If Zambia has 60% of the freshwater in the Southern African Development Community (SADC), why does it import fish from China?
The claim that the landlocked country is home to 60% of the community’s water has appeared beforein a 2012 tweet, a press release by the Southern Africa Zambia chamber of commerce and an investment policy review by the Organisation for Economic Co-operation and Development (OECD). It is also on the agenda for a conference about commercial farming in Africa to be held in October.
Zambia is one of 15 member countries in the SADC. Two big tributaries of the Zambezi river flow through Zambia, it contains lake Bangweulu and shares lake Mweru and the southern end of lake Tanganyika. Could it possess 60% of southern Africa’s freshwater?
“Sounds like a job for @AfricaCheck,” Matt Hill tweeted and we got to work.
Where does the 60% figure come from?
When Africa Check phoned Mwale, he said was misquoted and that he said instead that Zambia has 40% to 50% of the SADC’s freshwater. When asked on what he based it, Mwale sent Africa Check a paper in the International Journal of Fisheries and Aquatic Studies, but it did not contain data on Zambia’s freshwater resources.
The OECD did not reply to an email asking for the source of the claim.
How do scientists calculate freshwater levels at national scale?
Calculating the quantity of freshwater a country holds relies on long-term annual averages, an associate professor in water resources engineering at the University of the Witwatersrand, John Ndiritu, told Africa Check. It is therefore not “a perfect indicator of the reality” of how much freshwater there is.
Freshwater includes rainfall, groundwater and “streamflow”, which is surface water in lakes, rivers and streams and that is measured by dedicated monitoring stations.
Determining the levels of groundwater relies on indirect measurement, professor of water engineering at Wits, Akpofure Taigbenu, told Africa Check. This is done by drilling into an aquifer and determining the water pressure.
“A small [pressure] value, with a large discharge [amount of water displaced] means that there is a large amount of water in the aquifer,” Taigbenu said.
Data on rainfall, groundwater and streamflow is expressed in billion cubic meters per year and summed to arrive at a freshwater total.
This data excludes the volume of water contained in dams, such as Kariba, Africa’s largest dam at a volume of 188 billion m³ and which Zambia shares with Zimbabwe. “[Dams] are an essential part of managing water and dealing with droughts, but the water still comes from [rainfall],” Ndiritu said.
How much freshwater lies in Zambia?
The organisation rely on countries to supply data and noted that “the best quality data are frequently not satisfactory”. Part of it is due to incomplete measurement. “South Africa has quite a lot of streamflow stations but other countries [in SADC] don’t have the same resources,” Ndiritu said.
Keeping these possible limitations in mind, the database showed that Zambia has 104.8 billion m³ of “renewable freshwater resources”. This is less than a twelfth of the DRC’s 1,283 billion m³ recorded and puts Zambia fifth in the SADC region, after Madagascar (337 billion m³), Mozambique (217.1 billion m³) and Angola (148.4 billion m³).
Calculated as a share of the SADC’s freshwater resources, Zambia holds 4.5% and the DRC more than half.
|% of SADC
|Democratic Republic of the Congo||1,283||54.9%|
Conclusion: Zambia has about 5% of the SADC’s freshwater
The claim that Zambia has 60%, or even 40% to 50%, of the SADC’s freshwater does not hold against the best available data. A database kept by the UN’s Food and Agriculture Organization puts its share at 4.5%.
The DRC is the outright leader in the SADC, containing more than half of the total freshwater volume in the community.
SOURCE : Africa Check