1. Helmut Kroiss, Christoph Lampert, Matthias Zessner daNUbs-project: Nutrient management in the Danube Basin and its impact on the Black Sea (EVK1-CT-2000- 00051) NEW CHALLENGES FOR NUTRIENT MANAGEMENT IN THE DANUBE BASIN

2. Institute for Water Quality and Waste Management, TU Vienna, AUSTRIA; CO-ORDINATOR Danube Delta National Institute for Research and Development, Tulcea, ROMANIA Stichting Waterloopkundig Laboratorium, Delft Hydraulics, Delft, NETHERLANDS Bureau of Sustainable Agriculture, Hanhofen GERMANY Institute of Fisheries and Aquaculture - Varna, BULGARIA Institute for Freshwater Ecology and Inland Fisheries, Berlin, GERMANY Institute of Hydraulics, Hydrology and Water Resources Management, TU Vienna, AUSTRIA Institute for Land and Water Management, Petzenkirchen, AUSTRIA Institute for Marine Research, University Kiel, GERMANY National Centre for Marine Research, Athens, GREECE Romanian Marine Research, Constanta, ROMANIA Institute for Water Pollution Control, Vituki Budapest, HUNGARY Department of Sanitary and Environmental Engineering, Budapest, HUNGARY Institute of Public Finance and Infrastructure Policy, TU Vienna, AUSTRIA Department of Meteorology and Geophysics, University of Sofia, BULGARIA Institute of Water Problems, Bulgarian Academy of Sciences, Sofia, BULGARIA Department of Systems Ecology, University of Bucharest, ROMANIA Partners

3. map catchment DANUBE RIVER 2.857 km long catchment: 817.000 km 2 Population within: 85 million BLACK SEA Total catchment: 2.300.000 km 2 population within: 190 million surface area of 461.000 km 2, average depth 1.240 m. WESTERN BLACK SEA surface area: 30.000 km 2 depth coastline Bulgaria: 70 m, average depth shelf: 140 m 13 Danubian countries (with area >2000 km²) Danube catchment area Germany Austria Hungary Slovakia Croatia Serbia- Montenegro Romania Bulgaria Bosnia- Herce- govina Czech Republic Ukraine Moldova Slovenia

4. Aspects of nutrient management Why are nutrients especially interesting:  Nutrients are matter of transboundary transport and pollution  Nutrient discharges affect the marine coastal areas by eutrophication (even if river quality standards are met)  Emissions stem from diffuse and point sources  Storage capacity of nutrients in the catchment is orders of magnitude higher than yearly turnover (delays of effects)  Nearly the whole population is contributing (life style)

5. CONCEPT of the daNUbs project

6. Actual results from Danubs research project Danube is the main contributor to eutrophication phenomena in Western Black Sea coastal area.  The situation in WBSC has improved significantly since the late eighties and early nineties. Reduced nutrient inputs led to :  reduced eutrophication (algae production),  Bottom hypoxia has disappeared  regeneration of zoo-benthos and  regeneration of phytoplankton.

7. Since 1997 hypoxia has disappeared from the Western Black Sea (RO, BG) except a very short period (1-2 days) in 2003. The situation is close to the sixties now. Hypoxia is clear indicator of eutrophication. loads in 1997 (MONERIS): TP 25 kt/a, 400 kt DIN critical loads??

8. Saturation of dissolved oxygen near the bottom in September 1996, 1999 and 2003 on the Romanian shelf of the Western Black Sea from A. Cociasu. 28.629.029.429.830.0 43.8 44.0 44.2 44.4 44.6 44.8 45.0 28.629.029.429.830.029.830.029.830.029.8 43.8 44.0 44.2 44.4 44.6 44.8 45.0 28.629.029.429.830.028.629.029.428.629.029.428.629.029.4 43.8 44.0 44.2 44.4 44.6 44.8 45.0 43.8 44.0 44.2 44.4 44.6 44.8 45.0 43.8 44.0 44.2 44.4 44.6 44.8 45.0 September 1996 September 2003 Danube September 1999 Danube Oxygen saturation at the bottom

9. Total N- and P-emissions into the Danube river system by pathway

10. MONERIS Results: Nitrogen loads for river outlets 1998 - 2000 N-retention 240 kt/a N Load DIN = 390 kt/a N TN = 450 kt/a N DIN-emissions

11. MONERIS Results: Phosphorus loads for river outlets 1998 - 2000 P-retention 45 kt/a P 8.4 kt/a P Iron Gate P-load 22 kt/a P

12. Decrease since 1990: N: minus, 25%, P minus 50%. P is the limiting nutrient now in the Western Black Sea. Main reasons for the decrease of nutrient discharges: Economic crises  Reduced fertilizer application  Reduced fertilizer production  Closure of large animal farms Introduction P-free detergents P and N removal at treatment plants (A, D,CZ) favourable weather conditions (e.g. wind directions)?

13. Main risks for not reaching good ecological status in respect to WBSC eutrophication:  Development of sewerage (fulfilling EU Urban Waste Water Directive)  Recovery of the economic situation in the Eastern Danubian Countries (EDC) in the future  Actual situation of agriculture is not sustainable from the economic point of view

14. A “stand-still” scenario can only be related to the nutrient load to the Black Sea but not to the economic development. Economic development in these countries is desired even it leads to an increase of nutrient emissions e.g. from agriculture in some regions. Management of nutrient emissions is required even the quality of the Western Black Sea has improved!

15. connections (% of population) to sewer systems and ww treatment plants sewer systems wwtp Slovak R.54 51 Slovenia 53 35 Czech R.75 69 Hungary61 34 Bulgaria72 63 Romania51 30 As compared to: Germany (Danube Basin) 91 90 Austria 85 84

16. Impact of the Urban Waste water Directive about 50% of the population is connected to a sewerage system; about 20% of the collected waste water is discharged untreated now (40% out of this stem from settlements < 2000 inh.). 85% of the population lives in settlements > 2000 inh. and have to be connected according the Urban Waste Water Directive (UWWD): UWWD: C-removal is required:  35% N-removal,  0,6 g P/inh.d removal (ca. 30%)

17. in 2000: 13 200 t P = 0,44 g P/inh.d laundry detergents: A, D: 0 gP/inh.d others: 0,08 – 0,74 g P/inh.d assumption: all countries except A and D use 2 g/in.d in laundry detergents: + 37 600 t P = 50 800 t P = 1,7 g P/inh.d P-free detergents are an important measure use of detergents in the DB

18. Development of phosphorus emissions and river loads (Danube discharges to the Black Sea) in the Danube catchment 1955 - 2000 (adopted from Behrendt et al., 2004) and waste water scenarios for future development.

19. Development of phosphorus emissions and river loads (Danube discharges to the Black Sea) in the Danube catchment 1955 - 2000 (adopted from Behrendt et al., 2004)

21. Spatial distribution of nitrogen contributing areas; Regional geologic, morphologic and climatic conditions heavily modify N-surpluses

22.  Soluble P reduction from point sources has a fast response in P discharge to the receiving Sea.  Measures for the reduction of diffuse N-emissions have no immediate effects.  The retention in the groundwater (denitrification) heavily modifies the area specific N-surpluses; large areas in “dry” do not contribute to the N-load of the rivers.  Danube Delta and wetlands along the large rivers have only a small relevance for nutrient retention (main flow through main channels) Summary

23.  The ecological improvement is endangered by the (desired) economic development in the eastern european countries. Increased nitrogen emissions from agriculture in these countries have to be anticipated.  Development of sewerage (fulfilling EU UWWD) has to be strictly bound to adequate waste water treatment with nutrient (N and P) removal otherwise nutrient loads will increase.  A “stand-still” scenario can only be related to the nutrient load to the Black Sea but not to the economic development - nutrient management is crucial Summary

24. daNUbs Team project homepage: http://danubs.tuwien.ac.at/http://danubs.tuwien.ac.at/ 16.12.2004: Conference: “NUTRIENT MANAGEMENT IN THE DANUBE BASIN AND ITS IMPACT ON THE BLACK SEA” Venue: Vienna University of Technology