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Under threat: Lakes being driven to deathbed by human activities


Dying lakes

As good as dead. This is how Tourism Cabinet Secretary Najib Balala recently described Lake Nakuru National Park.

As good as dead. This is how Tourism Cabinet Secretary Najib Balala recently described Lake Nakuru National Park.

He called for the formation of a team to address land encroachment at Lake Nakuru, Naivasha and Elementaita, and asked scientists from the Kenya Wildlife Service to address the loss of biodiversity and the flight of flamingos from Lake Nakuru in a bid to restore it to its former glory.

HealthyNation toured the lakes and came face to face with the human activities that are threatening to dry up the famous Rift Valley lakes.


POLLUTION

In October 2017, divers from the Kenya Navy and other organisations worked for days to retrieve the bodies of four people who were in a helicopter that crashed in Lake Nakuru.
Rescuers retrieved three bodies, but for the last one, resigned loved ones threw flowers in honour of the victim, and to date, the body has never been retrieved. Rescuers disclosed that retrieving the bodies had been difficult because the lake was filled with raw sewage and silt.
Two years later, the pollution continues unabated as effluent from the settlements that inch ever closer spill into the lake.
Just 10 years ago, the riparian zone around the lake was intact, and the closest human settlements – Rhonda, Langa Langa, Racecourse, Kivumbini and Madaraka – were kilometres away.
But gradually, human settlement has moved closer and closer, bringing with it pollution.
Besides effluent from residential areas, water treatment plants located around the lake have been blamed for draining untreated waste into the lake.
“Lake Nakuru is a protected wetland and a UNESCO World Heritage Site, but the pollution from untreated sewage, chemicals and industrial waste is taking away its glory.
“Already thousands of flamingos have migrated to other areas,” said environmentalist James Wakibia.
A walk around the Lake Nakuru National Park validates Mr Wakibia’s claims. HealthyNation identified 26 inlets that drain dirty water from residential areas and another six that were discharging industrial wastes into the lake, in the parts of the lake that were accessible to the team.
Moreover, on May 8, the Kenya Wildlife Service (KWS) retrieved 2,000 kilogrammes of solid waste from the lake – an assortment of polythene, plastic bottles and rags.
KWS warden Sirman Kioko admitted that the agency was having a hard time controlling the flow of waste into the lake.

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Workers cleaning up Lake Nakuru on May 8, 2019.

In Lake Baringo, Kenya Marine and Fisheries Research Institute Baringo Station Coordinator Cyprian Odoli said that increased agricultural activities upstream have become a threat to the survival of aquatic species, as fertilisers flow into the freshwater lake.
Dr Odwoli said that the activities, which remain largely unchecked, have led to the eutrophication of the lake (having too many minerals and nutrients which induce excessive growth of algae) especially at the mouth of River Molo and Lake 94.
A technical assessment of Lake Baringo submitted to the authorities in March, recommended continuous assessment and monitoring of the riverine ecosystems that drain into the lake to curb the problem of siltation.
“We have tried to come up with remedies which could be used to rejuvenate the lake, but they have not been successful. The state of the lakes is something to worry about and we need to pull up our socks and do much more in terms of research. Our managers should ensure that research findings are implemented,” said Dr Odoli, blaming the current state of affairs to lack of implementation of various research findings, with most of the work gathering dust on the shelves.


DEFORESTATION AND SILTING

Last year, the Kenya Wildlife Service released reports saying that water levels in Lake Nakuru had risen, submerging some buildings and spilling onto roads in the Lake Nakuru National Park.
Liboi Dispensary located near Lake Bogoria, was also submerged. The Rift Valley lakes – Baringo, Bogoria, Nakuru, Elementaita and Naivasha – had water levels superseding the record 2012 and 2013 levels.
However, Silas Simiyu, a geologist, said that the lakes did not swell.
“What is happening is like depositing sand into a glass full of water. The sediment will settle at the bottom and the water will spill over. This does not mean that the amount of water has increased, it only means that the volume has been reduced. If you keep adding sand, the water will eventually be completely replaced by the soil. That is what is happening to the lakes. They will diminish,” he explained, saying that this is caused by silting, as sediment from erosion flows into the lake unchecked due to deforestation.
An analysis conducted by Jackson Raini, a research scientist at FlamingoNet, assessing the water quality and quantity of Lake Nakuru, indicates that forest cover in the lake basin has declined from 47 per cent in 1970 to only seven per cent currently.

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Aerial view of Nakuru town showing settlements that are inching ever closer to Lake Nakuru.

Further, a comparison of two National Aeronautics and Space Administration (NASA) images taken in 1972 and 2017, showS that the area around Lake Nakuru has experienced gross deforestation.
“Human settlement has caused deforestation in the areas around the lake. And because of deforestation, when it rains, water flows erode the soil, carrying dirt and everything else in its path into the lake,” Dr Simiyu, the geologist, told HealthyNation.
Clay sediment, silt, sand, organic debris and chemicals flow into the lake affecting the net water balance.
“All these things that are swept into the lake change its chemical-biological profile. As erosion progresses and organic content that has to undergo decomposition increase, demand for oxygen content rises and the lake is depleted of oxygen."
“What happens when the oxygen is no longer available? Fish is affected by the deficiency and they move to the walls of the lake to lay eggs. Sadly, these eggs are covered by the sediments and the fish cannot multiply,” said Dr Simiyu, adding that even the flamingos and other animals flee because their habitat becomes uninhabitable.
In addition, bottom sediments become enriched in organic material and bottom plants spread throughout the shoreline zone.
“The eventual effect of this is that the lake may be no more through loss of water or infilling by sediment and other materials,” added Dr Simiyu, echoing recent fears by Tourism Cabinet Secretary, Najib Balala that Lake Nakuru is dying.
As infilling happens unabated, the plant-choked shore spreads towards the lake, turning the zone into a swamp and the central part of the lake diminishes into a pond.
“When the lake finally ceases to exist, terrestrial vegetation may flourish, even to the extent of reforestation,” he said, adding that the phenomenon will soon create a situation worse than what was experienced in the 1940s, when the lake receded causing the trees that are currently visible in Lake Nakuru to grow.
Massive destruction of the Mau Forest Complex has also been blamed for the drying up of the three major rivers that feed the lake – Rivers Njoro, Makalia and Nderit – leaving only polluted water to flow into it.
Dr Odoli, the Kenya Marine and Fisheries Research Institute (KMFRI) Baringo Station Coordinator, warned that most of the Kenyan lake’s ecosystem is “disturbed” by high human pressure especially in the upstream areas.
He noted that wetlands had been cleared and farming activities along River Molo and Pekerra, were interfering with the health of Lake Baringo, and called for the restoration of riparian zones.
“If we don’t stem these activities, then we don’t have a future to talk about. Lake Baringo will be a water mass with no aquatic life that largely supports livelihoods in this part of the country,” warned Dr Odoli.

OVERFISHING
While fishing is the main activity at Lake Baringo, recent trends spell a bleak future for the fishermen, who rely on the lake for their livelihood.
According to the KMFRI Baringo Station Coordinator Cyprian Odoli, reduced catches are a cause for concern for a lake that recorded 600 metric tonnes landings in the 90s.
“Today we are recording close to 120 metric tonnes, which is less than a quarter of previous catches,” said Dr Odoli, who attributes the state of affairs partly to the decline of the dominant tilapia stock, after the introduction of the predatory African lungfish.
A technical assessment of Lake Baringo presented to the authorities in March, noted that between 2000 and 2005, fishing almost collapsed due to a pronounced decline in water levels and quality.
The decline was caused by massive water evaporation due to climate change, while water quality was affected by pollution, with increased turbidity compromising primary productivity.
Researchers said that the establishment of fish breeding and conservation areas is faced by management challenges such as fishermen failing to keep away from breeding areas.

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Fishermen surrounded by hyacinth on Lake Naivasha in 2017.

On Lake Naivasha, one of Kenya’s six Ramsar sites, Kenya Marine and Fisheries Research Institute (KMFRI), researcher George Morara, has called for strict controls to curb fishing on breeding grounds, especially the major ones of Crescent Island, Oserian Bay, Korongo Bay and Malewa River mouth.
He said that the stocks should be left to breed naturally with a controlled number of fishing boats because the resource is being overexploited.
“Some unscrupulous fishermen cast their nets in the breeding areas, harvesting the spawning stock and juvenile fish,” said the researcher.
“Do the allowed fishing crews match the available resources (fish stocks)?” posed Mr Morara, worrying that the fishing industry may not be sustainable in future if there are no measures to curb overfishing.
A technical report released in 2017, found that there has been an increase in catches from 60 metric tonnes in 2004 to 1,160 tonnes in 2015, followed by a decline to 964 metric tonnes in 2016.

DECLINE IN FISH STOCKS
Researchers attributed the higher catch to the high number of fishermen operating in the four landing beaches after the fishery was re-opened after a three-month periodic ban in 2001, that was in force for 13 years before it was lifted.
“Not all the fishermen have the recommended number of gillnets (10). Most have up to 50 or more gillnets set out.
“This has resulted in early warning signs of a decline in fish stocks,” noted the report certified by researcher Christopher Aura.
“For sustainability of the fishery and enhanced fish production, an ecosystem-based approach to fisheries management of the lake that holistically takes into account the whole lake basin should be taken into consideration and relevant stakeholders should be involved in the formulation and implementation of the decisions to manage the fishery,” stated the report.
The researchers recommended increased surveillance and monitoring of the lake activities due to the illegal, unregulated fishing as well as protection of breeding and nursery sites to allow recovery of the fish stocks.
“There should be increased research activities to determine the carrying capacity of Lake Naivasha in order to provide better estimates on the production capacity and how much fish can be safely removed without severe adverse effects to the fishery resource,” suggested the report.

OTHER PROBLEMS

Lake Naivasha Water Resources User’s Association (WRUA’s) Chairman Enock Kiminta notes that illegal water abstraction has perennially affected water levels in Lake Naivasha. Mr Kiminta said that measures to protect the lake should be put in place to restore the flow to the freshwater lake and ensure sustainability of livelihoods and ecosystems.
The increase of water hyacinth, which hinders navigation and access to fishing grounds, has also been of concern, with aquatic biologist and acting CEO of Imarisha Naivasha Mbogo Kamau blaming the phenomenon on increased human activities that have led to the proliferation of nutrients that aid the growth of the invasive weed.
In Bogoria, Senior Warden James Kimaru said that reduced lake levels were caused by the dry spell, but he noted that increased human activities such as encroachment, deforestation and farming in the upper catchment areas, also affect the natural flow of water into the lake.
To preserve biodiversity, the Kenya Wildlife Service is engaging locals to involve them in conservation efforts.
“We work closely with the local community in preserving the lake which has helped in reduction of illegal logging and unlicensed water abstraction mainly in the upstream,” said Mr Kimaru.
In Lake Nakuru and Lake Elementaita, there is also the issue of increasing salinity, during the dry spell which causes water to evaporate.

Report by Stella Cherono, Macharia Mwangi and Richard Maosi