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Modeling diffuse soil contamination from agriculture. introduction. SUMMARY: Soil contamination, as defined in the Soil Thematic Strategy. Local soil contamination and Diffuse soil contamination Modeling Tools of Diffuse soil contamination. SWAT Description SWAT application, two cases - PowerPoint PPT Presentation

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Page 1: Modeling diffuse soil contamination from agriculture

Modeling diffuse soil contamination from agriculture.

Page 2: Modeling diffuse soil contamination from agriculture

SUMMARY:SUMMARY:•Soil contamination, as defined Soil contamination, as defined in the Soil Thematic Strategy.in the Soil Thematic Strategy.

•Local soil contamination and Local soil contamination and Diffuse soil contaminationDiffuse soil contamination

•Modeling Tools of Diffuse soil Modeling Tools of Diffuse soil contamination.contamination.

•SWAT DescriptionSWAT Description

•SWAT application, two casesSWAT application, two cases

•Leaching Modeling. Pesticide Leaching Modeling. Pesticide soil contamination. soil contamination.

•PRZM and PEARL descriptionPRZM and PEARL description

•PRZM and PEARL applicationPRZM and PEARL application

•ConclusionConclusion

introduction

Page 3: Modeling diffuse soil contamination from agriculture

Soil contamination, as defined in the Soil Thematic

Strategy.

introduction

The introduction of contaminants in the soil may result in The introduction of contaminants in the soil may result in

damage to or loss of some or several functions of soils and damage to or loss of some or several functions of soils and

possible cross contamination of water. The occurrence of possible cross contamination of water. The occurrence of

contaminants in soils above certain levels entails multiple contaminants in soils above certain levels entails multiple

negative consequences for the food chain and thus for negative consequences for the food chain and thus for

human health, and for all types of ecosystems and other human health, and for all types of ecosystems and other

natural resources. natural resources.

Page 4: Modeling diffuse soil contamination from agriculture

Local and Diffuse Soil contamination, Sources.introduction

Local (or point source) contamination is generally Local (or point source) contamination is generally associated with mining, industrial facilities, waste associated with mining, industrial facilities, waste landfills and other facilities both in operation and landfills and other facilities both in operation and after closure.after closure.These activities can pose risks to both soil and These activities can pose risks to both soil and water.water.

Local Soil contamination, Sources.Local Soil contamination, Sources.

Diffuse pollution is generally associated with atmospheric deposition, certain farming practices and inadequate waste and wastewater recycling and treatment.

Diffuse Soil contamination, Sources.Diffuse Soil contamination, Sources.

Page 5: Modeling diffuse soil contamination from agriculture

Diffuse Soil contamination, Sources.

introduction

•Atmospheric deposition is due to emissions from industry, traffic and Atmospheric deposition is due to emissions from industry, traffic and agriculture. Deposition of airborne pollutants releases into soils acidifying agriculture. Deposition of airborne pollutants releases into soils acidifying contaminants (e.g. SO2, NOx), heavy metals (e.g. cadmium, lead arsenic, contaminants (e.g. SO2, NOx), heavy metals (e.g. cadmium, lead arsenic, mercury), and several organic compounds (e.g. dioxins, PCBs, PAHs).mercury), and several organic compounds (e.g. dioxins, PCBs, PAHs).

•Production systems where a balance between farm inputs and outputs is Production systems where a balance between farm inputs and outputs is not achieved in relation to soil and land availability, leads to nutrient not achieved in relation to soil and land availability, leads to nutrient imbalances in soil, which frequently result in the contamination of ground- imbalances in soil, which frequently result in the contamination of ground- and surface water.and surface water.

•Pesticides are toxic compounds deliberately released into the Pesticides are toxic compounds deliberately released into the environment to fight plant pests and diseases. They can accumulate in the environment to fight plant pests and diseases. They can accumulate in the soil, leach to the groundwater and evaporate into the air from which soil, leach to the groundwater and evaporate into the air from which further deposition onto soil can take place.They also may affect soil further deposition onto soil can take place.They also may affect soil biodiversity and enter the food chain.biodiversity and enter the food chain.

•With regard to waste, sewage sludge, the final product of the treatment With regard to waste, sewage sludge, the final product of the treatment of wastewater, is also raising concern. A whole range of pollutants, such of wastewater, is also raising concern. A whole range of pollutants, such as heavy metals and poorly biodegradable trace organic compounds, as heavy metals and poorly biodegradable trace organic compounds, potentially contaminates it what can result in an increase of the soil potentially contaminates it what can result in an increase of the soil concentrations of these compounds.concentrations of these compounds.

Page 6: Modeling diffuse soil contamination from agriculture

Diffuse Soil contamination, Sources.

introduction

Production systems where a balance between farm Production systems where a balance between farm inputs and outputs is not achieved in relation to soil inputs and outputs is not achieved in relation to soil and land availability, leads to nutrient imbalances in and land availability, leads to nutrient imbalances in soil, which frequently result in the contamination of soil, which frequently result in the contamination of ground- and surface water.ground- and surface water.

Modeling the fate of contaminants requires an understanding of the soil-water-air continuum. The modeling tool should be able to simulated

physical, chemical and biological processes occurring in these different compartments.

Page 7: Modeling diffuse soil contamination from agriculture

The modelling approach ...

AIR

SOIL

GROUNDWATER

RIVER

Atmospheric depositionN fixation

Fertilizer applications

Surface and subsurface runoffN

Leaching

Point discharges

Plants consumption

Plants consumption

Simulation of soil processes: organic matter turnover, crop growth, nitrogen uptake, water infiltration, evaporation from crop and soil

surface, nitrification, denitrification, interception of precipitation and emissions to the atmosphere.

Atmospheric emissions

NITRIFICATION/ DENITRIFICATIO

NSTORAGE

Page 8: Modeling diffuse soil contamination from agriculture

• Vertical flow in the unsaturated zone links the soil processes to the 2-D overland flow and to the 3-D groundwater flow.

Estimation of loads at representative sites, aggregation at landscape scale, and upscaling to regions .

Calculation of the impacts of the agricultural sector under selected land use scenarios.

… a nested approach

• A fully distributed physically based model representing variations in catchment characteristics and driving variables by a network of uniform grids or sub-basins.

Page 9: Modeling diffuse soil contamination from agriculture

• Scenario analyses (socio-economic, climate, environmental) to improve resource management and provide information that will aid for the sustainable management of the watershed.

• Impact assessment of waste management strategies, tourism, urban areas, mining activities, land use changes.

An Observational Network of European Watersheds

Page 10: Modeling diffuse soil contamination from agriculture

Modeling of Diffuse soil contamination.

Modeling tools

Modeling Tools: able to considering processes Modeling Tools: able to considering processes occurring in the soil-water-air compartments in the occurring in the soil-water-air compartments in the studied area, mainly used for Nitrogen and studied area, mainly used for Nitrogen and Phosphorus modeling.Phosphorus modeling.

•SWAT (Soil Water Assessment Tool, Blackland SWAT (Soil Water Assessment Tool, Blackland Research Centre, Texas US-Arnold et al., 1992)Research Centre, Texas US-Arnold et al., 1992)

Page 11: Modeling diffuse soil contamination from agriculture

SWAT description

mainswat

characteristics

basin-scalecontinuous timedaily time stepphysically basedcomputationally efficientlong-term simulationswater, sediments, nutrients, pesticides

Page 12: Modeling diffuse soil contamination from agriculture

Hydrologymodel

SWAT description

Page 13: Modeling diffuse soil contamination from agriculture

Physical model SWAThydrology

evapo

precipitation

surfacerunoff

lateralflow

infiltration

transpiration

Page 14: Modeling diffuse soil contamination from agriculture

Physical model

Surface runoff

use of SCS curve number method to estimate surface runoff

SWAThydrology

Evapotranspiration

Three methods included in SWATPenman-MonteithHargreavesPriestley-Taylor

ET is evaluated from soils and plants as well

Snow melt

melting if the second soil layer temperature exceeds 0 C and proportional to the snow pack temperature

Page 15: Modeling diffuse soil contamination from agriculture

Physical model Soil moduleSWAT

Water that enters the soil may move along one of several differentpathways. The water may be removed from the soil by plant uptake or

evaporation. It can percolate past the bottom of the soil profile and ultimatelybecome aquifer recharge. A final option is that water may move laterally in the

profile and contribute to streamflow. Of these different pathways, plant uptake ofwater removes the majority of water that enters the soil profile.

SWAT considers:

•Soil StructureSoil Structure•PercolationPercolation

•Lateral FlowLateral Flow

Page 16: Modeling diffuse soil contamination from agriculture

SWAThydrology

physical model

Soil StructureSoil Structure

Swat considers three phases in the soil:solid, liquid and gas.

The solid phase consists of minerals and/or organic matter that forms the matrix or skeleton.Between the

solid particles, soil pores are formed that hold the liquid and gas phases. The soil solution may saturate the soil completely or partially. Swat calculates the balance in every layer and once (..and if ) this layer

reach the saturation moves the water to the next one.Soil Name: s1Db Soil Hydrologic Group: C Maximum rooting depth(m) : 900.00 Porosity fraction from which anions are excluded: 1.000 Crack volume potential of soil: 0.000 Texture 1 : LFS-LFS-S Depth [mm]: 300.00 600.00 900.00 Bulk Density Moist [g/cc]: 1.46 1.46 1.41 Ave. AW Incl. Rock Frag : 0.17 0.28 0.35 Ksat. (est.) [mm/hr]: 1.00 2.40 200.00 Organic Carbon [weight %]: 1.50 0.86 0.52 Clay [weight %]: 22.00 5.00 3.00 Silt [weight %]: 59.00 76.00 7.00 Sand [weight %]: 19.00 19.00 90.00 Rock Fragments [vol. %]: 0.00 0.00 0.00 Soil Albedo (Moist) : 0.06 0.06 0.06 Erosion K : 0 .23 0.23 0.23 Salinity (EC, Form 5) : 1.00 0.00 0.00

Page 17: Modeling diffuse soil contamination from agriculture

SWAThydrology

Percolation

physical model

percolationpercolationPercolation is calculated for each soil layer in the profile. Percolation is calculated for each soil layer in the profile. Water is allowed to percolate if the water content exceeds Water is allowed to percolate if the water content exceeds the field capacity water content for that layer. When the soil the field capacity water content for that layer. When the soil layer is frozen, no water flow out of the layer is calculated. layer is frozen, no water flow out of the layer is calculated. The volume of water available for percolation in the soil The volume of water available for percolation in the soil layer is calculated:layer is calculated:

SW ly excess= FC ly – sSW ly if FC ly SW ly excess= FC ly – sSW ly if FC ly > > SW ly SW ly SW ly excessSW ly excess = 0 , = = 0 , = excess ly if FC ly excess ly if FC ly < or = < or = SW lySW ly

wherewhere SWly,excess SWly,excess is the drainable volume of water in the is the drainable volume of water in the soil layer on a given day (mm H2O), soil layer on a given day (mm H2O), SWly SWly is the water is the water content of the soil layer on a given day (mm H2O) and content of the soil layer on a given day (mm H2O) and FCly FCly is the water content of the soil layer at field capacity (mm is the water content of the soil layer at field capacity (mm H2O).H2O).

Page 18: Modeling diffuse soil contamination from agriculture

SWAThydrology

physical model

Lateral FlowLateral FlowLateral flow will be significant in areas with soils Lateral flow will be significant in areas with soils having high hydraulichaving high hydraulicconductivities in surface layers and an impermeable conductivities in surface layers and an impermeable or semipermeable layer at a shallow depth. In such a or semipermeable layer at a shallow depth. In such a system, rainfall will percolate vertically until it system, rainfall will percolate vertically until it encounters the impermeable layer. The water then encounters the impermeable layer. The water then ponds above the impermeable layer forming a ponds above the impermeable layer forming a saturated zone of water, i.e. a perched water table. saturated zone of water, i.e. a perched water table. This saturated zone is the source of water for lateral This saturated zone is the source of water for lateral subsurface flow.subsurface flow. lateralflow

Page 19: Modeling diffuse soil contamination from agriculture

Physical modelweather

SWAT

driving variables• precipitation• temperature

• solar radiation• wind speed

• relative humidity

daily measurements

Monthly measurements

In case of missed values, a weather generator is included in the code

Page 20: Modeling diffuse soil contamination from agriculture

Physical model

sedimentsswat

sediment yield

MUSLE: Modified Universal Soil Loss Equation(USDA, Williams et al. 1977)

Page 21: Modeling diffuse soil contamination from agriculture

Physical model

crop growthswat

heatunits

leaf areaindex

solar radiation energyinterception

cropparameter

biomassproduction

harvestindex

cropyield

Page 22: Modeling diffuse soil contamination from agriculture

Physical model

nutrientsswat

NITROGEN model in SWAT

Residue

NO3Active organic N

Stable organic N

Plant uptakeharvest

Inorganic fertilizer

Mineralization

Decay

Mineralization

Denitr

ifica

ti

onOrganic fertilizer

Page 23: Modeling diffuse soil contamination from agriculture

Physical model

nutrientsswat

PHOSPHORUS model in SWAT

Residue

Dissolved labile P

Sediment-bound labile P

Lumped Active/Stable

organic P

Plant uptake

harv

est

Inorganic fertilizer

MineralizationOrganic fertilizer

Sediment-bound fixed P

Minera

lizatio

n

Page 24: Modeling diffuse soil contamination from agriculture

OUSE Catchment (UK)

BURANA PO di VOLANO Catchment (IT)

TWO EXAMPLES DEVELOPED USING SWAT COUPLED WITH GIS (ArcInfo and ArcView, ESRI)

MAIN ISSUES OF THE MODEL APPLICATIONS

Allowing the quantification of the total load of pollutant affecting a watershed. This model should

be used to understand how the soil quality and water quantity/quality are affected by agricultural

activities.

Models application

Page 25: Modeling diffuse soil contamination from agriculture

Examples: OUSE Catchment (UK) Soil Map

Page 26: Modeling diffuse soil contamination from agriculture

OUSE Land Use: (%)

•FRSE 2.25•PAST 27.02•RANGE 32.88•WWHT 29.10•URBAN 8.75

Examples: OUSE Catchment (UK)Landuse Map

Page 27: Modeling diffuse soil contamination from agriculture

OUSE HYDROLOGY

0

20

40

60

80

100

120

140

160

180

gen-86 gen-87 gen-88 gen-89 gen-90

OU

TFLO

W (cm

/s)

mesurated NEW SETUP

OUSE WATERSHED MONTHLY TIME STEP OUSE WATERSHED MONTHLY TIME STEP SIMULATION(30 years simulation): FLOW OUT [mSIMULATION(30 years simulation): FLOW OUT [m33/s] and /s] and

LINEAR CORRELATIONLINEAR CORRELATION

OUSE HYDROLOGY, STATISTICAL ANALYSIS

R2 = 0.9239

0

50

100

150

200

0 20 40 60 80 100 120 140 160 180 200

OU

TFL

OW

/cm

/s)

NEW SETUP Linear (NEW SETUP)

Page 28: Modeling diffuse soil contamination from agriculture

0.00E+00

2.00E+05

4.00E+05

6.00E+05

8.00E+05

1.00E+06

1.20E+06

1.40E+06

1.60E+06

1.80E+06

2.00E+06

Jan-87 Jan-88 Jan-89 Jan-90

TO

TAL N

ITR

OG

EN

(Kg)

mesurated NEW SETUP

OUSE WATERSHED MONTHLY TIME STEP SIMULATION(30 years simulation): TOTAL

NITROGEN [Kg]

Page 29: Modeling diffuse soil contamination from agriculture

LANDUSE SCENARIO: COMPARISON BETWEEN N EXCESS AND N PLANT UPTAKE WITH TWO DIFFERENT APPLICATION RATE OF ORGANIC NITROGEN IN THE OUSE WATERSHED

Page 30: Modeling diffuse soil contamination from agriculture

LANDUSE SCENARIO: COMPARISON BETWEEN NO3 TO RIVER AND NO3 LEACHING WITH TWO DIFFERENT APPLICATION RATE OF ORGANIC NITROGEN IN THE OUSE WATERSHED

210 Kg/haORGANIC NITROGEN

170 Kg/haORGANIC NITROGEN

AVERAGE ANNUAL CHANGE:-6.34 %

Page 31: Modeling diffuse soil contamination from agriculture

Examples: Burana Po di Volano (IT)

Page 32: Modeling diffuse soil contamination from agriculture

Examples: Burana Po di Volano(IT)

Page 33: Modeling diffuse soil contamination from agriculture

Scenario attuale

Scenario I

Scenario II

Present scenario

Scenario I

Scenario IIGCM Scenario

CGCM1 e HadCM2

year 2050 Usi non a seminativo

0-67-1213-1819-2425-3031-3637-4243-4849-5455-6061-6667-7273-7879-8485-90

Influence of Climate Change on Nitrogen Influence of Climate Change on Nitrogen Percolation from Soils to GroundwaterPercolation from Soils to Groundwater

Burana-Po di Volano watershed

NO3 leaching (Kg/ha)

Page 34: Modeling diffuse soil contamination from agriculture

Leaching Models: applied to determine the Leaching Models: applied to determine the quantity of Pesticide leaching thought the soil quantity of Pesticide leaching thought the soil profile reaching the shallow aquifer.profile reaching the shallow aquifer.

•PRZM2: Pesticide Root Zone Model, PRZM2: Pesticide Root Zone Model, Environmental Protection Agency, US - Carsel et Environmental Protection Agency, US - Carsel et al. 1984.al. 1984.

• PEARL: Pesticide Emission Assessment at PEARL: Pesticide Emission Assessment at Regional and Local Scales by Alterra Green World Regional and Local Scales by Alterra Green World Research.Research.

Modeling of Diffuse soil contamination.

Modeling tools

Page 35: Modeling diffuse soil contamination from agriculture

TREVIGLIO Catchment (IT)

EUROPEAN SCALE

TWO EXAMPLES DEVELOPED USING PRZM and PEARL coupled with ARCVIEW GIS

Models application

MAIN ISSUES OF THE MODEL APPLICATIONS

Models are run at field and regional scale to be tested (PRZM, PELMO) then the necessary information are collected at European level and run with a model like PEARL (able to work with big database) to estimate the persistence of selected substances at European scale.

Page 36: Modeling diffuse soil contamination from agriculture

PRZM2 is a one-dimensional, dynamic, PRZM2 is a one-dimensional, dynamic, compartmental model that can be used to compartmental model that can be used to simulate chemical movement in unsaturated simulate chemical movement in unsaturated soil systems within and immediately below soil systems within and immediately below the plant root zone. It has two major the plant root zone. It has two major components:components:

•hydrologyhydrology

•chemical transport. chemical transport.

The model was specifically designed to The model was specifically designed to provide loading to selected media, including provide loading to selected media, including air, water, groundwater. PRZM2 runs on air, water, groundwater. PRZM2 runs on daily time step. PRZM2 is extensively used daily time step. PRZM2 is extensively used from the U.S. Environmental Protection from the U.S. Environmental Protection Agency to simulate the transport of field-Agency to simulate the transport of field-applied pesticides in the crop root zone.applied pesticides in the crop root zone.

Examples: TREVIGLIO catchment (IT)

Modeling of Diffuse soil Modeling of Diffuse soil contamination.contamination.Regional scaleRegional scale

Page 37: Modeling diffuse soil contamination from agriculture

Examples: TREVIGLIO catchment(IT)

Concentration limits applied for classification of the Maps.

Soil Vulnerability to Pesticide Leaching Concentration (µg/l)

Very Low Vulnerability < 0.001

Low Vulnerability 0.001 – 0.01

Medium - Low Vulnerability 0.01 – 0.1

Medium - High Vulnerability 0.1 – 1

High Vulnerability 1 – 10

Very High Vulnerability > 10

Alachlor (app. Rate 2.0 Kg/ha)

Atrazine (app. Rate 1.5 Kg/ha)

Page 38: Modeling diffuse soil contamination from agriculture

Use a process based model supported by the FOCUS working group that includes all major processes involved with pesticide transformation and fate. For instance, we are currently using the PEARL model which is used to evaluate the leaching of pesticides to the groundwater in support to the European and Dutch pesticide registration procedures.

Ponding

Soil water fluxes

Seepage

Satu

rate

d zo

neUn

satu

rate

d zo

ne

Heat flow

Transpiration

Water uptake

Lateral dischargeto ditches / drains

SWAP

Leaching

Volatilization

Pesticideuptake

Dissipation

Washoff

ConvectionDispersionDiffusion

Transformation

Solid/liquid/gaspartitioning

PEARL

December 14 1990

Bentazone concentration (mgl-1)

0.0 0.1 0.2 0.3 0.4 0.5 0.6

De

pth

(cm

)

0

20

40

60

80

100

120

140

measuredpredicted

Bentazone soil concentration 22 and 278 days after application of 0.8 kg/ha of bentazone on field

under winter wheat (NL)

Page 39: Modeling diffuse soil contamination from agriculture

Deliverable: map of pesticides persistence in the top layer, in the root zone, and leaching below the root

zoneCollect the necessary information at European level and run the PEARL model to estimate the persistence of selected

substances

Page 40: Modeling diffuse soil contamination from agriculture

CONCLUSION:

• These kind of modeling tool could be useful to analyze and simulate the water contamination in a

medium-big scale watershed.

•They are able to determine soil limitations (topography, rooting depth, chemical fertility, organic

carbon) of European soils (using harmonised European soil information system).

• It is also possible to derive crop suitability zones and compare the capability maps with land use maps.

•Useful to make some general conclusion about the effect of the global climate change could be done.LIMITATIONS:

•The calibration of the model is time-consuming and it would need more efficient tools

•The quality of the model simulation depends on the quality of the data available.