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Dr. (Mrs.) Ruby Asmah
Senior Research ScientistEnvironmental 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
• White Volta at Nawuni
• Oti River at Sabari
• Volta Lake at
– Yeji
– Kpando Torkor
– Adawso (Afram Arm)
LEGEND
B U R K I N A F A S O
5°00'N
3°00'W
6°00'N
7°00'N
Sediment and Nutrient Samples
Physico and Chemical Samples
Fish Monitoring
2°00'W
10°00'N
C O T
E D
' I V O
I R E
8°00'N
9°00'N
11°00'N
Bui
Ntereso
Chibrungo
Kpando Torkor
Intern. Boundary
National Capital
Dzemeni
1°00'W
River/Stream
Lake
Town
0°00'
0 40 80
Adowso
ACCRA
SCALE
1°00'E
120 KM
Sabari
Yeji
Nawuni
T O G O
Black Volta – Bole Bamboi
Yeji
Black Volta - Bui
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