- This article highlights the importance of dredging in India.
- It talked about Maintenance and Capital dredging.
- How can the UDA framework help with the issues faced in dredging?
- How can the UDA framework help with the issues faced in dredging?
What is Dredging, and why is it important?
Dredging is the underwater excavation or removal of sediments, rocks, and other materials from the bottom of waterways, harbours, and other aquatic environments. It involves using specialized equipment and machinery to dig up and remove accumulated sediment and debris from the floor of water bodies. This process helps maintain proper depths for safe navigation of ships and boats, prevents flooding by removing obstructions from channels and rivers, and enables new coastal development projects.
Dredging is critical to India’s economic growth and environmental management since it serves its enormous network of ports and waterways. With over 7,500 kilometres of coastline and several rivers, dredging is critical to ensure the efficient operation of India’s maritime infrastructure. In financial terms, dredging can be quite costly. The Dredging Corporation of India (DCI), a key player in the country’s dredging industry, has reported significant expenditures on various projects.
Dredging projects are normally classified into capital, maintenance and remedial dredging. India primarily undertakes two distinct forms of dredging: (1) maintenance dredging and (2) capital dredging, each serving specific purposes and addressing unique challenges.
Maintenance Dredging
Maintenance dredging is a process that aims to remove the accumulated silt, sand, and other deposits that gradually build up over time in navigational channels, ports and harbours. Considering a tropical region like India, we can expect higher sedimentation rates due to various conditions such as high rainfall, river discharge and coastal erosion.
To employ these sediments for operations like beach replenishment and land reclamation, they are dredged and dumped in authorized offshore and onshore places. In India, ports like Jawaharlal Nehru Port (Nhava Sheva), Mumbai Port, and Chennai Port usually undertake maintenance dredging every year due to high sedimentation rates and heavy traffic.
Maintenance dredging has both immediate and long-term impacts. In the short term, changes in turbidity significantly affect water quality during dredging operations. The increase in turbidity disrupts the local benthic environment. Long-term effects arise from fine suspended solids that take longer to settle, leading to prolonged elevated turbidity levels at greater depths. This persistent turbidity can adversely impact the local aquatic ecosystem. Once a dredging operation has been completed, maintaining the site or port is essential to ensure that the initial investment remains intact and functions as planned.
Furthermore, maintenance dredging is crucial for the economic sustainability of ports and coastal communities. By keeping channels and berthing areas clear, ports can accommodate larger vessels, essential for global trade. This prevents delays and reduces shipping costs, making ports more competitive. Additionally, reusing dredged materials for coastal protection and development projects can help mitigate the effects of coastal erosion and provide new land for infrastructure and development. In densely populated and economically significant coastal regions like India, efficient maintenance dredging supports ongoing maritime activities and fosters regional development, ensuring long-term economic growth and stability.
What is Capital Dredging?
Dredging, carried out in a new location and in material that has never been dredged before, is referred to as a capital project. For example, land reclamation for airport platforms and artificial islands, new port development, deepening and enlarging access channels, berthing areas, docks, and turning basins are all permanent necessities to meet the demands of growing trade and economy. In the case of capital or new work dredging, it is most likely that the work will be done by contract. Dredging equipment involves expensive capital plant investment, specially trained operators and logistical support, and experienced project managers. This fact makes it particularly suitable for performance by contractors equipped and staffed to accomplish such work and with proven expertise.
Capital dredging plays a crucial role in developing infrastructure and the economy by enabling the creation and expansion of vital maritime facilities. For instance, constructing new ports and deepening existing access channels facilitate increased cargo traffic and accommodate larger vessels, thereby boosting trade and economic activities. This is essential for countries relying heavily on maritime transport to import and export goods. Additionally, capital dredging supports the development of strategic infrastructures such as artificial islands and airport platforms like Kansai International Airport, which are pivotal in regions with limited land space. These projects provide new commercial and industrial opportunities, enhance connectivity, and support tourism, contributing significantly to economic growth. Moreover, by creating deeper berthing areas and turning basins, capital dredging ensures the safety and efficiency of maritime operations, reducing congestion and lowering operational costs for shipping companies. The strategic implementation of capital dredging projects is a foundation for sustainable economic development, fostering growth in trade, tourism, and other related industries.
Environmental impact assessment
Since capital dredging takes place in virgin soil, it is necessary to do an environmental impact assessment to determine the effects on the benthic ecosystem precisely. Consider the instance of capital dredging in Australia’s Gladstone Harbour, which resulted in extremely high turbidity levels and threatened the Great Barrier Reef.
Comparisons and Considerations Between Capital and Maintenance Dredging
The key differences between capital and maintenance dredging lie in their objectives, scale, and environmental impacts. Project-owned and operated dredgers sometimes carry out maintenance work, but this practice is generally being phased out as more work is awarded to contractors. Government-owned and operated dredging fleets have been phased out in many maritime nations. For example, most maintenance work in India is carried out by the Dredging Corporation of India (DCI), a public sector company. Capital dredging projects, which require complex planning and equipment, are often undertaken by private contractors with specialized expertise and advanced technology. These contractors are responsible for executing the dredging operations, ensuring compliance with environmental regulations, and managing the logistical challenges associated with large-scale projects.
There are many guidelines and formalities that should be carried out before deploying the dredgers. This is referred to as the planning phase. Because dredging has a substantial environmental impact, a complete Environment Impact Assessment (EIA) report should be prepared before starting a dredging project to detect potential consequences and eliminate uncertainty about the magnitude of such impacts. Surveys are undertaken during maintenance dredging to determine sedimentation rates and locations that need to be dredged. Sediment samples are also analysed to determine their composition, which aids in selecting and implementing dredging units. In capital dredging, stakeholder engagement is critical. Before beginning any project, it is recommended that you host a public hearing and solicit feedback from local communities, environmental groups, and other stakeholders. Because this is a one-time investment, a detailed knowledge of the trade-off between economic rewards and drawbacks resulting from dredging’s substantial impact on the local benthic ecosystem is required.
How can the UDA framework help in this issue?
The planning process for dredging is essential to ensure the project is successful and environmentally friendly. Good planning includes carefully studying the dredging site to choose the right equipment and methods. It also involves checking the environmental impact to prevent local wildlife and ecosystem harm. Engaging with stakeholders, such as local communities and government agencies, is crucial to address concerns, obtain necessary permits, and gain support for the project. Effective planning helps to manage unexpected issues, keeping the project on track and within budget. Overall, thorough planning reduces risks, improves efficiency, and balances environmental, economic, and social needs.
Depending on the scenario, the dredging process can have multiple requirements, such as analysing sediments to determine the appropriate equipment, monitoring local aquatic life, and identifying stakeholders.
In conclusion, integrating the UDA framework with the planning and deployment phases of dredging will address several key issues, enhance efficiency, and promote a more sustainable approach to dredging operations.
Arulanandan S (IIT Kharagpur), MRC Intern 2024
About Author
Arulanandan S is a final-year student pursuing a B.Tech in Electrical Engineering at IIT Kharagpur and works as an Intern at the Maritime Research Center.