If we thought the world running out of consumable water is the worst thing that could happen in the coming decades, think again… there is one more natural resource that is universal, vital and at the heart of our daily lives that we risk running out of ……. SAND.
It may be hard to estimate the actual consumption of sand and gravel because they primarily go into making of cement and thus concrete with the construction industry gobbling up huge amounts of this raw material. But demand from other industries such as glass, electronics, aeronautics and more importantly land reclamation, beach nourishment are causing a huge imbalance in the sustainability of sand.
Sand and sustainability:
Riverbed sand mining and coastal area sand excavation operations have a crippling impact on the environment and society at large by disturbing and damaging the existing ecology, aggravating erosion, collapse of coastal slopes, flooding, lowering water tables and exacerbating drought occurrence. Most large rivers of the world have lost between half and 95% of their natural sand and gravel delivery to oceans and an estimated 40-50 billion metric tons is extracted from quarries, pits, rivers, coastlines and the marine environment each year.
With more than half the world’s population living in cities, unprecedented urban growth has resulted in mind boggling requirements of sand. In the past decade, China and India’s cities have used more cement than America did in the entire 20th century. Singapore has increased its land area by reclaiming watery areas by reportedly buying 517 million tons of sand from countries such as Malaysia and Indonesia over the last 20 years. Dubai exports most of its sand with its architectural marvels like Palm Jumeriah consuming ~187 million tons of marine sand , and to build the Burj Khalifa sourced sand for its concrete skeleton from Australia.
‘Sun and Sand’ tourism is one of the most popular travel activities ensuring economic development for seaside destinations, but studies show that the environmental side of sustainability are often not met resulting in degradation of coastal ecosystems and reduced tourist satisfaction. Sand mining makes the problem worse. Huge coastal developments of ports, jetties, river dams cut off flow of sand to feed beaches. Instead of spending millions on re-shoring beaches and artificially bulking up sand from elsewhere for tourism revenue and environmental impacts, some countries are relocating their cities inland. Indonesia is planning on moving their capital from Jakarta to Borneo to save its sinking city.
Sand mafias : India is infamous for sand mafias and illegal mining of sand to sell to the construction sector. Though sustainable sand management guidelines have been released with alternatives to sand tapping, rules are violated and private players and sand contractors continue to plunder river beds resulting in barren farms and huge economic losses.
What are our alternatives ?
Recycled and alternative materials : Waste by-products of other processes, for example, fly ash left over after waste incineration such as in municipal waste, waste foundry sand, stainless steel slag ,oil palm kernels, coconut shells, sawdust, waste plastic, waste rubber etc. are found as effective replacements for natural sand in construction.
Manufactured Sand + V7 Sand: Manufactured sand(M-sand) is sand produced by crushing quarry stones such as granite, sandstone, limestone etc. in a multi-step crushing process. Japanese equipment manufacturers innovated a technique called V7 dry sand making system that produces high quality sand product from crushed rock sand for ready-mix concrete. Reliability of V7 sand has made it a go-to substitute in infrastructure projects such as bridges, flyovers, and underground metro tunnels.
Green Concrete: Usage of natural resources such as coal bottom ash (CBA) which is a by-product of the coal fired thermal powered plants reduces temperature swings in buildings and conserves energy. Permeable pavements (sometimes called porous pavement) is one example of green infrastructure that replaces traditional concrete and asphalt and allows rainwater to be absorbed and infiltrated into soil rapidly, helping reduce urban flooding. Ever-expanding paved surfaces accompany ever-growing cities and with heavy rains, urban flooding is more severe as we saw in the Hyderabad floods in 2020 where clogged stormwater drains and land encroachments resulted in a deluge despite the city having around 2800 natural lakes for water discharge.
In conclusion: We cannot avoid the usage of sand and the sustainable alternatives outlined above cannot yet substitute the demand for sand in the world. While we look at sustainable sourcing and responsible mining, it is also important to reduce consumption such as avoiding surplus construction projects and demand in parallel. And not to forget, implementing strict marine, freshwater, and coastal zone management policies to preserve our vulnerable and endangered species such as sea turtles and pristine mangrove forests.