The dredging sector plays a critical role in maintaining and expanding port infrastructure, ensuring that ports can accommodate larger vessels, enhance navigability and improve overall operational efficiency. Dredging involves the removal of sediments and debris from the bottom of waterways, which is vital for maintaining channel depth and width. At Cochin Port, regular dredging keeps the Ernakulam (260 m width, 13.25 m depth) and Mattancherry (183 m wide, 9.75 m deep) channels navigable. The 16 km long outer channel, dredged to 260 m wide and 14.5 m deep, accommodates larger vessels. The port also houses key terminals such as the international container transshipment terminal (ICTT) at Vallarpadam, along with Indian Oil Corporation Limited (IOCL) and Bharat Petroleum Corporation Limited terminals (BPCL), all of which depend on ongoing dredging to maintain efficient operations. At a recent India Infrastructure conference, Jassar S.M., Chief Engineer, Cochin Port Authority, discussed key capital and maintenance dredging projects at Cochin port, the challenges faced and upcoming dredging requirements. Edited excerpts…
Recent dredging projects
One of the most significant dredging initiatives at Cochin Port is the annual maintenance dredging of its channels and basins. This long-term activity remains a critical part of port operations. The most recent contract, valued at Rs 1.57 billion, was awarded to Dredging Corporation of India Limited, for dredging a quantity of 24 million cubic metres (mcum) over a one-year period. Similar contracts have been executed consistently in the past, and this effort is expected to continue in the future.
Another major dredging initiative at Cochin Port was the capital dredging for the North naval jetty, undertaken for the Indian Navy. The contract was awarded to Ultra Dimensions Private Limited at an approximate value of Rs 500 million, with a dredging quantity of around 1 mcum.
Another key project was the capital dredging for the multi-user liquid terminal jetty basin, undertaken as a deposit work for IOCL. This contract, valued at Rs 650 million, was executed by Rock and Reef Dredging Private Limited (RRDPL) for a dredging quantity of 1.56 mcum. RRDPL also carried out capital dredging for the Indian Coast Guard (ICG) jetty basin, a deposit work for the ICG, at a contract value of Rs 374 million for a dredging volume of 0.44 mcum.
In addition to these projects, routine dredging works below Rs 100 million are regularly being carried out. The port also operates its own dredger, Nehru Shatabdi, for smaller-scale operations.
Over the past decade, annual maintenance dredging contracts at Cochin Port have typically ranged between Rs 1 billion and Rs 1.5 billion. In the past three years (2022-23 to 2024-25), values have consistently exceeded Rs 1.3 billion. With the proposed increase in draught to 16 m, annual contract values are expected to rise further to Rs 1.5 billion-Rs 2 billion, with dredging volumes likely surpassing the current average of around 24 mcum.
Key issues and challenges
Seabed conditions
One of the primary challenges in dredging operations at Cochin Port, particularly around Willingdon Island, arises from the island’s artificial nature. The seabed material in this area consists of 90-95 per cent silt, which has no productive or commercial use. This limits options for reuse and significantly increases disposal challenges.
Another major issue is related to suspended particles in the dredged material. Measurements taken at different frequencies often show a variation of 1-1.5 m, creating inconsistencies in depth assessment. This makes it difficult to maintain the required draught levels and hampers smooth vessel navigation.
Siltation patterns further add to the challenge. Heavy monsoons in Kerala cause significant fluctuations in siltation rates, but no clear pattern has been established. This makes it difficult to accurately estimate dredging volumes and plan operations in advance.
Other operational challenges
The outer channel presents a significant operational challenge for Cochin Port. Extending into open seas, it makes Cochin one of the few Indian ports that require regular dredging in the outer sea. This renders maintenance dredging both essential and expensive, accounting for 20-25 per cent of the port’s annual budget, while also limiting the possibility of diverting dredgers to other seas.
The monsoon season adds further complexity. Surveying in the outer channel becomes highly unreliable due to weather and sea conditions. This often leads to contractual challenges, as verifying dredged quantities and maintaining proper documentation becomes difficult under such conditions.
Mitigation measures and expectations from contractors
To address dredging challenges, Cochin Port is adopting a combination of technological upgrades and cost-efficient strategies. One key approach is the shift towards need-based dredging, where required depths are provided based on confirmed vessel arrivals. However, this becomes challenging in cases of unscheduled vessel calls, where adequate draught may not be available at short notice.
Reuse of dredged materials remains limited. While efforts are also being made to sell dredged sand, only a small portion is suitable for commercial use or landfilling. The bulk of the dredged material, particularly from maintenance dredging, consists of high silt content and is disposed of in the outer sea. Although the Maritime India Vision 2030 emphasises the reuse of dredged material for beach nourishment, studies have shown that the dredged silt is unsuitable for such purposes. This creates a challenge in communicating the limitation to stakeholders, especially given the consistently high volumes of dredging undertaken at the port.
Long-term strategies are also being explored. These include identifying alternative locations for container terminals to improve operational efficiency and reduce dredging requirements in the future.
Furthermore, contractors should possess strong technical expertise and the ability to handle complex operational challenges of the port environment. Given the narrow channels, the efficient manoeuvrability of dredgers is crucial, especially when equipment malfunctions. Contractors are expected to deploy state-of-the-art dredging equipment capable of delivering the required draught on time. Accurate and timely hydrographic surveys, even during the monsoon season, are essential to avoid contractual and legal issues. Additionally, contractors should ensure the proper disposal of dredged material and explore the feasibility of its reuse, including for beach nourishment wherever possible.
Upcoming dredging requirements and projects
Cochin Port has consistently undertaken annual maintenance dredging to ensure safe navigability across its channels. This effort continued in the current year and is expected to remain essential in the coming years due to natural siltation and operational requirements.
Capital dredging projects form a key part of the port’s future expansion plans. A major focus is on the deepening of the approach channels at the ICTT, Vallarpadam. Commissioned in 2011, as one of India’s first transshipment terminals, ICTT’s growth has been limited due to draught restrictions. Plans are now under way to increase the draught to 16 m, enabling it to handle larger vessels and enhance transshipment operations. The Ministry of Ports, Shipping and Waterways (MoPSW) has agreed to consider the case positively, and the detailed project report (DPR) is under preparation. The public-private partnership operator is expected to invest around Rs 20 billion (Rs 13.5 billion for capacity augmentation and Rs 6.5 billion for equipment replacement), while the Cochin Port Authority will invest approximately Rs 4.75 billion, specifically for the capital dredging component, involving an estimated 25 mcum of dredging work.
The development of an outer harbour is also under consideration to reduce recurring maintenance dredging and enable long-term expansion. First conceived in 2011, the project was supported by a DPR in 2017, which proposed the reclamation of around 3,000 acres but was deemed unviable at Rs 250 billion. To address these concerns, a revised DPR was prepared in 2025. This new plan proposed constructing the outer harbour more than
10 km offshore, using reclaimed material from the seabed. Despite the innovative approach, the revised cost estimate of Rs 550 billion was again found to be financially prohibitive. The port is currently exploring more economically viable alternatives, and in a recent meeting, the Minister of State for Ports, Shipping and Waterways is positive in considering the case, subject to a detailed viability assessment.
Cochin Port is also playing a key role in supporting the infrastructure development of island territories, having signed MoUs with both the Lakshadweep and Andaman administrations. In Lakshadweep, two jetty projects, each valued at around Rs 3 billion, have already identified the lowest bidders and are close to contract finalisation. Further, the port has been directed to develop full-fledged jetties across all 10 inhabited islands in the Lakshadweep group. For the next phase of this project, DPRs for jetty development in Andrott, Chetlat and Kiltan islands have been submitted to the MoPSW, and approval is expected during 2025-26.
