Alena Bartosova Berit Arheimer, Johan Strömqvist, Göran ...€¦ · Regional Environmental Change...
Transcript of Alena Bartosova Berit Arheimer, Johan Strömqvist, Göran ...€¦ · Regional Environmental Change...
Analyses of background nitrogen concentrations in Sweden: evolution of landscape processes and hydrology
Alena BartosovaBerit Arheimer, Johan Strömqvist, Göran Lindström
15 November 2016
International Workshop on Estimation of nitrogen loads to the marine environment around the time of the year 1900Sandbjerg Estate, Sønderborg, Denmark
Historical perspectiveLand use change:
• 2 449 lowered or drained lakes I Sweden during 1800s and 1900s.• 29 864 drainage companies• End of 1800s: 10 000 ha (100 km2) new arable land per year.
SMHI, 1995, SMHI Hydrologi, Report No. 62
Previously estimated effect on nitrogen reduction:
2500 reduced/drained lakes: reduced natural capacity to capture N by 30 000 ton
Hoffman, M., Johnsson, H., Gustafson, A. & Grimvall, A. 2000. Leaching of nitrogen in Swedish agriculture – historic perspective. Agriculture Ecosystems and Environment, 80, 277-290.
Drainage: natural N removal reduced by 20%
Andersson, L. and Arheimer, B., 2003. Modelling of human and climatic impact on nitrogen load in a Swedish river 1885-1994. Hydrobiologia 497(1-3):63-77.
Sources Andersson, L. and Arheimer, B., 2003. Modelling of human and climatic impact
on nitrogen load in a Swedish river 1885-1994. Hydrobiologia 497(1-3):63-77 Andersson, L. and Arheimer, B., 2001. Consequences of changed wetness on
riverine nitrogen – human impact on retention vs. natural climatic variability. Regional Environmental Change 2:93-105
Andersson, L. and Arheimer, B., 2002. Modelling of regional changes of riverivenitrogen flow in the Svartå River, Sweden. FRIEND 2002 --- Regional Hydrology. Bridging the Gap between Research and Practice. Proceedings of the 4th
Internation FRIEND Conference, Cape Town, South Africa, March 2002. IAHS Publ. no. 274, 2002
Lindström, G. & Bergström, S. (2004) Runoff trends in Sweden 1807-2002. Hydrological Sciences Journal, Vol. 49, No. 1, pp. 69-83.
Unpublished work from Soils2Sea project (http://www.soils2sea.eu/) SMHI Vattenwebb (http://vattenwebb.smhi.se/)
N retention Long-term difference between
The sum of all N emissions and soil leaching Total river basin outflow
Lumped description Biological uptake Sedimentation Denitrification Other biogeochemical processes
Highly affected by residence times Lakes in southern Sweden
Retention rate 30-40 kg/ha-year (Arheimer and Brandt 1998)
Svartån study 1400 km2 Upper part: hilly forested morraine with several lakes Lower part: farmland with very little lakes Shallow groundwater with relatively short residence times (months-few years)
#
##
Lake Sommen
Lake Roxen
Linköping
Marsta
Ledberg
Mjölby
Agricultural dominatedForest dominatedLakesRiversUrban areas
N
EW
S
0 10 20 30Kilometers
L.Roxen
L.Sommen
N
SWED
EN
Baltic Sea
Model setup HBV-N
Process-based. Semi-distributed conceptual model Based on HBV-96, also simulates N
Diffuse soil leaching, point sources, rural households, atmosphericdeposition
Physiography: 1885, 1905, 1927, 1956, 1976, 1994 40 subbasins
Climate data 10-year period 1985-1994 110-year time series (with 1994 data only for physiography)
Modeling results
#
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Lake Sommen
Lake Roxen
Linköping
Marsta
Ledberg
Mjölby
Agricultural dominatedForest dominatedLakesRiversUrban areas
0 10 20 30 Kilometers
N
EW
S
0 10 20 30Kilometers
L.Roxen
L.Sommen
N
Ledberg (main stream)R2=0.81
0255075
100125150
jan-
85
jan-
86
jan-
87
jan-
88
jan-
89
jan-
90
jan-
91
jan-
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jan-
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jan-
94
simulationobservation
Marsta (upper branch)R2=0.65
0
1
2
3
jan-
85
jan-
86
jan-
87
jan-
88
jan-
89
jan-
90
jan-
91
jan-
92
jan-
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jan-
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simulationobservation
Wat
er fl
ow (m
3s-
1 )
Wat
er fl
ow (m
3s-
1 )
Skenaån (upper branch) R2=0.36
0
4
8
12
16
jan-
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jan-
86
jan-
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jan-
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jan-
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jan-
90
jan-
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jan-
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jan-
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jan-
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simulationobservation
Tota
l Nitr
ogen
Con
c. (m
g L-
1 )
Svartåfors (main stream)R2=0.24
0123456
jan-
85
jan-
86
jan-
87
jan-
88
jan-
89
jan-
90
jan-
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jan-
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jan-
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jan-
94
simulationobservation
Tota
l Nitr
ogen
Con
c. (m
g L-
1 )
SWED
EN
Baltic Sea
Water discharge and Nitrogen concentration modelled with HBV-N
Agriculture activities
Total leaching comparable Increase in crop production compensated by decrease in fallow
0%
25%
50%
75%
100%
1885 1905 1927 1956 1975 1995
Clay Loam Loamy sand
0
100
200
300
400
500
600
1885 1905 1927 1956 1975 1995
km2
Total areacrops grassland fallow
Total agric. area in Sweden increased from 0,8 mil.ha in 1800 to 3,5 mil,ha in 1925
Human impact on retention
Agriculture statistics for parishes Information on tile drainage and drainage projects (lowering of lakes, open
ditch drains) No significant changes in tile drainage after 1927
Human impact on retention 75% drainage projects completed between 1770 and 1950
0
2
4
6
8
1885 1900 1915 1930 1945 1960
km2Lowering of lakes
agriculture dominated forest dominated
0
2
4
6
8
1885 1900 1915 1930 1945 1960
km2
New damsagricultural dominated forest dominated
Population
012345
tot-N
(kg/
capi
ta-y
ear)
Production per personPoint sources contributionDiffuse sources contribution
0
10000
20000
30000
40000
50000
60000
020406080
100120140160180200
1927 1956 1976 1994
Pop
ulat
ion
tot-N
(ton
/yea
r)
Point source emissions Rural source emissions Total emissionsUrban population Rural population Total population
Urbanization and migrationIncreased N-content of the dietIncreased used of toiletsSewage systems (small portion exported
outside the watershed)Wastewater treatment (1959)
20% removal at WWTP does not compensate for 50% increase of per capita N emission
Changes in load and retention by source
0250500750
100012501500
1885 1905 1927 1956 1976 1994
tot‐N (ton
/year)
Total load
Net load Retention
0250500750
100012501500
1885 1905 1927 1956 1976 1994
tot‐N (ton
/year)
Agriculture
Net load Retention
1994: net load 753 t/yr (69% arable, 17% urban point sources, 9% other land, 5% rural PS, 1% atm.dep.retention 29% (18% in groundwater, 7% in lakes, 4% in mainstem)
0
50
100
150
200
1885 1905 1927 1956 1976 1994tot‐N (ton
/year)
Deposition on lakes
Net load Retention
0
50
100
150
200
1885 1905 1927 1956 1976 1994
tot‐N (ton
/year)
Point sources
Net load Retention
0
50
100
150
200
1885 1905 1927 1956 1976 1994
tot‐N (ton
/year)
Other land
Net load Retention
Long-term simulation 110 years (change in gaging not evaluated) 1994 conditions
0250500750
1000125015001750
tot-N
(ton
/yea
r)
0500
10001500200025003000
tot-N
(ton
/yea
r)
y = ‐0.0001x + 0.4465R² = 0.6204
0%5%10%15%20%25%30%35%40%
500 1000 1500 2000
Retention of N, %
tot‐N (ton/year)
1825-1934:Low flowsHigh temperature
Runoff anomalies
Trend in runoff anomalies
Impact of rating curve
Individual impact on N transport
17
11/17/2016
-30-20-10
01020304050
A B C D E F G H I J K L
Cha
nge
of N
-load
(%)
Hydrological and climate related
Variables related to changes of land use, arable practices, and household emissions
Ara
ble
prac
tices
1927
Clim
ate
1905
-191
4
Und
rain
ed s
oil
No
WC
Eatin
gha
bits
188
5
No
low
ered
lake
s
Atm
.dep
. 190
0
Land
cov
er 1
985
No
dam
s
Land
cov
er 1
976
Ara
ble
prac
tices
1976
Clim
ate
1974
-198
5
TN retention in S-HYPE Retention in groundwater only Method compatible with Daisy/MIKE-SHE
Inputs to groundwater includehorizontal flows in S-HYPE
No retention for horizontal flows Preliminary unpublished results On-going work for Soils2Sea project
Background simulation with S-HYPE
Atmospheric deposition of nitrogen is reset Emissions from point sources and private sewers set to 0. Urban and semi-urban land is replaced with "other land". Farmland (spring sowing, autumn sowing, potato / sugar beet, oilseed rape and
grass) are replaced by extensive grassland. Secondary crops are removed. Forest clearings replaced with forest.
0.00001
0.001
0.1
10
1000
100000
10000000
0.001 0.1 10 1000 100000 10000000
Backgrou
nd Gross N Loa
d
Present Gross N Load
Total
Background Gross N Load Perfect Fit
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
Backgrou
nd re
tention
Present retention
Total
Perfect Fit Background retention
110100100010000
100000100000010000000100000000
1 100 10000 1000000 100000000
Backgrou
nd N re
tained
Present N retained
Total
Perfect Fit Background N retained
Summary Climate has a significant impact on N loads and retentions
Retention in Sweden mostly driven by processes in surface water (lakes) Possible negative effects of increasing TN retention in surface waters
Eutrophication of inland waters Change in silicate loads Change in algae composition Change in internal loading of other nutrients