Second tank of mild water in the world, Tanganyika Lake is going on decreasing. The lake, a true inner sea of 670km long and 150 km large, shrinks in for countries (Democratic Republic of Congo, Burundi, Tanzania and Zambia) which line it. It’s a pity, due to water hyacinth.

From its scientific noun Eichhornia Crassipes ,water hyacinth with blue flowers, grows into muddy and polluted water of hot regions .Hyacinths make a kind of floating carpet, reducing available water quantities and make disappear different water animals. When hyacinths are developed and extend, it’s just impossible to navigate, to drain, and in water adduction. They make fish die and other bio aquatic resources .They progressively diminish water of lakes and make papyrus disappear gradually.

This nice plant would originate from Brazil, where it is called “millions of dollars weed” to mean that eradicating it is very expensive. This plant has just attacked more than 50 countries in the 5 continents of the world. Where it is active, there is no life. On Tanganyika Lake, in Burundi, damages are incalculable.

From 5 years over, this plant is spreading over all lac coastal .At less than a kilometre of the lake in the northern part of country, not far from Bujumbura port, one can imagine hyacinth has got back it’s developing area: nice leaves with interesting mauve flower with a shape of waves, are spreading on over 100m squared till now. Very intrusive, this plant grows quickly .It grains and trees develop also quickly. When water hyacinth is taken away by heavy rains, it spreads all over .Fighting against this destroying plant is difficult. Unrooting and making this plant out of lake waters requires much work force and equipment –ships and rakes, regularly.

Specialists advocate that water hyacinth has many impacts: it blocks canoes and fishing net, limit water during irrigation, promotes evapontranspiration, and diminish water lever. Covering water surface, it blocks photosynthesis of phytoplankton (aquatics micro vegetables) main food of fish .It’s a barrier for fishing and for biodiversity. Last, on health side, it creates water pool, the main growing area of mosquitoes, and origin of malaria disease.

Pulling it up, pulling it up, and always pulling it up: From nearly 5 years, Burundians have fight against water hyacinth regularly. It is an incomparable fight. Every day, three or four people pick it up and put it together especially leaves laid down by Lake Tanganyika waves. Without that regular activity, that small Burundian beach of over 100 m long would be quickly attacked.

A small piece of water hyacinth may grow and become a whole plant in a few time. Spread all over the lake, water hyacinth leaves, small or big float and move slowly with waves, smoothly like secret soldiers.

This harmful plant is also reported in northern Lakes of the country and in Ruvubu River, principal affluent of Nile River in BURUNDI.

National mobilisation

Three main means of fight against water hyacinth are used: chemical fight, biological fight and mechanical fight. The latter is the only one used in BURUNDI.

From October 2006, the Burundian federation in charge of fishing and protection of watery has organised days to pull water hyacinth up in order to save lake fishers’ attic. About 150 members often fight against that vegetable by hands in order to pull it up. They dry it before burning it.

The Bujumbura Mayorship is much concerned. Every 22nd of July, a lake day mayorship’s authorities organise works relating to pulling water hyacinth up. Mayorship mobilises inhabitants of the capital, students and civil servants included .Inspite of all these efforts, results are still unsatisfactory because the fight need to be regular.

Experience of RWANDA

The extent of infestation of lakes in RWANDA is very pitiful. Twelve lakes of Akagera National Parc and other five of Bugesera, the very hot regions of the country, are particularly attacked.

”It hasn’t been a long time, inhabitants of Bugesera, a region of with many lakes, had fish as their principal meal. Now this food is almost absent in our lakes», says a villager of Bashora zone, in Eastern party of the country.

According to the minister of Lands Environment and Mines,the Gishanju I Lake of AKagera National Park ,In East, has completely disappeared, while Gishanju II is nearly about to follow, others like Mihindi and Shakani are recovered at a half .The Gishanju II lake which was the biotope of hippopotamus became the one of sitatungas (antelopes of forests).

Of course, the water hyacinth is considered as wound .However; it is plant that makes waste water be potable. Water hyacinth may also be used to farmyard, to make compost and feed animals. In the northern part of the country, water hyacinth has been used for a long time feed smaller livestock (pigs and goats).

According to agronomists of Agronomic sciences Institute of Rwanda (ISAR) in BUTARE (south) when leaves, stems and roots are treated as compost, they make a good organic fertilizer.

The association SAM which produces briquette using household waste says we can get a good fuel from water hyacinth when it is dried and compressed.

Harmful, this floating plant that attacks rivers and lakes is becoming, maybe, a source of money.

It is stems and leaves when seriously dried during 3 weeks, may give slender fibres raw materials for paper manufacturing and basket –making .

Squattering Rwandese lakes from water hyacinth and making good biodegradable baskets with its slender fibres, this is what is done successfully by an association of women in the Eastern part of the country .This is interesting example of getting money from a disaster. Nice hat, bags of different shapes, dishes and under caps, wallets, pen carrier, plaits……all these objects made from water hyacinth fibres make the richness of Gashora basket making (Covaga) in Eastern part of Rwanda.

Owing to the activities of that association from 2004, an important part of Rumira Lake in Bugesera region has got back its free water and fish while the coasts of Rumira are navigable. This rational exploitation of water hyacinth may also be a solution to environmental problems in Rwanda, because all these objects below are biodegradable.