Coastal erosion has significantly impacted the world’s coastlines. This article delves into the process of coastal erosion and how dredging is becoming an effective tool in battling this serious challenge.
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A Brief Overview of Coastal Erosion
Coastal erosion is the gradual wearing away or removal of rocks, soils, and sands along the coast, primarily attributed to rising sea levels, powerful wave activity, and occasional coastal flooding.
All coastlines are susceptible to erosion due to the influence of natural events like storms. However, the most destructive erosion occurs when storm surges coincide with high tides and are further compounded by the forceful impact of strong waves.
Harmful Impacts of Coastal Erosion
Around 45% of the global population is located in coastal areas. The escalating sea levels and the resultant coastal erosion, driven by the effects of climate change, pose a substantial and socio-economic threat to these areas.
Seawater encroaches on coastal land, causing coastal villages and the residents to move inland to the densely populated cities. This limits living space, causes significant harm to biodiversity, and disrupts the ecological balance, ultimately affecting people and the ecosystem.
Coastal erosion and its associated processes can disrupt shipping ports by hindering the ship's access to harbors and ports, potentially causing delays or altering the movement of goods. Such disruptions can significantly affect trade in regions particularly susceptible to erosion. With rapid climate changes, coastal erosion and the ensuing challenges are expected to escalate.
Dredging: A Front Runner Against Coastal Erosion
The preservation of coastal ecosystems demands meticulous planning and consideration. A strategic approach is necessary in mitigating coastal erosion and dredging plays a vital role in combating this serious issue. Dredging involves the extraction of sediments from the coastal areas or river beds to develop sustainable water routes.
Dredging is essential in beach nourishment projects. By moving sand from the sea to eroded shores, coastal engineers can restore beaches. This process provides an immediate solution for erosion and supports coastal ecosystems and tourism. This process is a natural defense against waves and storms, reducing the risk of further erosion and protecting coastal communities.
In addition to erosion control, dredging can serve as a means to revitalize natural habitats in coastal regions. Executing properly planned dredging procedures makes breathing new life into impaired or deteriorated habitats like salt marshes, seagrass beds, and mangrove forests possible.
These revived habitats are crucial in mitigating erosion by stabilizing the shoreline and serving as a protective zone during storms. Furthermore, thriving ecosystems enhance biodiversity, water quality, and the capture of carbon gases, rendering dredging a valuable instrument within comprehensive coastal management.
Dredging plays a vital role in maintaining the operational efficiency of navigable water routes, which are of utmost significance to coastal communities relying on marine transport. Eliminating sediment accumulation enables dredging to avert the blockage of shipping routes, ports, and harbors.
The unconstrained accessibility to these water routes streamlines trade and commercial activities and boosts disaster response and recovery initiatives. This highlights the critical role of dredging in upholding coastal regions' economic vitality and resilience.
Advancements in Coastal Dredging
The coastal dredging technology has also undergone several developments throughout the years. Recently, excavator-based pump attachments have been introduced for pumping sediments efficiently.
Remotely operated unmanned autonomous dredging platforms are being researched extensively with various famous companies investing in this platform. Auger Suction Dredges find application in various dredging scenarios involving liners like polyethylene, clay, concrete, or different plastic liners. These dredges are typically outfitted with wheels to ensure gentle dredging while retaining the capacity to disintegrate compacted substances.
Damen Shipyards has introduced two series of Trailing Suction Hopper Dredgers (TSHDs) that incorporate a range of innovations to enhance operational efficiency and sustainability. These new technologies elevate these vessels' safety, durability, and ease of maintenance to a higher standard.
Along with the Damen Trailing Suction Hopper Dredger (TSHD), data collection systems have also been incorporated with the latest technology. These systems analyze engine performance, fuel consumption, and navigational data, offering valuable predictive maintenance insights. They also provide data on dredge production and hopper contents, contributing to more efficient operation and maintenance.
Practical Cases of Dredging
The Sunshine Coast employed a method toward the end of the previous year to facilitate the future restoration of Maroochydore Beach. This technique involved importing sand from Moreton Bay and depositing it approximately 300 meters offshore.
The project utilized a process known as nearshore nourishment, wherein a dredging operation gathered sand from the Spitfire Channel and subsequently transported it to Maroochydore Beach for placement. This operation potentially employed two distinct techniques for the sand release.
One of the techniques entailed releasing the sand from the bottom of the barge, while the other method involved spraying the sand in a rainbow-shaped pattern into the water. These techniques were useful in significantly reducing the effects of coastal erosion.
Another major example is Plum Island, which is facing severe coastal erosion, and efforts to protect it involve adding 200,000 cubic yards of sand. The Army Corps of Engineers and H&L Contracting dredged a nine-foot-deep harbor channel. The project focuses on safeguarding the most critical sections of Plum Island's coastline.
Environmental Impacts of Dredging
Data from the Centre for Analytics within the UN Environment Program (UNEP) highlights the substantial effects of dredging on biodiversity and coastal communities. Given the challenges posed by rising sea levels and severe weather events like storms, coastal communities heavily depend on sand for constructing coastal defenses.
Dredging is a cause for concern due to its adverse effects on biodiversity, increased water cloudiness, and the noise disturbance it poses to marine mammals. Dredging and related actions directly disturb seabed communities and stir up potentially harmful sediments from the seafloor, dispersing contaminants. The need of the hour is to promote sustainable dredging practices to protect coastal habitats.
Coastal erosion, exacerbated by rising sea levels and powerful wave activity, poses a significant threat to coastal regions and the global population concentrated in these areas. This article has explored the efficacy of dredging as a strategic tool in mitigating the adverse impacts of coastal erosion. While dredging proves essential in beach nourishment projects, habitat revitalization, and maintenance of navigable water routes, it is crucial to acknowledge the environmental concerns associated with this practice.
The evolving technology in coastal dredging, exemplified by innovations like excavator-based pump attachments and data collection systems, reflects a commitment to enhancing operational efficiency and sustainability. Practical cases, such as the successful restoration of Maroochydore Beach and the protection efforts for Plum Island, underscore the tangible benefits of dredging in real-world scenarios.
However, it is imperative to address the environmental impacts of dredging on biodiversity and coastal communities, emphasizing the need for sustainable practices to safeguard coastal habitats in the face of ongoing climate challenges.
References and Further Reading
Allen, B., (2023). Sand dredged off Plum Island to prevent flooding; residents want long-term solution. [Online] Available at: https://www.bostonglobe.com/2023/01/01/metro/sand-dredged-off-plum-island-prevent-flooding-residents-want-long-term-solution/ [Accessed 9 October 2023].
Australian Government Geoscience Australia, (2023). Coastal erosion. [Online] Available at: https://www.ga.gov.au/education/natural-hazards/coastal-erosion [Accessed 07 October 2023].
Coherty, A., (2021). The Effects of Coastal Erosion. [Online] Available at: https://seasidesustainability.org/post/the-effects-of-coastal-erosion [Accessed 03 October 2023].
Damen, (2023). The most cost-efficient dredging solution. [Online] Available at: https://www.damen.com/vessels/dredging-and-dredging-equipment/trailing-suction-hopper-dredgers [Accessed 7 October 2023].
GeoForm, (2022). Dredging 101: What It Is, How It Works, Benefits & More. [Online] Available at: https://geoforminternational.com/sediment-removal-101/ [Accessed 08 October 2023].
Jones, F., (2023). UN warns against the environmental impact of sand dredging. [Online] Available at: https://www.mining-technology.com/news/un-environmental-impact-sand-dredging/?cf-view [Accessed 9 October 2023].
Nicholls, R. J., (2022). Coastal erosion is unstoppable – so how do we live with it?. [Online] Available at: https://www.preventionweb.net/news/coastal-erosion-unstoppable-so-how-do-we-live-it [Accessed 6 October 2023].
Reiff, N., (2022). The Economic Impact of Coastal Erosion. [Online] Available at: https://www.investopedia.com/the-economic-impact-of-coastal-erosion-5220483 [Accessed 03 October 2023].
Todesco, R., (2022). Dredging up a solution for the future of Maroochydore Beach. [Online] Available at: https://www.pumpindustry.com.au/dredging-up-a-solution-for-the-future-of-maroochydore-beach/ [Accessed 8 October 2023].
U.S. Climate Resilience Toolkit, (2023). Coastal Erosion. [Online] Available at: https://toolkit.climate.gov/topics/coastal-flood-risk/coastal-erosion [Accessed 6 October 2023].
Weeda, S., (2022). Combined innovations improve dredging efficiency. [Online] Available at: https://www.dredgingtoday.com/2022/05/10/combined-innovations-improve-dredging-efficiency/ [Accessed 7 October 2023].
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