Institute of Freshwater Ecology and Inland Fisheries Changes of agricultural diffuse nutrient inputs...

Institute of Freshwater Ecology and Inland Fisheries

Changes of agricultural diffuse nutrient inputs in major European river systems

and their contribution to the nutrient loads

Horst Behrendt*Institute of Freshwater Ecology and Inland Fisheries, Department of Shallow Lakes and

Rivers, Mueggelseedamm 310, D-12857 Berlin, Germany

Introduction

Results

1. Sources of nutrient emissions into river systems

2. Longterm changes

Conclusions


Investigated rivers systems in Europe*

Number (>2000 km²): 450Total area: 8,060,200 km2 Population: 616 MillionMean specific runoff: 10 - 1400 mm/(m²·a)

Investigated rivers: 7Total area: 1,625,470 km2 (20%)Contributing countries: 3 - 18Population: 224 Million (36%)Mean specific runoff: 120 - 670 mm/(m²·a)

The investigations are related to the EU-Projects EUROCAT and DANUBS or founded by NATO-CCMS or national projects


* Tonderski (1996); ** Billen & Garnier (1999)

Characteristics of the investigated rivers

River Period Area Population Pop Density spec. runoff[1000 km²] [1000 Inh.] [Inh./km²] [l/(km²·s)]

Rhine 83/87 159,7 42315 265 15,6Rhine 93/97 159,7 45115 282 14,5Rhine 98/00 159,7 45767 287 16,8Po 91/95 73,8 16302 221 20,5Elbe 83/87 134,9 20796 154 5,4Elbe 93/97 134,9 21205 157 5,4Elbe 98/00 134,9 20953 155 5,0Vistula 96/00 190,3 25918 136 6,8Vistula 91/95 190,3 25918 136 4,9Odra 93/97 111,9 14977 134 4,7Daugava 98/00 86,0 2800 33 9,6Danube 98/00 802,9 82158 102 8,6


Applied model

MONERISBoundaries:

Input to catchment soil and water, losses from soils to surface waters, riverine output from the catchment

• The model starts with the distributed estimation of the surplus on agri-cultural and non-agricultural areas.

• Long term changes for consideration of the residence time in groundwater (N) and accumulation processes (P).

• Distributed nutrient emissions into the surface waters of a river basin for 6 diffuse pathways and point source discharges (municipal WWTP`s and direct industrial discharges).

• Distributed retention coefficients for groundwater (N) and surface water.


Database: Borders of catchments and subcatchments


Mineral Fertilizer

Lifestock

Crop Yields

Database: Statistical data e.g. for agriculture

0

50

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NL

DK

DE

w IR SI

UK FI

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e

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HR IT CZ

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LT GR

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HU LV ET

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N S

urp

lus

(kg

/ha

)

Country value for 2000

Average of all countries

0

20

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IR DK LT HR FI

FR NL

UK SI

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urp

lus

(kg

/Inh

.)

Country value

Average of all countries


Nutrient emissions into the river systems


Contribution of pathwas to the total emissions into the river systems

N-emissions for Period

Rhine 1998-2000Elbe 1998-2000Po 1991-1995Vistula 1996-2000Oder 1993-1997Danube 1998-2000


Contribution of different human sources and natural background to the N-emissions in the

Danube basin


Regional differences of the agricultural N-emissions in European river systems


Regional differences of the agricultural P-emissions in European river systems


Identification of intensities of processes

Intensity of N-retention in unsaturated zone and in groundwater


Intensities of retention processes in terrestric and aquatic spheres

Catchment Specific N-surplus total total N-retention N-retentionrunoff agriculture N-inputs N-load in soil in surface watersmm/a kg/(ha·a) kg/(ha·a) kg/(ha·a) [%] [%]

Rhine 430 99,7 28,7 19,7 71,2 31,2Po 681 45,6 35,6 23,9 86,7 32,9Elbe 159 56,8 15,5 10,5 86,8 32,2Vistula 185 28,0 9,6 5,8 83,9 39,3Oder 172 35,7 7,9 4,7 83,2 40,7Danube 280 27,7 8,6 5,6 83,7 34,2Daugava 301 19,2 8,5 5,8 57,7 32,2


Total emissions

surface water

retention and load

N

PS

pec

. N

-flu

xes

(kg

/ha)

05

101520253035404550

NL/

GE

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FIE LIS

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GE

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HU

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spec

. N

-flu

xes

(kg/

ha N

)

N-load N-retention SW

0.00.20.40.60.81.01.21.41.61.8

NL/

GE

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LUA

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(kg/

ha N

)

P-load P-retention SW

Sp

ec.

P-f

luxe

s (k

g/h

a)

If the retention in surface waters is not included in the model, the load and the source estimation can completely fail.


Longterm changes of nutrient emissions and loads


Longterm changes of observed and calculated nutrient loads for the Odra at Krajnik Dolny

For nitrogen the human induced changes are overlayed by flow changes

The TP load shows a clear decrease since mid 1980‘s


Longterm changes of DIN and TP load calculated based on observed flow, longterm average flow and without Iron Gate.


Changes of nutrient emissions by human activities and natural background in the Odra

The reduction of N emissions is mainly due to reduction of agricultural & urban discharges

The reduction of P emissions is only due to reduction of urban discharges


Changes of nutrient emissions by human activities and natural background in the Danube

The longterm changes of the sources in the Danube are similar than in the Odra.

But the reduction of N and P emissions is lower


Results of Scenario calculation


Efficiency of different measures to change the situation in the Elbe river system

Only the introduction of a taxis on mineral N-fertilizer (Ntaxis) leads to a clear reduction of the agricultural N-emissions

For a set of maximum reduction measures the total N-emissions will be remain about 400% above the geogenic background.


A substantial reduction of agricultural N emis-sions is only possible for SC4, which assumes a reduction of meat consumption to 0.1 AU per inhabitant

Efficiency of measures to change the situation in the Danube

Agricultural P sources can be effectively reduced by management of arable land without ploughing


• Agricultural inputs (N) and point sources (P) are the dominant source of nutrient loads in the most of the investigated river basins. A gradient exists from west to east.

• The N and P emissions and loads into Eastern European rivers are increased from the 1950s to the 1980s by a factor of 2 to 3.

• A substantial decrease was found for P loads in the 1990s. The reduction of N loads is often overlayed by flow variation.

• The consideration of the retention of matter in the surface waters is of similar importance for the modelling of loads as the the estimation of sources and pathways.

• MONERIS can be applied for the estimation of the nutrient emissions and loads in the European river systems

Conclusions


Results VI: Nutrient loads within subcatchments & for river outlet

Observed and calculated loads (MONERIS) of TP and DIN for the tributaries of the Danube

River Period TP DIN TNRhine [%] 30.0 20.0 25.2

[#] 110 125 41Po [%] 69.7 62.0 54.1

[#] 36 36 36Elbe [%] 42.7 29.8 31.9

[#] 149 196 129Vistula [%] 44.7 33.4 28.5

[#] 38 38 38Odra [%] 33.1 22.6 22.3

[#] 42 43 42Daugava [%] 21.6 14.8 33.7

[#] 5 5 4Danube [%] 33.8 20.5 23.2

[#] 64 92 16

Deviation between observed and calculated loads for the

different river systems

Institute of Freshwater Ecology and Inland Fisheries Changes of agricultural diffuse nutrient inputs...

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