The water hyacinth which has invaded Lake Victoria since early 1990s have had significant on social, economic and environmental impacts to Nyanza region.

Though this has remained largely unquantified, the biological control administered by Kenya Agricultural Research Institute (KARI) coupled with other control measures, confirmed they have reduced water hyacinth levels from 6000 hectares to an estimate of 400 hectares on the Kenyan side of the lake as a start.

According KARI The impacts of water hyacinth are well known to residents of Nyanza regions and the neighboring Western region. This follows the harsh economic and environmental effects it inserted to the locals who rely on the lake as their source of livelihoods.

“The lake is said to have employed close to 50 thousand people directly and another 200 thousand indirectly,” Phillip Ochieng said.

According to Salmon Orimba, County Executive Commissioner for Water, Environment, Climate Change and Natural Resources in County Government of Kisumu, majority of fisherfolks lost jobs and cases of insecurity has since increased.

Orimba stated most residents in the 6 counties on Nyanza region are fishermen and depends on the lake as their main source of income. Though there are other income generating activities region, fishing industry is the highest employer.

According -Pamela Kogogo, before water hyacinth invaded the lake (1986- 91), parents took their children to good schools through fishing, selling fish, but the period of water hyacinth (1992-2016) fishermen and related activities in the lake were hit hard economically.

She said those days data indicated that there was an increase of fish production from 140,597 to 168,019 tons signaling an increase of 20% over the two periods. However, significant increases were reported in Nile Perch and Prototerus, while significant decreases were realized with Mormyrus and other mixed fish species.

“The results also showed that there was an increase in the incoming cargo and a decline in the outgoing marine cargo handled at the Kisumu pier(landing-stage) covering the period 1996-1998. Water supply to then Kisumu Municipality decreased by 25% in the year 1999, although time series data was not available,”Kogogo explained.

Kogogo observed that increases or decreases in fish production and water supply points confirms the fact that water hyacinth might have had an effect. On the contrary, there were mixed and unclear trends on the incidence of water hyacinth related diseases such as malaria, bilharzia, cholera and gastro-intenstinal disorders which could not be directly associated with water hyacinth when the two periods are compared.

He regretted that inadequate data was as result of subdivision in the government administration thus various districts and the fact that it was not easy to apportion the disease incidence resulting from water hyacinth and other related causes.

Weed effects

Investigative Journalism can report here that to date, there is poor record keeping of data in the region. And this could tell the reason why water hyacinth infestation might have taken too long to initiate and establish its removal.

However, the impact of water hyacinth on bio-diversity, water quality and supply, ecological succession and health and nutrition in the region is tangible. For example, the outright evidence anyone could see and observe are reduction of fish catch or harvests, transport difficulties for water vessels, unclean water supply, stomach health problems, suffering bio-diversity, rapid increase of aquatic weeds all which contributed to high poverty index in the region.

A visit to Winam Gulf the headquarters of Fishing Industry and the Lake Management, the staff admitted the weed invaded the lake in 1990s and it disrupted commercial and artisanal fishing and boat transport.

“Yes, the weed affected infrastructural facilities including water supply intake points, port facilities and the hydroelectricity power generation plant at Owen Falls, Uganda,” Jael Adhiambo said.

The weed is also associated with increased incidence of water-borne diseases. In Lake Victoria, ideal environmental conditions caused by anthropocentric environmental degradation and the lack of biological control agents such as phytophagous insects, mites and microbial pathogens were responsible for rapid growth and spread of the water hyacinth during the last decade.

Adhiambo stated efforts to remove water hyacinth through biological control and mechanical harvest in reduced the infestation levels to 2 about 400 hectares. Most was due to the resurgence emanating mainly from the river mouths on the Kenyan side of Lake Victoria. The Kenyan portion of the Lake stretches for 600 km from Berkeley Bay (Busia County) in the north to Muhuru Bay (Migori County) in the south.

“Most of the fishing activities and transport operations are concentrated here in the Gulf, an important economic lifeline to the riparian communities,” Adhiambo affirmed. Fish production, marine cargo and human transportation take place here,” she added.

Controlling the weed

Efforts at managing the water hyacinth have paid dividends as the water hyacinth has been effectively controlled bringing back life to the various beaches that were infested. But there were still some hyacinths noticed on the lake due to the resurgence, which emanated from major riverine systems flowing into the lake including Kuja-Migori, Sondu, Miriu, Nzoia, Nyando and Sio.

Most of the districts bordering Lake Victoria were infested by water hyacinth but at different intensities. The districts with highest intensity included Kisumu, Rachuonyo and Homa Bay while moderate intensity is reported in Migori County.

Districts with low intensity include Siaya, Suba and Busia. Low infestation refers to the state where the beaches and passage ways are clear of floating hyacinth mats with free access to water by fishermen and transport boats, while moderate infestation is the situation where there are a few and sometimes resident mats of water hyacinth with partial access to the lake.

High intensity is where the beaches, piers, and ports are completely clogged most of the time with no access to water by boats, animals and humans. The truth of the matter is that there has not been proper record of water hyacinth cover on the lake since 1992, when water hyacinth became visible, on the Kenyan side of the lake.

However, available records (Radarsat International, 1998 and 2000) indicate that the total area covered by water hyacinth was estimated to be 6000 ha on the Kenyan side of Lake Victoria (April 1998) and was reduced to 900 ha. February 2000 and was estimated at 400 hectares. (2001).

In 1998, the highest concentration was reported in Nyakach bay with 3200 hectares while the distribution was as follows in other bays: Osodo bay (1200 hectares), Kisumu (1000 hectares) and Sondu Miriu Delta (600 ha) (Anon. 1998).

The resurgence has since notably been sighted in Nyakach, Kendu and Homa bays. There is need to watch the trend of water hyacinth movement back. Otherwise, Winam Gulf contributes significantly to fish production, commercial and artisanal fishing in the national economy.

Rehabilitation of the Lake

The World Bank funded programme of eradication of water hyacinth, an invasive plant that chocked huge sections of the lake. This was under management of Lake Victoria Environmental Management Project (LVEMP), an East African Community’s initiative.

The agency bought two boats at Sh60 million, a water harvester and seven sewage exhauster machines to clear sewers that usually drain into the lake.

According to madam Francisca Owuor, LVEMP Project National Coordinator, the two boats are for fisheries research and surveillance.

“The vessels aid the fisheries department in carrying out research in the lake on matters pertaining to fishing activities as well as provide surveillance in the Lake Victoria waters on the Kenyan side,” Owuor said.

Madam Owuor said LVEMP procured a Sh90 million water harvester for the mechanical removal of water hyacinth. The machine is managed by the Kenya Maritime Authority.

She said water hyacinth still remains a challenge on the Kenyan side because of the Winam Gulf that harbours the invasive weed.

“There is need for concerted efforts to ensure elimination of the weed. Currently we are addressing the sewerage systems in Kisumu, Bomet and Homabay Counties to reduce the waste discharge into the lake, which also leads to growth of the hyacinth weeds,” Owuor said.

She regretted despite the weed completely removal in the lake, it is likely to thrive back as its seeds take many years under water alive and because of water pollution mainly from upper catchment of rivers and raw sewage discharge.

“Industries discharge the waste into the Lake fertilising the weeds, hence may contribute to the seeds revival, germination, growth and multiplication,” she said.

The coordinator said the new headache is controlling water pollution. She however disclosed that seven exhaust machines worth Ksh 65 million have been purchased and distributed to market centres in seven towns to assist in pollution control near the lake.

“The exhaust machines are particularly meant to address the sewage waste management in the markets to reduce pollution. They have been removing waste from pit latrines and sewer tanks,” she added.

Madam Owuor noted that LVEMP II rehabilitated, constructed and expanded sewerage systems in three counties at a cost of Ksh507 million. The investments include renovation works at the Homabay sewerage facility as Ksh215 million as well as expansion of the Kisumu sewerage facility at Ksh146 million.

“It also includes construction of Bomet sewerage facility at Ksh146 million,” Coordinator said. The seven exhauster machines are stationed in Kisumu, Siaya, Homabay, Migori, Kisii, Bomet and Kericho counties,” she added.

Water pollution with raw sewerage and chemical waste matter is now the major problem facing the lake at the moment.

This Investigative piece was made possible with support of WITS Journalism and the African Investigative Journalism Conference (AIJC) Project.