using earth observation data for monitoring river...
TRANSCRIPT
Using Earth Observation Data for Monitoring River Basins
The NBI Experience
NBDF, 23rd -25th October, Kigali Convention Center, Kigali, Rwanda
By
Milly Mbuliro
GIS/ Remote Sensing Specialist
Nile Basin Initiative Secretariat
EGYPT
SUDANSOUTHSUDAN
ETHIOPIA
D R CONGO
UGANDA
RWANDA
BURUNDI
KENYA
TANZANIA
The Nile Basin Initiative (NBI) is a regional intergovernmental Partnership among 10 countries.
Objective is to Promote sustainable utilization of the Nile Basin resources.
It is our Mandate to Monitor the status of the basin to promote informed evidence -based decision making
NBI: Overview
• The Nile cuts across diverse climatic zones(humid to arid conditions)
• Spatial and Temporal variation in its processes.
• Highest population growth rates in the region.
• Each riparian state has development master plans ( irrigation master plan, Energy master plan etc
• Leading to increased need and pressure on the finite resources.
• Faces environmentally related challenges such as floods, Land degradation, surface water pollution, sediment load and others
The Nile Basin
• Is the Nile basin water Secure?• Is Climate change a real threat to the
Nile basin region?• How much water is available to meet
the demand• Are our resources sustainable?• What will be the status 10-50 years
after and how was it 100-50 years before?
• Is there any potential for development? Untapped potential
• You can not manage what you can not measure; That is why we monitor
Fundamental questions
NBI Response• The NBI informs and provides a platform
for dialogue over such issues through Strategic Analysis and group discussions
• Preparation of periodic state of River Nile Basin Reports, first one in 2012, next issue in 2018
• Under the Hydro-Met project, the NBI aims to set up a regionally recognized monitoring system to capture and store readings of key climatic variable.
• Design stage, agreed upon by countries already completed, looking for funds to implement the regional monitoring System in phases
• The proposed regional system comprises of ground measurements and satellite based measurements
Basin Monitoring• NBI promotes good data management, data sharing
and data communication to resource managers in a consistent, harmonized and understandable way
• Variables monitored include• Rainfall,• Evapotranspiration,• Relative Humidity,• Land and Air Temperature,• Water levels,• Soil erosion Vulnerability,• Land-cover /use change, • Seasonal Variation of Wetland areas ,• Soil Moisture , Vegetation cover and socio economic
indicators among others.
Nile Basin Rainfall• Monitored by both observed and
satellite data• Data Products are mainly TRMM
3B43v7 monthly product and the 3B42 daily product.
• Other rainfall data products include• CRU_TS, from the Climatic research
unit (includes rain-guage data• Chirps, • RFE from the NOAA.• A comparison of how the different
products estimate rainfal over the different subbasins was made
• Analysis to compare with ground measurements is ongoing
Nile Basin Rainfall-Annual
Find more in the Nile Basin Water Resources Atlas http://atlas.nilebasin.org/
Nile Basin Rainfall- Comparative assessmentBaro- Akobbo- Sobat Subbasin
Lake Victoria Subbasin
Bahr el Jebel Subbasin
Lake Albert Subbasin
Nile Basin Rainfall- Comparative assessment
Blue Nile Subbasin
Main Nile Subbasin
Nile Basin Rainfall- Comparative assessment
Actual Evapotranspiration• ET is an important component of
the water balance• Is the only “consumer” of water• Water balance models were used
to estimate ET as the remainder after determining all other balance components
• Now, Satellite based techniques have emerged
• NBI has generated Actual Evapo-transipiration estimates over Nile Basin Countries based on MOD16ET
• Spatial resolution;1km cell size • Temporal resolution is 8 days,
monthly and annual
Actual Evapotranspiration• The data shows
Temporal and spatial variation over the Nile Basin.
• ET accounts for 87% of basin rainfall
• There is variation even at sub-basin level
• Highest in the Nile Equatorial lakes region due to moisture availability
Sample analyses• ET: ETo ratio gives an indication of moisture
availability• Highest ET/ETo ratio occurs in the Lake Albert
Sub basin and the Sudd area• Lowest ET:ETo is found in the Main Nile and
Tekeze Atbara Subbasin which are mostly dry.• Ratio of ET:P shows the conversion rate of
available moisture to evapotranspiration• When ratio is less than 1 there is potential for
generation of runoff or recharge ground water
• When ratio is more than 1, all the rainfall and water coming in through the river is lost as AET
Products•11 Long Term and Seasonal Variation of Wetlands.
Small water body mapping in the Sudd region Based on Sentinel-data• Uses soil moisture retrieval
technique
Other water quality indicators that can be measured from satellite data include:• TDS• Lake Surface Temperature• And others
From this analysis, point source contamination can be identified
White regions show no data
Flood mapping• Flood prone areas• Threshold classification• Historical flood mapping
Data requirementsENVISAT ASAR data
Erosion potential / VulnerabilitySoil erosion PotentialHot Spot Detection
Data RequirementsNOAA RFE Rainfall dataFAO SoilsSRTM DEMESA GlobCover Landcover
Knowledge Products• Nile Basin Water Resources Atlas
http://atlas.nilebasin.org/
• State of River Nile Basin Report http://sob.nilebasin.org/
• MSIOA reports
• Understanding Nile Basin Hydrology: Mapping Actual evapo-transipirationover Nile basin countries
• Visit http://nileis.nilebasin.org/ for more publications
Implications for River Basin management• You can not manage what you can not measure or monitor.• In view of all country development master plans, monitoring is a
must• Satellite data has been recognised as a feasible technique for
monitoring a wide range of earth processes.• Satellite data and techniques keep evolving, so should resource
managers.• River basins like the Nile basin with ungauged catchments/limited
ground observations need EO data.• Data management and sharing are key components for river basin
management and this calls for regional cooperation.• NBI offers such a platform where transboundary data can be
shared.• NBI has designed a regional hydromet system (with a component
on EO data) with all key stakeholders consulted, agreed upon by countries and awaits implementation.
• Use of Earth Observation data is encouraged to compliment ground observations for River basin monitoring/management
