Understanding riverine wetland-catchment processes using … · 4 20 34 10 30 8 Wetlands...
Transcript of Understanding riverine wetland-catchment processes using … · 4 20 34 10 30 8 Wetlands...
Understanding riverine wetlandUnderstanding riverine wetland--catchment processes using remote catchment processes using remote sensing data and modellingsensing data and modelling
Yunqing Xuan (UNESCO-IHE, NL)Didier Haguma (KIST, Rwanda)William Niyonzima (UNESCO-IHE, NL)
Ann van Griensven (UNESCO-IHE, NL)
UNESCO-IHE Institute for Water EducationDepartment of Hydroinformatics and Knowledge Management
Catchment modellingHill slope hydrologyInclusion of agricultural processes
Water quality: from river reach to river basinHill slope hydrologyInclusion of agricultural aspectsImportance of natural landscape elements
Wetland processes- Water retention- Sediment/Nutrient trapping- Anaerobic processes- Groundwater recharge- Habitats
How to represent wetland-catchment hydrology?
What is the value of remote sensing data?How to model wetlands at catchmentscale?
How to represent wetland-catchment hydrology?
What is the value of remote sensing data?How to model wetlands at catchmentscale?
Kagera basin
Study area
GIS/RS DataDEM: Watershed delineationDEM: Watershed delineation
Remote sensing data
GIS/RS DataDEM: wetland delineationDEM: wetland delineation
Remote sensing data
GIS/RS DataDEM: wetland delineationDEM: wetland delineation
Remote sensing data
GIS/RS DataSoil dataSoil dataLand use dataLand use data } Usefull for catchment modelling
Not well representing wetlands
Remote sensing data
GIS/RS Data: soil water
ZAIRE
SUDAN
LIBYAALGERIA
MALI
CHAD
NIGER
EGYPT
ANGOLA
ETHIOPIANIGERIA
NAMIBIA
ZAMBIA
SOUTH AFRICA
TANZANIA
MAURITANIA
KENYA
SOMALIA
BOTSWANA
MOROCCO
CAMEROON
ZIMBABWE
GABON
GHANA
GUINEA
UGANDA
MOZAMBIQUE
MADAGASCAR
CONGO, THE
TUNISIA
SENEGAL
CENTRAL AFRICAN REPUBLIC
BENIN
BURKINA FASO
IVORY COAST, THE
WESTERN SAHARA
MALAWI
ERITREA
LIBERIA
TOGOSIERRA LEONE
LESOTHO
BURUNDIRWANDA
DJIBOUTIGUINEA-BISSAU
SWAZILAND
EQUATORIAL GUINEA
GAMBIA, THE
CAPE VERDE
COMOROS, THE
CAPE VERDECAPE VERDE
SAO TOME AND PRINCIPE
COMOROS, THE
GAZA STRIP, THE
Soil water for the entire Africa January-02-1995
0 1,700 3,400 5,100 6,800850Kilometers
Legendafrica_adm0
January-02-1995% Soil water
-20 - 0
0 - 10
10.00000001 - 16
16.00000001 - 23
23.00000001 - 29
29.00000001 - 35
35.00000001 - 43
43.00000001 - 55
55.00000001 - 71
71.00000001 - 99
.
TANZANIA
ZAIRE
UGANDA
BURUNDI
RWANDA
KENYA
Kagera Basin Area .
0 150 300 450 60075Kilomete
Legendafrica_adm0
Riv2
watsub2
January-02-1995% Soil water
-20 - 0
0 - 10
10.00000001 - 16
16.00000001 - 23
23.00000001 - 29
29.00000001 - 35
35.00000001 - 43
43.00000001 - 55
55.00000001 - 71
71.00000001 - 99
25 km x 25 km25 km x 25 kmUniversity of AmsterdamUniversity of Amsterdam
Remote sensing data
GIS/RS Data: soil waterWetland identification?Wetland identification?Spatial resolution too lowSpatial resolution too low
Remote sensing data
GIS/RS Data: soil waterWetland identification?Wetland identification?Spatial resolution too lowSpatial resolution too low
Dail soil water in Nyabarongo
0
20
40
60
80
100
120
1-Jan-05 1-Mar-05 1-May-05 1-Jul-05 1-Sep-05 1-Nov-05
%
agricultural wetland
Daily soil water for 2 Nyabarongo gridsDail soil water in Nyabarongo
0
20
40
60
80
100
120
1-Jan-05 1-Mar-05 1-May-05 1-Jul-05 1-Sep-05 1-Nov-05
%
agricultural wetland
Daily soil water for 2 Nyabarongo grids
Remote sensing data
Rainfall dataRemote sensing data
How to represent wetland-catchment hydrology?
What is the value of remote sensing data?How to model wetlands at catchmentscale?
Soil and Water Assessment ToolSimulation of processes at land and water phaseSpatially distributed (different scales)Semi physically based / empirical approachesSimulation of changes (climate, land use, management etc.)Water quantities, incl. different runoff componentsWater quality: Nutrients, Sediments, Pesticides, Bacteria, (algae and oxygen), etc.
…. all that on a daily time step and at different spatial scales and (more or less) readily available data sets!!
Wetland-catchment Modelling
Wetland representation
As reservoirs
As irrigated potholes
Ponds or wetlands
Wetland-catchment Modelling
New land use mapSlope (DEM)Slope (DEM)Google earthGoogle earth
Wetland-catchment Modelling
SWAT modelWetlands located in the south part of Rwanda, and north of Burundi, eastern part of Rwanda and West of TanzaniaTotal number of Subbasinis 35, and HRU number is 323
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21
3
27
7
15
13
17
9
2 126
5
24
32
1
16
22
14
19
11
18
2623
28
2933
25
35
31
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20
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Wetlands delineation, including Lakes and Reservoirs
{
LegendLakes and reservoirs locations
!( Reservoirs location
# Linking stream added Outlet
# Manually added Point Source
Kagera river Network
Subbasins number
Wetelands areas0 25 50 75 10012.5
Kilometers
Wetland-catchment Modelling
Preliminary results Surface Q Assessment for wetland modeling
comparison
70,26 70 70,26 70,26
122
0
20
40
60
80
100
120
140
Different scenarios for modelingw etlands
(Scenarios)
Valu
e (m
m)
Surface Q (NoWetlands)
Surface Q (As ponds)
Surface Q (AsWetlands)
Surface Q (AsReservoirs)
Surface Q (AsPotholes)
Water Yield (YLD) Assessment for wetland modeling comparison.
169,34
94
169,34170,82
376
050
100150200250300350400
Differents Scenarios for modelingw etlands
(Scenarios)
Valu
es (m
m) Total w ater Yield (YLD):
No Wetlands
Total w ater Yield (YLD):As Ponds
Total w ater Yield (YLD):As Wetlands
Total w ater Yield (YLD):As Reservoirs
Total w ater Yield (YLD):As potholes
Average flow Assessment for wetland modeling comparison
352,9
191,2
66,1994,41
176
050
100150200250300350400
Different scenarios for modelingwetlands
(Scenarios)
flow
(cm
s)
Average flow : NoWetlands
Average flow : AsPonds
Average flow : AsWetlandsAverage flow : AsReservoirs
Average flow : AsPotholes
Groundwater (GW) Assessment for wetland modeling
69,89 73 69,8971,37
219
0
50
100
150
200
250
(Scenarios GW)
Different scenarios for modeling wetlands
Valu
e (m
m)
Groundwater (Gw): NoWetlands
Groundwater (Gw): AsPonds
Groundwater (Gw):AsWetlands
Groundwater (Gw): AsReservoirs
Groundwater (Gw): AsPotholes
Wetland-catchment Modelling
Conclusion (1): RS Data
-YES/NOSatellite rainfall data
NOYES/NO?Soil water (25 km x 25 km)
NOYESSoil map
NOYESLand use map
YES (slopes)YES DEM
WetlandCatchmentData
Conclusions
Conclusion (2): modelling
Many different types of wetlandsDifferent modeling conceptsNeed to link concept-type
Conclusion