{"id":20664,"date":"2025-09-13T20:38:09","date_gmt":"2025-09-13T20:38:09","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/20664\/"},"modified":"2025-09-13T20:38:09","modified_gmt":"2025-09-13T20:38:09","slug":"extreme-rain-warming-climate-what-hong-kong-is-doing-to-address-an-evolving-threat","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/20664\/","title":{"rendered":"Extreme rain, warming climate: What Hong Kong is doing to address an evolving threat"},"content":{"rendered":"

HONG KONG \u2013 Two years ago, extreme rainfall inundated Hong Kong, turning roads into raging rapids, submerging cars and flooding malls, making it one of the city\u2019s most costly weather events ever. <\/p>\n

When another round of <\/p>\n

record-breaking rain drenched the city<\/p>\n

<\/a> in August, the damage and disruption were comparatively minimal. <\/p>\n

\u201cI was looking outside the window, seeing the rain coming down, and I was expecting way more impact than I saw afterwards,\u201d said Dr Andreas Prein, a weather expert who was in town for a forum on extreme rainfall the same week of the deluge. <\/p>\n

Other overseas attendees also remarked on how quickly Hong Kong returned to business as normal: They gathered for drinks downtown within a couple of hours of the rain subsiding.\u00a0<\/p>\n

The severe storm notched the highest-ever August daily rainfall total, but it was also up against the city\u2019s sharpened flood management strategy: In the past two years, Hong Kong has more than doubled its annual spending on stormwater drainage to an estimated\u00a0HK$3.17 billion\u00a0(S$524 million)\u00a0to address the evolving threat from extreme rain turbocharged by a warming climate. <\/p>\n

Other regions have also spent handsomely in their quest to tame stormwaters. <\/p>\n

Tokyo boasts a world-class flood defence system, Singapore has splashed out on drainage infrastructure, and the Netherlands continues to rely on its network of barriers, dams and wind-powered pumps. <\/p>\n

But globally, work on climate-proofing has slowed and the gap between required and needed adaptation finance is at least US$187 billion (S$240 billion) a year, according to the UN. <\/p>\n

For now, billions in investments in sprawling infrastructure in Hong Kong have kept the full wrath of natural disasters in check. <\/p>\n

That vital but little-known work began decades earlier, long before climate risks entered the public consciousness. <\/p>\n

Much of\u00a0Hong Kong is densely packed and perched on, or built at the foot of, steep slopes. The city averages 2,400 millimetres of precipitation annually \u2013 nearly double what New York City gets \u2013 and tropical rain is notoriously hard to predict. <\/p>\n

As a coastal city, storm surges and rising sea levels put additional stress on its drains.\u00a0<\/p>\n

This combination of factors \u201cis quite unique to Hong Kong\u201d, said Professor Huan-Feng Duan, professor of hydraulics and water resources at the Hong Kong Polytechnic University. <\/p>\n

\u201cThe very fast flooding issue means it requires a very high standard of research and also engineering.\u201d\u00a0<\/p>\n

Now, ever-higher temperatures are risking more intense rain, requiring more improvements to Hong Kong\u2019s extreme-weather response.\u00a0<\/p>\n

Driving that effort is the Drainage Services Department (DSD), which oversees some 2,800km\u00a0of stormwater drains \u2013 more than the length of the city\u2019s public roads. <\/p>\n

In the nearly four decades since its establishment, the DSD has invested over HK$32 billion in drainage works to reduce flooding impact. That is no longer enough. <\/p>\n

\u201cThe extremely heavy rainfall of 2023 was a wake-up call for us. And we also learnt a lesson: It confirmed our thinking that we cannot only rely on adaptation,\u201d said Mr Ringo Mok, director of the DSD. <\/p>\n

\u201cWe have to implement many different measures at once.\u201d <\/p>\n

While large-scale engineering projects will still form the \u201cfirst line of defence\u201d against inundations \u2013 the department currently has HK$17.1 billion budgeted for 15 stormwater drainage projects\u00a0\u2013 temporary and non-structural measures will be crucial for the city\u2019s resilience, Mr Mok said.\u00a0<\/p>\n

To that end, the drainage department has expanded its\u00a0flood-fighting tactics over the past two years. It has identified some\u00a0240 blockage-prone drains citywide, and more than doubled the number of emergency response teams to rapidly unclog them when heavy rainfall hits. <\/p>\n

For better monitoring, it has installed 100 battery-powered flood monitoring sensors citywide that can ping instant alerts, and plans to gradually expand that network. <\/p>\n

It is also working with academics to develop a machine learning model trained to spot flooding from CCTV images. And it has procured nine mobile pumping machines\u00a0to quickly clear major blockages. <\/p>\n

The approach seems to be bearing fruit, Mr Mok said. All reported floods in 2024 were fully cleared in under two hours. <\/p>\n

The DSD is \u201can unsexy department with a compelling story, especially today in the light of climate change\u201d, said Professor Christine Loh, chief development strategist at the Hong Kong University of Science and Technology and formerly the city\u2019s undersecretary for the environment.\u00a0<\/p>\n

The private sector is stepping up its game, too. Real estate investor Link Reit\u00a0got a rude shock when the <\/p>\n

September 2023 deluge flooded<\/p>\n

<\/a> one of its malls. <\/p>\n

It was not that the company had ignored potential hazards \u2013 it had recently completed an assessment of flood and heat risks at each of its 150-plus properties. <\/p>\n

But the shopping mall that ended up with the worst flood damage had never been flagged by its risk models. <\/p>\n

\u201cWas it that the model failed, or were we dealing with something different?\u201d said Dr Calvin Kwan, managing director of sustainability and risk governance at Link. <\/p>\n

\u201cThe answer is we were dealing with a whole confluence of worst-case situations.\u201d <\/p>\n

The risk models had failed to simulate the perfect storm of events: record-breaking rain,\u00a0a subway station\u2019s floodgate\u00a0diverting\u00a0flood waters into the mall, and muddy run-off from a construction site nearby. <\/p>\n

Shops in the mall\u2019s basement level were submerged under 3m of water, shutting the entire floor for nearly two months and resulting in\u00a0millions\u00a0in insurance claims.\u00a0<\/p>\n

Link realised that its risk models cannot look at an asset in isolation \u2013\u00a0they must account for changes in the surrounding environment that can create new hazards. <\/p>\n

It\u00a0took steps to reduce those risks, including putting up new floodgates, installing real-time flooding sensors and redesigning drainage covers for higher efficiency. <\/p>\n

All told, Link has spent HK$8 million on flood measures in the past two years, compared with the estimated HK$500,000 in the three to five years prior, according to Dr Kwan. <\/p>\n

Railway operator MTR\u00a0also learnt lessons from the downpour two years ago. It has installed flooding sensors at more than 30 high-risk station exits and entrances since then, and now has a protocol to put up flood boards and activate floodgates when the Hong Kong Observatory hoists its most severe rainstorm warning signal, according to a spokesperson. <\/p>\n

Ultimately, even the best flood defence system will fail. <\/p>\n

The challenge for governments is communicating openly that things will go wrong, while still encouraging the public to assess their own flood risk exposures and take steps to mitigate damage, said Mr Bas Kolen, director of research and development at Dutch flood risk consultancy HKV lijn in water. <\/p>\n

\u201cIt\u2019s a challenge for the government to say that we cannot prepare for everything. Of course, they like to say that you are safe, but everybody knows that something can go wrong,\u201d he said. <\/p>\n

\u201cThat\u2019s not failure. It\u2019s just to be clear what you can expect.\u201d\u00a0BLOOMBERG<\/p>\n","protected":false},"excerpt":{"rendered":"HONG KONG \u2013 Two years ago, extreme rainfall inundated Hong Kong, turning roads into raging rapids, submerging cars…\n","protected":false},"author":2,"featured_media":20665,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[273,111,139,69,147],"class_list":{"0":"post-20664","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-environment","9":"tag-new-zealand","10":"tag-newzealand","11":"tag-nz","12":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/20664","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=20664"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/20664\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/20665"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=20664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=20664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=20664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}