Download Presentation - Soil and Water Assessment Tool

Experimental drought early warning system in
the Inner Niger Delta
2013 International SWAT Conference, Toulouse, France
Samuel Fournet1,2, Stefan Liersch1, Valentin Aich1,
Léo Zwarts4, Bakary Koné3, Fred F. Hattermann1
1 Potsdam
2 UMR
Institute for Climate Impact Research
G-eau, Montpellier Supagro
3 Wetlands
4
International
Altenburg & Wymenga
Wednesday 17th of July 2013
Impacts of climate change and upstream river management
on the flood regime in the Inner Niger Delta
Outline
1.
The Inner Niger Delta: case study characteristics
2.
SWIM setup, development and calibration
3.
Climate change and upstream water management scenario
4.
Hydrological change and trends
5.
Integration of the results in an operationnal drought early warning
system in the Inner Niger Delta
2
Case study introduction
Inner Niger Delta
3,27 M inhabitants
Large wetland inundation
plain (40.000 km²) in the
Sahelian climate zone
Drastic seasonal and
inter-annual variation in
discharge (30 to 50 hm3/y),
flood extent (5 to 25.000 km²)
Flood peak delay ~2 months
30 to 50% water losses
Zone crucial for fishing,
livestock, agriculture in
free submersion and the
biodiversity
High vulnerability from
upstream management
Source: http://earthobservatory.nasa.gov/
Zwarts et al., 2005, Niger the lifeline, Wetlands International
SWIM Soil and Water Integrated Model
Development of Inundation module
Pre-processing in the delta floodplain: upstream of each sub-basin´s outlets, inundated area
and the water volume accumulated and trapped in ponds are identified into sequential layers
Processes
Parameters
1. Flooding
> Flooding: flow-threshold
2. Routing, backwater
3. Evaporation (water surface)
4. Percolation
5. Release
1
> Flood release (linear)
2
5
Source: Liersch et al., 2011, SWAT conference
SWIM setup (1)
Topography, Land-use, Soil, Sub-basins
Digital Elevation Model
Shuttle Radar Topographical Mission
SRTM Version 4, 90m resolution
Land-use classification
Global Land Cover 2000 GLC
Soil classification and parameterization
Hydrotope
FAO Digital Soil Map of the World
Harmonized World Soil Database
Sub-basin delineation
Hydrological
Response
Unit
Number of sub-basins: 1923
Sub-basin average area: 1150km²
5
SWIM setup (2)
Climate inputs
Watch Forcing Data (WFD)
• ECMWF
reanalysis ERA40
• from 1960-2001 at
daily time step
• 0.5° resolution
• Bias corrected
with Global
Precipitation
Climatology
Centre (GPCC v4)
and Climate
Research Unit
(CRU TS2.1)
Source; Weedon et al., 2010 , Watch tech report6 22
Aich and Fournet 2013 in Dewfora D4.6, PIK
SWIM calibration
Discharge Global Runoff Data Centre (GRDC)
ID Monitored Gauge Calibration period NSE
1964-1974
0.93
1 Koulikoro
1964-1974
0.88
2 Douna
1975-1995
0.87
3 Ibi
1964-1974
0.86
4 Kouroussa
1972-1982
0.85
5 Lokoja
1964-1974
0.83
6 Dire
1975-1981
0.82
7 Kirango Aval
1976-1986
0.82
8 Kandadji
1965-1975
0.8
9 Selingue
1968-1979
0.76
10 Ansongo
1975-1985
0.76
11 Niamey
1968-1979
0.75
12 Tossaye
1976-1986
0.54
13 Malanville
1985-1995
0.18
14 Yidere Bode
Calibration Koulikoro gauge
6
1
4 9
7 2
10
8
11
13
14
5
3
Source; Aich and Fournet, 2013 in Dewfora D4.6,7PIK
Climate change projections
Air temperature trends in the Upper Niger Basin
4 Earth System Models (ESMs)
Downscaled and bias corrected by Inter-Sectoral Impact
Model Intercomparison Project (ISI-MIP)
•GFDL-ESM2M (GFDL)
•HadGEM2-ES (Had)
• IPSL-5 CM5A-LR (IPSL)
• NorESM1-M (Nor)
Use of 2 Representative Concentration Pathways underlying
assumptions about radiative forcing
•2.6 - “moderate”
• 8.5 - “extreme”
Source; Liersch et al., 2013, AFROMAISON internal report,8PIK
Climate change projections
Precipitation trends in the Upper Niger Basin
4 Earth System Models (ESMs)
Downscaled and bias corrected by Inter-Sectoral Impact
Model Intercomparison Project (ISI-MIP)
•GFDL-ESM2M (GFDL)
•HadGEM2-ES (Had)
• IPSL-5 CM5A-LR (IPSL)
• NorESM1-M (Nor)
Use of 2 Representative Concentration Pathways underlying
assumptions about radiative forcing
•2.6 - “moderate”
• 8.5 - “extreme”
Source; Liersch et al., 2013, AFROMAISON internal report,9PIK
Upstream river management
Reservoirs and Irrigation schemes
1. Current and future irrigation water uptake with restricted minimal flows were setup
in line with the development plan of the Niger Basin Authority and the future dams
in line with engineering technical report.
2. The scenario matrix was defined with local stakeholder representatives from the IND
region
Source; Liersch et al., 2013, AFROMAISON internal report,
10PIK
Results: climate change projections
Impact on discharge at the combined IND´s inlet
11
Results: river management scenario
Impact on annual maximum inundated area
3 dams
Irrig.
Ef.high
Irrig.
3 dams +
Irrig.
Ef. Med. Irrig. Ef. High Ef. Low
Source; Liersch et al., 2013, AFROMAISON internal report,
12PIK
Results: Scenario 3 dams + irrigation (Markala: 250.000)
Impact on discharge at the IND´s oultet
Source; Liersch et al., 2013, AFROMAISON internal report,
13PIK
Conclusion
Summary and planned research
• Climate change projections: increase of interrannual variability but trend
agreement on flow in/de-crease remain unclear
1 >> Use RCMs projection from CORDEX project to enlarge the spectrum and the
state of art for regional climate change impact
• Upstream water management: results shows clear gradual impact on the
flood propagation and extent
2 >> Test the impacts with other managerial options for dams
3 >> Vulnerability assessment of flood-dependent water uses
14
Conclusion
Dissemination with OPIDIN Drought early warning system
Tool to predict flood peak and retreat water level and timing
based on statistical regression function from historical water
level time series
Range of early warning signals in use for the
annual flood peak in Mopti
Annual flood peak
water level
Classes
Really low (80´s to 00´s)
Low (70´s to 00´s)
Normal (70´s to 00´s)
High (80´s)
Really high (50´s to 60 ´s)
OPIDIN stakeholder platform: dissemination via key persons,
radio, bulletin
Mopti
Range
Freq. Rang
440-550 cm.
10 330-4
551-590 cm.
9 411-4
591-640 cm.
11 451-5
641-680 cm.
10 501-5
681-730 cm.
12 551-6
Workshop with sheperds to interprate and
disseminate the results of OPIDIN prediction
Source: Fournet , 2013 in Dewfora D4.8,15PIK
Koné Bakary, Wetlands International
Thank you for your attention !
16
Questions ?
17
Spare slides
18
Case study introduction
Niger river
3rd longest river in
Africa watercourse 4200km
9th biggest fluvial
system area 2.1M.km2
~ 25% located in Mali
9 countries Benin, Burkina
Faso, Cameroon, Chad, Ivory
Coast, Guinea, Mali, Niger and
Nigeria
Major cities Tembakounda,
Bamako, Timbuktu, Niamey,
Lokoja, Onitsha
4 climate zones
•
•
•
•
Humid tropical zone
Tropical zone with dry seasons
Sahelian zone
Desert zone
UNEP. 2010 , Africa Water Atlas
Zwarts et al., 2005, Niger the lifeline, Wetlands International
Case study introduction
Upstream river basin management
The Upper Niger
The zone of the Offices
The Bani catchment
2,43 M. inhabitants
1.44 M. inhabitants
0.53 M inhabitants
• Covers the Guinean part of
the basin and stretchs to
Selingué dam included.
•
•
Reservoir of Talo and
Djenné (planned
extension)
•
High potential of rural
development of more than
100.000 ha (agriculture,
fishing and livestock)
•
Projects of minor dams in
Baoulé, Gbado and
Bagoué
• Crucial for the generation of
water ressources with the
Fouta Djallon mountains
• Regulation and storage
infrastructure with Selingué
and the future Fomi dams
•
•
Intensive irrigated rice
production with Office du
Niger (Markala dam), Office
de Ségou and Office de
Baguinéda with a high
potential to extend
agricultural area
Bamako and the
hydropower dam of Sotuba
High potential for navigation
• 5 RAMSAR sites
Source: NBA, PADD, 2010
Scenario matrix
Reservoirs and Irrigation schemes
1.
Current and
future Irrigation water
uptake and efficiency
were setup in line with the
development plan of the
Niger Basin Authority and
the future dams in line with
engineering technical
report.
2.
Water uptake
was restricted to minimal
flows (40m3/s at Markala
and 10m3/s at Fomi,
Sélingué, and Djenné)
Irrigation Scheme in ha
Sélingué
Baguinéda
Markala (ON)
Sélingué planned
Djenné planned
Talo planned
Fomi planned
Markala ON extension 1)
Markala ON extension 2)
Markala ON extension 3)
Rice
1600
3000
77000
3200
68000
20000
3000
220000
220000
600000
Rice CS
400
7700
22000
22000
60000
Gardening Sugar Cane
15400
5000
44000
44000
120000
10000
30000
30000
30000
Irrigation Efficiency
m³/ha/y
31000
71500
30000 [SC:71200]
31000
13276
13276
11500
13500 [SC:71200]
20000 [SC:71200]
24000 [SC:71200]
Provision
in l/ha/s
1.5
2.2
2.7 [SC:3.4]
1.5
2.4
2.4
1
1.2 [SC:3.4]
1.8 [SC:3.4]
2.2 [SC:3.4]
3.
The scenario matrix was defined with local stakeholder
representatives from the IND region
21
SWIM
Soil and Water Integrated Model
Process based eco-hydrological model, simulates runoff generation, nutrient
and carbon cycling, plant growth and crop yield, river discharge and erosion
as interrelated processes with a daily time step on the river basin scale
New Features
• Reservoir-model to simulate effects of reservoir management, including
Hydropower production
• Conditionnal irrigation uptake in the river routing
• Inundation-model to simulate effects of wetlands (flood propagation,
evapotranspiration and discharge from wetland area)
Source: Krysanova et al., 2000, SWIM manual, PIK report 22
n°69
SWIM
Soil and Water Integrated Model
relative humidity
wind speed
surface roughness
land use
precipitation
evaporation
air temperature
transpiration
net radiation
soil texture
management
retention
coefficient
slope
LAI
surface drainage
field
capacity
passage time t
per layer
subsurface drainage
soil water
content
hydraulic
conductivity
drainage porosity
slope length
percolation
capillary rise
saturated
conductivity
drainable water
from the saturated
zone
Groundwater (shallow aquifer)
groundwater flow
23
OPIDIN (Flood prediction tool for the Inner Niger Delta)
Statistical tool
Example of regression curves for annual peak flood water
level from Mopti to Mopti the 30th of September
Source: Zwarts Léo, 2009, A&W report 24
1254
Fournet , 2013 in Dewfora D4.8, PIK
Calibration (with WFD_ERA40) Scenario A
Flood propagation in the IND: SWIM simulation vs. Remote sensing
25
Results Scenario B
Climate change impact on annual maximum inundated area
26