Transcript Effects of Climate Change on Volta Lake Resources (VOLTRES)

Dr. (Mrs.) Ruby Asmah
Senior Research Scientist
Environmental Chemistry Division
Effects of Climate Change on Volta
Lake Resources (VOLTRES)
Outline of Presentation
•
•
•
•
•
•
Collaborating Institutions and Research Team
Background and Introduction
Objectives
Methods
Activities for year 1
Challenges
Collaborators/Research Team
• Collaborating Institutions
– The CSIR Water Research Institute
– Department of Biosciences, Aarhus University,
Denmark
WRI Research Team
• Dr. Ruby Asmah (Project
Coordinator/Lake Ecosystem)
• Dr. Hedrick R. Dankwa (Fishery
Biology/Aquaculture)
• Dr. Emmanual Obuobie (Climate
Change/Hydrology)
• Ms Deborah Ofori (PhD Student –
Hydrology/WQ)
• Mr. Emmanuel Mensah Tetteh Doku
(PhD Student-Fisheries/Aquaculture)
Danish Research Team
• Dr. Hans Estrup Andersen
(Soil Science and
Hydrology)
• Dr. Dennis Trolle
(Biological Science and
Environmental
Engineering)
• Dr. Torben L. Lauridsen
(Fisheries)
Funding/Duration
• Funding
– Danish Foreign Ministry and DANIDA Fellowship
Centre
• Duration
– Three (3) Years
Background and Introduction
• The Volta Lake:
– Formed in 1964 by damming of the
Volta River
– Surface area of the 8500 Km2
– Volume at maximum level is 149
Km3
– Total length of 400 Km
– Located between 1° 30’W and 0°
20’E and Latitude 6° 15’N and 9°
10’N
Background and Introduction (Cont’d)
• The Volta Lake:
– Total drainage area of 394,000
km2
– Source of livelihood for more
than 1230 communities
Background and Introduction (Cont’d)
• Lake Volta (Cont’d)
– The Lake is the main source of freshwater fish in Ghana
•
•
•
•
Accounts for about 15 % of total annual domestic fish production
85 % of inland fish production
80 % aquaculture production in Ghana.
A source livelihood for riparian communities
– Main/Other uses of the Lake are:
•
•
•
•
Hydroelectric power generation
Potable water supply
Irrigation
Transportation
Background and Introduction (Cont’d)
• Climate change is projected to impact widely across
– ecosystems,
– societies and
– economies, increasing pressure on all livelihoods and food
supplies (IPCC 2007).
• Its implications for fisheries and aquaculture, is said
to be enormous (FAO 2010).
Background and Introduction (Cont’d)
• Short term impact to freshwater fisheries is anticipated
would come through:
– incremental changes in water temperature,
– hydrological changes in rainfall affecting nutrient mobilisation
and other pollutants (FAO 2007).
– lower dry season water levels (FAO 2007)
– Changes in reproductive processes, larval and juvenile
development and survival of fish (Pankhurst and Munday
2011).
Justification
• Nearly all the models used by IPCC agree that the
frequency of intensive precipitation will increase for the
Volta Lake and Entire West Africa Region (IPCC, 2007).
• Between 1°C and 1.5 °C rise in air temperatures in the
Lake region are expected by middle of the 21st century
(Obuobie et al., 2012, Obuobie and Sasu-Asante, 2013;
Jung, 2006; Andah et al., 2004)
Justification (Cont’d)
•
The Lake’s role in supporting
livelihoods and nutritional welfare is
critical in a country where fish is
estimated to account for up to 60%
of its total animal protein
requirement and contributes 6% of
GDP
•
Ghana is listed among the countries
that are most vulnerable to climate
change because of the high
vulnerability of the country’s fishery
sector to climate change (Allison et
al. 2009).
•
Africa’s response to climate change is
believed will be dictated by how well
it is understood by its people (BBC
WST 2010).
Main Objectives
• To assess the impacts of climate change on
hydrology, water quality, primary production and
fish production of the Lake and improve the
understanding of the lake ecosystem functioning
• To build and strengthen local capacity in climate
change research and biophysical modelling
Specific Objectives
• Develop future climate change scenarios for the Volta
basin (400,000 km2) including Lake Volta;
• Adapt biophysical and ecological models to the Volta
basin and Lake Volta for understanding the Lake
ecosystem functioning;
• Quantify the indicative effects of climate change on
water, sediment and nutrient inflow as well as primary
and fish production in Lake Volta;
Specific Objectives (Cont’d)
• Build knowledge and tools for improving the understanding
of lake ecosystem functioning and fish production;
• Build capacity in climate change research and
biophysical/ecological modeling in Ghana;
• Raise awareness and facilitate adaptation to climate change
by informing local, regional and national stakeholders on
prognoses for future inland fish production
Project Hypothesis
• Climate change, particularly increased temperatures,
will alter the hydrology, water quality, primary
production and fish production in Lake Volta.
Materials and Methods
• Sampling Sites
• Black Volta at Chilbrungo
BURKINA
FASO
11°00'N
10°00'N
• Volta Lake at
Sabari
Ntereso
TOGO
• Oti River at Sabari
9°00'N
COTE
• White Volta at Nawuni
D' I V O I R E
Nawuni
Chibrungo
Yeji
Bui
8°00'N
7°00'N
Kpando Torkor
Adowso
Dzemeni
– Yeji
6°00'N
ACCRA
– Kpando Torkor
SCALE
5°00'N
0
3°00'W
– Adawso (Afram Arm)
2°00'W
1°00'W
40
80
0°00'
LEGEND
Sediment and Nutrient Samples
Intern. Boundary
River/Stream
Physico and Chemical Samples
Fish Monitoring
Lake
Town
National Capital
120 KM
1°00'E
Black Volta –
Bole Bamboi
Black Volta - Bui
Yeji
Materials and Methods (Cont’d)
• Data Collection
– Primary and secondary data on the following:
• lake inflow- and outflow-volumes,
• inflow concentrations (sediments chemistry),
• lake water chemical, physical and biological data (e.g.
temperature and dissolved oxygen profiles, nutrients,
chlorophyll a, phyto- and zooplankton biomass, fish
biomass).
• Sampling frequency is monthly
Methods and Methods (Cont’d)
Work Package 1 (WP 1)
• Climate change scenario development and catchment
modeling
– Analyze climate outputs of all RCMs for the 2 (Upper and
lower limits) of the 4 representative concentration pathways
(RCPs) used in the CORDEX program.
• The period 1981-2010 will be taken to be the baseline, considering
the existing fish catch data, while the period 2051-2080 is considered
the future.
– Upgrade existing Volta Basin SWAT model (VB-SWAT) to
include components on sediment and nutrients and improve
soil data through sampling and analysis of essential soil
parameters in major soil types
Work Package 1 (Cont’d)
• Adapt the upgraded VB- SWAT model to simulate
the inflow of sediment and nutrients into Lake
Volta through the processes of calibration and
validation.
• Simulate and quantify the effects of changes in
precipitation and temperature (climate change)
on the flow of water, sediment and nutrients into
Lake Volta.
Work Package 2
• Lake ecosystem modeling
– Set up of a 3D model of lake hydrodynamics and
biogeochemistry based on data from WP1.
– Field data collection and laboratory analysis.
– Test and validate lake models on field data and remotely sensed
data.
– Make future projections on lake physics and primary production
under different climate forcings providing input to WP 3.
Work Package 3
• Fish Productivity
– Collect historical information on fish catches and
establish empirical relationships to lake water level
fluctuations and water temperature
– Field data collection.
– Analysis of stored gut material and mapping of seasonal
food habits of the most important fish species.
– Establish empirical relationships between biomass and
temperature, oxygen concentration and primary
production. Estimate fish mortality rates.
Work Package 3 (Cont’d)
– Set up of EcoPath, an ecosystem model for the
higher trophic levels (Christensen and Pauly, 1992)
to explore the dynamics and sensitivity of climatic
forcing on fish productivity using data from WP 2
on future lake physics and primary production.
– Make predictions of future climate change effects
on the fish stocks by using established
relationships between fish catches/fish
productivity and environmental factors.
Expected Outputs
• Downscaled future climate scenarios over the Volta Basin
• Biophysical/ecological models (watershed, lake and fish
models) adapted to the Volta basin and Lake Volta,
• Indicative effects of projected climate change on water,
sediment and nutrients inflows to Lake Volta and
consequences for fish production;
Expected Outputs (Cont’d)
• Ghanaian scientists trained in climate change
impact research; (v)
• Journal publications;
• Four post graduates (2 PhDs and 2 Mphils)
• Improved awareness at local and national level of
climate change effects and adaptation in relation
to inland fish production
Dissemination
• Nationally
– through policy briefs,
– workshops for local and national stakeholders, and
– seminars covered in print and electronic media
• Internationally
– Publications in peer reviewed journals,
– Presentations in international and regional
conferences, and
– Project website
Challenges
• Availability of reliable long term secondary
data on water quality
• Delays in acquisition of equipment for the
project
Way out
• Use of remote sense data – these will be
calibrated with field data
TNAKS FOR YOUR ATTENTION