Creation of 1,500 hectares of land in the region is flawed on environmental and demographic grounds, say experts

Green hillsides stretch out behind Ruy Barretto's stone house and trains to China slip under the hill in the designated conservation area where his family home has stood for generations. Down by the waterfront, Tolo harbour is teeming with visitors. Behind it, a narrow, neglected road crawls up the Sha Lo Tung hillside through dense trees, birdsong, wild rushes, ferns and fresh air.

But if Hong Kong's planners have their way, tonnes of construction waste will be dumped in and around Tolo harbour, disfiguring shorelines, despoiling uninhabited islands and wrecking a rare recreational resource.

The plan is part of a broader aim to create 1,500 hectares of land to provide homes and land space for millions more people. The planners talk of creating 25 islands and waterfront extensions of hundreds of hectares. They would dump concrete in the sea to join up islands where weekend sailors see porpoises and turtles, and wipe out natural pebble and sand beaches.

Possible Hong Kong reclamation sites. Photograph: Graphic

Thousands have signed petitions against the plans. Experts on population, environment, urban design and sustainability say that instead of creating new lifestyles for residents, the plans will allow the government to save the cost of shipping waste to China and garner huge profits from land sales.

"They are trying to kill two birds with one profitable stone," says Barretto, a barrister. The WWF says the environmental cost of the redevelopment is too high. Among the sites targeted for reclamation, Po Toi island is home to Romer's tree frog; Hei Ling Chau island is home to a special burrowing lizard; and the waters around Beaufort island support more than 30 species of coral. Porpoises, mangroves and spawning grounds for fish would all be put at risk.

However, the 25-location plan will create land in one of the planet's most heavily populated places. The authorities are also thinking about creating new land for a third runway at the international airport.

The government's civil engineering and development department (Cedd), which refused to speculate on the 25-location plan, says it is merely seeking public opinion on the best way to meet future development needs. It issued a brochure suggesting that new land could be created at 25 locations outside Hong Kong's central harbour area, which is protected from development by law. It embarked on a "public engagement process", in which the plan was outlined at seminars and exhibitions. Responses are being analysed with a view to shortening the list of 25 sites down to 10.

The trouble, says a range of experts, is that the department's assumptions are wrong, its reasoning faulty, and the process flawed. Take the Cedd's claim that Hong Kong's population (of 6.9 million) will reach 8.9 million by 2039. "I don't believe it," said Prof Paul Yip, Hong Kong's top demographer, from the University of Hong Kong's department of social work and social administration.

Hong Kong has one of the lowest fertility rates in the world, at 1.04%, and a rapidly ageing population. The daily quota for 150 new migrants from mainland China is rarely full. Without a massive inward migration programme it is hard to see how it could produce such significant population growth.

As for the need for new land, the countryside is already scarred by storage of shipping containers and old factory areas are left to rot. The government has admitted that 200,000 flats are standing empty; more than 5,000 hectares of other land has also been identified for rezoning.

"Reclamation should be the last resort," said Roy Tam Hoi-pong, chairman of environmental pressure group Green Sense. The Hong Kong Institute of Planners says that reclamation "at an appropriate scale and level of overall sustainability is a possible option" but warns that study of a large number of criteria, including environmental and ecological, is necessary.

"The identification of 25 sites, prematurely released and belatedly presented, is confusing … 'island' sites in particular are extremely unlikely to be viable," it said in a submission to the government.

Government sources the Cedd's plan was a surprise to policy units usually involved in such significant planning processes. A 2007 government study called Hong Kong 2030 stressed the need for a more sustainable quality of life and warned against rampant reclamation.

"We're suffering from a lack of decision-making," said Peter Cookson Smith, architect, urban planner and president of the Institute of Planners.

Some allege a broader lack of vision, saying Hong Kong's land needs depend on its future relationship to the mainland. The border between the two different jurisdictions is becoming more porous, which is partly why mainland Chinese feel less need to live in more expensive Hong Kong. It also raises questions about why Hong Kong should build more land, when there is the huge space of China next door. For Barretto, the most disturbing aspect of the 25-site plan is that the government appears to have forgotten, or thrown out, the most basic principles of international practice for sustainable planning.

After researching the figures, local commentator Tom Holland said: "It's hard to conclude anything except that the planners and their construction industry cronies have run completely amok, crazed by the prospect of getting their hands on the government's huge fiscal reserves, and using them to build ever more grandiose, expensive and unneeded civil engineering projects. They need to be stopped."

Hong Kong's reclamation tradition



When British and other foreign traders' ships first sought safe harbour in Hong Kong in the 1840s, the island offered a mere strip of flat land which rose precipitously to the 550-metre peak. Reclamation - taking land from the sea – was envisaged from the start.

Begun in 1889, the first major project added almost 4.5 hectares of new land, creating what is now called Central, the primary business district A subsequent reclamation of what is now called Wanchai added another 4.8 hectares.

Since then, Hong Kong has grown exponentially. The government has been creating 500-700 hectares of land every five years, until 2005 when new environmental awareness and legal sanction cut the growth back to under 100 hectares over five years.

As of early 2011, about 6% of land in Hong Kong (6,824 hectares) has come from reclamation, the government says.

Traditionally, reclamation has been done by dredging, using rock and sand fill and taking out mud that could not be built upon. New techniques involve the use of large concrete blocks. This involves less dumping of mud, and makes better use of existing construction waste. Engineers say it also provides more stable land.

Hong Kong's international airport was built on new land made by taking marine mud away. If a third runway is agreed, the new land it will require will almost certainly involve the use of construction waste.

• This article was amended on 1 June 2012 to clarify the area of waterfront extensions in the 25-location plan. The original also stated that the Cedd refused to be interviewed. This has been corrected.