Nutrient concentrations at the limnic-marine transition point as an indicator for environmental targets (Art.10) under the MSFD in Germany

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1 Baltic Marine Environment Protection Commission Eighth Meeting of the Working Group on Reduction of Pressures from the Baltic Sea Catchment Area Berlin, Germany, April 2018 PRESSURE Document title Nutrient concentrations at the limnic-marine transition point as an indicator for environmental targets (Art.10) under the MSFD in Germany Code 7-11 Category INF Agenda Item 7 - Measures to reduce nutrient loads Submission date Submitted by Germany Reference Background For the implementation of the descriptor 5 eutrophication of the Marine Strategy Framework Directive (MSFD) Germany has set the environmental target Seas without significant impacts by anthropogenic eutrophication and the operational target Nutrient inputs from rivers need to be further reduced. To follow up on these targets an indicator for the nutrient concentrations at the limnic-marine transition point was established. For the follow-up assessment of the MSFD in 2018 the indicator was assessed for the first time and preliminary results are reported here using the format of an indicator fact sheet. The indicator provides an example for how nutrient reduction requirements for rivers and coastal waters have been aligned in Germany with those of the BSAP. Action requested The Meeting is invited to take note of the assessment results of the German indicator Nutrient concentrations at the limnic-marine transition point and to use the information, as appropriate, in the further discussion on aligning nutrient reduction requirements for rivers and coastal waters with those of the Baltic Sea Action Plan. Nutrient concentrations at the limnic-marine transition point as an indicator for environmental targets (Art.10) under the MSFD in Germany For the implementation of the Marine Strategy Framework Directive (MSFD) Germany has set for eutrophication the environmental target Seas without significant impacts by anthropogenic eutrophication and the operational target Nutrient inputs from rivers need to be further reduced. To follow up on this target an indicator for the nutrient concentrations at the limnic-marine transition point was established. Threshold values for this indicator were set and are laid down in the German Surface Water Ordinance. For total nitrogen a specific management target of 2.6 TN was set based on a modelling approach (Schernewski et al. 2015). This management target needs to be reached by all rivers entering the Baltic Sea. It will ensure that good ecological status of the coastal waters under the Water Framework Directive (WFD) can be achieved as well as good environmental status under the MSFD. For total phosphorus there was no need to set a management target since it was found that the river typespecific orientation values set are sufficient to achieve good status of coastal and marine waters under the Page 1 of 6

2 WFD and MSFD. The target values set for TN and TP will also contribute to achieving the country-allocated nutrient reduction targets of the Baltic Sea Action Plan. To make the target value for TN operational for water managers and in particular to formulate nitrogen reduction requirements for upstream waters the catchment model MONERIS was applied considering retention. Based on this, nitrogen reduction requirements for catchments have been set. These are used as a basis for planning measures in the respective WFD River Basins Management Plans. For the follow-up assessment of the MSFD in 2018 the indicator was assessed for the first time and the results are reported in Annex 1 using the format of an indicator fact sheet. Public consultation on the MSFD follow-up assessment is currently ongoing, hence the assessment results shown in Annex 1 are preliminary. References LAWA (2014): Prognose der Auswirkungen einer nach Gewässerschutzaspekten novellierten Düngeverordnung auf die Qualität der Oberflächengewässer in Deutschland. Bund-Länder Arbeitsgemeinschaft Wasser (LAWA), 32 pages (In German only). Schernewski, G.;Friedland, R.; Carstens, C.; Hirt, U.; Leujak, W.; Nausch G.; Neumann, T.; Petenati, T.; Sagert, S.; Wasmund, N.; von Weber, M. (2015): Implementation of European marine policy: New water quality targets for German Baltic waters. Marine Pollution Bulletin No. 51, pp Annex 1 Draft of the indicator fact sheet Nutrient concentrations at the limnic-marine transition point Key messages Key assessment Coding for reporting Based on the data of 2011 to 2015 only the rivers Schwentine, Aalbek and Warnow achieve the management target value for total nitrogen concentration. Hagener Au and Uecker only marginally fail to achieve it. Koseler Au, Lippingau and Hellbach exceed the management target value by more than double. In the same period Koseler Au, Aalbek, Warnow, Barthe and Maurine achieve the river type-specific orientation values for total phosphorus concentration. The remaining rivers fail to achieve the river type-specific orientation values only marginally, with the exception of Langballigau, the Oldenburger Graben and Duvenbaek which exceed them considerably. Table 1 contrasts the 5-year mean values of total nitrogen und total phosphorus concentrations with the management target value for nitrogen Page 2 of 6

3 and the river type-specific orientation values for phosphorus. All rivers apart from Schwentine, Aalbek and Warnow fail to achieve the target value for total nitrogen, with the highest values measured at Koseler Au, Lippingau and Hellbach. All rivers apart from Koseler Au, Aalbek, Warnow, Barthe and Maurine fail to achieve the river type-specific orientation value for total phosphorus, with the highest values measured at Langballigau, Oldenburger Graben and Duvenbaek. Table 1: 5-year mean values (2011 to 2015) for total nitrogen (TN) and total phosphorus (TP) concentrations as compared to the management target value or river type-specific orientation value in accordance with the German Surface Water Ordinance (Oberflächengewässerverordnung - OGewV). Green Management target value or orientation value achieved. Red Management target value or orientation value exceeded. River TN (Total nitrogen) 5-year mean of Target concentrations value in ( ) in TP (Total phosporus) 5-year mean of Orientation concentrations ( ) in values in : Langballigau Füsinger Au Koseler Au Schwentine Kossau Goddesdorfer Au Oldenburger Graben Aalbek Schwartau Lippingau River TN (Total nitrogen) TP (Total phosphorus) 5-year mean of concentrations ( ) in Target value in 5-year mean of concentrations ( ) in Orientation values in Hagener Au Trave Peene Warnow Barthe Duvenbeck Hellbach Maurine Recknitz Ryck Page 3 of 6

4 Stepenitz Uecker Wallensteingraben Zarnow Indicator definition Indicator purpose Policy relevance (apart from MSFD) Policy targets (apart from MSFD) Publications (with URL) Pursuant to Art. 45 (e) Federal Water Act (Wasserhaushaltsgesetz) and in implementing Art. 10 MSFD the environmental target was set as Seas unaffected by eutrophication. In order to achieve this environmental target nutrient inputs via rivers must be reduced further. Indicator for this are the nutrient concentrations at the limnic-marine transition points of rivers entering the Baltic Sea. Nutrient concentrations of rivers with estuaries outside the German territory are measured at those points where the rivers leave said territory. For the River Oder this means the monitoring station Hohenwutzen. Nutrient concentrations of rivers entering the Baltic Sea in Germany are measured at the fresh water monitoring stations at the limnic-marine transition point. The target values for nitrogen concentrations and the orientation values for phosphorus concentrations must be considered separately. For nitrogen a management target value was set pursuant to Art. 14 Surface Water Ordinance (OGewV) (as amended in 2016); it is 2.6 total nitrogen as an annual mean for rivers entering the Baltic Sea. The management plans and programmes of measures for river basin districts are oriented towards this target value in order to protect the marine waters. The target value is aimed at achieving good environmental status pursuant to MSFD (and good ecological status according to WFD). No management target was set for phosphorus as the river type-specific orientation values in the lower course of rivers entering the Baltic Sea are sufficient for determining achievement of good environmental status with regard to eutrophication (descriptor 5) in accordance with MSFD (and good ecological status in accordance with WFD). Pursuant to Appendix 7, table of the Surface Water Ordinance the river type-specific orientation values for total phosphorus as an annual mean for rivers entering the Baltic Sea are 0.10 or 0.15, depending on the river type. The indicator also contributes to monitoring achieving good ecological status in accordance with WFD and the targets of the HELCOM Baltic See Action Plan with regard to eutrophication. The indicator and its target and orientation values also contribute to achieving the targets of the HELCOM Baltic Sea Action Plan, in particular with regard to maximum allowable (nutrient) inputs (MAI) und the countryallocated reduction targets (CART) for Germany. BLANO 2014: Harmonisierte Hintergrund- und Orientierungswerte für Nährstoffe und Chlorophyll-a in den deutschen Küstengewässern der Ostsee sowie Zielfrachten und Zielkonzentrationen für die Einträge über die Gewässer. Konzept zur Ableitung von Nährstoffreduktionszielen nach den Vorgaben der Wasserrahmenrichtlinie, der Meeresstrategie-Rahmenrichtlinie, der Helsinki- Konvention und des Göteborg-Protokolls. Bund/Länder Ausschuss Nord- und Ostsee. 97 pages (in German only) _Ostsee_BLANO_2014.pdf LAWA 2017: Empfehlung für eine harmonisierte Vorgehensweise zum Nährstoffmanagement (Defizitanalyse, Nährstoffbilanzen, Wirksamkeit landwirtschaftlicher Maßnahmen) in Flussgebietseinheiten. Ständiger Ausschuss Oberirdische Gewässer und Küstengewässer LAWA AO. 42 pages (in German only) Page 4 of 6

5 Monitoringhandbuch MSRL D5 Eutrophierung (BALDE_Mon_021), Nährstoff- Einträge aus landseitigen Quellen (BALDE_Sub_083) Link Surface Water Ordinance (Oberflächengewässer-Verordnung - OGewV ): Verordnung zum Schutz von Oberflächengewässern. Bundesgesetzblatt Jahrgang 2016 Teil I Nr. 28, published in Bonn on 23 June pages (in German only) Citation (Terms for this field still to be clarified for 2018) Version Last amended: 5 December 2017 Publication date: 1 March 2018 Results explained Confidence a) Results and status --- b) Trends --- The indicator confidence has not been assessed as yet. In the future standard deviation could be used for this purpose. This depends on the number of measurements per year and flow-dependent fluctuations of concentrations. Data confidence Indicator methodology confidence: Confidence with regard to the target/orientation value: Conclusions Outlook Method Rivers flowing into the Baltic sea and failing to achieve the target value for total nitrogen concentration or the river-type specific orientation values for total phosphorus concentration require additional measures to reduce the nitrogen and phosphorus input into the rivers thus enabling achieving good environmental status with regard to eutrophication (descriptor 5 of the MSFD) in coastal and marine waters. In the future not only a 5-year mean value will be taken into account but also the gliding 5-year mean value of a time series starting in This would allow forecasts of future developments and the expected target achievement (recommended: S-value of an extended Mann-Kendall trend test). In addition to the concentration, the necessary load reduction requirement should be computed from the management target concentration and a long-term mean flow value (MQ) of the reference level. This helps assess the effectiveness of measures intended to reduce the input (LAWA 2017). First of all, a monitoring station at the limnic-marine transition point or where a river leaves German territory was determined for all the rivers. Nutrient concentrations were measured at this station at least once a month and an annual mean value was calculated. In order to compensate for flowdependent fluctuations in the concentrations a 5-year mean value is calculated from the annual mean values. (Monitoringhandbuch, LAWA 2017). While for the river basin district Oder the values of just one monitoring station have to be assessed, for the river basin districts Schlei/Trave and Warnow/Peene several monitoring stations have to be determined and their values be assessed. As yet these monitoring stations have only been determined provisionally and adjustments might be necessary in the preparation of the 3rd management cycle pursuant to WFD. At present, both Schleswig-Holstein and Mecklenburg-Vorpommern also carry out separate assessments of smaller inflows into the Baltic Sea. Furthermore, it has to be clarified whether the management target value for total nitrogen also applies to the River Oder on the border. Therefore the River Oder has not yet been assessed. Page 5 of 6

6 Assessment elements and their selection criteria: Assessment area and reporting unit (including MRU-ID): Assessment period Methodology for indicator calculation Methodology for monitoring (URL of monitoring manual) Indicator unit: Reference and threshold values and their methodological derivation: Target value for TN: 2.6. Rivertype-specific orientation values for TP: 0.1 to 0.15 Reference values and their methodological derivation: ziele_ostsee_blano_2014.pdf Reference literature (including URL): Descriptor D5 - eutrophication MSFD criterion MSFD environment al target Element (Annex III) --- Environmental target 1.1: Nutrient inputs via rivers must be further reduced. Reduction targets have been specified in the programmes of measures as part of the WFD management plans. Table 2(a) Substances, litter and energy: - Inputs of nutrients - from diffuse sources, point sources, atmospheric deposition Coastal federal Länder, river basin associations ( Flussgebietsgemeinschaften ) Procedure for national assessments in 2018 still needs to be clarified (WG Data). May not (yet) be relevant for 2018 (WG Data). Data sources Assessment dataset INSPIRE topics Access and terms of service Contact Wera Leujak (German Environment Agency UBA II 2.3) Procedure for national assessments in 2018 still needs to be clarified (WG Data). Page 6 of 6