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The Oder/Odra estuary case study (SSA 3)

G. Schernewski, H. Behrendt, M. Grossmann, J. Hirschfeld, T. Neumann & N. Stybel

Peene- Policy Issue: strom Oder/Odra Estuary en ag Water quality improvement & eutrophication abatement sh arl K itz Baltic Sea ow inn in Z p w em ro e Pomeranian Bay Background & ecological dysfunctions: Already for centuries, the river basin Wolgast Z se se Dziwna N Ko in olp itz (Oder Bay) is under strong human influence. Agricultural land covers 70% of the upper K er e ck j R Szczecin Ü ro E in rf d river basin and 58 % of the middle basin. However the contribution of D W E s o z an sd y O B ng z Finland NOTEC eri ck d agriculture to the gross product is only 3.9 %. Several larger cities and many H e Swina ie hlb S A M WA industries are located in the river basin (total population 15.4 millions). The RTA Usedom Wolin cie Swe- oujs nitrogen (N) and phosphorus (P) loads in the early 1960’s were already high (N: Anklam win den Zielona Poznan S Baltic 50,000 t/a; P: 6,000 t/a), increased further and reached its maximum during Sea Kleines Haff the 1980’s (N: 116,000 t/a; P: 16,000 t/a). Due to economic changes, warm Oder/Odra Glogow O Lodz Szczecin (Oder-) Poland and dry years as well as improved sewage treatment a significant decrease of D River Basin N Lagoon

R E A Germany I Wielki Zalew

S nutrient loads took place until the late 1990’s (N: 94,000 t/a; P: 8,500 t/a).

S Wroclaw Ueckermünde E The Odra river flows through Szczecin and enters the large, shallow Szczecin Poland Germany (Oder) Lagoon. The river and its loads are responsible for the poor water Catchment of the coast O 10 km quality in the lagoon and its highly eutrophic state. Temporary anoxia, fish (10 000 km²) D Oder/Odra R kills, algae bloom and poor water transparency reflect the poor water quality River basin of the Oder A Map of the Ode/Odra river basin and the estuary (120 000 km²) Katowice state. Ostrawa Major pollution ‘hot spots’ Major Questions: Process: A systematic and comprehensive analysis of existing regional ¾How do different stakeholders perceive documents ended in a list of most important regional policy issues. The water quality? availability of a political commitment with pre-defined focus issues (German- CATWOE DPSIR Polish Regional Agenda 21), discussions with Federal State (Land Mecklenburg- ¾What are their demands with respect to Vorpommern) ministries and authorities (what would they support) as well as Customers: Driver: water quality? the competence of the (project) consortium were finally responsible for the Beneficiaries: The coastal community and Intensive human activities in the ¾Would a “good” water quality (according to choice. This choice does not reflect the priority setting in the region itself but coastal tourism river basin the Water Framework Directive) satisfy all political reasons, a lack of competence, a lack of a critical financial mass etc. (Victims): Farmers, industries and stakeholders? did not allow to tackle other issues. communities in the river basin ¾Can a “good” water quality be reached in the Actors: Pressure: entire estuary? If no, what would be the System definition: High input of N and P into the alternatives? European Union (through the Water Physical system: Framework Directive), the Oder/Odra coastal system ¾Which measures in the river basin are Social & Baltic Sea Coastal waters (model ERGOM) Commission and regional authorities necessary? Administrative system: Pommeranian Bay German coast Transformation: ¾Which nutrient sources have to be tackled 2 Districts State: Changes in land use & farming practice, preferably? Economic system: Concentrations of N, P, Chl.a; Coastal region reduced fertilizer application & improved ¾On which nutrient (nitrogen or phosphorus) water transparency sewage treatment should the focus be? Social & administrative system:

¾What are the costs for reaching a good water R Polish coast (Woiwodship) Worldview: E Szczecin D quality status? O The majority of the society perceives Impact: NOTEC W eutrophication as a major coastal ecological ¾How would a cost-efficient approach look ART Ecological: Eutrophication, N A problem (with strong economical and social like? algae blooms, fish kills Zielona Poznan implications) ¾Which measures in the estuary would support W E Social & economic: hampered Owners: a water quality improvement and how S Glogow bathing tourism O Lodz efficient will they be? N D

R E

A

Farmers, industries and communities in the I Oder/Odra S ¾How long would it take to reach a good S Wroclaw river basin E Economic system: status? River Basin River basin Environment: Response: Catchment of the coast (10 000 km²) O Regulatory laws, administrative structure, Improved nutrient management D River basin of the Oder R Physical system: biological carrying capacity, morphometric in the river basin A (120 000 km²) Katowice River basin and hydrodynamic situation Major pollution ‘hot spots’ Ostrawa (Model MONERIS) Conceptual models

(from Behrendt & Dannowski 2005) The models MONERIS and ERGOM will be used. Both models are (after Behrendt & Dannowski 2005) Atmospheric deposition Urban areas documented, calibrated and validated Paved population Precipitation urban areas runoff Erosion Surface runoff MONERIS is applied to calculate the nutrient inputs and loads in the Slope Arable land Soil loss Runoff surface Surface runoff area (km²) (mm/a) Combined sewer system Separte sewer system entire Oder River basin. The model calculates the annual nutrient Sediment P, N concentration N, P in input N, P in sus- Sewers without WWTP top soil pended solids No sewage load into the coastal waters, resulting from point and various diffuse P, N input Loss per Discharges sources. MONERIS is based on a geographical information system P, N i np u t inhabitant P, N input (GIS), which includes various digital maps and extensive statistical Tile drainage information. The use of a GIS allows a regional differentiated N-surplus Field capacity Leakage Point sources Municipal sewage Industrial discharge quantification of nutrient emissions into river systems. Tile drained P, N Precipitation Retention drain flow in river Fish farms Digital area concentration elevation Nitrogen Nitrogen To be able to run the model, large amounts of spatial information P, N input Water content in discharge P, N input model Land use surplus of arable soils had to be compiled and transferred into the GIS: The river system, N & P agricultural Ground water load areas catchment and administrative borders, land use classifications, soil Average N-surplus Average 1995 Seepage annual maps, topographical information, ground water tables, hydro- N in seepage water level precipitation annual Atmospheric evaporation deposition geological and hydro-meteorological information as well as data on N-retention Water balance Residence Depth of atmospheric deposition, river flow and water quality. Details about N in groundwater Base- & inter- time flow groundwater sources and data quality are given in Behrendt & Dannowski (2005). Schernewski (2007) table P, N i np u t Point discharges from waste water treatment plants and industrial Data requirement for the river basin model MONERIS entering the river system directly, but diffuse emissions into surface Conceptual model of the river basin model MONERIS and the waters have very different pathways and have to be modelled nutrient loads towrds the coast

(after Behrendt & Dannowski 2005, Grossmann 2007) separately. Nutrient Nutrient Measures Basis features: input Altogether six diffuse pathways are considered in MONERIS: point N-Fixation2 Blue-Greens pathways P. only (sub-models) sources Agricultural policy sources, atmospheric deposition, erosion, surface runoff, Spatial coverage: Estuary & Mortality Detrit. Baltic Sea Diatoms Atm. deposition Nutrient surplus Soil concervation groundwater, tile drainage and paved urban areas. Along the Horizontal grid: 1.8 km Grazing Zoopl. tillage Vertikal grid: 1.5 m Flagellates Surface runoff Soil loss pathway from the emission source into the river many Riparian buffer Calculation time step: 6 minutes Respira- Solar radiation Uptake Erosion Sediment transformation, retention and loss processes have to be taken into Temporal resolution of input tion deliverable area Regulation of data: 3-6 hours P Settling Resuspen- Tile drainage drainage & account. Water sion Drainage area drainage ponds discharge N & P & flow NH4 Recycling Ground water load Fen wetland & The ecosystem model ERGOM is an integrated biogeochemical model Nitrifica- floodplain reactivation Denitrifi- tion NO3 linked to a 3D circulation model covering the entire Baltic Sea. The cation Sediment Urban areas Atmosph. Urban areas O-Input2 O2 Drainage of biogeochemical model consists of nine state variables. The nutrient Population urban areas Point sources state variables are dissolved ammonium, nitrate, and phosphate. Storm water Industrial State retention & Primary production is provided by three functional phytoplankton variable discharge treatment groups: diatoms, flagellates and cyanobacteria (blue-green algae). Process Connection to WWTP decentral WWTP Diatoms represent larger cells which grow fast in nutrient-rich WWTP technology Wind 1.8 km conditions. Flagellates represent smaller cells with an advantage at (after Neumann et al. 2002) Source: lower nutrients concentrations especially during summer conditions. 1.5 m Behrendt et al. (2007) The cyanobacteria are able to fix and utilize atmospheric nitrogen, and therefore, the model assumes phosphate to be the only limiting Links between Economic and agricultural measures, nutrient nutrient for cyanobacteria. Due to the ability of nitrogen fixation, Conceptual model of the coastal water and Baltic Sea model input sources and the nutrient pathways in the river basin cyanobacteria are a nitrogen source for the system. ERGOM