"vibrant" lakes

Now that the cause of the mass death near the lake is known and the way to prevent similar disasters is known, it is to be hoped and assumed that the budgeting will be found.

There are many freshwater lakes in Africa, including some of the deepest, largest and richest, and also the most "vibrant", since many of the lakes lie on the African depression line, an active region where volcanoes and hot springs are often present. Some of the sinkhole lakes were formed inside ancient volcanic craters and this is probably where their danger comes from, the most well-known of which are three: Lake Kivu on the border of Rwanda Congo, and lakes Nyos and Monoun, both in remote rural areas in Cameroon.

Lake Naios burst into world awareness in 1986 when what was described as a mysterious event caused the death of 1700 people and hundreds of domestic animals near the lake. Researchers who examined the cause of death concluded that all the people (and animals) died of suffocation, suffocation caused by a sudden and high concentration of carbon dioxide.

It turns out that the source of the gas is in the lake. The volcanic environment that causes the constant bubbling of gases from the magma into the rocks and into the lake, the lake is deep, its bottom is cold and thus the cold and the weight of the water "holds" the gases at the bottom.

A (mild) earthquake, a strong storm, or a rock slide caused the release of large amounts of the gas in what is described as a "Limnic eruption". The wind drove the gas to the shore, the event took place at night and therefore there was no one to recognize the danger and warn and thus people and animals died in their sleep.

Two years earlier in 1984, about 40 people died near Lake Monon. The "small" number of victims did not cause a stir, but even then researchers began to look into the event and it turns out that in the tradition of the local tribes, events of mass death for no apparent reason are known and told.

After the cause of death became clear, they began to look for a way to prevent future disasters, teams of researchers inserted a tube into the bottom of the lakes to check the composition of the water and large deposits of gas were indeed discovered. In the 90s, attempts began to drain the gas first in Lake Monon and then in Lake Naios, in 2001 the drainage project began in Lake Naios and in recent weeks the pipeline is ready to release gas from the depths of the lake. After the initial suction, the release continues by itself (like the gas that is released in carbonated drinks).

There are two main problems. The first is preventing the gas from being released in the immediate environment, as mass suffocation will then occur. Therefore, the gas should only be released when there are strong winds that will disperse the gas and prevent it from sinking to the ground. The second problem is the high acidity of the water in the pipe, an acidity that causes the pipe to be digested in a short time. To overcome the digestion, the pipe is "electrified" which will prevent "corrosion".

After almost a decade of preparations, the "Pressure Release" project in Lake Naios in Cameroon is approaching its final stage.
In the first phase, the installation of one pipe was completed by a team led by engineer Michel Halbwachs who began the research as part of a team from the University of Savoie in Chambéry in France, and continued the implementation phase as a team leader at the gas utilization company "Data Environnement".

According to the developers, in order to ensure complete drainage, more pipes will be needed to drain gas pockets from the bottom of the lake and thus after a while the gas concentrations will not pose a danger. For this purpose, approximately two million dollars were raised from the United Nations Development Program. In the future, the developers also intend to finish draining the gas in Lake Monon. And so, within five years, the two lakes will be freed from the danger of a "reversible eruption".

Lake Kivu in Rwanda harbors an even greater danger because in its bottom, in addition to concentrations of carbon dioxide, increasing amounts of methane accumulate. They intend to turn this danger into an advantage by producing methane and using it as a fuel for electricity generation.

Two experimental collection facilities have been sunk to the bottom of the lake, the gas is fed to a power plant that supplies about eight megawatts of electricity. The entrepreneurs intend to produce gas that will be enough to produce about 350 megawatts.

In order for the water that is pumped (back) into the lake not to cause confusion and eruption as well as not to harm the rich biological diversity in the lake, a place and a proper way to return water to the lake, for production and to carry out the project, must be found.

Lake Kivu is connected by a narrow passage to the Gulf of Kabuno. Unlike in other lakes where the gas concentrations are at a depth of hundreds of meters here (in Kabuno Bay) the gas is found at a depth of 12 meters. It is clear that gas concentrations near the surface of the water constitute a "ticking bomb". The World Bank allocated $3 million for draining the gas, but the developers claim that to carry out the work, an additional two million dollars is needed... and urgently, since there are larger amounts of gas in the Gulf and many settlements around it.

Now that the cause of the mass death near the lake is known and the way to prevent similar disasters is known, it is to be hoped and assumed that the budgeting will be found.