By Dan Collyns
BBC News, Lima
Abel Cruz is campaigning for easy access to water
They look like huge abandoned volleyball nets facing west towards the Pacific Ocean on one of the many hillsides in the Peruvian capital, Lima.
They started as an experiment two years ago and now they are giving a lifeline to some of Lima's poorest residents.
The Peruvian capital gets an average of just over 40mm (1.5 inches) of rainfall a year but what it does not get in showers, it makes up for in fog.
For nine months of the year, much of the coastal city is shrouded in sea mist and these nets are being used to trap it.
The nets capture the fog in their thick plastic mesh and the drops fall into makeshift gutters that run along the bottom and drain into swimming pool-sized collection tanks further down the hillside.
Using four of these simple 8m x 4m structures, this community, perched on the foothills of the Andes in Lima's Villa Maria del Triunfo district, can harvest around 240 litres of water every night and the similar amount during the course of the day.
Ironically for a place almost constantly shrouded in fog, it is called Bellavista, which means "nice view".
The nets capture the sea mist so that Peruvians can make use of the water
"These fog nets have improved our quality of life. We can grow vegetables for our families and use all this moisture in the fog which would otherwise be wasted rather than having to buy water," said Noe Neira Tocto.
The vegetables helped to feed the low-income families but they still had to buy water for domestic uses such as washing and cooking, he said.
They are also growing Tara trees, whose fruit contains tannins which are used for treating furniture leather.
The community hopes the money earned from selling the fruit will help pay for the maintenance of the fog-catching nets.
"Our dream is to make this water fit for drinking," he said.
Although they live on the fringes of the city, the residents of Bellavista are all from rural areas who migrated to the capital to find work.
The newest arrivals get the land further up the hill which is not connected to the municipal water supply.
Farming comes naturally to residents like Olga Arce, who migrated to Lima two decades ago.
"Everyone who lives here is originally from the countryside. For us it's natural to plant crops and we all have our vegetable gardens," she said.
Tens of thousands more Peruvians could end up migrating to the city as climate change appears to be already disrupting the rhythm of the seasons in the Andes.
Resident Olga Arce migrated to Lima to try to find work
Peru, home to 70% of the world's tropical glaciers, is one of the countries most vulnerable to climate change.
As the glaciers shrink, there is increasingly less melt-water flowing into the rivers which supply the arid coast, home to almost three-quarters of the population.
Climate change models predict that eventually they will disappear altogether.
Chaotic growth in Lima is also posing a serious threat to already scarce water resources.
The population of the city of 8.5 million has more than doubled in the last 30 years.
It is one of the world's largest desert cities and around a quarter of its inhabitants lack basic water services.
On the other side of the city in San Martin de Porres, a very different picture from Bellavista emerged.
There is no piped water and also far less fog.
"Here we are 15 minutes from the government palace and the people have been living here for 50 or 60 years without water," said Abel Cruz who heads the campaigning group Peruvians without Water (Peruanos Sin Agua).
"It's incredible that this is happening, there's internet, telephone and cable TV connections but no water - the most basic necessity for human life," he said.
More than 250,000 people in this neighbourhood rely on private water trucks. They pay up to 10 times more than residents of middle-class Lima suburbs like Miraflores who have water on tap.
To fill up one barrel costs around 50 cents.
"My children suffer from parasites and intestinal infections because the water we pay for isn't even treated, it's from a well," said Amanda Solis, another community leader campaigning for the government to lay water pipes in her street.
"We've spent half a lifetime waiting for what is a basic service - something essential to have a decent standard of living.
"Realistically speaking it will probably be 2012 before we get running water here."
Water for all?
Guillermo Leon, director of Lima's water board, Sedapal, said they are committed to making sure 100% of Lima residents have running water and are connected to a sewerage system by 2011.
"We understand that democracy means access to basic services.
"But we have to appeal for the solidarity of the people who already have water to reduce their consumption - there's no point in laying new water pipes just to deliver a trickle."
Lima residents who are lucky enough to have running water consume some 250 litres a day, according to Sedapal.
Amanda Solis worries her children's health is being affected
This is simply incompatible with the capital's water resources. If residents cut down consumption by 10 litres a day, officials say they could supply a further 130,000 families with water.
Sedapal's centre of operations is a comfortingly blue glass building set on an irrigated grass lawn next to an artificial lake.
Practically all of the capital's main river, the Rimac, is dammed and treated as it runs through the Sedapal's grounds.
But it is a trickle compared to the River Nile which provides Cairo, a desert city with almost twice the population of Lima, with vastly more fresh water.
"When Francisco Pizarro founded the city of Lima he never imagined there would be so many people living here," said Mr Leon.
A third of Peru's population now live in the capital and it continues to be swelled by new waves of new migrants.
Even with plans to build tunnels to bring fresh water from the Amazon on the other side of the Andes, plus desalination plants for seawater and an overhaul of the capital's leaky water pipes, there still won't be enough water, said Mr Leon, unless Lima residents change their habits.
"Without these and other changes, Lima will be totally unsustainable and we'll probably just have to change the capital."