It is Friday morning, and the southeastern fringe of Kibera slum comes alive as teams of women and youngsters converge on the edge of the Nairobi dam.
There, on its northern perimeter, some rake and pile garbage for collection while others plant saplings on cleared terrain.
Known as riparian land, the area they are planting is the strip adjacent to the dam that can absorb flooding. Under Kenyan law, this is public land and it may not be built on.
Their work might look like simple civic pride, but something more is going on: This is a message to developers who might want this unused land for themselves.
"Nairobi dam's riparian land is not for grabbing," said Yohana Gikaara, the founder of Kibera 7 Kids, a non-profit that works with young people in the slum.
Forty years ago, this shore was underwater and safe from land-grabbers, he said. At that time, the dam was a popular recreation site for residents of Kenya's capital.
But years of siltation due to human encroachment and the dumping of waste saw the waters recede. Over that time the dam's main water source — the Motoine River — was choked by garbage, leaving it just a thread of slimy effluent.
Today, of the original 88 acres the dam once occupied, only a chunk of water about half the size of a football pitch remains, said Gikaara.
Given that land near the dam is worth about 80 million Kenyan shillings ($800,000) an acre, the attractions for developers are clear.
Kibera residents like Gikaara fear the 30 acres of riparian land, and perhaps even the remainder of the dam itself, could disappear thanks to the booming property development industry.
"No one knows when [developers] strike," he said. "You wake up one morning and find earth-movers in the neighborhood, and that is when you know you or your neighbor will soon be homeless."
Apartment blocks sprung up in 2014 on the dam's southeastern flank and, in 2017, greenhouses began popping up too. That prompted non-profits in Kibera to raise the alarm.
Last year, the National Environment Management Authority (NEMA) ordered the apartments to be demolished — because, said David Ong'are, the government body's director in charge of compliance and enforcement, they had been built illegally on riparian land.
Any building near a water body must be between six and 30 meters from the high-water mark, depending on the type of water course, he said.
"The buildings that have breached this threshold at the Nairobi dam are going to be demolished," Ong'are told Reuters in an interview, adding that some developers had filed court cases in an effort to halt that.
On'gare said more than 4,000 buildings built on riparian land in Nairobi had been earmarked for demolition to date.
One prominent site demolished last year was the South End Mall, which NEMA ordered flattened after ruling it had been built over a section of the Moitone River's course, he said.
In January, Gikaara worked with lobby groups to oppose plans by a parliamentary committee to fill in the rest of the dam — ostensibly as a way to deal with the issue of pollution.
But, said local resident James Makusa, that was simply a ruse cloaked in the name of rehabilitating the dam.
"The real motive is to prepare the ground for property development," said Makusa, who makes a living by scooping sediment from the Motoine River and selling it to construction sites.
Makusa views his job of clearing the river of sediment as a form of environmental conservation — a better way to rehabilitate the dam, and preferable to filling it with soil.
Mary Najoli, who heads the Shikanisha Akili Women's Group, suggested another use that would protect the land. Her group, whose name translates as "using your imagination," makes beadwork from recycled waste collected in Kibera.
But like many others in informal settlements, they lack a permanent venue from where to sell their wares.
"We would like to be allocated [a small area of] the dam's land as a place where we can display and sell our beadwork. In return, we will ensure that the environment is clean and watch out for illegal encroachment," she said.
?That might happen, said local MP Nixon Korir, whose constituency includes the dam.
However, he said, the process of reclaiming the land must be finished first: that includes clearing waste and ensuring the planted trees can sustain themselves.
Korir said the reclamation process, which started last year, was designed to benefit Kibera's residents.
"The rehabilitated riparian land will be turned into a tourism site that can bring revenue and create employment," he said.
Juliette Biao Koudenoukpo, the director of the Africa office at the United Nations Environment Program (UNEP), said Kibera residents were best-suited to keep Nairobi dam clean and safe.
"The people do not have any other alternative but staying where they are and caring for the dam because there is need to restore life here in Kibera through restoration of this dam and its ecosystem," she said.
She blamed Kibera's waste problem on poor urban planning, which meant open spaces had become dumping grounds — including the dam's shores.
Meantime, some view the issue of pollution as a silver lining — among them is Ian Araka of the Foundation of Hope youth group, which combines garbage collection in Kibera with art, drama, traditional dance and poetry.
His 60-strong group has partnered with ASTICOM K Ltd., a social enterprise that is building a recycling factory in Kibera. He said the aim is to supply solid waste collected from the slum to the factory on a contractual basis.
Some will be collected from the dam's riparian land, and there are plans to recycle polluted water for use by small businesses in the slum, such as car washes and sanitation services, he said.
"This project is going to unite and equip us with a voice to not only be able to chase land-grabbers away, but also invite developers to do something constructive with us," Araka said.