Halda, one of the rare natural resources of the country, is said to be the only natural fish breeding grounds in South Asia. Sweet water fish spawn eggs in the ebb and flow of this river. This is a wonder of the world. Negligence is a threat to this rare resource.
There is a national propensity to grab all at once, to kill the goose for the golden egg, and this applies to the treatment of the river too.
Reckless experimentation has taken a heavy toll on Halda. There have been discussions about the predicament of the river. There has been protests. It has been raised in parliament. A movie has even been made about its plight. There has been concern about river training, rubber dams, indiscriminate approval of factories along the banks, allowing poultry farms, dumping municipal waste, transporting waste of power plants and so on.
In May there was heartening news of carp spawning the highest within 12 years.
The local administration removing illegal structures following the government's orders made headlines at the beginning of the year.
At that time, Manzoorul Kibria, zoologist at the Chittagong University, shared his anxiety with the media about the survival of the Halda fish eggs. He said, the industrial waste along with toxic chemicals from residential areas and hills were affecting Halda seriously.
Within a few months his fears proved true.
Excessive rainfall and onrush of water from the hills caused floods in Raozan, Fatikchhari and Hathazari. After the floodwater receded in many parts of the river over the last several days, dead fish and aquatic animals of different species floated to the surface.
The onrush was water from the hills and flash floods are nothing new for Halda. But the death of fish is new. Why is this happening this year? Last year an epidemic hit the fish and water birds of the haors and the mystery behind this has not been unravelled as yet. Monzoorul Kibria visited the Halda river site to investigate.
A team comprising members from Chittagong University and the environment department led by Monzoorul took water samples from 10 points of the river and they found an alarming state of water contamination.
Last two weeks' incessant rain and onrush of water from the hills caused toxic waste from factories and poultry farms to flow towards Halda through about 20 canals. These canals include one that was channeled towards the river by Chittagong Development Authority. The colour of the water has been changed so badly by this pollution in certain points, that it is hardly recognisable.
When contacted, Monzoorul Kibria this morning said, the oxygen level in Halda has dropped to less than 2mg per litre water which must be at least 5mg per litre for fish to survive.
He remarked that the contamination and the epidemic of the fish is the gravest disaster in the river's history. The scale of contamination is higher upstream than downstream. Residential and industrial waste of tanneries from Chattogram city's Oxygen area to Kulgaon area are mixing in a huge amount in the river.
The paper board factories constructed on the Hathazari road are also contributing to the waste. The waste has gathered in the low land of Hathazari and caused the dangerous contamination. It resulted in the death of different species fish in the feeder canals of Khandokia, Katakali and Madari.
From the estuary of Halda to the low land of Gorduara in Hathazari, and Raozan, dead fish are floating above the river water stretching 15 kilometres area. The locals said, initially small fish were found, but the ones found from Thursday are large in size. These fishes include Rui, Katla, Mrigal, Kalibaush as heavy as of 15kg too.
Few years ago, the contaminated furnace oil of a 1000 MW power plant was released in the rainwater which flowed through the feeder canals and contaminated Halda's sweet water. It was a time for fish spawning. A lot of fish egg collections were ruined.
As the news appeared in the media, the environment department was heard to fine the power plant authority one million taka. In 2015, furnace oil was spilled in the river again, as a train fell into a canal from a bridge collapse in Boalkhai, Chattogram.
Special measures should be taken to preserve Halda immediately. It should be declared as an ecologically critical area (ECA). Steps for the inclusion of Halda in the UNESCO world heritage site list must be strengthened.
* Gawher Nayeem Wahra is a relief and disaster management activist and teacher at Dhaka University. This piece has been rewritten in English by Nusrat Nowrin