Architects urged to tackle construction culture driving unregulated sand mining in the developing world
Unregulated sand mining in the developing world is wreaking devastation on rivers and coastlines in the process. Architects, engineers and materials suppliers can take action to release its stranglehold on the sector.
The frantic pace of urban growth is driving unprecedented demand for aggregates used in concrete, asphalt and glass, and a black market for sand extraction.
Demand comes largely from China, which is responsible for about 58% of the world’s cement production, followed by India where the need for aggregate is expected to quadruple over the coming years, according to a report on the global impacts of sand mining published by the World Wildlife Fund (WWF).
State or district authorities hijacked by commercial interests have allowed a network of illegal mining operations to spring up along local rivers. This has changed the shape of river beds and floodplains and altered habitats, groundwater reserves and water quality. It has affected the diversity and abundance of fish and riverside vegetation.
These operations are often run by highly organised and violent sand mafias that threaten or physically attack critics. Kiran Pereira, founder of SandStories.org, a website dedicated to raising awareness of the environmental impact of sand mining, says: ‘There have been cases in India where senior government officials have been transferred to other roles on the day they authorised a raid on a sand mining operation. Journalists have been killed in broad daylight; the term “dangerous” is an understatement in some areas.’ Pereira was herself intimidated by a youth on a motorcycle when she visited an unregulated dredging operation in India with a local activist.
Dependence on naturally occurring river sand by the construction industry can be reduced if local builders merchants and product manufacturers source alternatives, such as manufactured sand, artificial sand or aggregate substitutes like slag sand or other recycled material.
Europe has strict regulations governing aggregate extraction. Its supplies come from crushed quarry rocks, recycled concrete and marine sand (which must be washed first to remove sodium that can damage concrete).
The WWF study recommends that developing countries alter building designs and design methodologies to ensure that extraction is reduced to sustainable levels.
The failure of many clients to employ an architect or an engineer during design can mean that buildings are over-engineered with much thicker concrete structures than necessary, thereby increasing the volume of sand required.
Lois Keohnken, author of the WWF report, told RIBAJ: ‘Part of this is about trying to introduce new building codes that reduce the amount of concrete used in construction and making other building products as economically viable.’
However, widespread change will require a cultural shift given the cheapness of river sand and how embedded illegal extraction has become. ‘Sand has always been incredibly inexpensive, which does not reflect the huge environmental and societal cost of what is happening as a result of extraction. People just expect there to be a local supply, and cities are usually close to rivers where sand is plentiful,’ Keohnken concludes.