Is it possible to artificially narrow the Jamuna River?
The Business Standard spoke to Bangladesh Water Development Board engineers and independent experts to gauge the effectiveness and outcomes of a technology to be used on the Jamuna River
Last week, a news headline about the Jamuna River caught the attention of conscious readers, especially environmental conservationists.
The lead news of a Bangla daily stated that the Bangladesh Water Development Board (BWDB) is planning to narrow the width of Jamuna from 15km to 6.5km, applying a 'new' technology called Top Blocked Permeable Groyne (TBPG) in Bangladesh, 'without' a feasibility study.
The news report, clearly eyebrow-raising, sourced the information from a 6 February meeting minutes of the Planning Commission where BWDB's development project proforma (DPP) was discussed. Quoting BWDB officials, the report said the World Bank-funded project would be designed to protect river banks while reclaiming land.
We know that the Jamuna is a comparatively new stream formed at Chilmari, from the Old Brahmaputra north of Bangladesh, less than 200 years ago. It flows as a braided river carrying numerous sandbars and shoals inside.
On average, the width of Jamuna, the country's most erosion-prone river, is 15-20km. During the dry season, the sandbars pop up, creating several channels within the river boundary. In the monsoon, almost all the sandbars get submerged.
As such, a question popped up in curious minds: is narrowing the Jamuna really possible?
The Business Standard (TBS) reached out to the BWDB engineers who drafted the DPP, who said narrowing the Jamuna's width to 6.5km was not their actual statement, and neither had it been inscribed in the DPP.
They said the Jamuna River is one of the most dynamic rivers in the world, and thus, tackling its flooding/ erosion to protect the economic life along the river bank requires a multi-sector multi-phased approach. The overall approach of the programme is to leave "room for the river" and apply "dynamic navigation."
Although BWDB did not directly speak about narrowing the Jamuna, the officials said the DPP includes a budget for drafting a River Master Plan which will examine whether the Jamuna River can be slimmed down or not, and what width can be achievable by 'river training.'
Local and internationally recognised experts will take part in the master planning, BWDB officials hinted.
The DPP was a part of facilitating the Jamuna River Economic Corridor Development Programme (JRECDP), which has several components, including a Tk383 crore piloting of TBPG.
This particular river training mechanism - the TBPG - is not new in the country, as mentioned in the Bangla daily. However, TBPG's effectiveness is an issue that is up for debate.
River water's stream velocity differs according to height of the water level. The water adjacent to the riverbed has lower velocity while the top level of water flows with high velocity. As the Jamuna water carries huge amounts of silt, the deeper water carries high sediment, while the surface water carries lowest sediment.
An official of BWDB, preferring to be anonymous, said, "The objective of the piloting is to divert the low silt carrying high velocity water to another direction, through TBPG. This structural intervention will accelerate sediment deposition at its downstream, and facilitate some land reclamation along the river bank. It will also protect the river bank."
According to the DPP, the TBPG will be implemented only at two channels of Jamuna, crossing Phulchhari of Gaibandha and Kalihati of Tangail.
The official added that this piloting will assist them in testing the effectiveness of TBPG for the Jamuna.
The BWDB's DPP followed two feasibility studies: morphological and hydrological study by a Canada-based consultancy firm Ahydtech Geopmorphic and the Environmental and Social Impact Assessment prepared by Center for Environmental and Geographic Information Services (CEGIS) – a Water Resource Ministry wing engaged by the World Bank.
So, the Bangla daily's claim of 'no feasibility studies' can be dismissed. But still, some independent experts have expressed their concerns about the project.
The CEGIS study mentions that groynes of TBPG are structures – made of stone, gravel, rock, earth or pile – stretching from the riverbank into the river, to divert the water flow from the critical zones of the bank and protect it from the erosive action of the river. Also, the groynes are used to 'constrict' the width of the river so that the river's navigability improves.
While assessing the potential impacts of the project, the CEGIS study states, "The proposed groyne would ultimately increase sedimentation processes along the protected bank, and
gradually contract the river width at the site by reclaiming lands."
The JRECDP is a 'Red Category' project, the highest category as per Bangladesh's Environmental Conservation Rules 1997.
According to the CEGIS study, the impacts and risks during the pre-construction and construction phases of JRECDP, including the piloting of TBPG, are mostly related to land acquisition and resettlement, labour influx and pollution. Among the construction activities, the pile driving for TBPG would cause increased noise levels, the lowest 44.88 dB at 2km from the source.
The environmental and social impact assessment also says, "The operation phase impacts are mostly related to the change of river course or planform, following the installation of TBPG and dredging. Generally, bank protection works to shift the erosion risk downstream."
Against the flow
Former Director General of the River Research Institute and the Water Resources Planning Organisation (WARPO), M Inamul Haque opposed the BWDB officials' claim that this project is not intended to narrow the Jamuna.
"All the feasibility studies the BWDB engineers suggest otherwise," he said.
Inamul believes that the width of Jamuna must be left as it is, because it is necessary to carry the monsoon-time overflow from upstream that is directly connected to the transboundary Teesta.
"River training like TBPG along the Jamuna has continued since the 1990s, following the Flood Action Plan. Very few of the projects lasted. So, a new TBPG will be nothing but a futile exercise," Inamul said.
Renowned water expert Professor Ainun Nishat is also skeptical about the sustainability of the groynes on the Jamuna.
"I am not against river training. The only thing I expect is sustainability. There are many shoals in the Jamuna which are now human habitats. If a river training attempt accelerates erosion downstream, consideration of human habitats must be a top priority," Nishat said.