Hydromemeteorological characterisation of the flood from the period 14-30 april 2005 in the Timis-Bega Basin

Viorel Alexandru Stănescu, Radu Drobot University of Civil Engineering , Bucharest,

1. Abstract The precipitations which generates the 2005 flood in Timis-Bega River Basin have been analyzed both as spatial distribution (total isohyets map) and as temporal one (time distribution at the meteorological stations). Further on, an analysis of the balance of the flood hydrographs volumes is made. Unusual values of the runoff coefficients have been resulted, as the duration and the quantity of the rainfalls were very high (over 200mm). A mathematical model has been applied aiming to the reconstitution of the flood hydrograph of Timis River at the border of Romania with - Montenegro. Then the volumes of water penetrating the ruptures in the dikes downstream Sag station have been determined. Thus the very large area that has been flooded has been explained by the huge volume of the flood downstream Sag station (720.106 m3). An analysis of the effects of the storages (permanent and non-permanent ones) led to the conclusion that they were less effective in mitigating the flood crest in the Timis-Bega River Basin. In continuation, an analysis of the hydrological and technical issues of the present embankments in Timis-Bega River Basin is made. Proposals for improving the defence system by gradually implementation of new structural measures deeming and keeping the principle “more space for ” as well as the improvement and diversifying the non- structural measures are presented in detail.

Key words: Precipitation, maximum discharges, flood volume balance, flood hydrographs, mathematical model, structural measures, ring-shaped embankments, fusible dikes, non-structural measures, informational system, education of population.

Meteorological origins of the flood The available observed data refer to the amount of precipitation fallen previously the flood period and to those produced since 14th to 22nd of April 2005 that trigger the occurrence of the flood. In the graphs in Figure 1 show three distinct intervals of times are observed which are separated by no-rainfall periods which vary between 30-45 hours during the 16-17 April period and 9-15 hours in the second period (21 of April). Shorter periods with reduced precipitation amounts continued after 22 of April but they only fed the high discharges without contributing to the increase of the water stages over the alarm levels. The kernel of the rainfalls that had the most abundant quantities in the zones of flood formation ranged between15 to 24 hours. It is worthwhile to emphasise that the period before the flood occurrence (8th to 13th of April) has been characterized by a sudden increase of air temperature which, in the hilly and mountain zones (flood formation areas) ranged between a daily average of 4-6oC. The wormer air and some rainfalls which totalized 10-15 mm during 27 of March-1st of April resulted in increasing with 24-40 mm the soil moisture due to the snowmelt. Nevertheless, the contribution of the snowmelt to the flood formation is poor. Under an elevation of 1000m (corresponding to 96% of the entire area of the river basin) the snowpack did not exist. One can assert that the flood was practically of pluvial nature. The poor snowmelt contribution provided by the small mountainous areas was retained into the reservoirs Poiana Marului (elevation= 650m) and Trei Ape (elevation=870m) and these volumes have not found in the flood hydrographs along middle and downstream sectors of the Timis river. Thus the snowmelt has contributed only to elevated soil moisture which partially explains the high values of the runoff coefficients. According to the data recorded at the pluvial stations the rainfalls that provoked the outstanding April 2005 flood ranged between 60 to 221 mm, the smaller amounts, being recorded only around a restrained area, in the western mountains zone concentrated in two large kernels in the central and north-eastern parts of the catchment where maximum amounts of 221mm and 217 mm were recorded. In the highest mountain zones the quantities were much more modest, they not exceeding 50-70 mm (54 mm at Bucova station - altitude= 591m) and 67 - 69 mm at meteorological stations Cuntu - altitude = 1450m) and Ţarcu -altitude=2180m, respectively).

1 6 Meteorological Station Tarcu (total 72mm) 4 29 mm 26 mm 17 mm 2 h(mm) 0 1 4 7 10131619222528313437404346495255586164677073 Interval of 3 hours

14 Meteorological Station Caransebes (total 168 mm) 12 10 45mm 88 mm 35 mm 8 6 h(mm) 4 2 0 1 4 7 10131619222528313437404346495255586164677073 Interval of 3 hours

14 Meteorological Station Lugoj (total 175mm) 12 10 56 mm 73 mm 30 mm 8 6 h(mm) 4 2 0 1 4 7 10131619222528313437404346495255586164677073 Interval of 3 ore

20 Meteorological Station Resita (total 159mm) 18 16 14 12 38 mm 103 mm 34 mm 10

h(mm) 8 6 4 2 0 1 4 7 10131619222528313437404346495255586164677073 Interval of 3 hours

10 Meteorological Station Semenic (total 114mm) 8 6 36 mm 62 mm 16 mm 4 h(mm) 2 0 1 4 7 101316192225283134374043464952555861646770 Interval of 3 hours

Figure 1. Timiş-Bega River basin: Temporal distribution of the rainfalls during the 14-22 April 2005

2 As it is seen in Figure 2, where the isohyets map is represented, the highest quantities have As seen in Figure 1, the highest amount of rainfall was in 18-20 April, which, as a matter of fact, generated the flood peak. In the history of the greatest floods produced in Timis-Bega River catchment those from Mai 1912, July 1966 and April 2000 have also been reported together with the 2005 flood. The flood from 25-30 May 1912 has been the highest one, the maximum discharge has been reconstructed as about 1600m3/s. This flood has been provoked by a rainfall that covered the entire basin area and exceeded 200mm in the mountainous areas of Semenic and Poiana Rusca.

Recas Surduc Timisoara

Buzias

Cebza 0 Cadar Duboz 5 1 1 Graniceri 50 Bucova

Tarcu Soceni Ohabita Gataia Cuntu Moniom Resita150 150 Semenic

Figure 2. Isohyets of the precipitation fallen 14-22 April 2005.

The flood from April 2000 has been provoked by the combined effect of the important rainfalls and the water resulted from snowmelt. Having a probability of about 2% the April 2000 flood produced the rupture dikes from the left-side bank of Timis River near the border with Serbia and Montenegro.

Hydrological analysis of 2005 flood The analysis of April 2005 flood has been performed on the basis of the records of the discharges at the 20 gauging stations. First the volume balance at the main nodes of confluence has been considered. This analysis has been performed in order to check the degree of reliability of the data concerning the gauged and rating curve – extrapolation discharges. The agreement of the volumes of computed floods obtained by addition of the upstream wave hydrographs (recorded and evaluated over the ungauged basins (RB-rest of basins)) in a node and the recorded ones is quite good. In the Table 1 a selected part of this checking is provided as an example. So, the data can be considered to have an acceptable precision for further statisticall computations. The check has been made for the total runoff (htotal) of the hydrograph, but also for the surface runoff (hs) and base runoff (hbase). Unusual high estimates of the runoff coefficients α (surface runoff versus rainfall) should to be pointed out in table 1.

3 Table 1. The balance of the surface volumes (Ws), base volumes (Wsub) total volumes (Wtotal), the corresponding depths of runoffs, the rainfall (hp) and runoff coefficient α during the flood period in Timis – Bega River Basin.

Basin area Wtotal 2 6 F(km ) (10 htotal Wbase Hbase Wsub hs 3 6 3 6 3 River Station m ) (mm) (10 m ) (mm) (10 m ) (mm) hp(mm) α Timis Teregova 167 24.9 149.19.49 56.8 15.4 92.2 120 0.77 Rece Rusca 163 28.05 172.08 9.26 56.83 18.79 115.25 150 Fenes Fenes 125 19.59 156.71 7.10 56.8312.49 99.88 130 Sum F 455 78.29172.08 25.86 56.8352.44 115.25 150 RB 105 18.07 172.08 5.97 56.83 12.10 115.25 150 0.75 Total 96.36 31.8 64.54 Timis Sadova 560 96.84 173 24.9 44.5 71.94 128.5 175 0.73 Golet Golet 41 7.91 192 3.07 74.9 4.84 118.1 165 0.72 Sebes T. Ruieni 122 21.44 5.42 44.4616.01 131.25 175 0.75 RB 349 61.31 175.67 36.18 103.67 25.13 72 120 0.60 Sum F 723 Total 187.5 69.6 117.9 90 Timis Caransebes 1072 185.9 173.4 69.8 65.1 116.1 77.2 Bistra 659 87.5 101.4 28.59 43.4 58.92 68.28 130 0.53 Nadrag Nadrag 35 7.97 227 2.65 75.7 5.32 152 200 0.76 CHE Turnu Ruieni 14.87 14.87 Suma F 1766 Without basin area of reservoir RB Poiana Mărului 736 141.06 191.66 36.18 43.38 104.88 142.5 190 0.75

Total 437.3 152.1 285.2 Timis Lugoj 2706 458.0 169 159.0 58.8 298.7 110.4 150 0.74

Hydrographs of the flood waves 14-30 April 2005 R. Timis River - Teregova-Lugoj Sector 1400 R. Timis S. H. Teregova 1200 R. Timis S.H. Sadova R. Timis S. H. Caransebes R. Bistra S.H. Obreja 1000 R. Timis S. H. Lugoj

800 /s) 3

Q(m 600

400

200

0 0 24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384 408 Time(hours)

Figure 3. Timiş River – Flood hydrographs along Teregova-Lugoj Sector

4 In Figures 3, 4 and 5 the wave hydrographs recorded upstream and downstream main nodes of confluences are represented, namely: • Timiş River : Sector Teregova Station (SH) –Caransebeş Station - Lugoj Station; • Timiş River: Sector Lugoj(downstream Bega River) – Şag Station – Grăniceri Station; • Bega River : Făget Station –Chizătău Station. Flood Hydrographs on Timis River (14-30 aprilie 2005) 1400 R. Bega- S.H.Chizatau;F=1660km2;Q1%=462m2/s 1200 R. Timis-S.H. Lugoj:F=2706km2:Q1%=1225m3/s R. Timis-S.H. 1000 Sag;F=5292km2;Q1%=1425m3/s R. Timis-S.H. Graniceri /s)

3 800 Q(m 600

400

200

0 0 24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384 408 432 Time(hours)

Figure 4. Timiş River – Flood hydrographs along Lugoj-Graniceri Sector

Flood hydrographs of Bega River (14-30 aprilie 2005) 400 Station Faget-F=474km2 /Q1%=216m3/s

350 Station Balint-F=1064km2 /Q1%=346m3/s

300 Station Chizatau-F=1660km2/Q1%=448m3/s Station Remetea-F=280km2 250 /s) 3 200 Q(m 150

100

50

0 0 24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384 408 Time(hours)

Figure 5. Bega River – Flood hydrographs along Faget-Chizatau Sector.

Similar with that occurred in the year 2000, the flood produced in April 2005 has formed over the entire catchment of Bega and Timis Rivers. Although the subbasins did not produced very high peak discharges, the composition of the component catchments resulted in remarkable, very rare

5 frequency peak floods in the downstream sectors of this basin. The peak discharge is situated among the four historical floods above-mentioned. For comparison, the wave hydrographs of these historical floods together with that of the April 2000 flood are overlapped by centring them at the time to peak and they are represented in Figure 6. The volume of the April 2005 flood was three times greater (about 720 million m3) than that of 2000 year flood, though the peaks of these two were very close. As a result of the high peak the embankment of the right-side bank of Timis River has been over spilled and the multiple ruptures of the dikes have been reported. But, due to the huge volume of the high waters over the inundated flood plain, the flooding comprised an area of about 30000 ha and a volume of inundation of about 250- 300 million m3. Flood hydrographs in 1912, 1966, 2000 and 2005 1600 2005 1400 1912 1966 1200 2000 1000 /s) 3 800 Q(m 600

400

200

0 0 50 100 150 200 250 300 350 400 Time(hours)

Figure 6. The wave hydrographs of the historical floods centred to their peak.

Table 2. Peak discharges of the floods at some stations in Timis- Bega River Basin Basin Mean Q2000 Q2005 Q1% River Station area elevation 3 3 3 2 (m /s) (m /s) (m /s) F(km ) H(m) Timis Teregova 167 901 37 65.7 244 Timis Sadova 560 936 328 276 446 Timis Caransebes 1072 765 441 425 650 Timis Lugoj 2706 766 1246 1135 1225 Timis Brod 5292 569 1200 1290 1451 Timis Sag 6118 424 1100 1083 1425 Sebes T. Ruieni 122 819 85 72.6 220 Bistra Voislova-Bucova 232 892 280 69.6 288 Bistra Voislova 404 827 450 80 380 Bistra Obreja 863 880 633 290 600 Nadrag Nadrag 35 742 9.62 21.5 70 Golet Golet 41 751 25.4 16.9 78 Bega Faget 474 470 150 164 204 Bega Balint 1064 335 283 252 346 Bega Chizatau 1660 278 352 346 482

6 In Table 2 the peak discharges of the flood are comparatively presented with those of the 2000 flood and the maximum annual discharges of 1% probability of exceedance. As shown in Table 2, only in few cases some remarkable floods have been produced as for example on Bistra River (stations Voislova, Voislova - Bucova and Obreja) a tributary of Timis River as well as on Bega River (Chizatau and Balint stations) where the probability of the peak discharges ranged between the 1% and 5%. In the subbasins of small areas the maximum discharges are not very high, being far to have rare frequencies. Nevertheless, in the downstream sectors, the probability of exceedance had frequencies comprised between 1-2%. TimisR. Timis-S.H. River-Graniceri Graniceri_Debite Station: Computed masurate under the assumption si of the integritycalculate of the in embankment ipoteza existentei and gauged digurilor flood wave discharge hydrographs 1200

Volum acumulat in 1000 The volume stored in the zonaflooded inundata area due to the mal dike stang rupture prin 800 ruperea digurilor

RecordedDebit masurat flow atla /s)

3 Graniceri Station 600 S.H. Graniceri Computed flow at Q(m GraniceriDebit calculat Station la S.H. Graniceri 400 6 3 VVaccumulatedacumulat=349.10 =300 m 200

0 0 100 200 300 400 500 600 Time(hours)Timp(ore)

Figure 7. Reconstructed flood wave hydrograph at Grăniceri Station

Under the circumstances of numerous ruptures of the embankment along the right-side bank of Timis River the combined effect of the high discharges and the huge volume of the flood in April 2005 led to a very large flooded area (called by the people “Sea of ”) where the water stagnated more than one and a half month because there were not many ways for gravitational drainage. As a result of this, the pumps installed in the area and the drainage ways made downstream in Serbia- Voivodina were the solution for the evacuation of water from the inundated localities and the surrounding areas. Four villages have been completely flooded, 3644 homesteads and 2344 distressed people has been reported. The reconstruction of the hydrograph in the section of the dike rupture (around Graniceri cross section) has been accomplished making use of a routing model. The reconstructed hydrograph without the dike ruptures is presented in Figure 7. The volume of water spilled over the dike ruptures into the flooded area was of about 300 million m3, which has been both gravitationally drained and by pumps. Due to the long duration of the 2005 flood, the volume of 300 million m3 that formed the “Sea of Banat” was two times and a half that of the flood from 2000 which, had the similar discharges spilled over the ruptures (650-750 m3/s) of the embankment (in 2000 the left-side of the embanked area has been inundated). Thus, “a cutting” of the dikes along the left-side bank would had been not more beneficial, as pretended by some people, because the huge volume in 2005 would have provoked an extension of the inundated area as compared with 2000 year flood. Thus, four communes (Grăniceri, Toagăr, Livezile, Giera şi Boroş), which in 2000 had been only partially flooded (due to the smaller volume and duration of flood) in the case of cutting the dikes. Moreover, such decision should be supported by a “plan of defence” with a law character, based upon substantial simulation on different scenarios which might provade the extension of the phenomena. Such scenarios have been made for another sector of Timis River but not yet in the border area. A bi- dimensional hydraulic model has been applied in the circumstances of simulated rupter of the dike along the sector Topolovat- Hitias which might jeopardise Timisoara City. At different instants after the

7 rupture of the embankment, the flooded areas, the isolines of the depths of water, of the velocities and the discharges flown through the inundated area have been determined. (INHGA, 2004). After, achieving such maps, the substantiated conclusions on the vulnerability of the area and on the involved risk become available and corect decisions could be taken. This types of simulations should be undertaken for a multitude of situations potentialy to occur in the flood prone areas due to the rupture of the dikes, concomitantly with enforsing the embankment work as well as with the re- evaluation the degree of the vulnerability and further on to assign a probability of exceedance to a class of importance of the construction and / or the protected areas.

The effect of the reservoirs on the flood flow The location of the reservoirs is presented in Figure 8. The main permanent reservoirs Poiana Marului and Surduc retained a total volume of 25.9 millions m3 (13.5 millions m3 in Poiana Mărului Reservoir and 12.4 millions m3 în Surduc Reservoir). As Poiana Marului Reservoir is located in the upstream part of the Bistra River Basin it did not substantially influenced the peak discharges of Timis River along its downstream sector where the inundations have been taken place. Also, as seen in the map of the isohyets the flood runoff has been modest, as the total rainfalls did not exceed 70mm. The Surduc Reservoir having a basin area of 135km2 had some influence in alleviating the flood peak of Bega River along the sector between Gladna River and the confluence with Timis River (through Topolovat Canal), the rainfall were here quite substantial (150-175mm). The Trei Ape Reservoir (Total volume =6.43 millions m3) is quite small, and it has only a local influence. The non-permanent reservoir Cadar Duboz Storage on Pogonis River was very efficient in attenuating the high peaks of this river. Also the Padureni non-permanent storage stored 20 millions m3 while Hitias non-permanent reservoir located at the confluence of diversion Canal Topolovat succeeded to store only 5 millions m3 out of its capacity of 20 millions m3 due to the insufficient hydraulic head. That is why, new solution for increasing the hydraulic head has been foreseen, by elevating a concrete threshold across the river Timis upstream the actual entrance gate into the storage. Ba ra j Ba ra j Ba ra j Giarmata Ba ra j Hodos Repas 3 Re c a s 0.88 mil.m3 1.6 mil.m3 1.21m il.m V= 3 V= V= V= 0.52 mil.m Ba ra j Dum bravita Ba ra j Bist ra 1.32 mil.m3 Ba ra j 3 Ba ra j V= Ianova V= 0.92 m il.m Iosifalau

.

R 3 4.65 m il.m Ba ra j

a l V= Topolovat 3 e 3.86 m il.m Sanmartinu h V= Sa n m i h a i u e Faget Luncani Maghiar- B Chizatau Balint Ro m a n Ec lu za Ec lu za RAUL Bega River CANAL Bega CANAL Bega Ba ra j C Su r d u c t a Vt= 44.1 mill m3 3 3 /s a n Vu= 24.2 mill m3 83.5m /s Timisoara City v a m lo l

Po l d e r (capacitate proiect) 4 C R. G l a d n a Ba ra j 0 o 0 o a 0 p m r Poiana. Marului 3 s t

5 o Hitia s s T t i - / e R. Bi st r a 0 l s i B Vu= 89 mil m3

Graniceri Sa g Bro d 1 a Lu g o j . Marului 4 n V= 20 mill m3 R a 3 C Obreja Vt= 110.1 milm V= 35 mil m V= 20.5 mil m3 Caransebes Po l d e r Po l d e r Bu zia s RAUL Tim is

Gad Pa d u r e n i River Ra c o v it a

.

s i

a Ba ra j Ba ra j

n

d r

i Silagiu Sa l c i a

a Ba ra j

B g

Ba ra j St i u c a o a 3 3 Marandesti

P 3 c 0.63 milm V= 1.52 milm. 3 . V= m n V= 1.6 mil. 2.3 mil.m

R V=

a

L

. P Po l d e r Cadar Duboz 3 V= 41.1 mil. m

Figure 8. Water works management scheme of Timiş-Bega River Basin In Timis Bega River Basin there is also the non-permanent storage Gad located at the confluence of Timis River with Lanca Birda River. In 2005, a volume of 13 millions m3 belonging to Lanca Birda basin were kept into it. Nevertheless, this volume had no any influence on Timis River peak, because

8 there is not a gate at the side of the course of Timis River which would have taken apart of the flood peak. Thus, to develop the capacity of Gad non-permanent storage a gate made at the Timis River side has been proposed (INHGA, 2004). Of a great importance for attenuation the flash floods which might occur on the tributaries of Bega Canal (downstream Topolovat strech) is the small storage capacities shown in the Figure 8. These permanent and non-permanent reservoirs are quite old (about 35 years), and their volumes ranged between 2-6 mil.m3. Their situation concerning the silting up of them as well as the questionable hydrology that has been used for their project, make them unsafe water works, which in case of destroying them, the towns as Timisoara City, and Buzias would been gravely affected. Thus, although they successfully stand up the flood from 2005, a re-evaluation of their structure to resist to other floods is compulsory.

Hydrological and technical issues of the embankments In Timis-Bega River basin an important part of the flood-prone areas is embanked. In the Timis catchment the all the jeopardised towns: Lugoj, Caransebes and Otelul Rosu have their own embankment works and 50% from the rural communes are protected by dikes. The protected villages the great majority of them is located along the Timis River downstream Hitias point (confluence of Bega River with Timis River through the high water diversion canal Topolovat-Hitias) In Bega River catchment, specific water defence works protect Timisoara City and Faget Town against floods to which another 9 communes are added. Thus the most important sectors along which there are flood protection works the following are mentioned: • Timis River-Sector Lugoj-Border; • Bega River-Sector Balint-Hitias; • Poganis River-Sector upstream Cadar Duboz storage • Bistra River –Sector Otelul Rosu-confluence with Timis. There are also local flood protection works, especially in the sectors of the mouth of tributaries where the backwater is present (the rivulets Timişana, Şurgani, Sebeş, Pogăniş, Lanca-Birda, etc.). After a research developed in the Study” Life-Timiş” (INHGA, 2004), and as a result of the damages provoked by the flood from April 2005, some issues are raised: and they have been inventoried as follows: • Timisoara City is protected only for the peak discharges of 1% probability, but given its socio- economic importance it should be protected for at least 0.1%. • In the zone located in the vicinity with the border with Serbia-Montenegro, due to the oldness of the works the frequent seepages occurred. • In the zone of Lugoj City under the circumstances of a peak discharge mear 1% (see case of 2000 flood) the dike located downstream the city has been overtopped. • On Sebes River in the zone of Caransebes City the dikes are strongly jeopardised due to heavy erosion of the banks and the riverbed • On Bistra River at Otelul Rosu due to the erosion phenomena the flood defence works have been washed down and the along a length of 1.5 km of the embankment 9 breakthroughs (770m) have been formed. • Due to intense silting along Poganis River upstream the storage Cadar Duboz the embankment work does not ensure the transition of the high discharges having probabilities, which exceed 5%. Fact that produced frequent overtopping events both during the anterior floods (1999,2000, 2001) and in 2005. • Given be the importance of Timisoara City, special caution should be given to the risks induced by the morphological changes, which are developed in the river bed of Bega Canal and on its tributaries.

Conclusions concerning the embankment work in Timis-Bega Basin On the basis of the priory made considerations a completion study on the flooding risk should be carried out. This study should consider both the un-embanked sectors of the rivers, which have a flooding potential and the sectors where there are dikes. The following hypothesis of rupture of the dikes should be considered: • Wrecking of the dikes in case of exceeding the peak discharges of small probabilities which might affect important socio-economic. In these flooding areas produced by rupture of the dikes the

9 construction of another new objectives or the developing of these already built, should be not anymore accepted. • Wrecking of the dikes condition of them is poor and the risk to crashing is high. The cause of the poor condition could be along the oldness, the coincidence of the floods on different tributaries, the development of silting phenomena, etc. Although the rehabilitation of the system of the dikes by consolidation / over lifting is already foreseen in the near future, until the works would be completed.

General conclusion concerning the flood defence actions to be taken in the future

Regardless the location of the protected area, the building of the dikes attracts an intensive process of economic development through the establishment of a great number of the inhabitants in the plain area and the achievement of important investments in industrial and agricultural activities. Over long term this socio-economic investment leads to an increased dependence on the dikes. The dikes offer a an efficient protection in case of small and medium size floods but they give a false impression ha have an absolute saving virtue. In case of large floods, the risk of overtopping and of destroying the dikes substantially increases. Especially, when the breakings are produced along large distances, the damages and the human lives looses are much more great than in case of this dikes would not have existed. In case of the overtopping the embankments during night time, the effect of surprising the population amplifies the damages which, cannot be saved either by population or by the authorities in charge with flood defence operative actions. This fact is confirmed by relatively recently produced floods in different countries which, even they have a high capacity of defence they supported large damages and human lives losses due to the disruption of the dikes on great distances along the river course. (Galloway, 1999 ; Kubat si Vrabec, 1999 ; Kindler, 1998). The principle “„more space for the rivers” derived from the lessons received after the failure of adopting only structural measures in the flood management is nowadays crucial in the policy of flood defense. The principle of “prevention” marked especially by developing hydraulic works aimed to reduce the magnitude and intensity of hazard should be harmoniously combined with the culture of “preparedness” meaning the rehabilitation of the embanked flood prone areas by creating large distances between the dikes on the both river banks as well as the application of the non-structural measures, aimed to reduce the vulnerability and to intervene more effective and timely in combating the disaster. In Romania the primordial concept of flood defense was the dike construction, often near the river banks, fact that resulted in an important accretion of the frequencies and the magnitude of the floods. Even in cases where the space dike-river bank is correctly designed, the progressive silting of this space leads to the diminution of the cross profile areas and therefore to the decreasing of the water transport capacity, that result in heightening the water levels. Further on, a new accretion of the periodical dike heightening become necessary and the dependence on the embankment becomes major and major. In respect to these considerations, a change in flood defense conception is foreseen, as follows: 1. The over heightening of the dikes, as a result of increasing the degree of saving or a modification of river hydrology, constitute a viable solution only after a careful cost-benefice analysis achieved at the scale of the ensemble of the river but not for a limited endangered area. The heightening implies high costs and due to the effect of silting the flood plain between the dikes, it has a continuous character. 2. Creating new flood defense water works with respecting the principle ”more space for the rivers” , namely: a) Construction of ring-shaped embankments around the localities and other important settlements; b) Achievement of non-permanent storages (polders) correctly dimensioned as far as their optimal capacity of water volumes accumulation should be warranted. c) Building up fusible dikes (to be controlled blowing up during major floods) to assure the needed space for water detention. Also, in order to mitigate the damages, the flood prone areas protected by longitudinal dikes should be compartmentalized. d) The gradual abandoning the old flood defense embankments and recalibrating them according to newly issued concepts. 3. The increase of the application the non-structural measures (Stanescu, Drobot, 2002) by: a) Generalizing the coupling of hydrological models for flood forecasts with meteorological short term forecast models and radar nowcasting, use of the Bayesian statistical concept in evaluating the

10 forecast performance and the ensemble hydrological forecasts of floods to take into account the spatial deviation of the forecasted rainfall fields. A special attention should be paid to the flood shape and volume forecast, as only the peak discharges prevision is often insufficient, especially where the storage water works are in service. b) Elaboration on hydraulic modelling basis, for each major river basin the different flooding scenarios, by rupture of the dikes in most vulnerable key points, indicating the spatial extension of the inundation, the water depth and velocities. c) Achieving different defense plans function of the flood magnitude and the peculiarities of the emergency situations. These plans should be conceived in liaison with the flood formation over the basin and the existing hydraulic works for flood defense. A thematic plan should be issued at central level of the “Direction of emergency situations” distributed then to the river basin authorities which, at their turn will carry out the concrete plans, taking into account the multitude of circumstances how, when and where and the flooding might occur. d) Vulnerability zonation of the territory of Romania and authoritatively application of the legislation concerning the authorization for building up different constructions in the flood prone areas and the obligation of the local authorities to assure the water flowing conditions in the small water courses. e) The education actions of the staff of the General Inspectorate for Emergency Situations in the domain of flood crisis management : - Courses for professional formation organized by the River Authorities in the domain of interpretation of the hydrological forecast and the pre-prepared simulations by hydrological and hydraulic models. - Revision of the concept of the organization of the informational flux between the River Authorities, Basin Committee and the General Inspectorate for Emergency Situations; - Establishment of precise and well delimited responsibilities and actions between the actors implied in the flood defense management. f) The education of the local authorities and of the population for enhancing their participation together with the flood defense people in charge as well as for increasing the awareness of the endangered population to timely action and stand to flooding and after it, for better contributing to the alleviation of the inundation effects. g) Revision of the legislation concerning the controlled inundation of the land and instituting a partnership between the state - the Water Management Authorities –local communities in view of establishing the rewards for the undamaged owners of the controlled inundated areas. h) Introduction of a insurance - re-insurance system by instituting a partnership between the Basin Committees, the Water Authorities, the insurance societies and the local communities. Acknowledgements The analysis made in this present work is based on primary data collected by the National Administration of Meteorology, the National Administration “Romanian Waters” and the National Institute of Hydrology and Water Management-Romania, to which the authors expressed their gratitude.

References Galloway, G.E., 1999 – Towards sustainable management of river basins: challenges for the 21st Century. Proceedings RIBAMOD Meeting. Walingford, U.K. Kindler, J., 1998 – 1997 Flood Emergency in Poland. A Lesson for Education and Training Program. In: Environment – Water, General Report. Vrije Universitet Brussel. Belgium. Kubat, J si Vrabec, M., 1999 – Flood forecasting in the Czech Republic. In: NATIONAL Weather Service. River Forecast System Workshop. Silver Spring. SUA. V. Al. Stănescu, R. Drobot, 2002– Non-Structural Measures for flood Management.(In Romanian) Ed. H*G*A, Bucureşti. INHGA, 2004 - Life-Timis: Protection of the River Life by Mitigation of Flood Damages-European Commission, Directorate Environment, Direction LIFE-LIFE00ENV/RO/000986)”. 2000-2004.

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