealingSoil sealing in recent years is estimated to be a substantial global threat not only tosoils but also to the intensity of formation of surface runoff due to heavy rains.Anthropogenic land /soil/ sealing is related to the use of soil for sustainabledevelopment of urban construction, industrial and infrastructure construction, tradeand transport sectors, road and rail network and others.The built area in Nishava River Basin in 2006 represents about 2.5% of the totalbasin (101.29 km2). Compared with 2000, the growth rate of soil sealing isinsignificant, the increase is 10.69 km2. Durable built-up areas in 2000 accounted for2.2% of the total area. This slight increase is primarily due to increased built-up areaof settlements with free construction by about 8.94 km2. The area of industrial and EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  5. 5. Програма за ТГС по ИПП България – Сърбияcommercial buildings and road infrastructure has insignificantly increased in 2006,and the area of sports and recreation and urban fabric, slightly decreased.UrbanizationGenerally, urbanization increases the frequency of flood occurrence and reduces thetime of the formation of high waves due to soil sealing and therefore increases theamount of surface run-off formed during intense rainfall, although in many casesmeasures are taken to reduce the negative consequences. There are sevenadministrative districts and eleven municipalities on the territory of Nishava Rivercatchment. Annex 10.Flooded river terraces of Nišava river and its tributaries are the preferred place forbusiness development. The settlement network is presented by 307 settlements/incl. 7 cities/. The density of the urban network is 7.5 settlements/100 km2.Almost half of the settlements /145 cities/ are placed or partially placed in 200 mbuffer zone around the rivers. The total area of these settlements constitute 72% oftotal area of the settlements in the Basin Nišava. Some of the most urbanized areasin the basin are located in the buffer zone of 200 m from the river /7 cities/.Therefore, urbanization is a factor for intensifying the risk of increased occurrence offloods in the basin.Up to the town of Dimitrovgrad /Serbia/, there are 32 settlements, including 4 citieswithin the catchment. Of these, 17 settlements lay within the buffer zone of 200meters, including 4 cities. Transport Infrastructure Main elements of transport infrastructure in Nišava River Basin are roads manyof which have been built since ancient times and most of them pass along the rivervalleys. Appendix 12 The total length of road network is 946, 18 km. Today through the territory of thebasin passes Corridor № 10 /E 80/ from Nis - Dimitrovgrad, Pirot - Dragoman toSofia. The first class road from Nis to Zajecar. Through the territory of the basin passsecondary roads from Pirot - Leskovets, Dimitrovgrad - Pirot and several regionalroutes. EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  6. 6. Програма за ТГС по ИПП България – Сърбия The length of the railway lines passing through the basin is 175.847 km. Therailway line from Nis-Bela Palanka, Pirot-Dimitrovgrad - Dragoman to Sofia andothers pass through the territory of the basin.Transport infrastructure ontensifies the processes of flood formation and theircatastrophic effect. The existing road network in Nishava river basin has unapropriatedrainage systems, which are the reason why during intense rainfall surface watersfrom other areas are redirected to the basin and can cause a rapid rise in river waterlevel and flood events. However, it should be taken into consideration that thenegative effects of the road infrastructure can not be completely eliminatedand inmany cases it is inappropriate to build expensive drainage systems. It should also betaken into account that the transport infrastructure in case of flooding is crucial forevacuation of the population and access to emergency service.Negative effects of past floodsInformation bout the negative effects of past floods in Nishava River Basin was notfound in the sources of information about past floods. However, it can be concludedthat the protected areas of primary importance are the categories "human health"and "business".In can be concluded from the history of floodings that the majority of settlements inboth the upper, middle and downstream of the Nisava river were affected by majorfloods in the river basin, occurred during the 19th and 20th century. Although thesources of information on past floods do not specify an exact number of drownedpeople, it is clear that in all past catastrophic flood had victims.For the category "business" in these catastrophic floods farm buildings andagricultural land were destroyed, damaged or allocated and livestock drowned.Damaged road infrastructure /roads and bridges/ were reported In all recordedfloods.Potential negative consequencesThe potential risk in Nishava River Basin is defined in terms of protected categories"human health", "business", "environment" and "cultural heritage".Assuming the criterion of 100 affected people for one village as a threshold value,then in the 48 settlements in the river basin, the number of potentially affected by EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  7. 7. Програма за ТГС по ИПП България – Сърбияflooding is greater than 100. The six cities located in the basin are characterized by asignificant potential risk for the category "human health" as the number of potentiallyaffected residents from flooding is greater than 500. The number of people affectedfor category of "human health" is presented in the table below. The potential floodrisk is significant in the villages are located in the middle and lower parts of the river. Potentially affected residents in the flood basin of the river Nisava Settlements Size of Area of the Population, Occupancy Number within a 200 m urban city, located number of density of of people buffer zone from area, in 200 m people population, affected rivers km2 buffer zone prs/ km2 of rivers, km2 Godech 6,14 3,72 4425 720 2677 Bela palanka 2,17 0,69 8112 3731 2575 Trun Dimitrovgrad 1,91 0,93 6247 3270 3052 Pirot 7,96 1,87 38432 4828 9039 Nis 22,32 1,87 177972 7974 32417 Potential flood risk exists for the protected category "business" in the river basinNišava. The greatest damage will be for industrial sites. Their total area which fallswithin the buffer zone of 200 m from the river is 1,09 km2. These are mostly industrialareas of cities located in the basin – cities of Godech Tran, Dimitrovgrad, Pirot andNis. Potential risk in Nishava river basin Criterion Total In buffer % ed area Protect 200m Industry activity Economic Industrial and 8,45 1,09 12,9 commercial objects, km2 EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  8. 8. Програма за ТГС по ИПП България – Сърбия Transport infrastricture Lenght of the 946,176 271,426 28,7 transport infrastructure, km Total lenght of the 175,847 61,48 35,0 railway network, km Agriculture Complexes of fragmented agricultural land, km2 436,57 55,86 13,0 Vineyards, km2 1,53 0,31 20,3 Non-irrigated arable land, km2 268,47 39,90 14,9 Agricultural land with significant areas of natural vegetation, km2 506,72 102,82 20,3 Pasture, km2 109,83 10,47 9,5 Fruit and berries plantations 0,73 0,11 15,1 Protected areas Natura 2000 ent" "Environm Birds Directive 467,28 58,10 12,4 Habitats Directive 453,05 70,73 15,6 Protected areas /R. Serbia/ 823,94 74,69 9,1The flood risk is also significant for the transport infrastructure, respectively, 28.7% ofroad network and 35% of the railway network is located 200 meters potentiallyflooded area. The potential risk of the different classes road network is presented inthe table.Potential risk of flooding to transport infrastructure in the Basin Nishava Class roads Length of road network, Length of % Of the km road length of the network, road network EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  9. 9. Програма за ТГС по ИПП България – Сърбия located in located in the buffer bufernnata 200 zone 200, m area. km Highway 6,843 1,369 20 Highway project 10,057 2,645 26,3 Second class roads 304,300 86,092 28,3 First class roads 170,232 40,379 23,7 Third class roads 454,742 140,939 31,0 With regards to protected category "Environment" the flood risk is alsosignificant because there are three sites which may discharged polluted water in theupper part of the river and thus present risk to aquatic ecosystems.Risk of flooding for Natura 2000 sites Name Area km2 Area km2 in 200 m % of area in 200 m buffer zone buffer zone Birds directive 2009/147/ЕС Noevci 3,69 0,82 22,2 Ruy 173,45 18,38 10,59 Rayanovci 90,24 10,70 11,85 Ponor 128,19 16,71 13,03 West Balkan 71,69 11,47 15,99 Habitats directive 92/43/ЕЕС Rebro 2,13 0,91 42,72 Dragoman 109,15 13,61 12,46 West Balkan 17,72 Mountain and 274,21 48,60 Forebalkan Kurvav kamuk 37,80 2,12 5,6 Ruy 17,06 5,25 30,77 Lubash 12,67 0,20 1,57 Protected reas /R.Serbia/ Erma river gorge 0,15 0,11 73,3 Temna dupka 0,19 0,03 15,78 Kotlite 0,17 0,15 88,23 Zaskogo 0,27 0,11 40,74 Uruchnik 0,16 0,08 50,00 Klisura Osanicke 9,1 80,84 7,36 reke EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”
  10. 10. Програма за ТГС по ИПП България – Сърбия Bifurkacija reke 90,02 74,21 66,81 NerodimkeSo far, the flood protection measures taken in Nishva River Basin are engineeringmeasures /corrections of watercourses, dams and dykes/. River flow is regulatedwithin the cities of Godech and Dimitrovgrad.The analysis of the functioning system of measures for flood protection shows that itis not efficient, especially in extreme floods with very little repetition. Acceptable levelof protection could be achieved only after detailed mapping of the flood risks undervarious scenarios and on this basis to determine an adequate scheme of measures(hydro-technical) and non-engineering measures and safeguards. The material was prepared by Ivan Babukov ET, together with the Managing Team Project andpresents the results of development of the project "Assessment of flood risk - the basis for sustainabledevelopment in the upper basin of the river Nišava" funded by the CBC program under IPA , Bulgaria, Serbia. This publication was supported by the European Union by CBC Programme CCI No2007CB16IPO006. The contents of this publication is the sole responsibility of NIS at Sofia University"St. University and in no way should be seen as an expression of opinion of the European Union or the MA Program. EUROPEAN UNION Bulgaria – Serbia IPA Cross-border Programme “Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”