Lake Kivu's Biodiversity Treasures

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Lake Kivu's Biodiversity Treasures Photo Courtesy of Wikimedia Commons

The panorama offered by Gisenyi bay beach is a scenic expanse of blue water that ends on the Congolese hillside. Gisenyi town is one of the most popular tourist destinations in Rwanda. In the middle of the Lake Kivu stands a pole. From far, it looks like a giant tree that grew from the deepest lake bed. But it is the methane gas extraction plant.

On the other side of the lake lives a farmers’ community. They raise their children and send them to public schools. Clarisse, 13 years old, is a young girl born in that community. She speaks normal Kinyarwanda tinted with the sweet Swahili accent. She knows the secrets of the water that she has paddled in with her brothers since her tender childhood. But the biggest secret she holds is the marvels of the thermal waters, amashyuza.

When you reach the water source, small children, boys and girls together are taking everlasting baths. The hot vapors that come from underground wrap their tiny bodies like invisible robes. These hot waters provide livelihoods opportunities for Clarisse and her young neighbors. After class, she fervently explains to tourists the curative powers and benefits of amashyuza before offering a massage using local herbs.

From her rural land, she has a picturesque view of the methane gas extraction plant. She doesn’t know the role of that pole in her Lake Kivu but she heard from her big brothers that it generates electricity and that they can’t fish in the 30 meters around it.

With its pacific blue, Lake Kivu itself offers a spectacular sight while its waters provide a meaning as a source of drinking water, for fisheries and a transportation corridor to the livelihoods of more than two million people from Rwandan and Congolese communities, including Clarisse’s family.

The main economic activities of these inhabitants are farming and fishing with the most abundant fish being isambaza, the Tanganyika sardines (Limnithrissa miodon). They were introduced into the lake in the 1960s to fill the obvious vacant niche of Kivu. Currently, only 31 fish species live in this lake compared to 400 species of Lake Tanganyika. This poor diversity in terms of biota is due to the steepness of the banks, age and the nature of the lake’s bottom.

The biodiversity of Rwanda is mainly conserved in protected areas like the three terrestrial national parks but these parks don’t represent the whole biodiversity and ecosystems of the country. For instance even if Lake Kivu’s fauna is poor due to its physical isolation or doesn’t shelter either hippopotamuses or crocodiles; it has several aquatic biodiversity, phytoplankton, zooplankton, more than 200 Afro-tropical superior plant species and vegetation.

Lake Kivu, situated around 100 miles north of Lake Tanganyika is a volcanic Lake of 2370 km2, almost the size of Mauritius or Moscow city, with a maximum depth that can attain 485m. It is located in the East African Rift Valley between Rwanda and the Democratic Republic of Congo. Its uniqueness consists of the prodigious quantity of dissolved gases (carbon dioxide and methane gas) in the deep water and far from the mountainous shores.

Kivu is among the 3 lakes in the world with high dissolves volumes of CO2, the two others being Nyos and Monoum from Cameroon. But contrary to them, it contains a considerable amount of methane gas and if not exploited might erupt within a century.

On August 21, 1986, Lake Nyos emitted CO2 and suffocated fauna, flora, livestock and caused a loss of around 1800 human lives.

To shun such a disaster, Rwanda has started the extraction of methane from Kivu. The origin of this gas is not yet very well known and there have been hot debates around the subject. Scientists don’t agree on its origin, some assume that it is caused by earthquakes and volcanic activity. However, according to Dr Klaus Tietze, a German scientist, this gas is a result of bacterial reduction of the magmatic CO2 that leads to methane but along with bacterial fermentation of acetate[1] in sediments.

Currently, there is no imminent danger of explosion in Lake Kivu that threatens Clarisse’s community because gases are trapped below 260 meters. Up till now, these gases are not harmful to the biodiversity although they hinder the development and expansion of numerous species accommodated inside the water. The surface water is totally isolated from deep water where carbon dioxide and methane gas are located. The living organisms and biodiversity, especially fish species, are found in the biozone comprising only between the first 50 and 60 meters from the surface. Biozone is the part of the lake provided with sufficient oxygen to support life.

As the risk of “bang” is relatively low, Clarisse will still be able to earn some cash from amashyuza and contemplate the lonely triple-colored national flag fluttering on the methane gas extraction site. What prevents Kivu’s methane gas from exploding is the presence of several layers with different densities in addition to the fact that the water pressure is twice higher than the total of partial pressures from the gases. The bigger hydrostatic pressures from the water block the methane gas and CO2 from ascending to the surface and to have a calamitous effect on the lake’s biodiversity.

In order to reduce the accumulation of the gases in Kivu, the Rwandan Ministry of infrastructure and the Congolese Ministry of hydrocarbons operate hand in hand to ensure safe, environmental friendly and economically sustainable extraction of methane gas in the lake.

The Rwandan government has contracted private investors to start the degassing process. Since 2008, the extraction work has been ongoing on a government funded pilot project called Kibuye Power Ltd (PK1) under the Rwandan Energy Company. This company is currently extracting methane and produce electricity in Gisenyi, generating 3.6 MW. The KivuWatt is another project that is supposed to start in a near future with a potential of producing 100 MW, almost equal to the current national power consumption. Captivatingly, in addition to its other numerous benefits, Lake Kivu has an opportunity of producing 700 MW of power over the next 50 years.

It’s worth noting that Rwanda has established Lake Kivu Monitoring Program (LKMP) to circumvent negative impacts of a wrong extraction technology to the surrounding environment. This unit is mainly in charge of overseeing the plant inspection, near plants and lake wide levels. According to Mrs Augusta M. Christine Umutoni, the LKMP Programme manager, LKMP ensures public safety by maintaining the stability of the lake and preventing any potential gas eruption, thus avoiding any hazardous impacts on the environment and people as well as maximizing the socio economic benefits.

The effectiveness of Kivu Lake Monitoring Program to prevent environmental hazards will enable the few fish species to evolve in the waters of this small and young lake of East African Rift valley. The local people will keep fishing in Lake Kivu; will continue to offer tourism boat tours and to trade with the neighboring Congo. But also Rwanda has gained another source of power generation that gradually will help to reduce the gap between national electricity demand and supply.

Even if Methane gas is being extracted and averts the outburst risk, the volume of electricity produced under KP1 is still insignificant considering the national consumption and Lake Kivu neighboring communities do not yet benefit from this power that their natural resource breeds. Clarisse is currently using the tadowa, a kerosene traditional lamp, to do her school homework. She is hoping that that electricity produced in Gisenyi and channeled in the national grid, will one day reach her house through the national rural electrification program.

But s long as the methane gas extraction prevents the detriment of the ecosystems, Gisenyi local communities gain from the surrounding biodiversity to earn their livings. Clarisse’s parents will still be able to farm their lands and pay her school fees. Her older brothers income from fishing will allow them to build their future households and she will keep making pocket money from the massage and satisfy her adolescence basic needs.

 


[1] Acetate is a salt or ester of acetic acid especially used to make fibers or plastic.

Caroline Numuhire

I am in love with Mr. Pen

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