"It flooded up to here in March," Agnes Shikoli says, pointing to a spot halfway up the six-foot [1.8m] corrugated iron wall of her home in Kibera, one of the largest informal settlements in Kenya.Her tiny house lies just a couple of metres from the Ngong river, which runs through this densely populated area in the capital, Nairobi.The scars of floods in the long rainy season earlier this year can still be seen - including a broken TV in the corner which was immersed in water.Tucked out of sight is a photo of her sister Beatrice Khalayi, 58, who died when intense rains caused widespread destruction in Kibera. She was among more than 60 people across the country who lost their lives."Someone called me to tell me that she had died of electrocution after her house flooded," Shikoli recalls. "When I see a picture of her, I feel uneasy, that's why I keep it far from me, so I don't see it."With Kenya's short rainy season now starting, Shikoli tells the BBC she is afraid – especially following warnings that the El Niño weather phenomenon could bring a new round of flooding."I feel like it can kill us.

These houses aren't made of stone," says the 62-year-old. "They can fall on us, or the water can drown us."Kibera - and Kenya more widely - are on the frontline of preparations for the potential impact of El Niño.Forecasters have warned that this year could see one of the strongest on record, bringing extreme weather to many parts of the world.In southern Kenya, that means the threat of rains even more intense than usual.Outside Shikoli's house, groups of men and women wearing high-visibility vests are shovelling and raking garbage out of the riverbed and disposing it far from the water.This programme called Climate Worx, under the office of President William Ruto, is meant to rehabilitate Nairobi's rivers. Such exercises have intensified since August when warnings increased about the possible scale of this year's El Niño.Similar work to unclog drainage systems is ongoing across Nairobi, a sprawling city built on hilly ground crossed by three major rivers.But the workers have a huge task on their hands.Blocked drains and inadequate sewage systems were widely blamed for the high number of deaths after the floods earlier in the year, as the excess rainfall had nowhere to escape.The Nairobi County disaster management chief, Bramwell Simiyu tells the BBC that drainage systems have been "untouched for many years" and that removing the rubbish from them will save lives.Floods disproportionately affect informal settlements in Nairobi, especially those near rivers, like Kibera and Mathare.In most of these settlements, houses sit just a few metres from rivers.

Some people, including Shikoli, live on the slopes of the river itself due to the constant expansion of the settlements. When flash floods occur, these houses are swept away, endangering the lives of their occupants.Nairobi's drainage system hasn't been upgraded to deal with the rapid growth in the population and infrastructure over the decades"The existing drainage system was developed 30 years ago to cater for a population of about 2.5 million residents but we're dealing with about 7 million in the daytime and 5.5 million night-time," Simiyu says.He adds that investment of up to $192m (£143m) is needed to upgrade the sewerage and drainage system entirely.

But there is little sign that either the cash-strapped national or city council will able to raise this kind of money.The Nairobi River Basin Regeneration programme, a government programme aimed at restoring the city's rivers, found that settlements near rivers, and where there is weak enforcement of regulations, have increased flooding risks. It recommended a "buffer" to protect rivers and "humane relocation" of communities where necessary.

However, rising poverty has driven many people to live close to rivers."Our worst case scenario looking at low-income settlements is that up to about 100,000 people are at risk," Simiyu says. "Moderate projections is about 5,000 households or about 20,000 people may be at risk."Anyone forced to leave their homes will be relocated to 167 designated holding grounds where a stockpile of relief food and supplies will be distributed, Simiyu says.