The revenge of the rivers

The Kosi River that flows down from Nepal into India used to be called ‘The Sorrow of Bihar’ because of the floods that historically inundated large parts of the state during the monsoon.

Now, it is the Kosi’s tributary Rosi that has become the ‘The Sorrow of Nepal’. But unlike the Kosi, the floods last week on the Rosi had more to do with unregulated quarrying and sand-mining in its catchment and much less with heavy monsoon rains.

The Rosi is a small stream at its source below the eastern slope of Pulchoki, which at 2,763m is the highest peak on the rim of Kathmandu Valley. By the time it reaches Panauti, the mountains flanking the river are mutilated by numerous quarries that crush stones to feed the capital’s construction boom.  

On the other side of Pulchoki on the west is Lele, quarries have also scarred the mountains in the catchment of the Nakkhu Khola that flows into Lalitpur and joins the Bagmati River near Chobhar (see map).

The Pulchoki catchment received more than 800mm of rain on 27-28 September – half the annual average for Kathmandu Valley. There was no way the Rosi and the Nakkhu Rivers could handle such record-breaking rain.

But whereas after previous heavy monsoons, the water just spread into the floodplain, both the rivers are now constricted into narrow channels with new settlements, warehouses, poultry farms and garages along the banks.

Added to this, the quarries, sand and boulder mining in the upstream watershed have increased the velocity of the water, and added a heavy sediment load into the flood waters.

The main cause of the massive death and destruction in both the Nakkhu and Rosi valleys last week was because the rivers were forced to flow through narrow channels, and the debris-filled waters swept into the populated floodplains.

“After two days of heavy rain, the slopes with the open stone mining were saturated and they just melted,” recalls Purshottam Adhikari, chair of Ward 2 of Panauti Municipality where 23 people were killed.

Panauti is a 13th century Newar town situated in the fertile Rosi Valley, situated 40km east of Kathmandu. The Shiva temple at the tri-junction of the Rosi with Punyamati and the mythical Lilamati is where the Makar Mela is held in January every 12 years.

 It appears as if the holy rivers took revenge for the desecration of the natural environment. By Saturday morning 28 September, the turbid brown Rosi had ravaged the town, taking away an entire hospital, many homes, schools, temples, bridges, and crops.

“We had never such destruction before, we have not even been able to assess all the destruction,” says Dinesh Lama, chair of Panauti Municpality.

Shocked residents surveying the damage murmur that the gods must have been angered. They say the river has transformed their town’s topography. Said one: “This destruction is much worse than the 2015 earthquake.”