Kishnev, Oct. 2006 H. Kroiss, M. Zessner, Ch. Lampert Institute for Water Quality and Waste Management, Vienna University of Technology

1. Nutrient management in Danube river basin
for eutrophication control in Western Black
Sea Coastal Area
Kishnev, Oct. 2006
H. Kroiss, M. Zessner, Ch. Lampert
Institute for Water Quality and Waste Management,
Vienna University of Technology

2. Introduction
In many regions of the world problems with eutrophication of
marine estuaries occurs due to excessive discharge of
nutrients (N, P) by large rivers.
This eutrophication problem is mainly caused by diffused
sources (land use, agriculture) and inadequate waste water
management.
The daNUbs Research Project within the 5th
European
Research Frame Work Program dealt with this problem in
regard to the Danube River Basin and Black Sea coastal area.

3. Danubs Team

4. Characteristics of the study region
Danube and Western Black Sea Shelf Area, WBSS
DANUBE RIVER
Length: 2.857 km
Catchment 817.000 km², incl. larger parts of 13 countries
Population within the catchment: 85 million people
BLACK SEA
Total catchment: 2.3 million km², population 190 million people
Surface Area: 461.000 km², average depth 1.240 m
WESTERN BLACK SEA SHELF AREA
Influenced by Danube plume; surface area about 30.000 km²
Depth along the coastline: ~70 m, shelf ~140 m

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MACEDONIA
SLOVAKIA
GERMANY CZECH REPUBLIC
SLOVENIA
HUNGARY
CROATIA
BOSNIA &
HERZEGOVINA
ALBANIA
BULGARIA
SWITZERLAND
ITALY
UKRAINE
MOLDOVA
ROMANIA
YUGOSLAVIA
Brno
München
BratislavaWien
Zagreb
Budapest
Kyiev
Ljubljana
AUSTRIA
Bucharest
Sarajevo
Sofia
Belgrade
POLAND
Prague 
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Chisinau
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State border
Coast line
Danube
Main River network
Border of the basin
City Danube River Basin
REP: SERBIA

6. daNUbs– Project Goals
• Understanding of the fate of nutrients (N, P, Si) from
their sources (point and diffused sources) to the sea
 quantitative description by: Source inventory, MONERIS,
Danube Water Quality Model, Danube Delta Model.
• Understanding of the relation between river nutrient
discharge and the eutrophication processes in WBSSA.
 quantitative description by: physical ocean model, biological
models of the shelf area influenced by Danube

7. daNUbs– Project Goals
• Development of technical and operational measures to control
point and diffuse nutrient discharges to the environment in order
to achieve sustainable good water quality in Danube and
WBSSA
• Design of different scenarios in order to show the link between
political and socio-economic development (decisions) and the
consequences for the status of all waters in Danube Basin as
required by EU WFD (special emphasis on WBSSA).
• Development of improved monitoring procedures.

8. CONCEPT
EUTROPHICATION
N P
Si?
DISPOSAL
TRANSPORT
TRANSFORMATION
STORAGE
NUTRITION
LIFESTYLE
AGRICULTURE
ECONOMY
Emissions Danube Basin BlackSea
SOCIO ECONOMIC ASPECTS

9. PROJECT METHODOLOGY
• MONERIS model, describes the transport and transformation of
nutrients from their source to the river system
• DWQ-model, describes the same processes in the large rivers
• DD-model, describes the fate of nutrients in Danube Delta
• Models are able to describe the consequences of the dramatic
changes in the catchment due to the economic crises in the CEE
countries for N and P discharge to Black Sea with adequate
accuracy for strategic decisions.

10. Historic development of P-discharge

11. The main anthropogenic driving forces for N and
P discharge to Danube and Black Sea are:
• Agriculture (nutrition, animal protein production)
• Wastewater management (sewerage, wastewater
treatment)
•
• Air pollution by combustion processes (e.g. traffic) with
NOX.

12. Nitrogen emissions
Total N-emissions about 700 kt/a
(N to Black Sea 420 kt/a (60%))
natural background
8%
agricultural
"background"
31%
agriculture
reduction potential
14%
urban settlements
reduction potential (UWWD)
11%
urban settlements
rest
20%
other diffused sources
16%
hardly to be reduced
can be reduced
during next 10 years
can be reduced and
increased with a delay
of ≥ 10 years between
implementation and
response
Total N-emissions about 700 kt/a
(N to Black Sea 420 kt/a (60%))
natural background
8%
agricultural
"background"
31%
agriculture
reduction potential
14%
urban settlements
reduction potential (UWWD)
11%
urban settlements
rest
20%
other diffused sources
16%
hardly to be reduced
can be reduced
during next 10 years
can be reduced and
increased with a delay
of ≥ 10 years between
implementation and
response
D D+P

13. Phosphorus emissions
total P-emissions about 70 kt/a
(P to Black Sea 20 kt/a +
P in Iron Gate 8 kt/a)
natural
background
8%
agriculture
reduction potential
20%
urban settlements
reduction potential
(UWWD)
23%
urban settlements
rest
33%
other diffused
sources
3%
agricultural
"background"
13%
hardly to be reduced
can be reduced
during next 10 years
can be reduced
total P-emissions about 70 kt/a
(P to Black Sea 20 kt/a +
P in Iron Gate 8 kt/a)
natural
background
8%
agriculture
reduction potential
20%
urban settlements
reduction potential
(UWWD)
23%
urban settlements
rest
33%
other diffused
sources
3%
agricultural
"background"
13%
hardly to be reduced
can be reduced
during next 10 years
can be reduced
D
P

14. Nutrient emissions to water system influenced by agriculture:
• Fertilizer management in plant production
• Production of animal protein and fat (milk, meat, eggs)
• Soil quality management, erosion abatement, etc.
• Agricultural Policy (financial support) on national, EU and WTO level
Natural influences on nutrient emissions to water system:
• Soil, geology
• Climatic conditions (precipitation, etc.)
• Slope
• Residence time in groundwater

15. Driving forces for transport and losses:
• Denitrification potential mainly from source to medium size rivers
with strong emphasis on processes in soil and ground water
(residence time) and interaction between ground and river water
(littoral areas).
• Erosion together with over-fertilization strongly contributes to
transport of particulate nutrient loads, their role for eutrophication is
still not well understood.
• The large dam at Iron Gate represents and important sink for
phosphorus even for the next decades.
• Large rivers (including wetlands along these rivers and the delta)
have only little influence on N transport and loss.

16. Actual Status of Western Black Sea Coastal Area (WBSC)
Indicators for improvement of water quality:
• Anaerobic conditions in the sediments (anoxia) have nearly
disappeared
• Number of macro-benthic species in the WBSC has markedly
increased
• Algae growth is phosphorus limited (in summer, in winter probably
light limited)
• Rare algae blooms (similar to the 1960ies)

17. Positive development in WBSSA is mainly caused by:
• Economic crisis in Eastern Danubian Countries (EDC) since 1989
– Change of agriculture from economically driven production to
nutritional survival of the population,
– closure of the large industrial animal production plants
– closure and of many fertilizer production plants (market fertilizer
application dropped to nearly zero) in the EDC countries
• Use of P free detergents in D, A, and increasingly in EDC
• N and P removal at municipal treatment plants in D, A, CZ
• Improved agricultural practice mainly in A, D

18. Conclusions
• Danube is the main contributor to eutrophication phenomena in
WBSC.
• Nutrient concentrations in Danube River will probably meet good
status requirements.
• The actual status of WBSSA is close to “good” (except fish
population).
• The climatic conditions during the last years were favorable for
WBSSA.
• Eutrophication in WBSSA is actually phosphorus limited and the
N/P ratio is “good”.

19. • Economic crises and improved dissolved P management from point
sources were the main drivers for the improvements in WBSSA.
• Agriculture is the main driver for diffused nutrient emission to water
systems.
• Nitrogen loads which can be influenced by agricultural practice are
actually in the same order of magnitude as from point sources
(municipal waste water systems).
• For dissolved phosphorus point source are of primary importance,
particulate phosphorus mainly stems from agricultural soil erosion.
• The establishment of a clear correlation between measures taken
and the response in the status of Danube and WBSSA needs long
term reliable monitoring and adequate models.

20. • Economic situation in the EDC actually not sustainable.
Economic development can result in important increase of
nutrient discharges from diffused (agricultural development) and
point sources (sewerage development without adequate waste
water treatment).
• A nutrient management policy for all Danubian countries
enabling economic growth without compromising water quality has
to be implemented (ICPDR); relation to EU Agricultural Policy
• Changes in climate can lead to increase the pressure.
• Nutrient management needs a long lasting strategy for
sustainable development with a perspective of about 30 years for
stable success.
Anticipated Pressures for Nutrient Management in Danube Basin

21. 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
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