HYDROMORPHOLOGICAL ALTERATIONS IN THE DANUBE RIVER FOCUS ON THE DELTA. Mikhail Kornilov Danube Hydrometeorological Observatory

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1 HYDROMORPHOLOGICAL ALTERATIONS IN THE DANUBE RIVER FOCUS ON THE DELTA Mikhail Kornilov Danube Hydrometeorological Observatory

2 The main impacts of hydromorphological alterations on the riverine habitats will cause: the decline of species biodiversity the decline of species abundance altered population composition hindrance of species migration and the corresponding decline of naturally reproducing fish populations Joint Danube Survey 2: HYDROMORPHOLOGY

3 JDS 2 was the first time that hydromorphological parameters were surveyed systematically with an uniform method for the entire navigable longitudinal Danube stretch over 2415 rkm and at all 96 JDS sampling sites For a project like JDS2 no standardized method for the hydromorphological survey and assessment existed. Therefore a special method was developed and defined in the Standard Operational Procedure (SOP), based on existing methodologies for large rivers meeting the requirements of the CEN framework standard EN14614(2004 ) for the assessment of hydromorphological features of rivers and WFD. Two approaches were used during the survey: Continuous longitudinal survey of about 50 km stretches, aimed to overview of the hydromorphological situation of the Danube from Kelheim (rkm 2,415) to the Danube Delta (rkm 0) Detailed site survey, aimed to hydromorphological site characterisation to support interpretation of biological results

4 Continuous longitudinal survey The five class evaluation for channel banks and floodplain is the base for the total evaluation (mean values out of the three categories). Channel in five classes: Degree of morphological and flow condition alterations (based on hydrological alterations, navigation map, historical maps (as reference base), plan form, validated by field survey) taking into account the types-specific reference conditions. Class 1: Channel nearly natural Class 2: Channel slightly modified Class 3: Channel moderately modified Class 4: Channel severely modified Class 5: Channel totally modified

5 Continuous longitudinal survey The five class evaluation for channel banks and floodplain is the base for the total evaluation (mean values out of the three categories). Banks in five classes (integration of left and right banks): Bank dynamics (based on navigation map, validated by field survey) taking into account the type-specific reference conditions. Class 1: Banks nearly natural Class 2: Bank reinforcements in small sections Class 3: Bank reinforcements in large sections Class 4: Continuous bank reinforcements Class 5: Totally modified banks

6 Continuous longitudinal survey The five class evaluation for channel banks and floodplain is the base for the total evaluation (mean values out of the three categories). Floodplain in five classes (integration of left and right floodplain): Based on the four ecological quality classes ( ecological potential ) according to the DPRP Wetland study 1999 (floodplain width (relation between active and morphological floodplain) and landuse Class 1: Floodplain with very high ecological value Class 2: Floodplain with high ecological value Class 3: Floodplain with moderate ecological value Class 4: Floodplain with low ecological value Class 5: Floodplain totally modified

7 A total of 66 homogenous stretches along the Danube including the three delta branches were prepared. Database form view allowing the entry of basic information as well as the evaluations for channel, banks and floodplains Continuous longitudinal survey

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9 Continuous longitudinal survey: CHANNELS

10 Continuous longitudinal survey: CHANNELS

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12 Continuous longitudinal survey: BANKS

13 Continuous longitudinal survey: BANKS

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15 Continuous longitudinal survey: FLOODPLAINS

16 Continuous longitudinal survey: FLOODPLAINS

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18 OVERALL ASSESSMENT longitudinal survey

19 OVERALL ASSESSMENT longitudinal survey

20 The extensive site survey results serves as hydromorphological characterisation used for the assessment of biological data and will be used for the synthetic analysis of the different teams. This figure summarize the covered preliminary Danube-Section-Types (Danube typology) and the distribution of analysed sites. Detailed site survey

21 The hydromorphological survey was successful in particularly as basis for an updated impact and pressure analysis and risk assessment of the Danube, and for the development of a programme of measures as well as to encourage the countries to develop further more detailed national investigations. The overall hydromorphological assessment showed that the hydromorphological situation of the Danube varies from source to mouth. It is in lower Danube much better than in the Upper Danube. The deterioration of status quo should be prevented and specific programmes of measures must start to enhance the situation for migratory species and to support floodplain restoration as well as habitat restoration/improvement. The JDS sites are not always representative for hydromorphological features of the Danube as they were often selected to detect discharges from agglomerations (water quality aspects). Further too much stations just upstream of dams in the impoundments, within cities and transition stretches (e.g. from cities to more natural stretches, or just downstream of dams) are not typical for long representative stretches. Beside the natural debris in form of wood and organic material, reaching only in some stretches larger amounts the waste debris in form of plastic bottles an bulky waste should be negatively mentioned. GENERAL CONCLUSIONS

22 The Danube Delta is the integral natural complex The water bodies are interconnected both morphologically and hydraulically The consequenses of water engineering have the transboundary character

23 By now many water engineering projects have been implemented in the Danube Delta for the following purposes: Towns, villages and arable lands protection from inundation Building and operating of irrigation systems Water exchange regulation between Danube and deltaic water bodies Industrial and municipal water supply

24 The most large-scale hydrotechnical works where carried out in the Danube Delta in order to improve the transit navigation between the Danube and the Black Sea. For this purpose in different years the following have been done in the Danube Delta

25 рук. Сулинский The most large-scale hydrotechnical works where carried out in the Danube Delta in order to improve the transit navigation between the Danube and the Black Sea. For this purpose in different years the following have been done in the Danube Delta dredging and strengthening of the Sulinskiy, Georgievskiy, Kilijskiy, Belgorodskiy, Polunochniy and Prorva Arms рук. Прорва

26 The most large-scale hydrotechnical works where carried out in the Danube Delta in order to improve the transit navigation between the Danube and the Black Sea. For this purpose in different years the following have been done in the Danube Delta рук. Сулинский dredging and strengthening of the Sulinskiy, Georgievskiy, Kilijskiy, Belgorodskiy, Polunochniy and Prorva Arms dredging of bars in the Sulinskiy, Potapovskiy, Prorva and Bystroye Arms рук. Прорва

27 р. Дунай рук. Килийский рук. Тульчинский The most large-scale hydrotechnical works where carried out in the Danube Delta in order to improve the transit navigation between the Danube and the Black Sea. For this purpose in different years the following have been done in the Danube Delta dredging and strengthening of the Sulinskiy, Georgievskiy, Kilijskiy, Belgorodskiy, Polunochniy and Prorva Arms dredging of bars in the Sulinskiy, Potapovskiy, Prorva and Bystroye Arms building of the wing dyke in the upper part of the Danube Delta on the Cape Chatal of Izmail

28 рук. Сулинский + + The most large-scale hydrotechnical works where carried out in the Danube Delta in order to improve the transit navigation between the Danube and the Black Sea. For this purpose in different years the following have been done in the Danube Delta dredging and strengthening of the Sulinskiy, Georgievskiy, Kilijskiy, Belgorodskiy, Polunochniy and Prorva Arms dredging of bars in the Sulinskiy, Potapovskiy, Prorva and Bystroye Arms рук. Быстрый building of the wing dyke in the upper part of the Danube Delta on the Cape Chatal of Izmail + building of piers and dykes in the mouths of the Sulinskiy Arm and Bystroye Arm

29 Sulina branch L, km L, km (-25%)

30 Sf. Gheorge branch L, km L, km (-30%)

31 Water runoff redistribution in the Danube Delta

32 Prorva branch L, km L, 0.00 km (0.0%)

33 The influence of water engineering activities in the Chilia Delta subsystem have the local character, does not extend to the Tulcea Delta subsystem and does not induce changes of the current tendencies in the hydrological processes. This is due, first of all, to the fact that the scale of the water engineering activities performed in Sulina and Sf. Gheorge branches exceeds the scale of those in Chilia Delta many times, including those being currently implemented.

34 The direct consequences of the water discharge decrease in the system of the Chilia Arm are the following: decrease of suspended solids discharge and the corresponding changes in the delta forming processes lowering of water levels, decrease of flooding of the deltaic islands and less water exchange with the internal lakes of the delta speeding up of the small passive watercourses dying-off (the Shabash, the Sredniy and the Zavodninskiy) increase in frequency and length of marine water penetration in the deltaic arms higher probability of water deficiency periods occurrence when the water resources available do not satisfy the needs of all the water consumers.

35 CONCLUSIONS (Needs) Using of basin approach is strictly needed when planning any hydrotechnical works in the Danube Delta Joint development of the hydraulic mathematical model of Delta as a tool for decision making and assessment of consequences is obligatory Joint environmental monitoring program has to be extended and carried out under umbrella of international organizations (ICPDR and others) Series of measures must be developed and included into Delta Sub-basin Management Plan

36 THANK YOU FOR YOUR ATTENTION