runoff mitigation - setacsesss12.setac.eu/embed/sesss12/runoff_mitigation_-_a_toolbox... · runoff...

Runoff Mitigation A toolbox approach for effective

and flexible mitigation of risks

Volker Laabs BASF SE, Germany

& MAgPIE Runoff Subgroup:

Colin Brown, University of York, UK

Jeremy Dyson, Syngenta, Switzerland

Katja Knauer, Bundesamt für Landwirtschaft, Switzerland

Björn Röpke, Bayer CropScience, Germany

Manfred Röttele, Better Decisions, Germany

SETAC Europe 12th Special Science Symposium Risk mitigation measures, risk assessment and labelling in the EU 28: Introduction to the MAgPIE toolbox

Society of Environmental Toxicology and Chemistry Environmental Quality through Science®

Photo: Julie Maillet-Mezeray, TOPPS-prowadis

Outline

Introduction

Basic toolbox of proposed regulatory mitigation measures

Methodologies for risk assessment

Implementation examples

Further ideas

Conclusions

Photo: Julie Maillet-Mezeray, TOPPS-prowadis 2

Outline

Introduction




Further ideas

Conclusions

3 Photo: Julie Maillet-Mezeray, TOPPS-prowadis

Runoff Mitigation - Background

Pesticide transfer with runoff from agricultural streams to surface water has the potential to cause adverse environmental effects

Zonal registrations make basic risk mitigation options necessary for countries

Risk mitigation measures that are to be applied by farmers need to be

o Applicable to the crop rotation

o Practical and economically viable (cost, time)

o Robust enough to be effective in most of the local cases

4

Runoff Mitigation – Status in EU

So far, many MSs have different regulatory measures available to mitigate runoff: e.g.

Vegetated filter strips (different widths): BE, CZ, DE, ES, FI, FR, IT, LI, PL

Retention systems for runoff (edge of field): DE, IT

Reduced tillage: IT

Soil incorporation: IT

Band spraying: IT

No-till strips: BG

A few MSs stated that no regulatory option for runoff mitigation exists: DK, GR, NO, UK.

(Source: MAgPIE survey among participating authorities, 2013) 5

Runoff Mitigation - Goals

For zonal registrations of products that need runoff risk mitigation for a safe use…

o …a basic risk mitigation need in respect to an exposure pathway / protection goal should be defined by the zonal RMS

o … countries should establish a toolbox of measures, accepted at country level, to meet a mitigation need

o … whenever possible, farmers should be allowed to choose one/several measures from this toolbox, which - meet(s) the required mitigation need AND - fit(s) to their production system

X %

6

Influencing Factors for Runoff

• Climatic conditions

• Soil type and condition

• Soil profile permeability

Other factors:

• Slope/landscape parameters

• Pesticide water-soil distribution

• Timing of pesticide use (season / weather)

Run-off mitigation measures are complex to design and explain

Fig

.: T

OP

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Surface

Run-off

Interflow /

Drainage

Soil-

Surface

Topsoil

Subsoil

Leaching

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Influencing Factors for Runoff

Mitigation measures can only influence soil permeability and speed of run-off water

Key Factors Higher Risk Lower Risk

Precipitation event Large volume / Intense Small volume / Weak

Soil infiltration capacity &

Soil permeability

Low Fine soil texture

Capping/crusted soil

Subsoil compaction

High

Soil moisture High Low

Speed of run off water High High slope

Smooth soil surface

No barriers

Low

Distance to water Short Long

8

Runoff Types

Runoff is sub-divided into how it tends to move downslope:

… in a uniform manner (diffuse) down the whole field or part of the field

… in a concentrated manner in discrete channels

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Concentrated Runoff

Concentrated runoff & erosion channels…

„Extend“ surface water channels into fields: this often causes the highest diffuse pesticide contamination

Lead to soil loss and land degradation

May also reduce the efficiency of other

mitigation measures

(e.g. vegetative buffer strips)

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Concentrated runoff is not considered in regulatory runoff

risk assessments, being addressed by general GAP

Concentrated runoff & erosion channels need managing as a priority via GAPs (BMPs), e.g.

Mitigating Concentrated Run-off

o Ploughing across the slope

o Managing tramlines

o Establishing vegetated buffers in talwegs

o Creating edge-of-field bunds or vegetated ditches

o Constructing fascines

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Diffuse Runoff Generation

Diffuse runoff is caused by precipitation not being able to infiltrate through soil fast enough key factor to influence: soil properties on the surface and/or sub-surface

Surface Infiltration Restriction - heavy texture - poor structure - capping - low cover - topsoil compaction

Saturation Excess - heavy subsoil - plow pans & sub- surface compaction - shallow groundwater

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Outline

Introduction




Further ideas

Conclusions


Perspectives for Runoff Mitigation

Farmers: Aim to reduce runoff within the field first and then buffer the rest to be compliant with legislation and maximize land in production.

Regulators: start working from mitigating calculated transfer rates/effects in surface water, defining e.g. buffer widths for standard field scenarios.

Goal of flexible mitigation concept: enable regulators to ensure safe uses & meet environmental protection goals, while farmers mitigate runoff & farm productively

&

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Objectives of Runoff Mitigation

1. Reducing risk to an acceptable level (requirement under EC 1107/2009)

2. Sound scientific reasoning for risk mitigation effects of measures and their combinations

3. Enable a flexible approach to runoff risk mitigation in the field let farmers choose from different measures & combination of measures

4. Translation into legally acceptable and understandable label language

5. Control of implementation of measures in the field must be possible

6. MSs shall have freedom to establish specific solutions/measures in MS

7. Ideally, measures should be eligible for promotion/funding under other pieces of EU legislation (e.g. CAP, WFDir, SUDir)

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Basic Toolbox of Mitigation Measures

The following basic runoff mitigation measures are proposed:

Runoff Mitigation Measure Strength of Scientific Evidence

Basic* Mitigation

Effectiveness

Proposed Modelling Tools or Parameter Modifications

No-till / reduced tillage ++ 50% Curve number reduction: -3

In-field bunds (in row crops)

+ 50% Curve number reduction: -3

Vegetated filter strip 5 m (in field)

++ 50% Adaptation of modelling approaches needed

Inter-row vegetated strips (in permanent crops)

++ 50% Proportionate consideration of curve numbers

Vegetated filter strip 5 m +++ 40% VFSMOD

10 m +++ 65% VFSMOD

20 m +++ 80% VFSMOD

Edge-of-field bunds + 40% Calculation of water retention, infiltration, and environmental fate

Artificial wetland / Retention pond

+++ 75% Calculation of water retention, infiltration, and environmental fate

Vegetated ditch ++ 50%

In-field

Edge-of- field

Off-field

* May be differentiated according to substance polarity class (see MAgPIE Proc. Appendix 2, Table 2.3) 16

Basic Toolbox Measures No-till / Reduced Tillage

Runoff mitigation mechanism

Enhanced infiltration capacity of soil: Increased - pore continuity - soil structure - soil organic matter content

Reduced rain-splash erosion /soil capping plant residues on soil surface

Critical factors

Number and type of tillage operations

Time period of establishment

Constraints

Amount of plant residues on soil surface must be kept high (≥30%)

Depending on crop, weed and phyto-sanitary problems may arise

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Basic Toolbox Measures In-field Bunds (Row Crops)


Small bunds between cropping rows stop water flow and enable infiltration

Critical factors

Distance and height of bunds must be adapted to rainfall and soil/slope conditions

Cropping should be done across slope

Constraints

Until now, well-tested for potatoes only

If slope becomes too steep, effectiveness limited

Bunds No bunds

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Basic Toolbox Measures Inter-row Vegetated Strips (Perennial Crops)


Enhanced - water infiltration - sedimentation of eroded soil - in-situ erosion prevention …in grassed/vegetated areas.

Critical factors

Plant species need to be adapted to climate/soil

Regular mowing may be needed (erect stems)

Constraints

Competition for water and nutrients with perennial crop needs to be managed P

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Basic Toolbox Measures Vegetated Filter Strips


Enhanced - water infiltration - sedimentation of eroded soil - in-situ erosion prevention in grassed/vegetated areas.

Critical factors

Placement near runoff source critical

Plant species need to be adapted to climate/soil

Regular mowing may be needed (erect stems)

Constraints

Wet soil and concentrated flow impede effects

Loss of land for agricultural production Ph

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Basic Toolbox Measures Edge-of-field Bunds


Retaining and infiltrating runoff volume in embanked area at downslope edge of field

Critical factors

Retention volume needs to be adapted for each field (standard volume per ha to be defined)

Regular inspection after rainfall needed (danger of concentrated flow generation)

Constraints

Works best on soils of heavier texture

Annual re-establishment needed

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Basic Toolbox Measures Vegetated Ditch


Retaining and infiltrating runoff volume in vegetated ditch (not connected to streams)

Critical factors

Retention volume needs to be adapted for each slope (standard volume per ha to be defined)

Plant species need to be adapted to floodings

Regular inspection after rainfall and occasional removal of sediments needed

Constraints

Legal status as habitat for species to be clarified

Loss of land for agricultural production

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Basic Toolbox Measures Artificial Wetland / Retention Pond


Slowing down, retaining, and infiltrating runoff volume in wetlands/ponds

Pesticide removal also via in-situ sorption and degradation (plants, sediments)

Critical factors

Retention volume needs to be chosen for each slope (standard volume per ha to be defined)

Plant species need to be adapted to floodings

Yearly removal of sediments needed

Constraints

Legal status as habitat for species to be clarified

Loss of land for agricultural production

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Outline

Introduction




Further ideas

Conclusions


Runoff Assessment Methodology

Basic runoff risk assessment for Zonal Annex III

(EU FOCUS tiered modeling)

Farmers choose mitigation measure(s) from national runoff mitigation toolbox

Outcome: XY % runoff mitigation needed for reasonable worst case

Outcome: Basic runoff mitigation need (% of baseline)

Specific runoff risk assessment for MS Authorization

(National risk assessment schemes)

Farmers choose from product-specific list of mitigation

measure(s) and combinations

- General effectiveness values - Maximum flexibility - No additional regulatory work

- Product-specific calculations - Pre-determined options - Extra regulatory modelling

MS Option 1 MS Option 2

Option 1 reflects the fact that runoff reduction is key to mitigate pesticide transport. Option 2 uses specific modeling to also consider influence of substance properties.

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Runoff Assessment Option 1 Basic toolbox approach

Runoff risk mitigation

need for product: XY pts

Farmer selects single or

combination of measures to

achieve necessary number

of mitigation pts

Toolbox List

Measure 1: 70 pts

Measure 2: 50 pts

Measure 3: 50 pts

Measure 4: 40 pts

Measure 5: 30 pts

Field evidence approach: General, average effective-

ness values per measure

Farmers choose mitigation measure(s) from national runoff mitigation toolbox

Conversion function

reflects conservativeness

and combinatory rule

Simple & flexible scheme, based on general runoff reduction potential of measures.

+

Runoff risk mitigation need for

product: % of baseline

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Runoff Assessment Option 2 Modelling Approach

Modeling 1 (e.g. using FOCUSsw,

VFSMOD, other

national models)

Modeling 2 (calculating combinatory effects,

e.g. via curve number ajdustments

for in-field measures)

Farmers choose from product-specific list of mitigation

measure(s) and combinations

Farmer chooses from list of

approved measures or their

combinations

Measure 1: 62 %

Measure 2: 50 %

Measure 3: 48 %

Measure 4: 36 %

Measure 5: 25 %

Measures 1+2: 82 %

Measures 1+3: 75 %

Measures 2+4: 55 %

List of Measures

Measure 1: 62 %

Measures 1+2: 82 %

Measures 1+3: 75 %

Modelling approach: product-specific

calculations per measure

Modeling-based scheme, based on specific calculations for measures/combinations.

Runoff risk mitigation need for

product: % of baseline

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Outline

Introduction




Further ideas

Conclusions


Example for Flexible Runoff Mitigation

Example: The virtual herbicide Super-Antiherb is evaluated at zonal level for use in corn and winter wheat.

The regulatory risk assessment for the product identified a risk mitigation need for surface runoff: 75% reduction of runoff needed in winter wheat 90% reduction of runoff needed in corn

Photos: TOPPS-prowadis 29

Flexible Runoff Mitigation Implementation in Country A

National risk mitigation approach: Basic toolbox of measures

The % mitigation need is translated into mitigation points: Winter wheat: 75% = 56 pts Corn: 90% = 86 pts Combination of measures result in additive points.

Defined national toolbox of measures for farmers to choose from, e.g.

No-till 30 pts Edge-of-field VFS 10 m 44 pts

In-field VFS 5 m 30 pts Edge-of-field VFS 20 m 64 pts

Edge-of-field VFS 5 m 21 pts Vegetated ditch 30 pts

Runoff mitigation

effectiveness

(%) Points

40 21

45 25

50 30

55 34

60 39

65 44

70 50

75 56

80 64

85 73

90 86

95 106

99 130

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Farmers‘ choice to manage risks at field level:

Winter wheat (56 pts needed)

o Field 1 (Farmer X): 10 m VFS & vegetated ditch

o Field 2 (Farmer Y): no-till & 5-m in-field VFS

Corn (86 pts needed)

o Field 1 (Farmer X): no-till & 5-m in-field VFS & vegetated ditch

o Field 2 (Farmer Y): 5 m in-field VFS & & 10 m VFS & vegetated ditch

+

+

+

in field edge of field


Flexible Runoff Mitigation Implementation in Country A

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Flexible Runoff Mitigation Implementation in Country B

National risk mitigation approach: Modelling-based mitigation tools

Modelling approach to evaluate the measures or combinations that cover the required % mitigation need ( acceptable TER)

Example results for modelling exposure calculations (e.g. for corn):

The product label would then list the acceptable measures/combinations, e.g.

o Winter wheat: 10 m VFS, 5 m VFS & no-till, 5 m VFS & vegetated ditch

o Corn: 20 m VBS, 10 m VFS & no-till, 5 m VFS & vegetated ditch & no-till

Modelling Step FOCUS scenario (acceptable conc.: 7 µg/L)

R1 pond R1 stream R2 stream R3 stream R4 stream

FOCUS Step 3 0.33 16.7 15.3 31.2 41.4

Step 4: 20-m VFS 0.09 0.42 0.56 5.15 0.42

Step 4: no-till 0.21 3.62 12.1 17.2 39.1

Step 4: no-till & 10-m VFS 0.14 0.81 1.07 6.28 0.08

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Farmers‘ choice to manage risks at field level:

Winter wheat (list of options on label)

o Field 1 (Farmer X): 5 m VFS & vegetated ditch

o Field 2 (Farmer Y): no-till & 5 m VFS

Corn (list of options on label)

o Field 1 (Farmer X): 20 m VFS

o Field 2 (Farmer Y): no-till & 10 m VFS

+

+



+

Flexible Runoff Mitigation Implementation in Country B

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Risk Phrases for Runoff Mitigation

Option 1: Basic runoff mitigation toolbox

SPe X1: To protect [aquatic organisms] only apply to fields [adjacent / within Y m to surface water] where approved mitigation measures(s) with [X% reduction of runoff potential / XY runoff mitigation points] are implemented. The official reference for approved mitigation measures is [detail official reference].

Option 2: Product-specific list of runoff mitigation measures/combinations

SPe X2: To protect [aquatic organisms] only apply to fields [adjacent / within Y m to surface water] where one of the following measures / measure combinations to mitigate runoff are implemented: [detail the list of appropriate measures or combinations thereof].

For both options, an official list/toolbox of accepted mitigation measures is needed: to specify in detail the correct establishment & maintenance procedures for each measure to define auditable criteria for adequate measure implementation

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Control of Measures in the Field

Prerequisites of efficient control are well-defined mitigation measure criteria and maintenance rules

Most measures are easy to control during the season, e.g.

o No-till / reduced tillage

o Vegetated filter strips

o Edge-of-field bunds

o Artificial wetland /retention pond

o Vegetated ditch

Other measures might need right-on-time control or photo documentation (time & GPS tracked), e.g.

o In-field bunds Ph

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Outline

Introduction




Further ideas

Conclusions


Ideas on Concentrated Runoff

In principle, concentrated runoff should be prevented by farmers based on GAP (soil & water protection)

If this pollution pathway shall be covered via pesticide legislation, a risk phrase may be defined (either for all or only for specific products)

SPe Y: To protect [aquatic organisms] only apply to fields [within Y m to surface water] where concentrated runoff is prevented by appropriate measures (see [detail official reference for concentrated flow mitigation measures]).

An official list of mitigation measures, detailing correct implementation and maintenance is needed

Control can also be based on diagnosis of erosion traces in the field

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Ideas on Holistic Runoff Prevention

In reality, the major part of runoff is caused by only a few fields in a catchment

To stimulate field-specific runoff diagnosis/ prevention schemes (e.g. Aquavallee, TOPPS- prowadis) the following risk phrase could be used:

SPe XY: These product-specific runoff mitigation obligations may be superseded by implementing field-specific runoff mitigation measures on the field/farmland, based on the participation in an officially approved national runoff risk diagnosis and management scheme ([detail names of officially accepted diagnosis systems]).

Control is based on documentation of diagnosis and control of implementation of measures on the ground

Fig.: TOPPS-prowadis

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Catchment Risk Diagnosis TOPPS / Aquavalle Concept*

Catchment Catchment (field visit) Plot (field visit) Plot & Catchment

Adapt tillage

practices and

cropping

Position and

establish buffer

zones, wetlands,

hedges, etc….

Adapt application

timing and pesticide

use

1 3 4 5 Plot (field visit)

2

Climate, soils, geology,

landscape elements,

cropping, farms …

Basic run-off risk during

spring/summer and

autumn/winter time

Data collection: Identification of soil

water flow regime:

Refinement of the basic

run-off risk for each plot

Identification of water

flow pathways & critical

landscape elements:

Tillage practices, crop

rotation, pesticide use

Mapping of farmer

practices:

Assign mitigation

measures to fields &

establish catchment

management plan:

Fig. : Arvalis Institute de Vegetal, FR 39

* TOPPS concept based on Aquavalle concept by Arvalis Institute de Vegetal, FR

Outline

Introduction




Further ideas

Conclusions


Conclusions

Effective runoff mitigation must consider highly variable pedo-climatic conditions, catchment topographies, and application-precipitation timing

Due to the complexity of crop rotations and farming conditions, farmers should be able to choose from a list of mitigation measures and their combinations

A risk mitigation concept and risk phrases were proposed to accommodate this flexibility

MSs would need to define a national list of appropriate measures and to re-evaluate the proposed mitigation effectiveness values/modelling approach


Thanks for your attention!

Any questions?

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