Vietnam Is Dumping 100 Million Cubic Meters of Material Into the Sea to Build a Massive Megacity

Across the construction site, convoys of trucks move in a continuous stream, hauling soil and rock while bulldozers spread each layer of material, pushing the boundary between land and water farther and farther outward. At the most distant reclamation fronts, the material must travel more than 10 kilometers before reaching the dumping area, gradually creating the foundation for a future city designed to accommodate more than 300,000 residents. But covering the water is only the first step. Beneath those layers of soil and rock lies soft marine sediment, where the ground could continue to sink under the immense weight of roads and high-rise buildings. So how do engineers strengthen the seabed, control settlement, and build an entire city on top of it? Let's explore it with Mandarin Tech in this video. The history of land reclamation has seen the Dutch build massive dikes, Dubai use 94 million cubic meters of sand to create Palm Island, and Singapore expand its national territory by around 30%. Ha Long Shan follows the same logic, transforming the coastal waters of Quang Ninh into new land for a vast future metropolis. Located along the Quang Ninh-Hai-Phong Hanoi Economic Corridor, this megaproject demands an enormous amount of space to accommodate a planned depot and a high-speed railway designed for speeds of up to 350 kilometers per hour. With coastal land increasingly scarce, the project has pushed directly into the sea to create enough room for a continuous urban district filled with boulevards, bridges, and large-scale service infrastructure. That decision has triggered a massive logistics campaign. Fleets of dump trucks, dredging vessels, and excavators operate like an endless production line. By placing more than 100 million cubic meters of material into deeper waters, an amount equivalent to the volume of around 40 Great Pyramids of Giza, load after load is turning open water into solid ground, steadily pushing the coastline farther out toward the sea. At the outermost reclamation front, dump trucks line up near the water's edge, raise their beds and unload one load of soil and rock after another. Excavators immediately pull the material into position, while bulldozers spread it into layers, creating enough new ground for the next convoy of trucks to move forward. But simply dumping material into the water would not be enough. Waves and currents could destabilize the edge of the newly formed ground. That is why perimeter dikes and revetment lines are built alongside the reclamation process, gradually enclosing construction cells, keeping the fill material within the designated boundaries, and defining the edge of the new land. The ground created today immediately becomes the temporary access road for tomorrow. Trucks advance another few dozen meters, unload another layer, bulldozers extend the working platform, and the cycle begins again. The farther the reclamation moves offshore, the longer the haul route becomes. At certain stages, soil and rock must travel more than 10 kilometers from the mainland before reaching the active construction front. At Huangtan, on-site footage once showed the newly reclaimed land coming within just over 10 meters of Bridge No. 4. The final stretch of water was then filled in, allowing the main embankment to connect directly to the bridge standing offshore. From the perspective of a single truckload, the change is almost imperceptible. But when the same cycle is repeated thousands of times, the water surface begins to disappear, and an entirely new coastline starts to emerge. At some construction zones, more than a dozen dredging vessels have been recorded operating at the same time, connected to floating pipelines stretching across the water. Think of them as giant industrial vacuum cleaners for the seabed. Soft mud and water are sucked up together into a fluid mixture known as slurry. Instead of lifting the material bucket by bucket onto barges, and then transporting it by truck, powerful pumps can push this mixture continuously through pipelines toward pre-enclosed areas onshore. But what comes out of the pipe is still far from being construction-ready material. It contains too much water and has almost no load-bearing capacity. The slurry is therefore retained inside containment cells, allowing the solid particles to settle while excess water gradually drains away, and the remaining sediment continues to dry. On-site footage shows that some of the dredged material is placed in drying areas and later reused for reclamation work, rather than being transported entirely to another location. This is what makes dredging such a unique part of the process. A single operation can both remove weak material from areas that need to be developed and generate a stream of material that may later be reused in the reclamation platform if it meets the required standards. According to observations from a person filming at the site, one dredging unit was estimated to handle a volume of material equivalent to more than 40 truckloads per day. This is not an official technical specification, but it helps illustrate why pipeline transport can replace a substantial amount of conventional truck hauling in certain parts of the project. After millions of cubic meters of fill are placed, the reclaimed ground becomes firm enough for heavy machinery, but deeper layers of soft, water-rich soil can still settle under long-term loads. Instead of waiting years for this to happen naturally, engineers use prefabricated vertical drains to speed up consolidation. These thin drains do not carry structural loads. They create short escape paths for trapped water. According to the FHWA, horizontal water flow in some layered soils can be up to 10 times faster than vertical flow. The impact can be significant. In one FHWA example, reaching 90% consolidation took 432 days naturally, but only 50 days with vertical drains. Engineers also place heavy surcharge fill on top, squeezing water from the soil and compressing the weak layers below. Settlement is continuously monitored until movement slows to an acceptable level. In simple terms, the ground is forced to undergo most of its settlement before roads, buildings and other heavy structures are built above it. At the Bridge No. 3 construction area, between 20 and 30 board pile drilling rigs have been recorded operating alongside multiple cranes and heavy lifting machines. Each pile begins with a steel casing being lowered into position. The drilling rig then bores down through the soft soil and sediment, continuously removing material until the required depth is reached. Next, a crane lifts a long reinforcement cage into a vertical position and slowly lowers it into the borehole. A tremie pipe is then placed near the bottom, allowing fresh concrete to flow in from below and rise upward, fully surrounding the steel cage to form a reinforced concrete pile deep beneath the ground. Multiple piles are connected by a pile cap. From there, the bridge pier rises above the water, the pier cap is completed and bridge girders are lifted into place one by one. Span after span is added until the construction areas, once separated by water, become part of a continuous transport route. As soon as a section of the bridge becomes usable, trucks and construction equipment can cross the water and carry materials to more distant reclamation fronts. In this way, every completed bridge span does more than extend the road network. It also allows the construction zone itself to advance farther out to sea. Beneath the roads of Ha Long Shan lies an underground utility network designed to handle two completely different water flows at the same time, stormwater from the surface and wastewater from the urban area. For stormwater, the challenge is not simply to drain water as quickly as possible. The system must also deal with tidal pressure from the sea. Rainwater is collected through drainage inlets, carried through pipes and channels, and then discharged through tidal control gates. When sea levels rise, these gates help prevent seawater from flowing back into the internal drainage network. Domestic wastewater is separated into an independent system and transported to centralized treatment plants. According to the project's environmental documents, Ha Long Shan is planned to include 10 wastewater treatment plants with a combined capacity of 113,600 cubic meters per day. After treatment, water quality must be monitored automatically and continuously before discharge into the environment. To install this network, excavators open trenches to the required elevations, cranes lower pipes and prefabricated components into position, and connection points must be completed before the ground is closed again. Water supply, electricity and telecommunications lines are also installed beneath the roads in a coordinated layout before backfilling begins. Once the underground utilities are completed, the trenches are refilled in layers and carefully compacted. If the backfill is not dense enough, the road surface above can later sink along the same trenches that were excavated. Once the underground infrastructure is completed, the first major roads begin to define the structure of the future city. Some primary boulevards are planned to be up to 60 meters wide. At this scale, the road cross section can accommodate multiple traffic lanes, central medians, sidewalks and large landscaped areas, forming the main transport framework for the urban districts behind them. The scale of construction above ground is even greater. Zone B alone is planned to contain nearly 49.5 million square meters of total floor area. This includes 38,952 low-rise residential buildings of up to five stories, as well as 82 high-rise buildings containing 6,344 apartments with maximum heights of 20 stories. These figures show that Ha Long Shan is not being developed as a single residential neighborhood. Zone B alone includes tens of thousands of buildings of different types and heights spread across an area large enough to form distinct residential, commercial and service districts. At the scale of the entire project, land that was once covered by water will eventually support tens of millions of square meters of construction. Wide boulevards divide the site into large urban blocks. While inside them, thousands of low-rise housing rows are mixed with clusters of taller buildings. This is the stage where reclaimed land truly begins to become a city. Not simply a platform for construction, but a complete urban environment with streets, neighborhoods and tens of millions of square meters of usable space. Land reclamation allows Ha Long Shan to create a large, continuous land reserve instead of expanding the city piece by piece along the existing coastline. This advantage supports not only housing development, but also creates space for commercial, tourism and service activities. Kwong Nin already attracts large numbers of visitors, thanks to Ha Long Bay and its network of coastal destinations. As a result, a new urban area here could serve demand for accommodation, entertainment, shopping and other services, alongside the everyday needs of local residents. According to the master plan, Ha Long Shan is expected to include more than 55,000 units. For a development of this scale to operate effectively, it must attract not only homebuyers, but also businesses, workers and visitors who use its urban services. That is why transport connectivity becomes a critical part of the project. A railway line with its terminal station and depot at Ha Long Shan is planned to cut travel time from Hanoi to just 23 minutes. If completed as planned, the line could give the urban area access to a much larger population, labor and tourism market, while strengthening connections with major economic centers across northern Vietnam. In essence, the project is turning a massive reclamation investment into developable land capable of generating long-term revenue from housing, commerce, services and tourism. However, infrastructure and planning only create the initial conditions. The real value of this newly created land will depend on whether the development can attract enough residents, businesses and economic activity to sustain a city on the scale being proposed. Vengroup's project demonstrates that modern engineering is not limited to building on existing land. It can also create new land to expand development space. From this newly created land, Kuang Ninh has the opportunity to establish another urban center alongside the existing Ha Long, with transportation infrastructure, public spaces, services and cultural and tourism destinations. To realize such an urban area, the project also requires large-scale marine construction management capabilities, where ground treatment, roads and bridges and urban infrastructure must be coordinated in a synchronized manner. These technical experiences could continue to support coastal development projects in the future. However, expanding the landmass also means altering part of the coastal environment. Although Ha Long Shan is not located within the core zone of the Ha Long Bay World Heritage Site, dredging activities may disturb sediments, while land reclamation and seawall construction could alter water flows, potentially leading to erosion, sediment accumulation or impacts on surrounding habitats. Therefore, water quality, mangrove forests and coastal ecosystems need to be monitored and managed over the long term. The value of Ha Long Shan, therefore, lies not only in the amount of land created or the number of structures built. More importantly, the new land should bring economic benefits, improve people's quality of life and provide better infrastructure while ensuring that the impacts on the marine environment remain within acceptable limits. From the very first truckloads of material dumped into the bay to the rise of a vast new metropolis, Ha Long Shan is far more than an ordinary construction project. It is an immense act of transformation, where humans are redrawing the natural boundary between land and sea on a colossal scale. But the ocean is never truly silent. Behind the wide boulevards and glowing city lights lies a constant and often invisible struggle between human engineering and the enduring laws of nature. Pushing the coastline kilometers farther out to sea is already an extraordinary achievement. But the real test for this generation is whether we can control, adapt to, and coexist with the consequences that follow after the sea is given way. So what do you think? Will these reclaimed megacities become launchpads for future development, or are they an enormous gamble against nature? Leave your thoughts in the comments below. And don't forget to like and subscribe to Mandarin Tech as we continue exploring the world's next generation of megaprojects. Thanks for watching and see you in the next video.