By Demise Mekuriyaw

As Asrat Mihretie, a 63-year-old fisherman, casts his line into Tana’s calm waters, he laments and then says “These ancestral waters flow through my veins, just as they flowed through the lands of my forefathers. But I fear my grandchildren will inherit nothing but a dead sea, drained of its bounty and sacred essence.”

“In my youth, these waters teemed with fish,” Asrat reminisces. “A day’s labour would yield enough to feed my family and have a surplus to sell at the market. But over the years, the catch has dwindled alarmingly.”

Asrat’s apprehensions are shared by many in the lakeside communities surrounding Tana. Mezgebu Alebel, another seasoned fisherman, corroborates Asrat’s account. “The depleted fish stocks have made our livelihood increasingly precarious. What was once a thriving trade can barely sustain us now.”

A vital ecosystem under threat

Ethiopia’s Lake Tana, the largest lake in Ethiopia and second largest in Africa, is the source of the mighty Blue Nile River and a vital lifeline that has nourished human civilization in northeastern Africa for millennia. Accounting for 50% of the country’s freshwater resources, the lake covers an area of 3,111 square kilometres, with a length of 90 kilometres, and a width of 65 kilometres.

Tana is endowed with resources critical for food, water, raw materials, energy, cultivation, organic fertilizers, genetic diversity, medicinal plants, fisheries, irrigation, and crop production.

The lake is home to 28 fish species, 21 of which are endemic, with an annual commercial fish production value of approximately $1.1 million. It feeds 60% of the Blue Nile, providing water for over 200 million people across Ethiopia, Sudan, and Egypt.

However, in recent decades, this ancient water body has faced mounting threats from unchecked development, invasive species, and disregard for its fragile shoreline ecology.

Ecohydrologist Yohannes Zerihun, Coordinator and Focal Person, for the UNESCO African Regional Center for Ecohydrology at the Ethiopian Ministry of Water and Energy, explains in his latest study on restoration of the Papyrus Wetlands in Lake Tana that invasive weeds can thrive when a healthy aquatic ecosystem is disturbed by human-caused interactions.

“When foreign objects enter a water body, the water body naturally loses its identity,” says Yohannes. Another factor contributing to invasive weed’s spread is the presence of animals around Lake Tana, whose waste, combined with other factors, has reduced the water’s filtering ability, creating a favourable environment for invasive weeds to thrive.

Yohannes’s study elaborates that when coastal vegetation around Tana was cultivated for offshore farming; foreign matter entered the lake, creating a favourable environment for weeds, particularly to water hyacinth that has several negative impacts on biodiversity, fishery, tourism, public health, and agriculture among other things.  Furthermore, plants in the upper basin, along the banks of the Gumera and Rib rivers, were converted for recession agriculture, and the lakeshore was ploughed up to the edge, allowing fertilizers and sediments to enter Tana via the rivers. Currently, Lake Tana is easily accessible for both agricultural runoff and solid wastes like plastic bottles.

The first technical Water Hyacinth Coverage Survey Report on Lake Tana found that more than one-third of Lake Tana’s shoreline which amounts to around 128km was invaded by water hyacinth. Additionally, tributary streams carry large amounts of soil and suspended solids into the lake, degrading water quality and promoting weed growth.

According to Ethiopia’s Integrated Strategy and Action Plan for Sustainable Control of Water Hyacinth 2019, more than 700,000 people participated in Lake Tana to manually remove the Water Hyacinth since 2012 and they were able to remove the invasive weed from tens of thousands of hectares. However, due to its resurgence potential, the weed immediately reinvaded all the cleared shores and expanded to new shores without sustainable results.

Harnessing the power of papyrus

Aware of these challenges, Yohannes has studied new ways to use papyrus, an iconic aquatic plant around Lake Tana, known for its woody, triangular stems up to 4.6m tall. He aims to harness papyrus as a bioremediator to stabilize and revitalize degraded shorelines. This approach not only enhances ecosystem health but also diversifies and improves livelihoods for lakeside communities, addressing the underlying causes of Lake Tana’s shoreline degradation

“The mighty papyrus plays an indispensable role in knitting together the health and vitality of the entire Lake Tana basin,” said Yohannes. “From water purification to habitat formation to sustaining indigenous livelihoods like papyrus boat construction and papyrus mat weaving, this remarkable plant truly embodies the ideal intersection of modern science and timeless ecological wisdom.”

Yet, another challenge looms here again too. The extensive papyrus swamps along Tana’s shorelines and its tributary river, Gilgel Abay have declined sharply over the past decades. As a 2023 study in the ResearchGate notes, the total surface area of papyrus swamps around Lake Tana has declined by almost 55%, from 152 km² to 64 km² in 35 years (1985–2020). 

The ever-increasing decline of papyrus swamps has therefore given way for papyrus plantation pilot projects that have brought together residents, international and national stakeholders, and academic institutions. One of the pilot projects to propagate the indigenous papyrus vegetation through vegetative reproduction was started by Bahir Dar University Research and Community Service back in 2014 followed by other related pilot projects thereof.

The result showed that papyrus competed with water hyacinth since it produces a canopy (shed) over water hyacinth and prevented growth. In addition to out-competing water hyacinth, papyrus builds lake and river buffer stability and serves as a sink for nutrient input from the catchment and this in turn contributes to controlling water hyacinth.

Yohannes’s research has also demonstrated that strategically replanted and maintained papyrus buffer zones can’t only help to control the proliferation of water hyacinth but also mitigate erosion, improve water quality, and foster a resurgence of native flora and fauna. The pilot areas that cover around 300 hectares of land at a place called Zenzelima and around have shown that dense stands of papyrus have almost single-handedly catalyzed the rebirth of bio-diverse marshlands in habitat zones once virtually devoid of life.

Distribution of water hyacinth (red) as compared with limited Papyrus (green) in the southern gulf of the lake.

Yohannes’s ecohydrological research has also introduced circular agriculture in this pilot project area by integrating rehabilitated papyrus stands with fishponds, horticulture, and small-scale irrigated farming in a regenerative landscape design. This systems approach replaces unsustainable “recession farming” practices that had encroached up to the lakeshore.

Community engagement and revitalization efforts

Inspired by such results, the Ministry of Water and Energy, in collaboration with other 25 concerned stakeholders established a five-year strategic plan to replace the existing vegetation around Lake Tana with water-friendly shoreline papyrus plants and establish a buffer zone. The plan also included awareness initiatives for surrounding rural and urban communities.

Worku Aweke, a resident involved in papyrus cultivation around Lake Tana since 2014, shared his experience. Previously, he grew vegetables like tomatoes and lettuce, but since 2014, papyrus cultivation has become popular in his locality. Worku and his fellow residents received papyrus seedlings from Bahir Dar University and were paid five Birr for every seedling planted, compensating for the income they would have earned from selling vegetables. As they witnessed the benefits, they increasingly focused on expanding papyrus cultivation, replacing other vegetables. Worku also earns income by selling the slender Papyrus leaves for home floor decorations once the plants reach a certain level of growth fitting to the purpose.

Dr. Nibret Asrade, the coordinator of the Papyrus Plantation Project at Bahir Dar University, has been behind the papyrus cultivation around Lake Tana for a long time. Initially saddened by the diminishing papyrus around the lake he enjoyed in his childhood, he aspired to reverse the visually appealing papyrus without discerning its far-reaching ecological benefits. However, Dr. Nibret later understood through research that papyrus is not only a visually appealing plant but a breeding ground for fish and a typical solution for water purification and erosion control.  

He stated that papyrus is excellent for water treatment and purification, and they have seen positive results by cultivating it around Lake Tana and adjacent rivers. Its buoyant stems help reduce water turbidity, allowing springs to emerge in areas where papyrus grows.

Yohannes’s research also claimed that if a lake is surrounded by a 3 to 15-meter belt of papyrus, the lake’s lifespan can significantly increase. Neither silt nor other debris can pass through the papyrus barrier.

Challenges and a shared global commitment

However, the strategic plan’s implementation has been unfortunate due to a lack of principled coordination among stakeholders, which was not binding. Additionally, the ongoing conflict in a part of the country has diverted administrative bodies’ attention, as they were preoccupied with seasonal agendas. The lack of commitment from the regional government’s administrative bodies and the inability to gain attention from the federal government were also noted.

Despite these challenges, this grand-scale vision of ecological rehabilitation centred on a native and culturally revered keystone species like papyrus could have profound relevance beyond Lake Tana, according to Yohannes. “If we can prove the merits of this inclusive, bio-cultural restoration model here at the cradle of the Blue Nile, it could help catalyze similar revivals up and down the entire river basin.” The pilot projects that have tried to protect Lake Tana’s shoreline with papyrus have shown visible results, though not executed at a full-fledged capacity and commitment until now, as indicated by Yohannes and residents.

Of course, the Lake Tana Shoreline Revitalization project has significant implications for countries in the Nile Basin, affecting food security, water resources, and economic stability for millions of people. To succeed, this initiative requires funding from various sources. One potential contributor is the United Nations Educational, Scientific, and Cultural Organization (UNESCO), which designated Lake Tana as a Biosphere Reserve in 2015. This recognition highlights the lake’s global importance and may support efforts to secure international funding for its revitalization.

“For too long, we have perceived the protection of waters like Lake Tana through an insular, provincially constrained lens that obscured the true international proportions of their worldwide importance,” said Yohannes. “From moderating climate impacts to preserving biodiversity to supporting food and economic security across an entire megaregion, environmental challenges like this truly have no borders in our inextricably interconnected world.”

Dr. Nibret Asrade, an expert at Bahir Dar University who works to revitalize Tana’s shoreline ecosystem also shares this idea. “A healthy and thriving Lake Tana ecosystem is absolutely vital to maintaining the ecological resiliency of the entire Nile basin system,” explains Dr. Nibret. He underscores that safeguarding the irreplaceable water source of the Nile is not just an environmental and cultural imperative for Ethiopia but a matter of international security and human welfare. 

He also emphasizes, “What befalls Lake Tana ultimately befalls the whole Nile River, for better or worse. All ten nations in the Nile basin have a shared stake in the success of this unprecedented effort to revitalize the river’s very source and headwaters.”

Dr. Nibret underscores that the local implications of restoring Lake Tana’s shorelines are immense and existential for the nearby community—but so too are the potential reverberations across international borders for all those bound to the life-giving waters of the mighty Nile. 

He further points out that, “A Lake Tana without papyrus is like a person without a kidney.” Papyrus is an essential organ for Lake Tana’s purification. As Tana is a treasure not only for Ethiopia but also for the international community, its protection demands the involvement of all actors from all walks of life.

The story has been produced in partnership with InfoNile and with funding from JRS Biodiversity Foundation and IHE-Delft’s Water and Development Partnership Programme. It is a collaborative effort between a journalist and a scientist, specifically Demis Mekuriyaw and Yohannes Zerihun.