Hanoi (VNA) – The adoption of underground plastic rainwater storage tanks has been highlighted as a sustainable, cost-effective, and scalable solution for addressing urban flooding in major Vietnamese cities, according to experts from the Ministry of Natural Resources and Environment.
The approach is also seen as a means to replenish groundwater reserves and optimise water reuse, contributing to urban sustainability.
The potential of this solution was underscored during a recent Vietnam – Japan joint seminar held in Hanoi on February 10. The event, organised by the Japan International Cooperation Agency (JICA) in collaboration with Vietnam’s National Centre for Water Resources Planning and Investigation (NAWAPI), focused on innovative measures for urban flood control, groundwater recharge, and water reuse.
Speaking at the seminar, Trieu Duc Huy, Deputy Director General of the National Centre for Water Resources Planning and Investigation, emphasised that rapid urbanisation and climate change have significantly strained water resource management, particularly in densely populated areas.
He noted that Vietnam faces mounting challenges, including increasing urban flooding, declining groundwater levels, and water scarcity. Ensuring water security for various uses is becoming increasingly complex, with issues such as frequent inundation, seasonal water shortages, and inefficient water use adding to the burden.
The rapid expansion of urban areas, coupled with outdated drainage systems, has exacerbated these issues, he stressed.
In response, Vietnam's national programme on circular economy, the Politburo’s Conclusion No. 36 on ensuring water resource security by 2045, and the 2023 Water Resources Law all prioritise circular water use and emphasise the importance of adopting circular economy principles, especially innovative and sustainable solutions, to improve water use efficiency.
A case in point is the To Lich River in Hanoi, where efforts to restore its water quality have been ongoing. While plans to supplement its flow with water from the Red River have been proposed, experts argue that effective wastewater collection and treatment infrastructure along its banks remains a prerequisite for long-term revitalisation.
Across various countries, including Japan, the use of underground plastic rainwater storage systems has demonstrated significant benefits. These systems not only store rainwater but also help reduce surface runoff, prevent urban flooding, and facilitate water recycling for non-potable purposes such as irrigation and industrial applications.
By integrating such systems into urban infrastructure, authorities can alleviate the pressure on existing drainage networks, enhance groundwater recharge, and promote environmental sustainability.
The effectiveness of these tanks in Japan suggests that similar implementations in Vietnam could yield positive results. Experts argue that such infrastructure investments would not only mitigate the risk of flooding but also bolster long-term water security and resilience against climate change impacts.
The state of urban drainage systems in Vietnam was also a key topic of discussion at the seminar.
Associate Professor Dr. Vu Thi Vinh, an urban infrastructure expert and former Secretary-General of the Association of Cities of Vietnam, noted that most urban areas in the country rely on combined drainage systems that channel both rainwater and household wastewater through shared pipelines. This often leads to system overload during heavy rainfall, intensifying the risk of flooding.
Many of these drainage systems were built decades ago and no longer meet the demand in rapidly expanding cities. Given those systems’ narrow pipelines and insufficient capacity, severe rainfall events often result in localised flooding.
Major urban centres such as Hanoi, Ho Chi Minh City, and Da Nang frequently experience inundation, particularly in low-lying areas where rainwater accumulation is compounded by rising tide levels.
Currently, urban drainage networks serve only about 50-60% of the population in big cities, and the coverage drops to approximately 30% in smaller urban areas. Meanwhile, wastewater treatment remains limited, with only about 15% of urban domestic wastewater being collected and treated as of mid-2022—a figure that saw a slight increase to 17% by April 2023.
With Vietnamese cities still heavily reliant on conventional drainage systems for surface water management, the unchecked expansion of impervious surfaces has heightened the risk of inundation.
Given these challenges, Vinh emphasised the importance of exploring alternative solutions such as underground plastic rainwater tanks as part of a broader flood mitigation strategy. She described the approach not only as a technical solution but also as a commitment to sustainable urban development.
A representative from the Japanese Embassy in Vietnam highlighted the urgency of addressing urban flooding, particularly in a country where motorbikes remain the primary mode of transportation. The disruptions caused by flooding, he noted, have significant economic and social consequences.
Given the increasing complexity of climate-related risks, the deployment of underground rainwater storage systems in both urban areas and industrial zones in Vietnam is seen as an important step forward.
The Japanese official expressed hope that the seminar would pave the way for strengthened cooperation between Vietnamese and Japanese stakeholders in disaster prevention and flood management./.
