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Brian Kronvang EEA Workshop 11-12 September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology.

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Presentation on theme: "Brian Kronvang EEA Workshop 11-12 September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology."— Presentation transcript:

1 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Brian Kronvang National Environmental Research Institute, Dept. Freshwater Ecology, University of Aarhus, Silkeborg, Denmark Ensemble modelling of diffuse nutrient loads and sources in EUROHARP catchments: Uncertainty in applying different models and the problem with retention

2 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology No European best model was nominated by the EUROHARP project ( ) but we learned a lot about models and the EUROHARP Toolbox is a potential money saver tool for catchment managers

3 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Conclusions and recommendations regarding nutrient emissions Net nutrient loads should always be quantified using monitoring/modelled results – the net load is the most accurate estimate as shown in EH. Gross nutrient emissions from background or non- anthropogenic sources should be quantified independently using monitoring data or models. Nutrient retention in surface waters should be quantified independently using model estimates at water body or river basin scale (EUROHARP NUTRET tool). EUROHARP has shown that ensemble modelling is a possible way forward to ensure that an estimate of the uncertainty involved in especially nutrient load partitioning can be given. Application of more than one model will be useful in the future emission reportings as e.g. one simple pan-European method (statistical model), one load apportionment method and one country specific method (source oriented).

4 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Continued Agricultural emissions should always be reported using three indicators: 1.Nutrient surplus 2.Leaching from root zone (1 m) (gross emission to groundwater and surface water). 3.Gross emission to surface water – edge of surface waters HYDROLOGICAL DATA IS CRUCIAL BEFORE EVERYTHING ELSE. OSPAR HARP-NUT has developed several guidelines concerning nutrient losses also an updated guideline 6 on diffuse nutrient losses and guideline 9 on nutrient retention both based on EUROHARP results is to be prepared by Denmark. EUROHARP has created a tool box to assist catchment managers in chosing the best model(s) for a given river basin.

5 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Nutrients Point Sources Nutrient Retention Nutrients Diffuse Sources Ecology of water body types Nutrients Reference Conditions WFD sets new standards and requirements for calculation of nutrient sources, emissions and retention in catchments with the purpose of achieving a concentration in surface waters below the level required for obtaining a good ecological quality

6 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Background concentrations of nitrate-N in Danish surface waters – large regional differences

7 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Nutrient losses from fields to surface waters – the problem of retention Surplus Leaching Root Zone Surface runoff Subsurface emission subsurface retention (b) surface water retention (c) Point sources, background, atm. deposition wetland retention (d) Catchment export Total retention = a+b+c+d+e root zone retention (a) buffer zone retention (e)

8 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Estimated Nitrogen retention in groundwater and surface waters for different Danish catchments used for WFD River Basin Management plans

9 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Daily simulations of flow and solute concentrations Annual predictions based on export coefficient approach Process oriented (deterministic) Data oriented (empirical) High Low Level of complexity Model type Methods differ profoundly in their complexity, level of process representation and data requirements SA NOPOLU REALTA NL-CAT SWAT NLES-CAT MONERIS EVENFLOW TRK EUROHARP model tools

10 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Nutrient emissions – the EUROHARP definitions

11 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Location of the EUROHARP river catchments and diffuse gross N-losses to surface waters

12 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Large differences in the bias involved when modelling net N export from European catchments

13 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology The mean deviation between the P-loads calculated by linear interpolation or by the OSPAR method is ~22%. More than 1/3 of the deviation between the model results for P-loads are due the uncer- tainty of the observed P-load Higher deviations occur also for Southern European catchments. Precision of loads depends on substance, observation frequency and catchment size.

14 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology

15 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology

16 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Mean deviation when modelling nitrogen (N=66) and phosphorus (N=50) in 17 EUROHARP catchments Mean deviation N P Net load (export from catchment):27% 41% Gross loss from agricultural land:37% 67% Gross loss from other diffuse sources:67% 75%

17 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology Nutrient retention in surface waters was the factor experiencing the largest variation between models.

18 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology EUROHARP Nutrient Retention Software - NUTRET Offer nutrient retention calculations in different Tiers Tier 1: Simple-Tier 5: Advanced

19 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology In future more emphasis has to be drawn on delivering nutrient modelling results from modellers to managers with some measure of the uncertainty involved

20 Brian Kronvang EEA Workshop September 2008 U N I V E R S I T Y O F A A R H U S Danish Environmental Research Institute Department of Freshwater Ecology General information about the EUROHARP project, partners and modelled European catchments Tools and models used in project, search in model capabilities, add new tools Educational pages related to diffuse pollution from European catchments, guidelines Policy instruments; European and international, relating to diffuse pollution Water Framework Directive


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