Download Smith:_Effect of Climate Change on Hydrology of Lake Victoria

The Effect of Climate Change on the
hydrology of Lake Victoria, Africa
Workshop on Water and Climate Change in Africa
Kara Smith
March 23, 2013
Lake Victoria
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Source of White Nile
Directly supports over 30
million people. Average
economic productivity
between $3-4 billion per
year.
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Provides water and
hydroelectric power (by
dams in Uganda)
Supports agriculture, trade,
tourism, wildlife and fisheries
in the lake basin as well as
upstream.
Lake Levels
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Sudden increase in levels 1961-64
Lake Victoria levels declining since
1964
March 2006: Lowest levels in 80
years
Excessive water release from the
dams has been said to cause 10%50% of the drop in 2004/2005.
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Power output from dams was as low as
120 MW.
Total power demand: 340 MW
Major power outages: 24 hours of
electricity every 2 days (48 hours).
Some areas had no power even during
the peak period (7pm-6am) until there
was enough electricity.
Drought also lowering lake levels.
Hydrology of Lake Victoria

To understand lake variability several water
balance models have been developed based
on the equation:
∆𝑆 = 𝑃 − 𝐸 + (𝑄𝑖𝑛 − 𝑄𝑜𝑢𝑡)/𝐴
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Precipitation (P) and Evaporation (E) are
almost balanced.
Evaporation is approximately constant.
Tributary inflow (Qin) is based on
precipitation, Outflow (Qout) is determined by
Agreed Curve, based on lake level.
Lake level is controlled mainly by
precipitation.
Projected rainfall A2
scenario
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Results for precipitation over Eastern Africa based on A2
scenario
Largest projected climate change signal over Lake Victoria for all
three types of projections
Projected Lake Levels
2070-2100
RegCM3
IPCC Ensemble
Near-term Levels
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To determine if and
when the precipitation
(and levels) will
increase, we need to
look at short term
climate models.
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PRECIS
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Others (CORDEX)
CEOP
GHP
GEWEX REGIONAL HYDROCLIMATE PROJECTS
Mackenzie GEWEX
Studies (MAGS)
Baltic Sea Experiment
(BALTEX)
Northern Eurasia Earth
Science Partnership
(NEESPI)
GEWEX Asia Monsoon
Experiments (GAME)
Monsoon Asian HydroAtmosphere Science
Research and
prediction Initiative
(MAHASRI)
HYdrological cycle in the
Mediterranean EXperiment
(HYMEX)
Climate Prediction
Program for the Americas
(CPPA)
Terrestrial Regional North American
Hydroclimate Experiment (TRACE)
Large Scale BiosphereAtmosphere Experiment
in Amazonia
(LBA)
Current RHP's
Former RHP's
Prospective RHP's
African Monsoon
Multidisciplinary Analysis
(AMMA)
La Plata Basin
(LPB)
Proposed
Hydroclimate Project
Murray-Darling Basin
(MDB)
for Lake Victoria
Basin (HYVIC)
Regional water cycles
29
HYVIC
Mission
The Lake Victoria Basin is proposed as a GEWEX
Hydroclimatology Panel (GHP) Regional Hydroclimate
Project (RHP). The goal of the Hydroclimate Project for
Lake Victoria (HYVIC) is to understand the relative role of
the hydrological components of the water balance over
the LVB in determining the trend of decreasing water
resources during the recent decades and to determine the
timing of the anticipated reversal during the next few
decades in response to the projected increase in rainfall
over the region. Equipped with this knowledge,
stakeholders will be able to make optimal decisions to
minimize hydroclimate-related risks in the management of
hydroelectric power generation, water, agriculture, and
other leading sectors.
RegCM downscaled rainfall for 2071-2100
used as input for the Tate et al (2004) WBM
to compute the LL. (Smith, 2011).
Lake Victoria Hydrologic Balance
Lake Surf.
Temp. Grad.
Orographic
Forcing
Rain
Tributary
Stream Flow
Land Cover
Change Forcing
Low Freq.
Lake Eddies
Qin
Ground
Water Flow
lake level
Qout
(River Nile)
Evap
Lake
Surface
Temperature
Cloud Cover
Lake
Surface
waves
SCIENCE STRATEGY: To understand the variability of the hydrological components of the LVB, it
is necessary to investigate the root climate physical processes involved-NEEDS enhanced
observations and coupled regional climate modeling
NEXT STEPS – Draft Science Plan & Proposed
HYVIC Workshop (early 2013)
A workshop is being planned in cooperation with the relevant WCRP communities, including
GEWEX and CLIVAR, to develop a comprehensive plan for HYVIC
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A preliminary draft of the HYVIC Science Plan is being prepared and will provide background
information for the workshop agenda.
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Science plan will build on results from a feasibility study HYVIC which was funded by the East
African Community (EAC, 2011; http://climlab.meas.ncsu.edu/HYVIC). The feasibility study made
the recommendation for the creation of HYVIC.
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Partial list of institutions and organizations that might be expected to participate in the workshop include : the
African Development Bank (ADB) and other Development Banks, DANIDA/Denmark, the EAC, the European Union (EU), the
Food and Agricultural Organization (FAO) of the United Nations, Global Lake Ecological Observatory Network (GLEON),
Google, the Intergovernmental Authority on Development (IGAD), the International Civil Aviation Organization (ICAO), the
International Council for Science (ICSU), the Korea Meteorological Agency (KMA), National Geographic, Nile Basin
Commission (NBC), representatives of the mobile phone service industry, SysTem for Analysis Research and Training
(START), UK Department For International Development (DFID), the United Nations Environment Programme (UNEP), US
Agency for International Development (USAID), the United States Department of Defense (DOD), the US Department of State
(US-DOS), the United States Geological Survey (USGS), the US National Oceanic and Atmospheric Administration (NOAA),
utility companies, the World Bank, the World Meteorological Organization (WMO), and the World Wildlife Fund (WWF).
Conclusions
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Lake Victoria levels have been decreasing,
but show an increase in A2 scenario.
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Will this increase actually occur?
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If so, when?
HYVIC project
Thank you!
http://placepics.triposo.com/Nalubaale_Hydroelectric_Power_Station.jpeg