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Loss of forests is making floods more devastating in Malawi - but efforts to replant trees on farmland could help
Cathy Watson is chief of programme development at World Agroforestry.
The village of Chibwana lies a kilometer from the Shire River in southern Malawi. In March. it was covered in water after a year’s worth of rain fell in two days during Cyclone Idai.
As water poured down from the highlands, youth canoed children to safety. Adults and livestock perched on anthills, then made their way, often neck deep, to higher ground. “The priority was life. No one drowned," says village head Changambatuka.
But the community is left at a loss by one consequence of the flood. Sand 1.5 metres deep now smothers their fields. Pristine white like a beach, it looks completely out of place.
It is almost end game for this village that this year also experienced a hail storm that broke houses, a dry spell that led to hunger, and an infestation of caterpillars.
No earlier flood left sand like this. Why did it come? They attribute it to tree loss in the highlands. “In the 1970s, you could see the hills all covered,” says village councilor, Marko Ben.
He points to a further loss – of the wetlands along the river that should trap sediment. "To make space for growing vegetables, people have removed reeds. The flood easily flows inland, full of what it is carrying."
The key problem is the highlands, which are eroded. "People lack fertile soil. So, they cultivate along the river."
Ideally, floods deposit silt and organic matter, boosting fertility in valleys. But in Malawi, soil is fairly sandy, and trees have been besieged for decades. As the trees were cut in the Shire highlands, so went the soil. What has been left to erode is almost entirely particles of quartz, the white sand on the fields.
"The implications of the removal of vegetation are a deterioration of soil health and increased erosion. This is what is leading to siltation downstream," says Tor Vagen from World Agroforestry.
His maps of vegetation cover in 1990 and 2017 show a growth in areas with less than 50% cover and far fewer areas with cover greater than 75%.
"In the zoomed-in areas, we can clearly see more zero vegetation cover along waterways," says the geoscientist.
The Shire River provides more than 98% of Malawi’s electricity; silt lowers hydropower generation. Countrywide, land degradation is harming agriculture, which contributes 90% of export earnings.
Causes of degradation include an ill-fated scheme in the 1980s to replace forest with plantations; a natural resource ‘free for all’ during the euphoria of the dawn of multi-parties in the 1990s; curing tobacco, Malawi’s top export, with indigenous trees; and a growing population needing land to till and charcoal. Malawi has the highest rate of deforestation in Southern Africa.
The rain began on 8 March.
"We had experienced floods, but this was really adverse. We used phones to mobilize our subjects. Even crocodiles were displaced," said the village head.
"Lower Shire is experiencing the effect of human activity in the highlands," says Hector Nkawihe. the district forestry officer for Chikwawa.
"The whole area was cut off, and it took us three weeks to get there. We lost 185,000 seedlings. During floods, trees are very important because they reduce water velocity and pressure."
The good news is that a large project led by the World Bank and the Malawian government is making inroads into these intertwined challenges. Fewer people died in the floods during Cyclone Idai than in the last big floods in 2015, according to World Bank documents.
The project rehabilitates catchments, with a strong focus on natural forest.
Forests urgently need protection, recognizes Isaac Nyoka, who is the head of World Agroforestry in Southern Africa. But what he also points out is that most catchments of the Shire River are now farmlands, not forest anymore.
Investing in trees on farms is key to solving the crisis and preventing more sand coating lowland fields, and more trees on farms will also help ensure the better harvests that the upland farmers yearn for.
"In both dry years and in years with excessive rains, yields are more stable when you have trees on farms. Trees on farms can build the resilience to reduce the predictable humanitarian caseloads that we see annually from droughts and floods."
