The Bioforsk and NIVA SeaLink Team:

1. Pros and cons of using INCA and SWATfor modelling the effects of mitigation measures: tillage, fertilization, buffer strips and wetlands The Bioforsk and NIVA SeaLink Team: Csilla Farkas, Johannes Deelstra, Per Stålnacke, Line Barkved,TuomoSaloranta, Øyvind Kaste, Richard Wright

2. The INCA model family Aquatic Environments Research Centre, Dep. of Geography, Univ. of Reading INCA and EURO-Limacs European Projects • INCA-N model (flow, nitrate and ammonium) • Brazil, Denmark, England, Finland, France, Netherlands, Norway, Spain, Sweden, Wales • INCA-SED (sediment transport and erosion) • Denmark, England, Finland, Norway • INCA-P • England, Finland (is being parameterized for Skuterud at the moment) • INCA-C • England, Finland • Other version for heavy metal transport etc. • Romania

3. The INCA models INCA model: • process-based • semi-distributed model of the N-cycle in the plant/soil and in-stream systems • dynamic INCA simulates at a daily time-step • water flow and storage • soil, N and P export from different land-use types within a river system • in-stream SS, nitrate, ammonium, total P and dissolved P concentrations Catchment hydrology: • direct runoff • soil zone • groundwater zone

4. 120 100 80 60 40 20 1 11 21 120 100 80 60 40 20 1 11 21 The INCA-N (Integrated Nitrogen in CAtchments ) model of the flow of nitrogen and water through a river basin Driving variablesin daily time-step • Average annual riverine load of N, P or SS • Soil loss and N and P- balance elements for different land use types • soil moisture deficit • hydraulically effective rainfall • air temperature • actual precipitation INCA Model parameters Daily estimates of water discharge and SS, NO3 , NH4 , TP, TDP concentrations in river water • sub-catchment • reach • in-stream • land-phase • general parameters

5. The structure of the INCA models In-stream cell Cell Model Land component Evaporation Precipitation Surface runoff to stream Hydraulically effective rainfall Soil surface Soil zone Transport to stream = (1 – b) * qsz Percolation = b * qsz Groundwater zone Transport to stream = qgz

6. Introducing different management strategies and mitigation measures in the INCA models The INCA models are semi-distributed • the location-specific mitigation measures can not be directly introduced in the model The models calculate for 6 different land use groups, but their retentions and losses are assumed of that of a “box” Management options, that can be considered in the INCA models • soil tillage (timing (directly), tillage systems (indirectly)) • mineral fertilization, manure – directly (timing and amount) • deposition – directly • channel or river bed changes, effecting the instream retention capacity – indirectly • wetlands – as a separate land use class, YES, as an accumulator of losses from other land use sectors – NO • vegetation buffer zones – NO • sedimentation ponds – NO

7. Possible future development • incorporation of vegetation buffer zones directly • incorporation of sedimentation ponds • incorporation of wetland retention • advanced calculation of winter conditions (freezing – thawing cycles) • uncertainty analyses tool for INCA-SED and INCA-P

8. Do we have models to deal with those situations Several models have been tested for Norwegian catchments • SWAT (water balance, nutrient and soil loss) • The SWAT model has also been applied in Norway as part of EuroHarp and Striver, two EU – projects (large scale). The model is tested now in Skuterud. • Needs modification (saturation from below, subsurface drainage, winter) • DRAINMOD, developed at NCSU (Skaggs) simulating subsurface drainage/surface runoff/nitrogen dynamics • HBV – model (hydrology) • INCA – model (hydrology, nutrient dynamics) • SOIL/SOIL_NO and COUP (hydrology,nitrogen); have been tested (developed by SLU) • AgriCat

9. The modelling process Step 1. Start a model journal Step 2. Set up a modelling project Step 3. Select and set up the model – Benchmark criteria Step 4. Analyse the model (sensitivity analyses & calibration) Step 5. Using the model (simulations & uncertainty analyses) Step 6. Interpret the results Step 7. Report • Van Waveren et al., 1999. Good modelling practice. A handbook.

10. Step 3. Select and set up the model the Benchmark criteria Benchmark criteria (Saloranta et al., 2003) provides a structured way to evaluate the suitability of model codes to be used in decision making Evaluation: 14 questions, 3-level scoring system Q1.1. How well does the model’s output relate to the management task? Q1.2. How well does the model’s span and spatio-temporal resolution compare with the requirements of the task? Q1.3. How well the model has been tested? (under conditions of the study site) Q1.4. How complicatedis the model in relation to the task? Q1.5. How is the balance between the model’s input data and data availability? Q1.8. How is the peer acceptance for the model with scientific theory? Q3.5. How is the model’s flexibility for adaptation and improvements? Saloranta, T.M et al., 2003. Benchmark criteria: a tool for selecting appropriate models in the field of water management. Environmental Management 32, 322-333.

11. Model choice – considerations and compromises • The model has to provide physically based description of the main processes governing erosion and phosphorus leaching from agricultural catchments • Model output input requirements of the MyLake model • Time resolution /fine enough to follow process dynamics but avoiding robustious calculations/ • Spatial resolution / fine enough to consider incorporation of different land use types but considering, that only integrated values from the particular catchment are needed/ • Applicability for physico-geographical conditions of Southern Norway • Available dataset and information driving variables; model parameters

12. Select and set up a model • Evaluated model codes are presented in a Table • Evaluation is connected to the following management/modelling task: „Describing surface water runoff formation and nutrient mobilisation in the Vansjø lake catchment in order to provide appropriate input data for the MyLake model and to analyse response of the whole system to future environmental changes using climate change scenarios.” (???) • MyLake model non-meteorological driving variables: • Inflow volume [m3 d-1] • Inflow temperature [Co] (can be set as missing value) • Inflow concentration of the passive tracer [-] • Inflow concentration of the passive sedimenting tracer [-] • Inflow concentration of dissolved inorganic phosphorus (phosphate) [mg m-3] • Inflow concentration of chlorophyll a [mg m-3] • Inflow concentration of particulate phosphorus [mg m-3]

13. Interactive model selection and set up Possible answers: Good; Adequate; Inadequate

14. Coming back to the “Morsa scenarios” 

15. Comparing the SWAT and INCA models with respect to representation of mitigation measures

16. SWAT Creating Hydrological Response Units Soil map Landuse map DEM map INCA Spatial resolution 36 subbasins 1869 HRU’s

17. Management , crop rotation SWAT

18. Comparing the SWAT and INCA models Model selection – particular case NO model can substitute the experts knowledge BUT Any model, used on a wise way – understanding its strengths and weaknesses - can be a useful tool in decision making