Experts and scientists on marine environment and ecology all expressed concern that submerging 200,000 m3 of material into Da Nang’s sea would harm the marine ecosystem.
With the People’s Committee of Da Nang City in principle agreeing to the Vietnam Maritime Administration (Ministry of Transport) to research, survey and implement procedures for submerging 200,000 m3 of material in the sea of Da Nang, experts say. There is a need for a careful assessment of the environmental impact (EIA).
Danang’s marine ecosystem is in decline
Associate Professor-Dr. Vo Van Minh, Chairman of the Council of Da Nang Pedagogical University, said that if there is no other dumping site, there is only way to sink into the sea. However, where to sink, in EIA techniques, it is necessary to determine which sea is the safest, least damaging to the environment.
“Currently, the waters of Danang are not included in the group of protected areas, so it can be submerged. However, from an environmental perspective, falling there will certainly affect immediately, especially coral reefs and seagrass areas. These areas are very important for their habitat and breeding grounds for marine life. Surely it will disturb the environment, affect species of marine fauna and flora “- Mr. Minh said.
Mr. Minh emphasized that in the EIA technique, it is only said to minimize to the lowest level, in the permitted level, not say that it is not impacting. Da Nang’s marine ecosystem is in decline, especially the coral system due to poor conservation, tourism and wastewater impacts.
“I want the EIAs to consult with scientists, but if they do not do well, it is dangerous for the environment” – Mr. Minh worried.
According to Dr. Nguyen Tac An, former Director of Nha Trang Institute of Oceanography, in order to carefully analyze the EIA capacity of submerging, it is necessary to understand the dredging method and the submerged technique. It can be said that all the material in the sea when lying still is okay, but when touched and bounced, many problems occurred. Therefore, it is okay to say just taking this place and leaving that place.
Mr. An said that the submergence principle must stay away from sensitive areas such as residential areas, fishing grounds, protected areas and special values of the sea. In addition, when submerged, it is necessary to avoid seas with strong motivations.
“Actually we dumped it, but it will run away. Submerging techniques must be very attentive. Must see if the quality of sediment and chemicals in the area we scraped up is toxic or not. This EIA agency is aware of both. The dynamic maps in Vietnam nowadays all have them. Therefore, when pouring, it must be considered and calculated. The EIA agency will have to take physical samples for testing, calculate the propagation pattern, size, dredging and dredging time “- Mr. An noted.
Mr. An emphasized: Dredging the sea channel is very important for economic development. Dredging cannot be helped. However, how to minimize the impact of the dredger to increase the overall economic value.
Experts believe that when evaluating the EIA, it is necessary to determine which sea area is safe, with the least damage to the environment. Photo: LE PHI
Dredging the sea channel into Tien Sa port will create 200,000 m3 of material and be calculated to submerge in the waters of Da Nang. Photo: TAN VIET
Worry about coral reefs
Talking about the material submerged in Da Nang sea, Dr. Nguyen Thi Minh Phuong, Dean of the Faculty of Environment – Chemical Technology (Duy Tan University), assessed that 200,000 m3 of material is much and will definitely affect the system. marine ecology.
“The affirmation is always going to impact the ecosystem. When we poured like that, we thought it would lie there, but in fact it was not there at all, it had extremely large currents, so it would be swept away. Must see under that sea there are corals or not, because the most fear is the influence of the coral. When pouring like that, the coral cannot withstand the mud, when the water is too turbid, the symbiotic algae of the coral dies and makes the entire coral carpet die “- Ms. Phuong said.
Ms. Phuong further analyzed the great possibility that the sea area is expected to be submerged deep enough that there are no live corals. Most worrying, however, is that the currents will sweep matter around. Especially sediments, if heavy sediments will be deposited, and fine-grained sediments will be swept away.
“Saying a 100-hectare sea area, it will actually wash away very far. The sediment in the dredging site is likely to be fine-grained, not coarse-grained sediment. Fine means it is light, can be washed away, coarse grain is deposited in place and moves slowly. In a period of a few years it will be swept away everywhere and swept seasonally, because the flow changes with the seasons. Wherever the flow is, the coral will die there. The symbiotic algae of the coral needs light, the coral ecosystem is extremely important. And the bottom ecosystem will be temporarily destroyed for a while, then recover “- Ms. Phuong said.
Ms. Phuong added that from a management perspective, any project will have an impact on the environment. If you consider the environmental impact less than the likelihood of economic development, that’s okay, it’s worth the tradeoff.
“Also saying no effect is not right. The impact at sea is difficult to control. If other ecosystems can recover over time, the corals will not, die will die ”- Ms. Phuong affirmed.
177 species of corals around Son Tra peninsula From 2016 to 2018, the Southern Institute of Ecology had the topic “Research on conservation and biodiversity restoration of terrestrial and underwater ecosystems in Son Tra Nature Reserve”. After nearly three years of restoration, the live coral cover increased by more than 10% compared to baseline. There is an increase in organisms living in the reef. The coverage of seagrass beds increases about 20% -30%. According to research by the Southern Institute of Ecology in 2019, the sea surrounding Son Tra peninsula has 177 species of coral belonging to 17 families and 52 varieties. There are also 130 species of fish living in coral reefs, belonging to 32 families and 65 varieties. This sea also has three species of seagrass distributed over a total area of 1 ha and 108 species of extremely diverse seaweed. However, the marine ecosystem here is seriously degraded.
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