Nishava flood risk_project_results_publication_en

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 of

Bulgaria and Serbia with an area 4113 km 2 /26.9% of this area is located within the

Republic of Bulgaria/.

Nišava river is a right tributary and also the longest and deepest one of South

Morava (Bulgarian Morava) River. The river 248 km long, of which 40 km are on

Bulgarian territory and 208 km on Serbian territory. Nišava river rises east of the

peak 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 Ginska

River on Serbian territory, near the village Sukova. Before the village of Gintsi

Nishava flows in a deep valley, and then passes through Godech Valley. After

Razboishte village and before the village of Kalotina it forms a beautiful gorge. West

from Kalotina Nishava leaves the territory of Bulgaria and passes through Caribrod

and Pirot in a field where it flows into the river Temska. After the region of Bela

Palanka Town it form the impressive Sichevska gorge. In Serbia Nishava passes

through the cities of Caribrod, Pirot, Bela Palanka, Nishka Banya and Nis.

The main factors that generally intensify the torrential processes are changes in land

use, soil sealing, urbanization and transport infrastructure.

Changes in land use

Land use in Nishava river basin is presented in Appendix 8 of CORINE - 2006

database. Data analysis shows that more than half of the size of the basin /54.7% of

total area/ is occupied by forests. Mixed forests /5.4% of forest area/, followed by

deciduous forests /3.5% of forest area/. The second largest area is occupied by

arable land, including rainfed and irrigated fields. In total they comprise of 1214.0

km2 /Fig.4/. Woodland and arable land are widely presented in the river basin. A

considerable 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”


Urban land /incl. settlements, industrial sites and road infrastructure, etc./, ponds and

areas occupied by bare rock, sand, and areas with sparse vegetation cover an area

less than one percent of the territory.

Changes in land use in Nishava river basin /CORINE 2000 and 2006/

Category of land use

2006,

km2

2000,

km2

Difference,

km2

Urban area 101,29 90,6 + 10,69

Natural and artificial grass area

542,7466,6

+ 76,10

Arable land

1214,021236,7

-22,68

Forests 2207,5

2271,1-63,60

Coast areas, bare rocks and areas of sparse

vegetation

37,2439,6

-2,36

Aquatic area10,96

9,11,86

Total area of the basin 4 113,71

4 113,7

1

EUROPEAN UNIONBulgaria – Serbia IPA Cross-border Programme

“Assessment of flood risk – a base for sustainable development in upper part of Nishava catchment”

Програма за ТГС по ИПП България – Сърбия Changes in land use are determined on the basis of data on land cover, according to

Corine – 2000. Analysis of the data in the table shows that changes in the main land

use categories compared to the same categories in 2000 were negligible. Increased

area is in urbanized territory with 11 km2. Some increase was been observed in the

pasture 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. Data

from 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

total area

2006 - % of

total area

Difference in

%

1. Settlements with

dense urbanization0,030663 0,029575 -0,001087821

2 Settlements with less

dense urbanization1,724978 1,942239 0,21726071

3 Industrial ot

commercial objects0,193782 0,205482 0,011699849

4 Transport

infrastructure and

related land

0,016126 0,016126 1,96021E-07

5 Airports 0,053472 0,055091 0,001618978

6 Quarries and opencast

mining0,17452 0,203593 0,02907369

7 Green area in

settlements0,032554 0,019134 -0,013419653

8 Area for sports and

tourism0,010272 0,010226 -4,64341E-05

9 Unirrigated arable area 6,599017 6,526317 -0,072699514

10 Vineyards 0,060472 0,037202 -0,023270167



Програма за ТГС по ИПП България – Сърбия 11 Fruit trees and berries 0,017743

12 Pasture 2,820408 2,669824 -0,150584149

13 Complexes of

fragmented agricultural

land

10,9228 10,61248 -0,310325963

14 Agricultural land with

significant areas of

natural vegetation

12,48132 12,31762 -0,163698457

15 Deciduous forests 33,62288 33,7931 0,170219704

16 Coniferous forests 1,730484 1,864477 0,133993036

17 Mixed forests 2,695711 2,913147 0,217436014

18 Natural grass area 8,489909 10,50342 2,013509696

19 Transitional tree-shrub

vegetation17,15798 15,09172 -2,066263929

20 Beaches, dunes, sand 0,017651 0,011399 -0,006251881

21 Bare rocks 0,135157 0,160906 0,025749138

22 Areas with sparse

vegetation0,809093 0,732839 -0,07625432

23 Inland moors 0,047042 0,089926 0,042883876

24 Rivers 0,006745 0,006745 5,34698E-08

25 Aquatic area 0,16696 0,169674 0,002714237

At the same time, changes associated with deterioration of the structure,

completeness and productivity of intact natural communities should be taken into

consideration.

As a result of these changes, flood retention and bioecological functions of forests

have weakened and the destructive activity of the torrential erosion has

strenghtened.

Soil sealing

Soil sealing in recent years is estimated to be a substantial global threat not only to



Програма за ТГС по ИПП България – Сърбия soils 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 sustainable

development of urban construction, industrial and infrastructure construction, trade

and transport sectors, road and rail network and others.

The built area in Nishava River Basin in 2006 represents about 2.5% of the total

basin (101.29 km2). Compared with 2000, the growth rate of soil sealing is

insignificant, the increase is 10.69 km2. Durable built-up areas in 2000 accounted for

2.2% of the total area. This slight increase is primarily due to increased built-up area

of settlements with free construction by about 8.94 km2. The area of industrial and

commercial buildings and road infrastructure has insignificantly increased in 2006,

and the area of sports and recreation and urban fabric, slightly decreased.

Urbanization

Generally, urbanization increases the frequency of flood occurrence and reduces the

time of the formation of high waves due to soil sealing and therefore increases the

amount of surface run-off formed during intense rainfall, although in many cases

measures are taken to reduce the negative consequences. There are seven

administrative districts and eleven municipalities on the territory of Nishava River

catchment. Annex 10.

Flooded river terraces of Nišava river and its tributaries are the preferred place for

business 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 m

buffer zone around the rivers. The total area of these settlements constitute 72% of

total area of the settlements in the Basin Nišava. Some of the most urbanized areas

in 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 of

floods in the basin.

Up to the town of Dimitrovgrad /Serbia/, there are 32 settlements, including 4 cities

within the catchment. Of these, 17 settlements lay within the buffer zone of 200

meters, including 4 cities.




Transport Infrastructure

Main elements of transport infrastructure in Nišava River Basin are roads many

of which have been built since ancient times and most of them pass along the river

valleys. Appendix 12

The total length of road network is 946, 18 km. Today through the territory of the

basin passes Corridor № 10 /E 80/ from Nis - Dimitrovgrad, Pirot - Dragoman to

Sofia. The first class road from Nis to Zajecar. Through the territory of the basin pass

secondary roads from Pirot - Leskovets, Dimitrovgrad - Pirot and several regional

routes.

The length of the railway lines passing through the basin is 175.847 km. The

railway line from Nis-Bela Palanka, Pirot-Dimitrovgrad - Dragoman to Sofia and

others pass through the territory of the basin.

Transport infrastructure ontensifies the processes of flood formation and their

catastrophic effect. The existing road network in Nishava river basin has unapropriate

drainage systems, which are the reason why during intense rainfall surface waters

from other areas are redirected to the basin and can cause a rapid rise in river water

level and flood events. However, it should be taken into consideration that the

negative effects of the road infrastructure can not be completely eliminatedand in

many cases it is inappropriate to build expensive drainage systems. It should also be

taken into account that the transport infrastructure in case of flooding is crucial for

evacuation of the population and access to emergency service.

Negative effects of past floods

Information bout the negative effects of past floods in Nishava River Basin was not

found in the sources of information about past floods. However, it can be concluded

that 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 in

both the upper, middle and downstream of the Nisava river were affected by major

floods in the river basin, occurred during the 19th and 20th century. Although the

sources of information on past floods do not specify an exact number of drowned

people, it is clear that in all past catastrophic flood had victims.



Програма за ТГС по ИПП България – Сърбия For the category "business" in these catastrophic floods farm buildings and

agricultural land were destroyed, damaged or allocated and livestock drowned.

Damaged road infrastructure /roads and bridges/ were reported In all recorded

floods.

Potential negative consequences

The 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

flooding is greater than 100. The six cities located in the basin are characterized by a

significant potential risk for the category "human health" as the number of potentially

affected residents from flooding is greater than 500. The number of people affected

for category of "human health" is presented in the table below. The potential flood

risk 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

within a 200 m

buffer zone from

rivers

Size of

urban

area,

km2

Area of the

city, located

in 200 m

buffer zone

of rivers,

km2

Population,

number of

people

Occupancy

density of

population,

prs/ km2

Number

of people

affected

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 basin

Nišava. The greatest damage will be for industrial sites. Their total area which falls



Програма за ТГС по ИПП България – Сърбия within the buffer zone of 200 m from the river is 1,09 km2. These are mostly industrial

areas of cities located in the basin – cities of Godech Tran, Dimitrovgrad, Pirot and

Nis.

Potential risk in Nishava river basin

Pro

tect

ed

area

Criterion Total In buffer

200m

%

Ec

on

om

ic activ

ity

Industry

Industrial and

commercial objects,

km2

8,45 1,09 12,9

Transport infrastricture

Lenght of the

transport

infrastructure, km

946,17

6

271,426 28,7

Total lenght of the

railway network, km

175,84

7

61,48 35,0

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

"En

viron

me

nt"

Protected areas Natura 2000

Birds Directive 467,28 58,10 12,4

Habitats Directive 453,05 70,73 15,6

Protected areas /R.

Serbia/ 823,94 74,69 9,1

The flood risk is also significant for the transport infrastructure, respectively, 28.7% of

road network and 35% of the railway network is located 200 meters potentially

flooded area. The potential risk of the different classes road network is presented in

the table.

Potential risk of flooding to transport infrastructure in the Basin Nishava

Class roads Length of road network,

km

Length of

road

network,

located in

the buffer

zone 200,

km

% Of the

length of the

road network

located in

bufernnata 200

m area.

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 also

significant because there are three sites which may discharged polluted water in the

upper 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

Mountain and

Forebalkan

274,21 48,60

17,72

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

reke80,84 7,36

9,1

Bifurkacija reke

Nerodimke74,21 66,81

90,02

So far, the flood protection measures taken in Nishva River Basin are engineering

measures /corrections of watercourses, dams and dykes/. River flow is regulated

within the cities of Godech and Dimitrovgrad.



Програма за ТГС по ИПП България – Сърбия The analysis of the functioning system of measures for flood protection shows that it

is not efficient, especially in extreme floods with very little repetition. Acceptable level

of protection could be achieved only after detailed mapping of the flood risks under

various 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 and

presents the results of development of the project "Assessment of flood risk - the basis for sustainable

development 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 No

2007CB16IPO006. 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.



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