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Lake Kivu, an eldorado under supervision

A real eldorado in terms of the amount of methane it contains, Lake Kivu, situated between the Democratic Republic of Congo (DRC) and Rwanda, also provides fish for the local populations. With major changes looking to take place in the next few decades, it is imperative we understand the mechanisms and empower the stakeholders who will have a role to play in its exploitation. Since 2002, one of the least studied great lakes in the region has gradually revealed a good number of its secrets to an international team of researchers from all fields. The report from the EAGLES project (1) (East African Great Lake Ecosystem Sensitivity to changes), financed by the Belgian Federal Science Policy (BELSPO), marks an end to this series of expeditions. It provides new keys to understanding how the lake functions and places its biogeochemical evolution in a historical, climatic and ecological perspective, at the heart of a problem where the sirens of economic profit are wailing on the one hand, and global warming forecasts are sounding the alarm bells on the other.

With their own particular ecosystems, some of them unique, the African Great Lakes are key to major human activities such as fishing and electricity production. At the same time, they are the source of great potential in terms of the exploitation of hydrocarbons. Lake Kivu stretches over more than 2,700 km2. At least 2 million people live along its shores in Rwanda and Congo, mostly in large agglomerations such as Goma and Bukavu, as well as Gisenyi and Kibuye to a lesser extent. Although fishing may be less widespread here than elsewhere in the region, it nevertheless represents 10,000 tons of fish per year, and is a cheap source of animal protein for the local riverside populations in both countries. A reality that risks changing considerably in the coming years for two main reasons: climate change on the one hand, and the industrial exploitation of the billions of cubic metres of methane dissolved in the deep waters of the lake, on the other. Up until now, Lake Kivu had kept many of its secrets well hidden. Lifting the few remaining veils to understand the most complex mysteries of its behaviour has become a priority within this context of large economic and ecological transformations.
African Great Lakes
The EAGLES project report completes a vast series of interdisciplinary studies on Lake Kivu, carried out by an interuniversity team of researchers. Healthy cooperation between scientists from the University of Namur, the University of Liège, the Katholieke Universiteit Leuven (KULeuven), Ghent University, the Royal Museum for Central Africa (RMCA) as well as institutes from France (Institut national de la recherche agronomique - INRA), Congo (Institut Supérieur Pédagogique – ISP) and Rwanda (University of Rwanda – UR), beginning in 2010 and ending this year, thanks to the support of BELSPO within the framework of the “Science for sustainable development” programme. This project is part of a series of older projects dating back to 2002 financed by BELSPO, the Commission Universitaire pour le Développement and the FNRS. Spanning such a long period of time, it was possible to focus on the unprecedented study of a multitude of biogeochemical, ecological, physical, paleolimnological, climatic and meteorological data, as well as developing forecasting models regarding changes in the lake and the region. A compilation of data provided the material for an initial work, published by Springer in 2012, which dealt with a good number of its characteristics and problems in detail (see “The secrets of Lake Kivu”). EAGLES is offering a new batch of material and information. The researchers would like to continue their work, but uncertainties concerning the federal research subsidies mean that it is impossible to make such plans. It is therefore time to draw up the results, provide access to a considerable database, and establish observations and advice for local teams, as well as for industries and decision-makers concerned with the lake’s exploitation and management. “There is a special historical context linking ULg to Lake Kivu”, explains Alberto Borges, from ULg’s Chemical Oceanography Unit, a specialist in greenhouse gases and co-promoter of the project. “Hubert Damas, an oceanographer and professor at ULg, organised an expedition between 1935 and 1936 to explore three African great lakes, including Kivu. At the time, studies of the lakes were generally limited to zoology and botany. Hubert Damas introduced a multidisciplinary aspect by including chemistry, physics and biology”. “He was also the first to reveal the lake’s special structure (Kivu is a meromictic lake) which allows it to accumulate gas in its deep waters”, adds Jean-Pierre Descy, professor emeritus at the University of Namur, scientific collaborator at ULg, and EAGLES project coordinator. In other words, Hubert Damas was one of the founding fathers of modern biogeochemistry, initiating a relationship with Lake Kivu which has come full circle with the publication of the EAGLES report.

The responsible conquest of an eldorado

Billions of cubic metres of methane dissolved in the lake’s depths remain trapped because of the waters’ strong stratification. A characteristic that is attracting investors from all over, especially because Rwanda has few natural resources that can produce energy. The principle is quite simple: by pumping these deep waters, it is possible to reduce the pressure providing they don’t come up to the surface. The dissolved methane naturally degases, and draws the water to the surface (self-priming pumps). It simply has to be collected and purified, because it is mixed with unusable CO2, and brought ashore. It could then be burned in a thermal power plant to produce electricity. Even though much still has to be done to set it up, industries have already set to work to extract this energy-producing treasure. “However, there are risks involved with this extraction and certain precautions must be taken”, the researchers point out. “These precautions mainly concern the reinjection of the water into the lake. It would be extremely costly to return these waters to their original depth and the resources would be diluted, thus diminishing the exploitation’s yield. On the other hand, these waters must be reinjected at the right depth to maintain the lake’s physical stability and the integrity of the ecosystem that supports fishing.”

(1)  East African Great Lake Ecosystem Sensitivity to changes final report, BELSPO, 2015

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