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