Assessing SWAT model performance in the evaluation of management actions for the implementation of the Water Framework Directive in a Finnish catchment

The ecological status of Lake Pyhajarvi may be classified as moderate due to its elevated nutrient concentrations and algal biomass production. Therefore, the Eurajoki river basin, including Lake Pyhajarvi, has been chosen as the Finnish test catchment in an EU project on benchmarking models for the Water Framework Directive. One aim of the project is to test the suitability of models for the assessment of management options proposed to meet the surface water quality targets. The catchment model SWAT is currently being tested for its applicability for analysing the effectiveness of proposed measures to reduce agricultural and sparse settlement nutrient loading. The model is being applied to the river Ylaneenjoki catchment draining to Lake Pyhajarvi. First results indicate that SWAT can be calibrated for flow and sediment yield using catchment scale parameters. For nutrients, however, parameters describing more detailed catchment processes have to be calibrated. The preliminary essay on measures such as buffer strips indicate that SWAT includes relevant management options that affect nutrient leaching. However, the descriptions of these management options require some modifications in order to describe correctly the reduction efficiency in local conditions.

[1]  Effect of soil tillage on erosion and nutrient transport in plough layer runoff , 1994 .

[2]  Axel Bronstert,et al.  Modelling river discharge for large drainage basins: from lumped to distributed approach , 1999 .

[3]  Lars Bergström,et al.  Simulated nitrogen dynamics and losses in a layered agricultural soil , 1987 .

[4]  E. Turtola,et al.  The interactions of buffer zones and phosphorus runoff , 1996 .

[5]  N. Haycock.  Buffer zones : their processes and potential in water protection : the proceedings of the International Conference on Buffer Zones, September 1996 , 1997 .

[6]  W. G. Knisel,et al.  Gleams model application on a heavy clay soil in Finland , 2000 .

[7]  P. Ekholm,et al.  Internal and external loading as regulators of nutrient concentrations in the agriculturally loaded Lake Pyhäjärvi (southwest Finland) , 1997, Hydrobiologia.

[8]  Ilona Bärlund,et al.  Modeling sediment yield and phosphorus transport in Finnish clayey soils , 2001 .

[9]  Tuomo M Saloranta,et al.  Benchmark Criteria: A Tool for Selecting Appropriate Models in the Field of Water Management , 2003, Environmental management.

[10]  H. Gijzen.  Anaerobic digestion for sustainable development: a natural approach , 2002 .

[11]  B. Braskerud,et al.  Buffer zones and constructed wetlands as filters for agricultural phosphorus. , 2000 .

[12]  Ilona Bärlund,et al.  Ranking of parameters on the basis of their contribution to model uncertainty , 2001 .

[13]  John R. Williams,et al.  LARGE AREA HYDROLOGIC MODELING AND ASSESSMENT PART I: MODEL DEVELOPMENT 1 , 1998 .

[14]  Hans-Georg Frede,et al.  SWAT-G, a version of SWAT99.2 modified for application to low mountain range catchments , 2002 .

[15]  Rebecca A. Kelly,et al.  Policies and tools for sustainable water management in the European Union , 2005, Environ. Model. Softw..

[16]  J. Grönroos,et al.  Estimation of the impact of fertilisation rate on nitrate leaching in Finland using a mathematical simulation model , 2000 .

[17]  Fayçal Bouraoui,et al.  Modelling diffuse emission and retention of nutrients in the Vantaanjoki watershed (Finland) using the SWAT model , 2003 .

[18]  E. Turtola,et al.  Nitrogen and phosphorus losses in surface runoff and drainage water after application of slurry and mineral fertilizer to perennial grass ley , 1998 .

[19]  A van Griensven,et al.  Sensitivity analysis and auto-calibration of an integral dynamic model for river water quality. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.