Unless you sacrifice your precious time and embark on a sojourn at Nkula Hydroelectric Power Station, you will never appreciate the silent but immense damage that silt and weeds, particularly water hyacinth (Namasipuni) are unleashing at the station.
The damage is purely massive.
The cost of siltation along the Shire River basin is just overwhelming, but perhaps little might be happening for Malawi to engage an extra gear and thwart such huge impact of severe soil erosion and resultant sedimentation in the Shire River basin.
And a tone from one of Escom’s senior officials last week spoke volumes of how weeds and sediments are dragging down efforts by the power utility company to ensure seamless electricity to Malawians.
Today, the word ‘blackout’ is almost synonymous to swearing if one dissects the huge cost of power outages on manufacturing entities and even at households.
Mostly, companies that are involved in production resort to using diesel-powered generators to sustain production lines and this is costly.
Management personnel of such companies should definitely nod in agreement to this indisputable fact.
In fact, in May 2008, Malawi Government undertook an analysis of the constraints to economic growth in Malawi in conjunction with the World Bank, British Department for International Development (DFID) and the African Development Bank (AfDB).
The Analysis generally identified unreliable electricity supply and high transport costs as principal constraints to economic growth.
Environmental degradation plaguing hydropower
A visit at Nkula A and B last week courtesy of the Millennium Challenge Account (MCA) Malawi brainwashed this reporter whose mindset completely realigned to a strong belief that weeds and sediments will continue to be a constant operational cost and a threat to hydroelectric power generation until soil loss in the Shire River basin is addressed.
Aquatic weeds on the islands on Shire River and the river bank as well as siltation along the river which triggers soil erosion were cited as two major environmental constraints facing officials working at Nkula.
Apart from water hyacinth, other invasive weeds clogging the Shire River include papyrus, hippo grass, water lecture and others that form large ‘floating islands.’
Nkula A, built in 1966 generates 24 megawatts (MW) from three main machines while Nkula B, built in 1978, generates 100MW from five machines but with aging machine coupled with environmental problems, the power station is grappling to generate the required capacity, hence the vexing word blackout.
It is exactly 70 kilometres from Liwonde Barrage to Nkula Hydroelectric Power Station and in between there are six tributaries pouring into Shire River and this induces siltation into the river’s basin.
Adding salt to the wound, communities are worsening the situation as they are cultivating along the river banks and this is interfering with efforts to ensure uninterrupted power supply as severe soil erosion is plaguing power generation.
Escom’s environmental expert Lawrence
Chilimampunga was at pains when he tirelessly explained to journalists the hassles of harvesting weeds and soil off the river bank.
He said 1 500 kilogrammes of weed is filled up to the brim in a dumper truck per trip.
On shore, trucks haul the weeds away to dumping sites where they are allowed to dry and are then burnt.
Showering your eyes with versatility, one thing quickly occupies your mind at Nkula and this is the fact that weeds are growing very health, greenish, plumb and well-built and this is because of the daily nourishment from nitrogen, calcium, among other nutrients, unleashed by fertiliser applied by communities that are cultivating along the river bank.
And there is a dredging machine at the power site which attempts to clear silt but its efforts are hampered because of its old age. It is a second hand machine, according to Chilimampunga, which started operating in 1998 but it continuously breaks down to the chagrin of Escom team at Nkula.
At Nkula, the original design was to have three million cubic litres of water but today one third of the dam is filled up with silt, hence poor performance of machines.
Inappropriate land management practices a menace to power generation
A critical peep into the middle and upper Shire River basin feeds you a conclusion that inappropriate land management practices has characterised the basin.
This is noticeable in Machinjiri, Blantyre where a certain river joining Lunzu River which pours into Shire River is a victim of bad agricultural practices as individuals cultivate very close to the banks.
Cultivation of marginal lands and hillsides, particularly for production of annual crops without appropriate soil conservation techniques are significant factors of deteriorating of river banks.
I spoke to one woman from Machinjiri who identified herself as Selefina Nkando. She confessed that she has all along been cultivating along Bondo stream which joins Lunzu River and she admitted that several times she has been a victim of flooding which saw her maize being washed away. She recalls that she lost her good chunk of maize in 2009 due to flooding.
In fact deforestation, erosion and sedimentation are Malawi’s most serious environmental threats.
“The problems are most pronounced in the southern portion of the country, in the Shire River basin, where population density is the highest,” said Chilimampunga, in an interview.
He is also convinced that poor land and natural resource management practices are severely damaging soil, water and other natural resources that Malawi depends on for water supply, hydropower, agriculture and other social services.
Chilimampunga added: “These problems are compounded by extensive aquatic weed infestation problem in the upper and middle Shire river basins.”
Quantifying the cost of weed infestation
The impact on the power generation infrastructure of the aquatic weeds infestation and erosion-caused sedimentation is large and costly.
Efficiency is reduced and the useful life of the infrastructure is significantly shortened and this is evident at Nkula.
A concept paper, which Business Review has seen, prepared by the MCA Malawi on its Environmental and Natural Resources Management (ENRM) indicates that overall, power shut down resulting from weed infestation alone are estimated to cost $27 000 (about K11.6 million) per day of shut down and to lead to industrial losses worth 10 times this amount.
Severe damage to infrastructure in 2001 due to weeds and debris cost $12 million (K5.1 billion) to repair.
It doesn’t end there. The load losses attributable to sedimentation, siltation and weed infestation as a result of catchment degradation account for an estimated 38 percent of total annual load losses from Nkula, Tedzani and Kapichira power stations.
According to the blue-print, the total cost in terms of revenues lost is about $1.58 million (K679 million), equivalent to one fifth of actual annual revenues earned.
Even electricity consumers are said to lose close to $.25 million per year due to the need to substitute electricity during power outages and to replace equipment broken down as a result of power outages.
The dredging operations are also costly to Escom and much of the dredging equipment being used is old and in need of repairs or replacement.
A ray of hope beaming from MCA not all is lost
To address the immediate problems of siltation and weed infestation limiting power generation by Escom, MCA’s compact plans to purchase mechanical equipment so that Escom manages the weeds and sediments that will continue to clog its facilities.
This will be undertaken under the MCA’s ENRM project whose goal is to reduce the scope and intensity of environmental factors along Shire River basin, according to MCA Malawi Environment and Natural Resources Manager Dwight Kambuku.
He said the project, which is being funded by the Millennium Challenge Corporation (MCC), will focus on mechanically removing weeds and sediments through the use of weed harvesters and dredgers.
“The second intervention takes a longer term perspective by addressing the causes of land use change that are producing erosion and thirdly we will support greater involvement of women and vulnerable groups in improved land use management activities in the Shire river basic,” he said.
He said MCC will fund the purchase of mechanical weed harvesting equipment and silt dredging equipment.
Kambuku said the equipment will be located at Escom hydropower dams and related facilities on the Shire River and will directly address the results of the environmental degradation plaguing power generation.
The ENRM project, according to Kambuku, is comprises three activities namely; weed and sediment management activity, environmental and natural resource management activity and social and gender enhancement fund.
At Nkula, to help manage weeds, the compact will fund the purchase and installation of a 300 metre standard floating trash-diversion boom, while at Liwonde, the compact will fund the purchase of a new weed harvester and shore conveyor, a trailer, a supply of spare parts, among others.
In Tedzani, the compact is expected to purchase and install a 300-metre standard floating-diversion boom, a new tipper truck and dredger while at Kapichira, the compact will fund the purchase and installation of a 48 metre long, 1.5 metre wide, 10 millimetre thick solid steel plate, among others.
However, it is a fact that the compact’s five-year lifespan will be inadequate to solve the problems of soil erosion and aquatic weeds infestation which have proven to be on-going challenges for the foreseeable future and will continue to plague the power generation facilities, including those replaced or upgraded through compact.