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Adaptation hydrological model_en
1. IPA CBC Programme Bulgaria - Serbia
ADAPTATION OF HYDROLOGICAL MODEL FOR NISHAVA RIVER BASIN
The determination of the maximum run-off with different security is a key task in flood
risk assessment. The availability of reliable and spatially distributed parameters of
extreme maximum run-off is essential for adequate flood risk management. In flood
risk mapping and planning of mitigation measures, it is crutial to calculate the
repetition period correctly.
Implementation of the regionalization method of maximum run-off for Nishava
River Basin
Theoretical approach
Eight factors and characteristics of drainage basins and river systems that are
essential for the formation of maximum flow are set out in LUBW, 2007:
• area of the catchment AEo [km2]
• urbanized territory S [%]
• afforestation W [%]
• average slope Ig [%]
• river length L [km] along the main rivers of the watershed to the confluence
• river length LC [km] from the center of gravity of the catchment to its estuary;
• average annual rainfall in the catchment hNG [mm]
• landscape factor LF [-]
The described characteristics and factors are included in multiple linear regression
equation, which equation is used to determine the maximum run-off with a different
security (ie, MHQ and HQT), especially for the unobserved catchment:
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“Assessment of flood risk – a base for sustainable development in upper part of Nishava
catchment”
2. IPA CBC Programme Bulgaria - Serbia
ln Y C0 C1 ln AEo C2 ln S 1
C3 ln W 1 C4 ln I g
C5 ln L C6 ln LC
C7 ln hN G C8 ln LF
where: Y, YT are dependent variables
Y MHq regionalization of the values of average maximum water levels / MHQ /;
Hq T : T = 2, ..., 10 000 a - for the regionalization of the values of maximum
YT
MHq
discharges HQT;
MHq: module outflow average maximum annual flow MHQ (m³ / s/km2)
HqT: module flow of maximum annual flow to a particular security or repetition period
(T) - HQT (m³ / s/km2)
C0 - C8: regression coefficients.
Used information
For the implementation of the method of regionalization (HQT-model), information
about the maximum run-off from 6 HMS located in the upper catchment of the river
Nisav was used. Information about the HMS and the observation period and their
catchment area is presented in Table. 1 and the spatial location of the HMS is
presented in Figure 1.
Table 1. HMS and observation period
Subbasin HMS-Nr. Observations Number Area
Name From/to years km²
Visochica River (HMS Brachevci – R. Serbia) 47937 1961 - 2010 49 227.00
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Erma river (HMS Strezimirovtsi – R. Bulgaria) 452 1961-1967 7 117,00
Erma River (HMS Trunski Odorovtsi – R.
557.00
Serbia) 47914 1961-2010 49
Erma River ( HMS Trun – Bulgaria) 11650/95 1937-1983 37 360,5
Nishava River (HMS Dimitrovgrad – R. Serbia) 47910 1961-2010 49 232.00
Nishava river (HMS Kalotina – R. Bulgaria) 11800/223 1967-1983 16 267,00
Fig. 1 Gauging stations in the basin of Nishava river
The estimated empirical probability curves of maximum run-off are presented in
Fig.2.
Figure 2 Empirical probability curves of maximum run-off
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catchment”
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Empirical distribution curve of Nishava river, HMS
Dimitrovgrad
m3/s
120
100
80
60
40
20
0
0 20 40 60 80 100 120
p%
Empirical security curve of Nishava river, HMS Trnski Odorovtsi
m3/s
180
160
140
120
100
80
60
40
20
0
0 10 20 30 40 50 60 70 80 90 100
p%
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Empirical distribution curve of Visochica river, HMS Brachevtsi
m3/s
140
120
100
80
60
40
20
0
0 10 20 30 40 50 60 70 80 90 100
The statistical parameters that define the curve of security log-Pearson Type III are
presented in Table. 2.
Table 2. Statistical parameters of the curve log-Pearson Type III.
Statistical HMS HMS HMS
parameters Dimitrovgrad Trnski Brachevtsi
Odorovtsi
X 1,4334 1,5569 1,5237
S 0,3212 0,2913 0,2749
G 0,1 0,2 0,1
Based on this, the annual probability of exceedance is determined and persented in
table 3
Table 3. Maximum run-off with different security of Nishava river
Annual HMS HMS Trnski HMS Brachevtsi, Repetition interval
probability Dimitrovgrad, odorovtsi, 3
Q m /s
3
Q Q m /s
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3
m /s
1,0 2.0229 3.94 3.6276 Each year
0,5 26.7285 35.25 33.0469 Every two years
0,2 Every five years
0,1 70.428 86.28 75.6502 Every ten years
0,02 129.1611 153.43 126.7377 Every fifty years
0,01 160.0589 189.26 152.5291 Every hundred
years
0,002 247.6213 292.58 223.0177 Every five hundred
years
The theoretical distribution functions which best approximate the empirical
security curves of the studied HMS and the statistical parameters that define them
are shown in Fig. 3
Figure 3. Theoretical distribution curve Nišava River HMS Dimitrovgrad
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300
m3/s
250
200
150 Имперична крива
Теоретична крива
100
50
0
0 20 40 60 p% 80 100 120
Theoretical distribution function of Nishava river, HMS Trnski Odorovtsi
350
300
250
200
Имперична крива
150 Теоретична крива
100
50
0
0 20 40 60 80 100 120
Theoretical distribution function of Visochitsa river, HMS Brachevtsi
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250
200
150
Имперична крива
100 Теоретична крива
50
0
0 20 40 60 80 100 120
Определяне на ландшафтните фактори
Figure 4. Main geological types in Nishava river basin
Figure 5. Main geological types
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Figure 6 Landuse map, Corine 2006
Determination of the maximum run-off by the regiuonalization method
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catchment”
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the values of water quantity (HQT), determined by the method of regionalization and
the empirical values of the maximum run-off /Plotting Positions/ are shown in Fig.7.
These graphics show that authoritative (relevant) HMS model adapted to the
regionalization can well estimate the values of water quantity.Fig.7.
Figure 7. Maximum run-off with different security of Nishava river determined by the
method of regionalization, HMS Dimitrovgrad
300
250
200
Имперична крива
150
Теоретична крива
100 Регионализирана крива
50
0
0 20 40 60 80 100 120
Figure 8. Maximum runoff with different security of Erma river set by the method of
regionalization, HMS Trnski Odorovtsi
350
m3/s
300
250
200 Имперична крива
Теоретична крива
150
Регионализирана крива
100
50
0
0 20 40 60 80 100 120
p%
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catchment”
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Figure 9. Maximum runoff with different security of Visochitsa river set by the method
of regionalization, HMS Brachevtsi
250
m3/s
200
150
Имперична крива
Теоретична крива
100
Регионализирана крива
50
0
0 10 20 30 40 50 60 70 80 90 100 110
Determination of the maximum run-off with different security of Nishava river
by the method of regionalization
Through regionalization (adapted to regional run-off values with a certain probability)
it is possible to easily and quickly determine the water levels with a certain probability
anywhere on the river area for future research in this area.
The values of the parameters and the factors of maximum run-off in Nishava river in
Godech are presented in Table.4
Table 4. Parameter values and factors of the Nišava river in Godech town
LF
HMS- Peri Leng AE NJa (Gemittelt LF
River - HMS № od ht . 0 AE0 U W IG L LC hr ) (Zielwert)
GI m
S km2 % % % km km m
Nishava – 83, 1,1 6 1, 26, 6,7 96 135
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Godech town 05 5 4 3 32 5 0
The values of the maximum run-off with different interval times, calculated by the
regionalization method are presented in Table.5
Table 5. Maximum run-off with different interval times, calculated by the
regionalization method
ln(Y) Y=MHq MHQ YT HqT HQT
[m3/s/km2] [m3/s] [m3/s/km2] [m3/s]
MHq -0.652608 0.520686 43.243
Hq2 50 -0.211010 0.8097661 0.422 35.017
Hq5 20 0.332801 1.3948698 0.726 60.318
Hq10 10 0.620712 1.8602528 0.969 80.443
Hq20 5 0.862025 2.3679504 1.233 102.397
Hq50 2 1.135126 3.1115644 1.620 134.553
Hq100 1 1.318140 3.7364666 1.946 161.576
Hq200 0,5 1.487383 4.4254975 2.304 191.372
Hq500 0,2 1.693249 5.4371176 2.831 235.117
Studies show that the regionalization method developed in Germany is applicable
both for Bulgaria and the Republic of Serbia and provides very good results. By this
method it was possible to reliably determining the maximum water levels in the river
Nishava Godech.
This publication was elaboraed with the assistance of the European Union, through IPA
Cross-border co-operation programme CCI No 2007CB16IPO006.
The contents of this publication is a responsibility of the SRD-SU „St. Kliment Ohridski” and
should in no way be accepted as a statement of the European Union or the Managaing
Authority of the programme.
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