Background

1. Building risk indicators of surface water contamination by pesticides at the small catchment scale. Taking into account spatial and temporal dimensions. Support for risk assessment and management : MIRIPHYQUE project. 2011-2013

2. Background Only few indicators exist at the catchment scale (Devillers et al., 2005). But there are still needs for : • tools to assess catchments’ potential to contaminate surface water, • methods to base the choice a priori between several mitigation solutions. … which take into account spatial distribution of pesticides uses and existing or potential buffer zones.

3. Project general aim To design a method in order to assess the potential of surface water contamination by pesticides at the small catchment scale, taking into account : spatial and temporal dimensions, man made structures’ influence on pesticides fluxes (buffer zones, ditches, banks, roads), Hypothesis Numerical simulation models versus Indicators  Hybrid method, associating indicators and hydrological modelling at the catchment scale

4. Methodology Numerical modelling at the different relevant scales Organization of simulated time-chart results in a spatio-temporal warehouse Modelling results aggregation ; statistical analysis of results, comparison with observed data. • Implementation on two catchments with contrasted agro-pedo-climatical characteristics: la Fontaine du Theil et la Morcille • Catchment typology (geology, pedology, climate, agricultural practices) in order to prepare the adaptation of developed tools from one catchment to another (similar) one.

5. Methodology Aggregating, at the catchment scale, results from modelling at the field scale, for “typical” fields and “typical” agro-pedo-climatical scenarii.  In order to lead to water quality “indicators”, CdF, and to compare them to observed data (chemical or biological data) T = return period Virtual example of resulting indicators : Concentrations exceedance durations x

6. Global chart Field Field typology typology ( ( slope slope , , soil soil ..) ..) « « Field Field » » warehouse warehouse Plot Plot scale scale model model Field Field scale scale modelling modelling results results ( ( discharges discharges end end concentrations time concentrations time - - charts charts , surface and , surface and Pesticides use Pesticides use strategy strategy (date, dose ..) (date, dose ..) subsurface subsurface R é é sultats EIS EIS « « Pesticides Pesticides » » Metrology Metrology Catchment Catchment description description Agricultural practices Agricultural practices Topological Topological connections connections Climate Climate (dry (dry year year , , wet wet year year ..) ..) « « Man made structure Man made structure » » warehouse warehouse Man made Man made Ratio of pesticides fluxes Ratio of pesticides fluxes reduction reduction , , transfer transfer from from structure model structure model surface to surface to siubsurface siubsurface Field use Field use Field use distribution Field use distribution (cultures et man made structures (cultures et man made structures « « Catchment Catchment » » warehouse warehouse Catchment Catchment agregation agregation results results : : discharges discharges and and Hydrological Hydrological model model concentration time concentration time - - charts charts Statistical Statistical analysis analysis Þ Þ Typology Typology scenarii scenarii Risk Risk indicators indicators ( ( CdF CdF ) ) Field scale modelling results (discharges and concentration time charts, surface and subsurface)

7. Methodology : Workpackage 1 Physical modelling at the relevant scales 1.1Defining pesticides uses scenarii 1.2 Field scale modelling 1.3 Man made structures modelling 1.4 Catchment scale modelling • Fontaine du Theil : • Assessment of hydrodynamical characteristics of soil layers .

8. Workpackage 1 La Morcille site Sandy soils upon weathered granite (UCS 1) Hydrodynamical characteristics (K-Psi-Theta)  Bimodal porosity.

9. Workpackage 1 Fontaine du Theil. Simulation at the field scale with MACRO (Jarvis et al, 1994) Brown non hydromorphic soil.

10. Methodology : Workpackage 2 Homogeneous unit 1 Vegetative filter strip Homogeneous unit 2 Exchange lines Exchange coefficients (surface, subsurface) • Organization of simulated time-charts in a spatio-temporal warehouse • 2.1Developing a conceptual model to represent data • 2.2 Designing a data warehouse for numerical modelling results

11. Workpackage 2 Alternative solution : SACADEAU (tree of fields outlets) • 643 outlets  simplification • Outlet trees • Field deconnection by hedges

12. Methodology : workpackage 3 • Aggregation at the catchment scale • 3.1 Design of the catchment scale aggregation method • 3.2 Validation of « SACADEAU » tool on La fontaine du Theil • 3.3 Sensitivity analysis at the different modelling scales ; reflection about implementation on other catchments • 3.4 Comparison with existing data

13. Workpackage 3 Data warehouse Simulation results ; year 2000 Field 5 : type « hydromorphic soil », slope 1% Soil occupation : winter wheat Pre emergence use of pesticides Field 3 : type « brown soil », slope 3% Soil occupation : corn Post emergence use of pesticides Vegetative filter strip. Efficiency varying with time C(outlet, t) = (f(field, buffer zone, t)) surface subsurface

14. Conclusion First year of the project. Next step : finalization of simulation results warehouse ; aggregation. Project which will lead to a method having both advantages of numerical simulations AND indicators …

15. Thank you for your attention Thanks for funding to :