Spatial modeling of pesticide emissions to groundwater and surface water in the Belgian context

Transcription

1 11/10/2012 Spatial modeling of pesticide emissions to groundwater and surface water in the Belgian context Bernhard s 30 minutes => 20 minutes + 10 minutes discussion and award for best debater!

2 11/10/2012 Spatial modeling of pesticide emissions to groundwater and surface water in the Belgian Flemish context N. Stuber, I. Joris, L. Van Esch, A. Gobin, J. van der Kwast, J. Bronders, P. Seuntjens

3 Setting up a spatial model for Flanders» Definition of critical areas with risk of pesticide concentrations > 0.1 µg/l in groundwater» Use of GeoPEARL model to assess the pesticide leaching potential on agricultural areas» Establishment of a spatial schematisation for calculations» Different test runs with defined spatial model parameterisation» Calculation of percentiles of leaching concentrations (20 years)» Plausibility checks and sensitivity analysis» Further improvements 11/10/2012 3

4 Spatial model in GeoPearl» Spatially distributed leaching model of the soil plant system (Pesticide Emission Assessment at Regional and Local scales)» Use on European scale for pesticide authorisation» Higher tier risk assessments» Meetings with Aaldrik within the project 11/10/2012 4

5 GeoPEARL model - setup» Hydrological model SWAP» Pesticide fate model PEARL Input files Plot def. Weather files Soil profiles ET parameters Spatially distributed parameters Files edited in standard applications Lower boundary cond. Drainage system Crop area per plot Output files 11/10/2012 5

6 Methodology-workflow Preparation of datasets Expert judgement Long-term daily weather Soil properties Lower boundary condition Agronomic practices Climate scenarios Soil scenarios GW depths Target crop(s) Creation of maps GIS Model parameter Leaching scenarios Plausibility checks Input files GeoPEARL Output files Probalility distribution 11/10/2012 6

7 Defining weather scenarios» MARS-STAT dataset, 50 x 50 km» Gridded ECA&D dataset 0.25 (E-OBS) (EU-FP6 project ENSEMBLES) Daily time serie combinations 11/10/2012 7

8 Soil data sources Digital map of soil zones (1: ; VLM 2007) 36 soil zones Digital map of soil series (1:20.000, VLM 2007) orig: soil series Aardewerk (Noord) soil database Soil profile and horizon descriptions 11/10/2012 8

9 Soil profile data Aardewerk Noord PRNOORD ID (dig.map): Zone & serie number soil profiles - reduction to basis series ID: zone, profile & map number HORNOORD ~ Horizon descriptions - Texture (Sand, Silt, Clay) - horizon thickness and deepness - ph KCl - Organic carbon OPPNOORD Soil properties for topsoil 11/10/2012 9

10 Defining soil scenarios soil series Digital map of soil zones 36 soil zones + Digital map of basis soil series Digital map of basis soil series per soil zone soil map entities + Soil profiles relevant for Flanders (Aardewerk) profiles, ~ horizon descriptions 536 soil map units Extraction of properties for dominant soil series, covering 80% of the area per soil zone Median profile per soil serie per zone 11/10/

11 GrwLevel U n s a t u r a t e d z o n e Defining soil scenarios - Description of soil map units» Description of every soil layer in every soil map unit with: 30 cm Horizon cm 5 cm» Soil physical properties Horizon 2» Soil hydraulic properties (PTFs) 100 cm Horizon 3 10 cm 300 cm Groundwater 11/10/

12 bottom flux (cm d -1 ) gw-level (cm) Fixed gw-level (Boundary Condition constant head) P ET gw-level Time (days) bottom flux Time (days) 11/10/

13 bottom flux (cm d -1 ) gw-level (cm) Fixed bottom flux (BC constant flux) Time (days) Time (days) 11/10/

14 14/04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/ /04/2008 Example gw level check Shallower gw-table predicted Recharge: 240 mm/yr! plot8_11zeg diepte_tov_meetpunt Calculation -2m 11/10/

15 Lower boundary condition» Map on mean highest groundwater depths (van der Kwast et al.,2009) Definition of fixed groundwater level condition 0-1 m 1-2 m 2-3 m > 3 m Definition of a free drainage condition for areas with GrwLev > 3 m 11/10/

16 Developed scenarios fixed groundwater levels Soil map (536 units) Climate (MARS+ECA&D) +» Groundwater depths (4 classes) 0 1 m 1 2 m 2 3 m > 3 m Groundwater depth map (4 classes) Fixed GrwLevels & Free drainage (> 3 m) 1434 unique combinations 11/10/

17 Leaching concentrations northwestern part of Flanders» Spring application: 0.7kg D/ha» Crop type: maize» Time period: 20 yrs» Evaluation depth: 1 m b) 90th percentiles of leaching concentrations c) topsoil sand content d) topsoil organic matter content. 11/10/

18 90th and 50th percentiles of leaching concentrations» Substance properties: solubility in water, sorption to OM and persistence in soil» Spring application: 0.7kg D/ha» Crop type: maize» Time period: 20 yrs» Evaluation depth: 1m and 50 cm 11/10/

19 Sensitivity analysis % of total area of Original GrwLev map Original GrwLev map +30 cm a Original GrwLev map + 50 cm b 70 Evaluation depth 1 m 70 cm 50 cm 1 m 70 cm 50 cm 1 m cm 50 cm conc. <0.1 (μg/l) conc. >0.1(μg/L) SWAP missers c highest conc. (μg/l) /10/

20 Conclusions» Flemish GeoPEARL approach: 1434 leaching scenarios that cover environmental variability and simulate spatial pattern of pesticide leaching» Identification of vulnerable areas could be used for further higher tier risk assessments» Importance of lower boundary conditions» Importance of soil organic carbon is highlighted => further need for spatial information, depth distribution and time dynamics» Potential land use (maize only) implemented => crop map and application rate from surveys 11/10/