In spite of the national endeavor to remove water hyacinth from some lakes, Ethiopia is still experiencing the impacts of the ever expanding invasive weed on its water bodies. The Water hyacinth locally known as Enboch has undergone a dramatic spread-outacross country's water bodies in the past 10 years. Withal, weed removal activities are yet being undertaken through preparing alien plant eradication management plan.
About 35 alien species in which six of them are most invasive ones, have invaded over two million hectares of land in Ethiopia. Among the six species, Parthenium,Prosopis, Lantana camara and water hyacinth are highly affecting the country's fish and crop production, grazing and wastelands and biodiversity in general, saidWendosenAbeje, an Ecohydrologist with the Ministry of Water and Energy (MoWE). The water hyacinth reduces fresh water thereby affecting aquatic flora and fauna, irrigation and hydro power generation among others.
This floatable and spongy (composed of 95 percent water) alien species, according to Wendosen, affects the aquatic ecosystem for easily spreading across water bodies reproducing sexually or asexually.It can thrive in a broad range of temperatures from 12 to 40 °C. Being spongy which increases water wastage due to evaporation has also enabled the plant to survive eradication efforts for being heavy to weeding and carry it out using labor force while growing easily if its tiny part drops.
The Ecohydrologist expressed that the invasive weed could be easily distributed across Ethiopia's water bodies for availability of fresh and salty waters, fertilizer remnants, and sediments, liquid and solid industrial and urban wastes among others.
A study conducted in 2020 indicated that the perennial invasive plant has covered about 4,392 hectare land on Lake Tana, 2,800 ha on Koka and its surrounding, 1,472 ha on Dembel Lake. It also spread to Lake Chamo and Tata.
MoWE Minister Office Head, Mamusha Hailu said that the Ministry is working on protecting water bodies and their biodiversity and it has recently launched a public campaign to remove the weed from Lake Koka.
Located in Oromia state, Lake Koka is a source of human and animal drinking water, hydropower, irrigation, and so on. The invasive weed is affecting the lake its aforestated purposes. "We are working with the Oromia water and energy bureau to mobilize government organizations, NGOs, religious leaders, private owners, the youth and others to contribute faire share to the removal of the weed through implementing an integrated plan,"Mamusha said.
The Ministry has a short and long term plan so as to eradicate the invasive plant permanently, he said, adding that it is implementing legal frameworks to protect water bodies and biodiversity. The successful removal of the wide portion of the hyacinth from LakeBatu in Oromia state, could be an important lesson to the next eradication activities. The deployment and effective performanceof stakeholders in the removal of the weed has helped to recover the lake and its purpose of drinkability, fishing, and tourism.
Mamusha believed that the successful national efforts to halt the expansion of the weed on LakeTana, Dembel and other water bodies indicated that the nation is capable of eradicating the invasive species if works are done in an integrated manner.
Koka Hydropower Dam Chief Morka Haile recalled that the water hyacinth had covered almost all parts of the dam reservoir last year. And this reduces the amount of water from the reservoir each year and made it difficult to know the level of the dam's contained water and share of intake for power generation.
Due to the age of the dam, it was impossible to use machines to get rid of the weed so that efforts have been done to eradicate it with manpower though a satisfying result was not achieved yet. The dam may not generate the expected amount of power unless the weed removed from the reservoir timely and properly, he stated.
For the time being, the weed has cleared out from the power generation area pushed by wind. Morka said, "This will not make us negligent. The weeding activities will be strengthened to remove the hyacinth lastingly. These activities will be carried out either through labor force or using machines depending on the depth of the water."
The Oromia State Water and Energy Resource Development Bureau Director Teshale Bekana the bureau has been working on the prevention of water hyacinth since 2021. The bureau has given the responsibility of removing weed from 147.2 hectare land in and around Lake Dembel to 28 private owners. "And they effectively removed the hyacinth though evaluation and inspection activities are not interrupted yet even after the lake recovered. We have done this by preparing green, yellow and red certificates that have been given to the stakeholders based on their performances of successful, minimally satisfactory and unsatisfactory respectively to encourage, alarm and reprimand them."
Drawing lesson from this success, Teshale's bureau also deployed various stakeholders to undertake hyacinth from Lake Koka. It recently has handed over site map of the weed, which covers 74.5 km of the lake, to 18 private owners to contribute fair share in the eradication activities.
On the other hand, the country is also working to resume the invasive weed removal activities from Lake Tana that had been interrupted for the recent conflict in theAmhara state. Unity for Tana Association founder and secretary, ZelalemShitahun expressed that the association has planned to conduct a research to resolve the problem sustainably.
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It has been trying hard to recommence the weed eradication activities that had been undertaken in cooperation with Bahir Dar University, and other water development and protection agencies. However, Zelalem said that it requires a wide range of study on the removal mechanisms to safeguard the lake sustainably. Currently, a proposal is being prepared to conduct the study thereby the association has planned to cover the maximum amount the cost of the study. Given the significance of the lake to the society, removing the weed should get full attention from all parties as it requires a relentless effort to eradicate the hyacinth and sustainably preserve the lake and its ecosystem.
An integrated effort is needed to remove the weed once and for all, Ecohydrologist Wendosen elaborated that this include, manual, mechanical and biological methods which are using labor, machines, and insects. A scientific and strategic method can be also applied to eradicate the hyacinth through promoting the usage of the plant for various purposes such as animal feed, biofuel, charcoal, and compost among others. Water hyacinth was first introduced to Ethiopia in 1956 for ornamental purpose.
