The monsoon season has not quite drawn to an end and just to prove it, the heavens open in an intense 15-minute downpour. The rain elicits more giggles from the children, who scamper for refuge under the trees lining the bank. Then a solar-powered boat with a sign "Nauka [Boat] School" suddenly appears on the horizon and slows down as it draws nearer to pull up beside the bank.
The dripping children queue to get to their classes on board - a rainy day is not an excuse to play hooky in this part of the world. "Nauka schooley jaye khoob moja hoye [When we attend the boat school, we enjoy ourselves]," a giggling Shakila Khatoon, 9, said in Bengali, or Bangla, the national language.
"It's different from other schools - I really love the Bangla boi [book] - it teaches us things we see in our villages, helps us identify the birds, kinds of fishes, and tells us about river erosion."
Women and older villagers watch the bobbing fishing boats from the bank while they wait patiently to catch the "health boat", the "library boat" or even the "agricultural extension boat", all due to arrive sometime that day.
In a few weeks, some of the landless families in the region might even settle permanently on houseboats lashed together to form small floating villages, with a community boat in between.
Architect-turned-activist Mohammed Rezwan is determined to prove that Bangladeshis can survive the climate change scenario, in which land steadily vanishes beneath relentlessly rising water, by staying afloat. "This is the future - various climate change forecast models have predicted that one-fifth of Bangladesh could be under water by 2050," he said.
The impact of global warming will hit Bangladesh hard. Soaring global temperatures are increasing glacial melt in the Himalayan ranges, swelling the rivers that flow down from the mountains and across the Bangladeshi floodplain, the largest in the world, far beyond their capacity.
The expanding volume of water is also causing higher sea levels to push inland. A rise above one metre, which could be reached in this century, means Bangladesh could lose 15 percent to 18 percent of its land area, turning 30 million people into "environmental refugees" by 2050, according to some estimates, says the United Nations Development Programme (UNDP).
Extreme weather events such as cyclones are also expected to become more frequent and intense as a result of global warming.
Couldn't go to school
Rezwan grew up in the nearby village of Shidhulai and was often unable to go to school during monsoons, when the roads were flooded. "Schools would be closed for months," he commented. In 2007 more than 4,000 primary schools were closed, at least another 4,000 were affected and 44 were washed by river erosion, the UN Children's Fund (UNICEF) reported.
"When I began studying architecture, I started playing around with the idea of trying to help the children in the region," said Rezwan, now in his early thirties. He homed in on "water and boats".
Water is a way of life for Bangladeshis: more than 150 million people are squeezed into a land area of 144,000 sq km with more than 230 rivers and their tributaries flowing through it. Living on boats seemed like a good idea, said Rezwan.
With about US$500 saved from odds jobs and scholarship money, he convinced friends to pitch in to set up an NGO, Shidhulai Swanirvar Sangstha (meaning a self-dependant organisation), in 1998 and launched the first boat school in 2002. Since then the organisation has built 90 boats.
It has also collected several awards, notably the Bill and Melinda Gates Foundation's Access to Learning Award in 2005, the UNDP Equator Prize in 2006 and the UN Environment Programme's Sasakawa Prize for outstanding achievement in 2007.
Locally available materials are used to build the solar-powered boats, with a shallow draft that allows them to glide across flooded land and along smaller streams, while the cane exterior blends in with the rural landscape.
The boats have multilayered waterproof roofs and side windows that can be opened for ventilation. A metal truss takes the weight of the roof so the interior is not obstructed by pillars, allowing room for benches and desks to accommodate 30 to 35 children or adults, library cupboards and reading tables, or a doctor's examination room and a small dispensary.
Each school boat conducts three classes a day along the 250km of interconnected rivers and streams that the organisation covers. Basic primary education up to grade four is provided in the only schools in the country where children can learn the Bengali alphabet, are taught to identify various fishes and birds, and how to harvest clean water in an area prone to waterborne diseases.
A whole new world
The boats equipped with computers have opened a new world to at least 90,000 families in the region, "especially for girls and women," said Fazila Begum, a subsistence farmer. Girls and women are brought up in conservative and protected households in mainly Muslim Bangladesh, and cannot always travel long distances to attend school or even to see a doctor, particularly in rural areas. "Now we don't even have to step out of the village," Fazila smiled.
Scientists like Samajit Kumar Pal and Yusuf Zai from the Bangladesh Sugarcane Research Institute volunteer their time and expertise in the agriculture extension boats, which present slide shows and films on farming techniques and new varieties of paddy rice. Women farmers like Runa Begum Akhtar also get tips on saving their crops from pests. "The method was so simple; I just had to wash the plant with detergents," said an amazed Akhtar.
A few men also turn up for the classes. "We work in the fields, so it is fine by us for the women to come to the classes - they provide us with the information," said one. "Well, ultimately, we both have to work together - tobhi shonshar chole [that's how households run]," a woman farmer remarked.
The scientists and doctors who volunteer their services said the work provided "immense job satisfaction". "We constantly work on new methods, particularly to address the challenges posed by climate change, such as increased flooding, for farmers but often very little of this information filters down to the farmers - this forum provides us with a direct access to the fields," said Pal.
A quick and easy technique developed by him to help farmers get rid of excess water in fields by boring holes in them to drain the water into an aquifer has saved many crops.
"When tearful and grateful villagers bless you, it makes everything worthwhile," said Mohammed Israel Hossain, a medical doctor who takes time off work and spends his holidays treating villagers along the waterways. He has noticed a rising incidence of viral fever over the past four years, which he associates with increased flooding in the area.
A sustainable future?
So are solar-powered floating villages the future? "Well, the school boats, etc., are a form of adaptation, but I am not sure about the houseboats. It is not really sustainable - solar power requires a tremendous amount of money," said Mohammed Shamsuddoha, general secretary of the Equity and Justice Working Group, a network of NGOs.
But Rezwan has a plan to make the house boats sustainable: his organisation has developed a "solar" lamp costing only $5 to $10, which it hands out to its top students as an incentive. The children bring the lamps every now and then to recharge them from the solar power stored in batteries on the boats.
"Building on that concept, we plan to sell hurricane lamps for around 500 taka [$7.30] each, and the villagers will have to pay 40 taka [about US $0.60] a month to recharge each lamp on our boats," said Rezwan.
An estimated 78 million people don't have access to electricity and still use kerosene or fossil fuels for lighting, each consuming around 144 litres of fuel per year. Burning kerosene emits at least 2.6kg of CO2 per litre of fuel, so the lamps will decrease this greenhouse gas emission. "It will also save the villagers money spent on kerosene oil," said Rezwan.
His NGO is putting the finishing touches to its pilot three-boat community, with a floating vegetable garden in tow to see if it will work. "We hope to cover the entire country one day," he said.
His organisation is also working with Gonoshasthaya Kendra, an NGO that is the country's second largest health care provider, to electrify health care centres in southern Bangladesh.
An octogenarian villager poring over a philosophical tome in the floating library gave Rezwan's efforts the best endorsement: he said he was getting to live again, and added, "This is very good - I get to read and think."