HAMBURG, Germany -- A plan by the Philippines to build a network of "sponge cities" is gathering steam, after Dutch engineering firm Haskoning submitted a feasibility study for flood prevention water storage systems throughout Manila.

President Ferdinand Marcos Jr. said in September that his flood master plan was finally underway after the country endured severe flooding in August. Philippine flood prevention plans had been mired in corruption claims over the past few years. Marcos began an investigation into those allegations but faced accusations of political attacks on opponents. In the meantime, the Philippines has been slammed with typhoons and heavy flooding.

Plans are now afoot to begin building the sponge cities next year, although the government has yet to open construction to bidders. The design concept adds small-scale water storage and absorption areas to traditional engineering solutions like dikes and pumping stations across the urban fabric.

Haskoning is well-positioned to design the flood prevention plans. The Dutch landscape is famed for its canals that have helped to prevent severe flooding. One-third of the Netherlands is below sea level, and two-thirds at risk of flooding. Yet, the country's survival is testament to centuries of innovation and forward planning.

"There are lots of dikes and pumping stations in Manila, but it's still flooding, and now our Dutch perspective comes in with spatial planning and space for water," Karel Heijnert, Haskoning's senior consultant and project manager, said in a recent interview. "Pumping stations, while easy to implement and politically visible, cannot alone handle extreme rainfall volumes, leaving water in the city for hours or days. Relying solely on 'gray' infrastructure will never fully resolve flooding in a dense, flood-prone city like Manila."

Five flood-prone sites of 39 in the capital are initially identified for development under the purview of the Metropolitan Manila Development Authority (MMDA), with funding from the Asian Infrastructure Investment Bank. These are planned to be constructed in the next one to two years as real-life demonstration projects that Haskoning hopes will support future upscaling throughout the urban area.

Local media outlet Manila Standard identifies the sites as Camp Aguinaldo, Miriam College, Remedios Circle, Rajah Sulayman and the University of the Philippines Sunken Garden.

For Southeast Asia, the stakes could not be higher. Since mid-September, 60 people have died in floods in Thailand alone and river levels are continuing to rise, the government said on Oct. 7.

In the Philippines, incessant monsoon rains blanketed Central Luzon in August, drenching 8 million residents and damaging infrastructure and agriculture to the tune of over 8.4 billion pesos ($134 million), according to the Department of Social Welfare and Development.

To cope with Philippine downpours, Haskoning looks to create temporary storage for rainfall through thousands of small interventions rather than one large project, Heijnert said. Examples include lowering road berms -- embankments at the edge of roads -- to capture water, integrating storage in parks and other public spaces and building subsurface storage beneath roads.

"The roads are still generally higher than the living areas, but if you lower the road berms, they can capture the water and lead it away from where people live," Heijnert said. "In parks ... you see a lot of suitable spaces. Space that is allocated to storing floods during intensive rainstorms can be used for other purposes for the remainder of the time." Heijnert said this approach is gaining traction in Europe. The floodplains of the Rhine river in the Netherlands are used for agriculture or camping in the summer, then cleared out to absorb rain in the autumn and winter.

Bangkok's Benjakitti Forest Park is an example of a sponge city, built by Beijing architectural firm Turenscape and Arsomsilp Landscape Studio, based in the Thai capital. (Screenshot from Turenscape website) Nature-based solutions already exist in Singapore, China and Thailand, such as Benjakitti Forest Park in Bangkok. The park, completed in 2022, was designed by architectural firms Turenscape in Beijing and Arsomsilp Landscape Studio in Bangkok.

Turenscape's late founder, Peking University professor Yu Kongjian, pioneered the concept of sponge cities.

Benjakitti Forest Park shows how millions of liters of monsoon rain can be captured, biologically purified and released in a controlled manner, rather than overloading the urban drainage system. Yet it was too small in scale to prevent the worst floods in Bangkok in 15 years recently.

"We cannot guarantee flood-free Metro Manila," MMDA Chairman Don Artes was quoted as saying in local media, underlining how vulnerable this part of the world is to torrential rain.

Apart from the ferocity of nature, the new flood prevention strategy also could face stumbling blocks, like the Metro Manila Flood Management Project funded by AIIB and the World Bank. That project has met such severe delays that the government dropped it from a list of projects to be completed this year. Authorities blamed persistent right-of-way disputes and local utility relocation issues.

Haskoning said that after providing authorities with data and advice, it is now a matter of laying down guidelines and convincing stakeholders.

"Although more effective, our space for water faces political, economic and social hurdles, including land ownership conflicts and limited stakeholder understanding," Heijnert said. "There's public land in the city, but larger spaces are all owned by companies or private individuals. They own the land, and they may want to build a mall or a housing project there in the future." Haskoning, which has offices throughout Southeast Asia, was appointed to lead the Consortium for Java Coastal Resilience to develop a master plan for long-term coastal protection across Jakarta Bay and Semarang Bay. Jens Kastner is a contributing writer.