When she first volunteered for a rural bridge-building project in Gansu province three years ago, Cheryl Cham Suet-ying fainted from the stifling summer heat.
That hasn't deterred the civil engineering student from returning to the mainland this summer on a similar venture.
'I felt so bad because instead of helping I was being attended to,' Cham says of her baptism as a helper. 'I volunteered because I wanted to do something for the villagers. I saw how accidents can occur when crossing the river - for example, a mother and child at Maosi [site of the first bridge] were swept away a few years ago.'
This year, however, the 22-year-old is leading a University of Science and Technology student team, which has designed a bridge to enable farmers in a Sichuan village to safely reach their fields even when melting snows or heavy rains can raise river levels up to 12 metres. Instead of just being one of the volunteers, Cham now bears heavier responsibilities.
'This time I have to co-ordinate, solve problems and take decisions on design. I realise there is a lot to do before we can begin construction,' she says.
Cham and her team form a cornerstone of the Wu Zhi Qiao Charitable Foundation. Set up last year, the charity recruits Hong Kong students to help mainland villages lacking a safe river crossing. The volunteers design simple bridges that they also construct in collaboration with villagers and mainland university students.
The idea is that rural communities will benefit while young Hongkongers gain invaluable hands-on experience in building infrastructure and a better understanding of rural life on the mainland. The young volunteers don't earn credits for their work for Wu Zhi Qiao, and must find time to fit it in between their studies.
'We could simply raise the money and employ a local contractor,' says Wu Zhi Qiao chief executive Sharon Chow Ka-wong. 'By having students to do it, the project takes longer, involves more effort and the cost is higher but we cherish the process.'
The foundation is building four bridges this year: at Baishisi village in Sichuan, Datan village in Gansu, Xinchang village in Guizhou and Xingshi village in Shaanxi, where the existing crossing is little more than a log and a couple of telephone poles. But the group's aim is to construct bridges not just on but with the mainland.
Wu Zhi Qiao, meaning bridge of sustainability, grew out of an initiative by Edward Ng Yan-yung, an architecture professor at the Chinese University. He was working on a school project in Maosi, a poor village in Gansu, several years ago, when he realised that access to the new classrooms was precarious: pupils had to cross a river on a makeshift bridge of mud and straw that was often swept away.
Ng recruited a team of 60 volunteers made up of students, architects, engineers and others and after two years of research, planning, and fund-raising, built a bridge for Maosi over six blistering summer days in 2005. The effort was so rewarding Ng set up Wu Zhi Qiao to fund and guide student teams from local universities in building more bridges. Working with the Chinese Ministry of Construction, the foundation has identified 24 sites requiring help and will collaborate with mainland universities in building the bridges.
Chow, who was a volunteer in the Maosi project, confesses that she was initially sceptical about whether a group of largely lay people could build a bridge but quickly became a convert as they heaved stones, hammered nails and exchanged banter with villagers.
'I saw student volunteers grow through the experience,' she says. 'Building a bridge in the city is different from building one in the village. Students learn to respect local culture and the environment.'
Wu Zhi Qiao is concerned as much with establishing human ties as building physical links, and encourages young volunteers to get to know the rural communities they are helping. For example, Cham and her team spent some time at Baishisi last October surveying the site, making friends with the villagers and learning about their needs.
'We observed the local farming methods and traditional ways of preserving food. The villagers enjoy having visitors as they feel that someone cares,' she says.
Even so, communication remains a challenge. 'It takes time to really understand their situation,' Cham says. 'It's not possible for us to visit the site often, so it's hard to design with limited information.'
Students from Chongqing University, who had participated in similar efforts and acted as translators and guides, offered useful tips.
Zhang Limin, an associate professor of civil engineering at HKUST who is supervising the group, says: 'To understand the people there, how they live, what they need and how we can help is as difficult as [solving] the technical issues. Very likely, some grand ideas we might have are not what they want. So this project really serves two purposes - to build the physical bridge and an emotional one.'
Chow says: 'Bridge building is a way for students to learn about conditions in rural China. This project is just a vehicle for them to get to the villages and see how they can help.'
The experience has certainly been an eye-opener for Li Bin, an architecture student at the University of Hong Kong who was born and raised in Beijing. 'I didn't know much about the conditions in poor villages and their local culture,' says Li, a volunteer in the Xinchang project in Guizhou.
She was particularly impressed by the villagers' pride in their bridge, an 18th-century stone structure that has become a cultural icon and gathering place. One of the arches was destroyed by floods, but discussions with villagers revealed that traditional stone masonry was not feasible so they will be replacing it with concrete. 'Rather than view the bridge as a link between point A and point B, we wanted to extend its social character,' Li says.
Although the projects involve simple bridges, they can present technical challenges. Cham's team planned to construct a 100-metre pontoon bridge at Baishisi, but news of a dam being sited upstream has forced them to change plans. The dam would put the original site under water, requiring a redesign - and a bigger budget.
Use of sustainable local materials, combining traditional construction wisdom with modern techniques and designs that can easily be maintained by the villagers are major planks of Wu Zhi Qiao's work. At the Xingshi project, for example, the Polytechnic University team incorporated bamboo into their design after spotting extensive use of bamboo in building greenhouses during a survey trip. However, the volunteers are exploring the use of laminated bamboo, a new material manufactured on the mainland.
Their visit also spurred action in other areas. The sight of a garbage-lined road leading to the village school prompted plans to devise a waste disposal programme for the children. And lack of running water for the school toilets inspired a mobile water tank project led by the university's design department.
'It's a big challenge for this group,' says Michael Chan Cheung, assistant professor of design who is supervising the Polytechnic University team. 'The design students are from Year One. The civil engineering students may be studying how to build the bridge but have never done it before. They are going to build a bridge with their own hands.'
Wu Zhi Qiao chairman Ng is delighted by their progress. 'With the first bridge, we only had a small team. It was like a family business. We had to solve a lot of problems, find the money, etc,' he says.
Now that they've established the foundation they're shoring up their human capital, he says.
'Someone once asked me how many bridges I was going to build,' Ng says. 'I told them I would be happy if I could build three. The next 3,000 can be built by volunteers who will carry on this dream.'