In March 2019, a group of fishermen from Bopitiya, a village north of Wattala, departed on a pilgrimage to the shrine of Our Lady of Madhu, in Mannar. Upon returning, they found a number of extensive sand pits in their fishing port.
Villagers noted that this was the third instance of covert sand mining they had experienced in the area.. This time the miners had extracted around 150-200 cubic metres of sand, exposing rocks along the coastline and obstructing the boats being taken out to sea.
Sand mining operations like this operate in numerous locations around Sri Lanka, such as the Deduru Oya, Malwathu Oya, and even the island’s largest river, the Mahaweli Ganga. But what is causing the demand for coastal and river sand mining, and what impact will it have on our environment?
What Is Driving This Trend?
As the world experiences rapid growth, the global construction industry is growing apace. As a result, the demand for, and price of, river sand—which is essential to the production of mortar and concrete—has also increased. “In Sri Lanka, in particular, demand has been rising since the early 1990s, and has taken a notable leap since the 2004 tsunami,” said Kiran Pereira, a researcher at the Water Integrity Network (WIN), a group of organisations working towards equitable and sustained access to water.
“[But even] aside from the post-2004 boom, there has been a steady growth of demand for river sand attributable to the growth of the economy and investments in several sectors following the end of the country’s civil war,” Pereira said, adding, “and much of the extraction is channelled towards the western regions around Colombo.”
Although there are many sources of sand, not all are of acceptable quality to be used in concrete “Some types of sand are suitable for human use as they are, some need to be treated before they can be used and others are not suitable for use in construction,” Pereira explained.
“For example, desert sand is unsuitable because the grains are too rounded and smoothed by the wind, and hence do not offer any cohesion and structural strength to concrete. Consequently, much of today’s sand supply comes from relatively limited sources.”
Therefore, in the construction industry in many developing economies, the most sought-after kind of sand is river sand, followed by coastal sand.
“In the reconstruction phase following the tsunami, when sand mining became most visible, the two rivers most affected were the Deduru Oya and the Maha Oya along the west coast,” Pereira said. “Traditional sand mining was replaced by mechanised dredging in order to meet the demand for additional sand required for reconstruction activities.”
According to the Global Water Partnership (GWP), it is estimated that more than 35 of the 103 rivers in Sri Lanka are subject to illicit river sand mining and that more than 50% of all sand used in the construction sector is sourced from unlawful operations. Additionally, a survey conducted by the Universities of Colombo and Ruhuna found that up to 10 times more sand is extracted than river sand mining permits even allow.
How Does Sand Mining Affect The Environment?
The impacts of sand mining can be grouped into three broad categories: physical, water quality, and ecological.
The large-scale extraction of streambed materials physically alters the river and its surrounding areas. The alteration of channel-bed form and shape leads to several impacts, such as erosion of channel bed and banks, increase in channel slope, and change in channel morphology. These impacts may cause the undercutting and collapse of river banks, increased flow velocity, and the loss of adjacent land and structures like buildings, bridges and roads. In Sri Lanka, the increasing use of mechanised extraction since the late 1990s has resulted in heavy localised turbidity, bank erosion, land degradation.
Additionally, river sand mining lowers water tables, which can decrease water levels in dug wells, sometimes leaving them completely dry. In the areas around the Deduru Oya, the groundwater table fell by 12-15 metres in some places, and up to 30 metres in others. This has grave implications for many Sri Lankans, especially those who are dependent on household cultivation.
Further, mining and dredging activities, poorly planned stockpiling, uncontrolled dumping of overburden (mined sand unsuitable for construction), and chemical/fuel spills will cause reduced water quality for downstream users, and poison aquatic life. According to a study conducted by the University of Colombo in the Nilwala River, sand mining can cause increased salinity further downstream, causing problems for paddy cultivation which does not survive in brackish waters.
And finally, all these processes, in addition to the clearance of vegetation, and stockpiling on the streambed, will have ecological impacts. These impacts may have an effect on the direct loss of stream reserve habitat, disturbances of species attached to streambed deposits, and reduced feeding opportunities.
What Can Be Done?
River sand mining in Sri Lanka is centrally regulated through the Geological Survey and Mines Bureau (GSMB), which had limited resources, until recently. This weak regulatory environment, in combination with a steep increase in the demand for sand due to rising prices, led to the development of illicit sand mining operations on a large scale.
Last year, the GSMB removed the requirement of a permit for transporting sand, clay, and gravel, citing the need to develop Sri Lanka’s construction industry. According to the GSMB, Sri Lanka’s largest construction raw material requirements are for the Colombo Port City projects, expressways, the southern railway line, the military headquarters and government offices in Battaramulla, irrigation and hydro projects, and residential apartments.
However, this deregulatory move has been criticised, as it can make it easier for illegal sand mining operations to sell their stock without the knowledge of the authorities. As environmentalist Jagath Gunawardena noted, “the transport license is linked to the mining license, and was the only way that the Police and the GSMB could monitor sand mining. Without this permit, the police won’t be able to tell if sand arriving at a construction site was mined illegally or not.”
The Sri Lanka Water Partnership (SLWP), a group of organisations committed to improving water resource management, initiated a campaign to combat the recent legislative changes with community action, as weak law enforcement mechanisms and legal loopholes meant that regulations alone were not enough to fully address the problem.
Their interventions included awareness campaigns and dialogues which engaged government officials at district and divisional level, local authorities, and the media.
An effective method to curb illegal river sand mining is to identify and develop viable alternatives to river sand. Offshore sand and manufactured sand are two options; however, they also have drawbacks. For example, although the cost of manufactured sand is lower per unit than river sand, the cost to transport manufactured sand is much higher as it must be moved to and from a central production location, and offshore sand may also have unforeseen environmental consequences.
Despite this, it is an ecologically better option than illegal sand mining, and SLWP — through one of their partner organisations, the Construction Industry Development Authority (CIDA) — has organised a series of workshops to raise awareness about these alternative sources.