Kenya’s most harmful water weeds become the fuel of the future

Published: 8 February 2019

One of the world’s fastest-growing floating water plants, the invasive water hyacinth (Eichhornia crassipes), has returned to Lake Victoria. This plant threatens the health and wealth of tens of millions of people who depend on the lake.

Kisumu city on the shore of Lake Victoria is Kenya’s third largest city. Kisumu County, which borders the lake, is one of the hardest-hit areas: a rotting layer of water hyacinths has developed here which is so thick that other plants and trees grow on top of it. Most aquatic life beneath that layer has been drastically affected. Inhabitants say the water has an unpleasant taste and smell, and that they are catching fewer and smaller fish. Health risks are increasing as a result of the mosquitoes and snails, toxic algae and bacteria that flourish in the weeds. Important functions of the lake, such as transport, tourism, fisheries and drinking-water supplies, are coming to a standstill. Wastewater discharge and poor land use mean that nutrients and fine sediment are continuing to flow into the lake and feed the growth of the water hyacinths.

In addition, the surrounding lush wetlands and marshes are being encroached and reclaimed more and more. They are being turned into farmland, which means they no longer act as a natural buffer for in-flowing sediment and fertilisers.

There are more problems in the lake area. Inhabitants often use locally-made charcoal or firewood for cooking and this has led to massive deforestation and erosion in the catchment. As the population is increasing by 3-4% a year, a solution looks further away than ever. Lake Victoria has become more sensitive to all sorts of disruptive factors such as climate change and pollution. The area is still known as a biodiversity hotspot but, in the current circumstances, unique species are disappearing quickly and for good.

Can you spot the lake ?

Solving problems with profitable solutions

Deltares knows Lake Victoria well and we have been involved in integrated water-quality studies here since the 1990s. We are currently combining the relevant lake knowledge in close collaboration with the relevant local public and private partners to develop a new fact-driven restoration approach. To tackle the immediate problem and also to address social and economic developments in the locality, we have used collaborative business modelling to generate profitable problem-solving cases and deliver visible returns on investment for nature, the local economy and society. A proof of concept is now running steady  on the shore of the lake and there is considerable appreciation from stakeholders in the public and private sectors. Several investors and authorities are interested in upscaling this practical approach further in the worst-hit areas of the lake and basin.

Using hyacinths to make bio-fuels

Over the past decades, around half a billion euros have been spent on fighting the water hyacinth in Lake Victoria. Mechanical, biological and chemical methods have been tried but nothing seems to work. A knowledge-driven Kenyan-Indian-Dutch project called Waste 2 Energy has now developed an integral method based on a sustainable business plan. Viable green and blue business cases are at the core of this approach. It is now possible to harvest the water hyacinth and use it to make all sorts of products: from biogas to paper and from cattle fodder to fuel pellets. A thorough study of the local market, a user analysis and implementation trials showed that processing hyacinths into clean cooking fuel leads the best result for everyone. This approach is inspiring many people to make the best of the present situation while slowly restoring the lake to its former glory.

Green means hyacints (pic width 100 km)