Dredging is an important element of fairway development, which is important for developing inland water transport (IWT). Besides dredging, fairway development involves river conservancy works, bandalling, channel marking, etc.
Cargo traffic on national waterways (NWs) increased from 30.4 million tonnes per annum (mtpa) in 2014-15 to 72.31 mtpa in 2018-19. At present, the Inland Waterways Authority of India (IWAI) is implementing the ambitious Jal Marg Vikas Project (JMVP) for navigational capacity augmentation on the Haldia-Varanasi stretch of NW-1. It envisages construction of three multimodal terminals, two intermodal terminals and a new navigational lock, and fairway development, river information system (RIS) deployment, and roll-on, roll-off terminals by December 2022.
A pilot study has been conducted near Nakhwa village on the Ganga river by the Indian Institute of Technology Roorkee to understand the impact of using a reinforced cement concrete jack jetty with bamboo submerged vanes as a means of controlling erosion in rivers. The pilot study was successful as it nearly choked the secondary left channel diverting water flow to the navigation channel along the right bank, and arrested erosion on the right bank. The transformed channel processes resulted in developing and sustaining the desired inland navigation waterway along the right bank as evidenced from satellite imagery as well as topographical surveys.
With the encouraging outcome of the pilot study, IWAI has identified 60 locations on the Ganga river to deploy the same technique. It plans to take up eight locations for stabilisation of channels instead of dredging in 2019-20. IWAI is trying to manage 50 per cent of the dredging requirement by bamboo bandalling.
IWAI also aims to keep dredging volumes low and save costs on those stretches where larger vessels cannot move in a sustainable manner. It plans to use the funds saved to subsidise private vessel manufacturers to build lower capacity vessels with low draughts. Further, the authority has drawn up agreements with state governments to dispose of dredged material on riverbanks or farmers’ lands. The district administration also auctions the dredged material and the proceeds go to the state treasury. However, there are numerous challenges faced in fairway development. There is inadequate draught availability for navigational works in most Indian rivers. Many rivers have braided channels and short radius bends, making dredging operations difficult. The existing structures across the waterways – navigational locks, dams, barrages etc. – further restrict operations. Moreover, there is an absence of automated information systems (RIS and vessel traffic management). Despite these issues, the IWT segment offers substantial opportunities for dredging.
Based on a presentation by Sanjay Kumar Gangwar, Member, Technical, IWAI, at a recent India Infrastructure conference