Sand-sucking machines taking away river dolphin home in Assam

Kishore Talukdar

Regulated manual mining of sand primarily for real estate growth is no threat to the last of the river dolphins in Assam. Sucking the sand out of the riverbed with monstrous machines is.

River Kulshi or Kolohi, the 210 km southern tributary of the Brahmaputra, was home of the gharial – a species of crocodile – less than 100 years ago. It is now the prime habitat of the shihu or freshwater dolphin (Platanista gangetica), India’s national and Assam’s state aquatic animal that figures in the Red List of International Union for Conservation of Nature (IUCN). The river has an estimated population of 33 freshwater dolphin.

An indicator species, the freshwater dolphin is to a river ecosystem what the tiger is to a forest ecosystem. Like the striped cat, this predatory aquatic mammal has been trying to evade poachers who hunt it for oil that is believed to cure rheumatism. Now, it is grappling with sand-sucking machines that are scraping the riverbed too fast for it to breed.

Kulshi originates in Meghalaya’s West Khasi Hill range at an elevation of 1900 metre and enters Assam at Ukiam after flowing down 100 km northward. Two other rivers – Umsiri and Drun – join it at Ukiam, which is called tribeni sangam (meeting point of three rivers) and Kulshi’s source point. After flowing 15 km downstream, Kulshi splits into two branches at the foothill of Kulshi Inspection Bungalow. The two branches cross NH37 at Kukurmara and Chhaygaon and reunite at Nagarbera before falling into Joljoli and finally into the Brahmaputra.

Kulshi is the lifeline of some 200 villages – as their primary source of water, fish and construction-grade sand. The pressure on the river is high because of its proximity to Guwahati, where real estate development is one of the highest among Indian cities. The demand makes sand miners plunder the riverbed without paying heed to the health of the river.

A nod from the Ministry of Environment and Forests was all that sand mining once needed. It became stricter in 2012 when the Supreme Court made environmental clearance from Union Government mandatory for mining minor minerals. There are two legal sand mining units or sand mahals (officially demarcated area for extraction) notified along the Kulshi under the provision of Assam Minor Mineral Concession Rule 2013. These are at Kukurmara and Amtola. 

The Kukurmara unit is permitted to extract 1.75 lakh cubic metres of sand from an 8-hectare stretch of the river for seven years. The specification for the Amtola unit is 10,000 cubic metres from a 4.5-hectare stretch. Mining is no threat at these units unlike unregulated extraction from other sand storage zones of the river. Worse, illegal sand mining there is done by machine.

According to Environment Impact Assessment Authority, sand has to be extracted manually. On an average, six miners can manually extract 10 cubic metres of sand in eight hours. By using a suction machine, two miners can take out double the volume within this timeframe.

Permission to mining units comes with a rider – they cannot do mechanical mining. But suction machines are extensively used in the interior stretch of the river. The consequences : formation of deep gorges in the riverbed, erosion of the banks (a miner named Pradip Rabha was recently buried alive by a mass of earth that came off the bank of river Batha flowing parallel to Kulshi) and, and as Former Professor of Zoology of GU Mrigrendra Mohan Goswami says, water turbidity that threatens the dolphins’ breeding behaviour. Besides, dolphins prefer the shallow stretches targeted by unscrupulous sand miners. A forest official told this reporter that he had seen dolphin migrating to Batha river during monsoon, a sub-tributary of Kulshi river.

“Sand extraction should be scientific and planned so that the depth of the river is maintained,” says ecologist Abani Kumar Bhagabati. But river ecology and riparian interest have been put in the backburner for commercial gains.

Illegal mining cannot thrive if there is official will to check it. In areas under the jurisdiction of Kulshi Forest Range, sand is transported daily with impunity. The onus is on the officials to sensitise the common people about the importance of the dolphin habitat.

The forest department did crack down on the sand ‘mafia’. It has seized 35 suction machines from various stand storage zones under Kamrup West Forest Division. It has also confiscated 80 illegal sand-laden trucks from March 2014 to July 2015. Diesel spillage from these trucks, usually parked in the riverbed for loading sand, threatens to suffocate the aquatic denizens including the dolphins. The Pollution Control Board of Assam has pointed this out.

Experts say sand is soul of a river. It provides stability to the river bed, and exploitative mining adversely impacts aquatic micro-organisms that are critical to soil structure and fertility. The sand also works as shock absorber against strong current during floods, and dictates the water holding capacity of a river.

According to IUCN, sand mining is mainly responsible for the dramatic near-extinction of the gharial in India. John Rowntree, the last British Conservator of Forest wrote in his book Memories of the Chotta Sahib about sighting a sizeable population of gharials in Kulshi. The reptile apparently migrated from Kulshi to the quake-created Chandubi Lake via a 2.5 km long channel called Lokiyajan. The last gharial in Chandubi was seen in 1977.

Chandubi, Chal and Beeldora three wetlands – all connected to the Kulshi – from where the dolphin gets its food. The dolphins frequent their confluence to feed on the fishes that move to and from the wetlands. The confluence of Chandubi is upstream of Beeldora, and dolphins move to the upper reaches during monsoon to meet its food requirement, usually 10 per cent of its body weight. The movement depends largely on the scale of sand mining activity along the river.

In 2014, three dolphin carcasses were spotted in the Kulshi. Though cause of death is not known one of them bore injury marks, indicative of poaching.

The mammal is fortunate to have residents of Kukurmara as friends. But there’s no safety elsewhere along the river, particularly from illegal sand mining. Concrete growth needs sand, but not at the cost of a river.

( Kishore Talukdar is an independent journalist based in Guwahati. His areas of interest include Development journalism and Environment journalism. He can be contacted at [email protected] )