Resilience Commons: Hong Kong’s Blueprint for Flood Resilience with Ringo Mok, Director of Drainage Services at Hong Kong SAR

[00:00:00] Piers Clark: Welcome to the Exec Exchange 15-minute podcast, in which a leader from the water sector shares a story to inspire, inform, and educate other water sector leaders across the globe.
[00:00:10] Piers Clark: My name is Piers Clark, and my guest today is Ringo Mok, the Director of Drainage Services at Hong Kong SAR. And what we're going to talk about today is how Hong Kong, a coastal city, shapes itself to be a flood resilient city.
[00:00:26] Piers Clark: Ringo, it is wonderful to have you with us here today.
[00:00:30] Ringo Mok: Happy to be here.
[00:00:31] Piers Clark: Well, we always start with a little bit of background on our podcaster. So, can you give me the potted history of how you got into the current role?
[00:00:39] Piers Clark: What was your journey through HKSAR?
[00:00:42] Ringo Mok: I'm a civil and structural engineer by training. After graduation from the University of Hong Kong in 1990, I began my career in the private sector with a global consulting firm before moving on to the Mass Transit Railway Corporation.
[00:00:59] Ringo Mok: In 1997, I transitioned into public service and joined the Hong Kong government. I took up the post for engineer in the Drainage Services Department for about 12 years. I was then posted to the Development Bureau and the Civil Engineering and Development Department.
[00:01:17] Ringo Mok: In 2023, I was appointed as the director of the Drainage Services Department, being the head of the government department to deliver our drainage services to the people and community of Hong Kong.
[00:01:32] Piers Clark: Brilliant. Now, for those who may not be familiar with what the Drainage Services Department does, can you tell me a bit more about it?
[00:01:39] Ringo Mok: The Drainage Services Department was established in 1989. Our vision is to enable a future-ready, climate resilient Hong Kong with our world-class wastewater and stormwater drainage services.
[00:01:53] Ringo Mok: We also have five missions including: embracing innovation and technology, supporting Hong Kong's sustainability goal, powering excellence through partnerships, forging a high-caliber team, and making every resource count
[00:02:10] Piers Clark: I love that number one there was embracing innovation and technology.
[00:02:14] Piers Clark: Now, can you give me a sense of the scale? How big is the organization?
[00:02:19] Ringo Mok: We have about 2,000 civil servant staffs managing over 370 drainage facilities, and our pipeline network gets near 5,000 kilometer.
[00:02:30] Ringo Mok: On the flood prevention side, we manage and operate drainage tunnels and channels, underground stormwater drains with a total length of about 2,800 kilometer. Other flood prevention facilities include five underground stormwater storage tanks and 36 pumping stations, which are fully operational to reduce flood risk in the urban areas.
[00:02:55] Ringo Mok: On the sewage treatment side, we manage and operate about 70 sewage treatment plants and 270 sewage pumping stations, as well as an extensive sewerage network with a total length of about 2,000 kilometer long gravity sewers and pumping mains.
[00:03:12] Ringo Mok: Every day, we treat about 2.8 million cubic meter of sewerage. Currently, our sewerage system is serving about 94% of Hong Kong's total population.
[00:03:25] Piers Clark: That's some incredible stats that you've just shared there.
[00:03:28] Piers Clark: Can you talk me through some of the signature projects that you've done?
[00:03:30] Ringo Mok: Actually, I'm proud of what our department has achieved. Up to now, the Harbor Area Treatment Scheme project, is without doubt in the history of Hong Kong, the most impactful and far-reaching sewage project, which has significantly improved the water quality of our Victoria Harbour.
[00:03:50] Ringo Mok: Another flagship project is the Regulation of Shenzhen River project. Shenzhen River is the natural border between Hong Kong and Chinese mainland. The project has greatly reduced the flood risk of Hong Kong and Shenzhen. Both cities are core economic and financial hubs of the Greater Bay Area.
[00:04:09] Piers Clark: Brilliant. Now, from your point as Director of the DSD, how has flood management landscape evolved?
[00:04:16] Ringo Mok: When we talk about extreme weather today, we are talking about more intense storms and record-breaking rainfall.
[00:04:24] Ringo Mok: Hong Kong is compact, coastal, and hilly. Most of our developed area are along low-lying shorelines facing both flash floods and coastal flood risk. Last year, we have got about 2,550 millimeter annual total rainfall, which is about 5% higher than normal.
[00:04:45] Ringo Mok: Over the decades, our government has invested heavily in drainage tunnels, underground storage tanks, and river training works. These have greatly reduced historical flooding in the past.
[00:04:58] Ringo Mok: However, our experience show that flooding is not only a matter of overall drainage capacity. That means we cannot rely solely on infrastructure expansion to eliminate the flood risk in a dense and evolving city like Hong Kong.
[00:05:14] Ringo Mok: There is a clear need for a holistic integrated flood management strategy to link up engineering works, operational measures, and stakeholders to strengthen Hong Kong's flood resilience against the backdrop of climate change.
[00:05:29] Ringo Mok: True resilience is a partnership which the communities share awareness, acknowledgment, and action.
[00:05:38] Piers Clark: You are absolutely right, Ringo. I used to be the asset director of Thames Water, and we had similar problems in London. You've got to work in partnership with your communities.
[00:05:47] Piers Clark: In many cases, flooding, of course, is aggravated by local blockages caused by leaves or silt or refuse washing down the drain, and the relevant parties have got to share the responsibility for maintaining the drains.
[00:06:01] Ringo Mok: Indeed. Inspired by Elinor Ostrom, the 2009 Nobel laureate in economic science — common-pool resources are best governed polycentrically with many centers of decision-making at multiple levels. Shared vessels, shared information, and shared routines is the 'last mile', which together determine how quickly community resume to normal after torrential rain.
[00:06:27] Ringo Mok: We call this the "Resilience Commons".
[00:06:30] Piers Clark: Wonderful. Now, I understand that the DSD has developed a framework to put this polycentric thinking into place.
[00:06:37] Piers Clark: Tell us a bit more about that.
[00:06:39] Ringo Mok: We organize this partnership through three pillars: Adaptation, Resilience, and Management — the framework of our integrated flood management strategy. Each pillar pairs a community contribution.
[00:06:52] Ringo Mok: Adaptation pair awareness. At the first level, the government realize flood risk and build the infrastructure to reduce the risk. But awareness cannot stop at government level, it must extend to the second level which is the public. We must educate our people that even the best system has limits. Instead of promising zero flooding, we explained realistic levels of protection, publish flood-prone areas, and shift the mindset from expecting absolute protection to understanding shared responsibility.
[00:07:30] Ringo Mok: Resilience, the second pillar, pair with acknowledgement. Many flooding cases stem from blockage of inlets and gullies by tree leaves and debris, instead of capacity shortfall of the drainage system. Resilience, therefore, cannot rest with the government alone. The community, business, and property manager must also act. We accept that extreme weather events will exceed design standards, so we shape the city to bend rather than break.
[00:08:00] Ringo Mok: In new development areas, potable parks performs double duties: leisure in fair weather, retention in storms. In fully developed districts, demountable barrier and inflatable dam work effectively when people actively participate. We aim to build a culture where people acknowledge their own risk exposure and role in mitigation rather than treating flood as solely the government's responsibility.
[00:08:29] Piers Clark: Incredible. Well, let's talk about that third management pillar, and how does that work when you can see the storm coming, what is management doing?
[00:08:37] Ringo Mok: Management pairs with action. We have weather and flood monitoring systems that give us real-time information.
[00:08:44] Ringo Mok: We have developed action plans specifying when, where, and what measures are to be deployed. We carry out drills before each typhoon season, so our emergency response teams and local stakeholders know their roles and actions when flood warnings are issued. The public-facing tools, such as wading-line markings on low-lying roads, River Water Level Warning System, and a 24-hour hotline for reporting flooding spots, enabling people to act alongside the government.
[00:09:19] Ringo Mok: That is the "Resilience Commons" in motion.
[00:09:22] Piers Clark: This ARM strategy is so compelling. I'm sure there have been some successful case studies. Can you give me an example of a real-life story, a flood that happened and what you did?
[00:09:32] Ringo Mok: Super Typhoon Ragasa in 2025 was a real test on Hong Kong's flood resilience. A week before the storm arrived, we already knew that Hong Kong would be hit by heavy rain and extreme high tide at the same time.
[00:09:48] Ringo Mok: A day before arrival of the Ragasa, relevant government departments, including our department, jointly held a press conference to the public, put out our latest flood risk assessment, told the public on response measures.
[00:10:02] Ringo Mok: By using our flood risk prediction model, we pinpointed 11 high-risk areas, and then we arranged our contractors to distribute sandbags, set up demountable and inflatable barriers, installed temporary walkways to ensure villagers in low-lying spots could commute safely.
[00:10:22] Ringo Mok: Also, we positioned 14 pumping robots at vulnerable locations, activated our Emergency Control Center ahead, and deployed over 200 emergency response teams across the territory in standby mode before the arrival of the storm.
[00:10:40] Ringo Mok: Ragasa escalated fast after midnight on the day of landfall, creating severe storm surge and overtopping waves. As soon as the condition eased a bit, the pumping robots and the emergency response team were dispatched to the reported location of flooding against the clock. We received over 500 service calls, and 24 flooding cases were confirmed as a result. We posted updated flood information on our social media channel every one to two hours, reminding the public to stay safe and also reporting progress of our flood relief and recovery actions.
[00:11:18] Ringo Mok: We cleared up most flooding cases within one to two hours. Hong Kong managed to resume its vibrant life on the next day.
[00:11:27] Piers Clark: And that's the most amazing thing in that story is obviously you can see the storm coming and you can prep for it, but mobilizing the team and the measure of success is how quickly you get things back up and running again. And to be able to get a global city like Hong Kong back up and running within just a couple of hours is absolutely amazing.
[00:11:47] Piers Clark: What lessons did you take from that? How is that experience shaping DSD's approach going forward?
[00:11:54] Ringo Mok: The lesson taken is resilience is not only about avoiding floods, but also about preparing, responding, and recovering. And that only happens when the government and the public are taking up their shared responsibility in the last mile.
[00:12:12] Piers Clark: Ringo, it is wonderful talking to you. We are unfortunately running out of time, and I always like to finish by asking the question: If you could go back 30, 40 years and talk to your younger self,
[00:12:25] Piers Clark: what advice would you give a young Ringo Mok?
[00:12:28] Ringo Mok: If I could go back 30 or 40 years and speak to my younger self, here is what I would say, not as a director, but as someone who has seen the weather rewrite the rules.
[00:12:41] Ringo Mok: First, accept this hard truth. We cannot eliminate the flood fully. Extreme weather event will come faster and fiercer than any model predicted. Bigger drains, higher walls, they will never be enough. So stop promising "zero flooding". That is a promise we cannot keep. Instead, be honest. Publish flood point areas. Explain our realistic level of protection. Trust the public with the truth.
[00:13:10] Ringo Mok: Second, do not rely solely on adaptation. Infrastructure is essential, but it is not the whole answer. The government cannot simply build our way out of every rainstorm. So, my strongest advice is this: start the public conversation now. Educate, engage, and shift the mindset from, "the government must fix this," to, " we all have a role." Because flooding cannot be coped with by the act of the government alone. It never could.
[00:13:42] Ringo Mok: If we had begin building the culture of shared responsibility 30 years ago — where every resident understands their risk exposure, their role in preparedness, and their part in resilience — our city would have been far more ready for climate challenges by now.
[00:14:02] Ringo Mok: So to my younger self, start building understanding, because a resilient Hong Kong is not built by drains. It is built by all of us together
[00:14:12] Piers Clark: You have been listening to the Exec Exchange with me, Piers Clark, and my guest today has been Mr. Ringo Mok, the Director of Drainage services for HKSAR.
[00:14:24] Piers Clark: Thank you to our sponsors, and until next time, keep asking questions, keep sharing, and keep safe.