Forever flooding in Metro Manila? An expert weighs in | The Howie Severino Podcast
Prominent flood control engineer Dr. Guillermo Tabios shares a harsh reality — some densely populated areas of Manila may no longer be livable.
In a wide-ranging conversation with Howie Severino triggered by recent devastating flooding, the UP professor emeritus of civil engineering explains that the low-lying metropolis could be facing unstoppable flooding.
Climate change, clogged waterways, and the lack of major infrastructure spell regular disasters for millions of residents. Unless large floodways are built to carry water to the sea, Tabios says certain residential areas need to be abandoned to avoid the certainty of worsening floods and regular evacuations and fatalities. Current flood control projects are a patchwork that hasn’t solved the problem. He calls for a new cabinet-level Department of Water Resources that will coordinate government efforts and focus on comprehensive solutions.
Tabios cites Iloilo City as an urban center that has built effective flood control systems by diverting water away from the city center.
In Metro Manila, such an approach may require tunneling from Laguna Lake to the Pacific Ocean. According to Tabios, the reclamation projects in Manila Bay only exacerbate the situation by blocking the flow of water to the sea.
In a wide-ranging conversation with Howie Severino triggered by recent devastating flooding, the UP professor emeritus of civil engineering explains that the low-lying metropolis could be facing unstoppable flooding.
Climate change, clogged waterways, and the lack of major infrastructure spell regular disasters for millions of residents. Unless large floodways are built to carry water to the sea, Tabios says certain residential areas need to be abandoned to avoid the certainty of worsening floods and regular evacuations and fatalities. Current flood control projects are a patchwork that hasn’t solved the problem. He calls for a new cabinet-level Department of Water Resources that will coordinate government efforts and focus on comprehensive solutions.
Tabios cites Iloilo City as an urban center that has built effective flood control systems by diverting water away from the city center.
In Metro Manila, such an approach may require tunneling from Laguna Lake to the Pacific Ocean. According to Tabios, the reclamation projects in Manila Bay only exacerbate the situation by blocking the flow of water to the sea.
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NewsTranscript
00:00Good morning, Podmates! This is Howie Severino again, reminding you that a long attention span is a gift of wisdom.
00:07Our topic today is flooding in Metro Manila and many other parts of the Philippines.
00:15Our guest today is Dr. Guillermo Tabios, a Civil Engineer, Flood Control Systems Expert, and Professor Emeritus, University of the Philippines.
00:26Good morning to you, Professor Tabios.
00:29Good morning to you too, Howie.
00:33Prof., there is no more flood on the roads as we speak, so the water is flooding.
00:39But as I pass through other parts of Manila, the garbage is still piled up, a vivid reminder of what our fellow countrymen have been through.
00:50So, Doc, as a scholar of flood control, you must be so frustrated that flooding is still a regular occurrence.
01:00It's not like this is such a surprise for us.
01:03There are old flood charts in Manila, even from the colonial era.
01:08It's 2024 now. Why can't we solve flooding?
01:15Well, geographically, or topography-wise, Metro Manila is a city built on swamplands.
01:26I mean, the big part of Metro Manila, your low-lying area, especially your old Manila, and of course, somewhere in Sao Paulo, Tondo, Binondo, you name it, Pasay.
01:40That's the floodplain, or not really a floodplain, but it's the delta of the Marikina River Basin,
01:48or Tolian River Basin, even parts of Valenzuela and Obando.
01:55Those are mountains coming from Sierra Madre and then going down.
01:59And then it ends up, like, after a few kilometers, it becomes a flatland.
02:06And when you reach a flatland, definitely that will be what you call a delta.
02:13You'll have a network of channels that form, like, a delta towards the sea.
02:20Now, you build a city on that.
02:22That's why you have esteros, Paco Estero, all those esteros in Manila.
02:31So it's really flood-prone to begin with.
02:34Then you have these developments where you modify the channel network in a delta.
02:43So if you build housing there or roads, the natural waterways will disappear.
02:52I think even in the 1500s, 1600s, we have swamps there, we have esteros, we have canals that bring out water from Marikina River Basin,
03:06or Tolian, all the way down.
03:08There are no people, so there's no flood disaster.
03:11Now you put people, so there's a disaster.
03:15Okay, Doc. Let's just pause there and think about what you just said.
03:20So Manila is basically part of a low-lying area of Luzon.
03:26That's why it's prone to flooding.
03:28That's why we put a lot of developments and a lot of population here.
03:33Because its location also has a strategic value.
03:37But Doc, we're not the only low-lying urban center in the world.
03:44I mean, we're reading about the history of flooding in other parts of the world.
03:49You're very aware of the experience of Holland, right?
03:52Yes.
03:53It's also low-lying in Europe.
03:55They also had devastating flooding in 1953, the Great North Sea Flood.
04:02A lot of people died in 1953, more than 50 years ago.
04:07And they had a whole-of-society approach.
04:11They made dams, levees, boulders, and other infrastructures.
04:17And now, they are considered a global leader in flood risk management.
04:26So why can't we do the same thing?
04:30Why do we have to suffer from this over and over again?
04:36So what is preventing us from managing flood risk?
04:41Other societies have done that.
04:45And we are suffering from this over and over again.
04:48One of the features is tropical countries.
04:52It's really a humid, tropical country where you can get lots of rains.
04:57Typhoons, in our case.
04:59We also have monsoons.
05:01We have even the intertropical converging zone.
05:04And when the trade winds converge, then you have these rains and so on.
05:10Now, in Europe, it's also the same.
05:13There are areas that are low-lying.
05:15And in fact, in Spain, or even in Rome, and then in Paris.
05:23But they have big rivers along those big cities.
05:29We also have a big river, Pasig River, which is maybe repatriated from those European cities.
05:35But I think the big difference is that we are in a humid, tropical country.
05:40Lots of rain.
05:42So that's a big difference.
05:44Now, when you think about flood risk management,
05:50it's so difficult to just kind of do this, do that.
05:56Because there are so many components as far as flood control.
06:00Structural measures, and then you have non-structural measures.
06:04But one of the things that I've been noticing in the Philippines,
06:09we're very good in master planning.
06:11But the problem with the master planning, it's dependent on foreign technical assistance.
06:19That's one.
06:20So once the study is done, and the foreign consultants leave, there's no follow-up.
06:32Now, if I look at flood dynamics, flood disasters, it's very evolutionary in nature.
06:43Very dynamic.
06:44Because you have, of course, land use change.
06:48When you change the land use, you'll have different impervious and impervious areas.
06:53You have encroachments.
06:55If there are land developments, the waterways will be gone.
06:59That will bring water from the inland towards the rivers and then towards the sea.
07:05And you have all kinds of modifications and even unwanted garbage, even in local drainage.
07:14There's no capacity because it's full of garbage.
07:17Now, how do you bring water all the way to the river and so on?
07:21Now, the other thing with flood control, we can always do master planning,
07:27but then your investments do not come right away.
07:31I mean, approved in 2012, your Metro Manila flood master plan,
07:36350 billion.
07:38The 350 billion, maybe 100 billion or so, was still done.
07:45But that was 10 years ago, 15 years ago.
07:48A lot has changed.
07:50There are new subdivisions here.
07:52There are condominiums.
07:54The waterways are gone.
07:57There's dirt.
07:59So it's overtaken by that, the changes.
08:03So should we keep on updating or revising our plan, which is no longer master planning,
08:10but really adaptive planning?
08:12You retrofit or you adapt because the river landscape or your landscape, so to speak,
08:20which is where all the dynamics of flooding.
08:30It's really affected by even social migration.
08:37There are more people here.
08:39So, Doc, I just want to ask you specifically about Typhoon Karina
08:44because that's a recent experience of many people.
08:48In the wake of that disaster, a lot of factors were mentioned.
08:56The President himself mentioned climate change, garbage.
09:00Other people, even senators, are saying that this reclamation project in Manila Bay is a big factor.
09:09A lot of things were taught.
09:11People were asked to clean up.
09:13Garbage was also mentioned.
09:15Master planning was also mentioned.
09:17Others said there was no master plan.
09:20Only small projects.
09:22And, of course, there's the issue of deforestation and lack of reforestation.
09:28How do these fit together?
09:30What's the biggest factor?
09:33Given that we're low-lying, given that Metro Manila can't be evacuated,
09:40what's the best way of adapting?
09:44Should we, for example, stop the reclamation projects?
09:49The reclamation is a different story.
09:51But when you look at flood control, definitely you have to start from the headwaters,
09:58uplands, watersheds, all the way down.
10:01Now, that's what we always say is a holistic approach to flood risk management.
10:07Now, one of the things that really reduces the capacity of the river is new sediments.
10:16So, how do you control sediments?
10:18Upstream, you have control, maybe a forest that will minimize sediment yield from the watersheds
10:30and then gets into your river.
10:32It then shallows the river.
10:34Imagine during Typhoon Ondoy, that area in Loyola Grand Villa, there was a Tumane Bridge there.
10:41And if you're aware of that, that crosses from Loyola Grand Villa to Balara.
10:49You go down there, and then you go across to San Mateo or Marikina.
10:55That is an overflow bridge.
10:58So, the top is passable.
11:00You have concrete.
11:02There's a culvert at the bottom.
11:04If the water level is high, it will overflow.
11:08But during Typhoon Ondoy, it must have been filled up with two to three meters of sediment
11:16over a period of seven hours.
11:19So, imagine that area.
11:22Of course, it was buried two to three meters.
11:25But think along the river.
11:27Two to three meters, that depth is gone.
11:30So, it will reduce that so much capacity.
11:33So, that's one.
11:34So, that's why you have to have controls upstream.
11:37Excuse me, Doc.
11:45That's one.
11:46Because if you have a lot of rain, it's hard to control the sediment that will erode from your watersheds.
11:54In archipelagic countries, that's the problem.
11:59Whether you're quarrying along the river banks and so on,
12:03but the bulk of the sediment comes from the overland flow plains, not watersheds.
12:11I mean, not in the river, but on the sides.
12:14So, because you just have so much rain.
12:18We were talking about humid tropic rains, which are like 400, 500 milliliters in one day.
12:27That's a lot of rain, you know, if you think about it.
12:30Anyway, so you go down to the downstream.
12:34So, the sediment is full.
12:36And the capacity of your river is gone.
12:40Now, you also have some debris coming from the mountains.
12:44Maybe logs or maybe some of this vegetation.
12:50They will also contribute to what we call great roughness or friction,
12:57because you have these roughness elements and so on.
13:01So, those are things.
13:03Now, if you think about those kinds of rains that we experienced,
13:09Ondoy, Carina, Ulysses, Habagat, or the sudden onset of typhoons and storms,
13:18it's just so much rain that you're experiencing.
13:22So, it's not quite easy to control that.
13:25So, that's the problem.
13:29You can do this.
13:31But one of the things that I've noticed in the Philippines,
13:33and that's where we don't really have a dedicated body to look at this flood risk management
13:40or flood planning or adaptive planning for flood control on a daily basis.
13:47When I say daily, it's like maybe you do a study every day,
13:51but good for the next three months or six months.
13:54Because a year ago, this is what happened.
13:57And if you look at Metro Manila, you have different sub-basins
14:04where you have Marikina, Tuliahan, and then Sapote, Bacor, and those areas.
14:12You have to, as an academic body, you have to run simulation models.
14:18Different scenarios, you change the land use, what will happen?
14:22If you do this kind of structural measure or non-structural measures, what happens?
14:28Will it work?
14:29Maybe it works here, but does it work in another place?
14:32When you think in terms of floods, the generating mechanism,
14:38typhoons are so much different from typhoons.
14:42In fact, if you look at the master plan that was made in 2010,
14:46World Bank was the one who designed it,
14:48all the design flood parameters, we call it, based on a two-day rainfall,
14:56based on a one is to 50, one is to 100, like one shot over the next two days.
15:02But we can have multiple peaks in our floods, our rain,
15:07and then it can even last for five days.
15:09Like the Abagat of 2012, August, that was seven days, ulan na ulan.
15:15Mahina your intensity, but over seven days,
15:19you have more than what you got from Undoy or Ulysses.
15:23Same thing with Carina.
15:25In three days time, you got more than what fell during Undoy over almost 24 hours.
15:33455 in Undoy, 24 hours.
15:36Carina, about 600 over almost three days, almost 65 hours.
15:44You mentioned Undoy in 2009.
15:47Maybe some of our listeners may be too young to even remember,
15:51but that was a defining disaster for many.
15:54Ang damay na-traumatize yung mga mulat na noon.
15:57That was nag-grabe, ang lalim ng baha noon.
16:02Nakakatakot yung taas ng tubig, et cetera.
16:06What should have happened after that?
16:09Sabi nyo nga, naglabas yung gobyerno ng master plan noong 2010.
16:14One year later, na-implement ba?
16:17May nag-improve ba mula noong Undoy noong 2009?
16:21That was 15 years ago.
16:23You would think may mga plano na in place to prevent a Carina
16:30from causing the same kind of disaster?
16:35Yeah.
16:36They were running the flood models to look at the performance of mga different flood components,
16:46flood control components.
16:47Here, they're structural, not structural.
16:49Based on a two-day, 50-year or 100-year,
16:52because Undoy was about 80-year return period of the flood.
16:56Over two days, merong ng peak na ganal. Tapos.
17:00But Carina, or Habakkuk 2012, it's a prolonged multi-peak,
17:08although mas mababa yung intensity.
17:11That's a different scenario as far as flood dynamics is concerned.
17:18I want to mention June 2009.
17:20A week after that, from October 2 to October 10,
17:25there was a typhoon peeping in Agno River Basin in Pangasinan.
17:31That one is a single-peak typhoon.
17:34Every time, kaya lang tatlong bes dumaan doon.
17:38Pumasok siya, luwabas.
17:40Patas pumasok uli, luwabas.
17:43Pumasok uli, third time, doon ang pinakamadaming rainfall.
17:48But during the time, the affected big flood structure,
17:53yung San Roque Dam, napuno yan.
17:56So on October 9, that was after five days,
18:01they had to release 5,000 cubic meters per second.
18:05That's like maybe 21 to 22 meter size sa Santo Niño,
18:10na mountain flow.
18:12Pero doon, binaya yung Carmen Rosales,
18:14hangga second floor ng SM Rosales during that time.
18:18So that was not tabagat, but it's three times pabalit-balit.
18:23So that's the difference.
18:24That's what you call Fujiwara effect na.
18:26During that time, meron typhoon dito.
18:28A little bit in Taiwan, meron typhoon.
18:30Hindi siya makapasok doon.
18:32Hindi siya makapunta doon yung peeping.
18:35Kaya pabalit-balit siya sa Pangasinan.
18:39We can have a similar situation in Metro Manila like that.
18:43It could be like a multi-peak typhoon
18:46over a span of four or five days.
18:49We haven't experienced that,
18:50but that's another scenario na pag nangyari yun,
18:54delikado.
18:56Parang magkaroon ka ng undoy three times.
19:01That's a possibility.
19:03Yeah, so Doc, is there a way of preventing flooding then?
19:07Parang lumalabas inevitable halos.
19:10These are acts of nature obviously,
19:13but so is there something we can do to prevent this kind of suffering of people?
19:19Yeah, in flood studies, what we do is really,
19:24if you have a sort of what we call a digital twin,
19:28like a mathematical model of the entire Metro Manila,
19:32you can run scenarios.
19:35Different typhoons, multiple peak typhoons, habagat, et cetera,
19:41and then look at what you do in Marikina,
19:44what you do in Pasay,
19:47what you do in Tuliahan.
19:49All these together.
19:51You look at all the possible scenarios as far as the weather.
19:55You look at the possible scenarios as far as
19:58nagkaroon ng land use na ganto,
20:01or maybe these kinds of sediment na nagbago yung river landscape mo,
20:10maybe nagkaroon ng debris,
20:12and then look at the performance.
20:13But you can always do all kinds of simulations
20:16and then look at the possible solutions
20:20and assess the performance of these different solutions
20:24because you're looking at a very complex.
20:27By the way, if you look at the flood problem,
20:30it's what we call a wicked problem.
20:32It's a highly nonlinear, large-scale, complex,
20:37unpredictable, uncertain, and you name it.
20:40I'll give you an analogy, a very simple maybe.
20:43You look at the traffic problem in,
20:46let's just talk about Cairn City area,
20:49bounded by EDSA,
20:51and then you have this Ortigas,
20:54Ortigas, to the south side na iyon,
20:56and then C5,
20:58and then maybe somewhere in Commonwealth.
21:00So, the C5, I mean this area,
21:04this kodrongan na ito,
21:06marami kang pumapasok lumalabas na vehicles, no?
21:12Tapos meron ng mga malls na parang magpaparking iyon,
21:15parang mga reservoirs iyon,
21:17pagkatapos yung pinaka-waterway mo yung mga road network.
21:20Some roads will be small,
21:22some become big,
21:23and then you have this mga vehicles tumatagbo,
21:28na meron mga driver na behavior na paganto, paganya, paganya-ganyan,
21:33and you look at the traffic flow,
21:35and then you have this MMDA, yung mga traffic enforcers.
21:38Stop dito, go don,
21:41pero the traffic enforcer in Katipunan does not know the traffic enforcers
21:47in Commonwealth, sa C5 Commonwealth.
21:50They don't coordinate.
21:52They don't know each other,
21:53but stop, go, and so on.
21:55As far as their eyes can see, stop.
21:57As far as their eyes can see, go.
21:59It's really a lot of chaos in Dibawi City like that,
22:02and the road network is just like the intricate network of the roads.
22:08It's just an intricate network of flood channels.
22:12If you look at the city of, even Keo City,
22:16the waterways from San Juan to, and so on, Araneta,
22:21galing dito sa Marikina, galing doong pag mag-meet sila sa Pandakan,
22:25parang ganun lang yan.
22:26Now, you think about a reservoir.
22:29You can store water like a detention pond,
22:32like a parking lot, papasok yung mga vehicles,
22:34and then at a certain time, lalabas na naman sila.
22:37Maybe it's rush hour, lalabas sila lahat.
22:40So these are very intricate.
22:42If you look at the discrete particles tumatagbo,
22:46the difference in water is just continuum na materials,
22:50but it's as complex, as uncertain, as large-scale wicked problem as that.
22:58Okay.
22:59So if you were to recommend a infrastructure solution,
23:05what would it be?
23:08It depends where you are.
23:10Yung parating lang pinapag-usapan niyo sa reclamation,
23:13they always make the terminology na,
23:16if you have this water coming from doon na sa Rojas Boulevard,
23:22so if you have the sea right away along Rojas Boulevard,
23:27maybe that was way back in the 60s,
23:30wala pa yung reclamation sa SMOA and CCP, wala pa.
23:35Yung tubig, pag tumalong doon sa Rojas Boulevard,
23:39there's a very wide river that gets to Manila Bay.
23:43So nakatalo na agad.
23:45Now you reclaim.
23:47Ganoon ka ng reclamation.
23:49So in a flatland, it takes more time,
23:52and farther away from the sea,
23:54para tatagbo yung tubig.
23:56So magkaroon sila mga waterways this way,
23:58parang mga fingers of channels.
24:01But some reclamations don't do it that way.
24:05If you go to Florida, if you go to even San Francisco or San Jose,
24:09meron mga reclamation doon.
24:11Ang reclamation lang, ito yung coast.
24:15I reclaim na dito na area, pero dito na part.
24:18Channel pa rin.
24:20Pag taos, to go across that, meron mga bridges.
24:25So yung main channel mo ay yung pinag-waterway mo
24:29connects the reclaimed area, which is an island,
24:33to the mainland.
24:35Do we do that? We don't do that, diba?
24:37If you go to Holland, it's the same thing, some of those.
24:40You go to yung kay Donald Trump ng Mar-a-Largo, ganun yun.
24:46Naka-ausley.
24:48Kaya in between, tatagbo yung tubig.
24:51Walang problema.
24:52Because we just go to the sea, diba?
24:54Yeah, sa madaling salita, Doc.
24:56The way the Manila Bay reclamation is being done
25:00will worsen flooding, sa palagay ninyo.
25:03Yes, because yun na sinabi po ni Loy Saga during the hearing,
25:07kasi nga, kinat mo na yung natural waterways,
25:11na it's an open, big, big, wide, prosperous boulevard.
25:16Pero kung lagay mo ng canal doon,
25:19mag-bridge ka pa punta sa kabilang side,
25:22parang hindi ganun yung reclamation mo.
25:27It will adversely impact yung pag-discharge ng tubig
25:33from the inland to the sea.
25:36So dapat ang design ng project, may daanan yung Pasig River?
25:42Oo, doon sa gitna ng reclaimed area.
25:46Oo, makaroon ng island doon.
25:48Yung reclaimed area is an island.
25:51Tapos meron mga bridges.
25:53You look at some areas sa Louisiana, sa Florida,
25:57ganun ang pag-reclaim nila.
26:00Na iwan doon sa gitna.
26:02Tapos nakalabas pa punta sa sea.
26:05So in other words, ito yung Ross Boulevard,
26:07dito meron kang reclamation.
26:10Sa gitna, open yung canal towards the sea.
26:15About a year ago, I think, there was flooding in Ross
26:18after they built yung Dolomite beach.
26:23Tapos meron nang problema yung pumping and so on.
26:28Kasi nga, na-reclaim mo na yung area na yun,
26:31pero dapat nilagay mo ng waterway in between.
26:36Parang cut-off channel, so to speak, all the way to the sea.
26:41So walang problema kung naganoon.
26:44So bakit nga hindi consider yun?
26:47Matagal na yung problema natin ng pagbabaha.
26:51If I were to think about flood control,
26:53those are things that if you run a digital twin,
26:56nung area na yun, you could see this scenario.
26:59If you do this, if you do that, what happens?
27:02So walang mga ganun sa atin.
27:05We don't do that.
27:06We don't vet it, so to speak.
27:09Kung ano yung mangyari sa flood dynamics.
27:13Now if you look at other areas,
27:15one of the things I've been advocating dito sa Marikina River,
27:18where the water coming from Sierra Madre
27:22and then going down to Marikina City,
27:25all the way to Pasig River,
27:28all the way to Manila,
27:31it's just so much because here are humid tropics.
27:34So how do we control that?
27:35Can you move the water from the mountains
27:39all the way to the other side right away?
27:41Which is, in the case of Kuala Lumpur,
27:44they diverted the water.
27:46This is the Klang River watershed.
27:50Instead of going forward to Kuala Lumpur,
27:53they diverted it dito.
27:55So Iloilo, we have this Haro River or Jaro River.
28:01No matter how you say Iloilo City,
28:04they put a channel that goes right to the sea.
28:08We can't do that.
28:10In fact, I've been suggesting again the other same thing.
28:13There's an area there where they may divert
28:16coming from Mount Kitangan in Bukit Non
28:19goes down to Cagayan River, Cagayan Dior City,
28:22instead of going to Ipunan River.
28:24So it will avoid the big city that you can't do anything about
28:30because it's already there.
28:32There are a lot of developers.
28:33You cannot remove them.
28:35Now, there are schemes in Marikina River where,
28:39of course, in 1982, we built the Mangahan Floodway, right?
28:42Where from Marikina River,
28:45we diverted through Mangahan Floodway
28:47to be temporized towards Laguna Lake.
28:49And part of that,
28:51supposedly, overall flood control scheme
28:54is that because you have now put so much water in Laguna Lake,
28:58and Napinan is a very small channel
29:01to evacuate the waters right away.
29:03That's how they do the spillway.
29:06But they didn't do that because
29:09that area is already very urban.
29:12So there's a scheme now, the World Bank study in 2010,
29:16somewhere in Montilupa, you dig a hole
29:19all the way down 30 meters below, a tunnel,
29:22and then 30 meters hole again,
29:27like a hole, to pump it out to Manila Bay.
29:31But definitely, that's not a good idea
29:35because sediments will come in,
29:37garbage can get in,
29:39and then you have to pump it on the other side.
29:41That's very expensive.
29:43And then part of the World Bank plan
29:45is to put a spillway,
29:47they call it also a spillway,
29:49somewhere in Pakil,
29:51Pangil, Pakil, that area.
29:53If you look at the lake, there are three lobes like this.
29:56There's the west lobe,
29:59there's the central,
30:01and there's the east lobe,
30:03which is somewhere in Jalajala,
30:05all the way to the Pacific Ocean.
30:07But that's Laguna Lake level,
30:10maybe it can go up to 3-4 meters of sea level,
30:13move it almost 22 kilometers to the other side,
30:16it will hardly move the water
30:18from that point all the way,
30:2022 kilometers away.
30:22So I think,
30:24somewhere in Marikina,
30:26a little bit upstream of Marikina Dam,
30:28put a tunnel all the way to
30:30Kaliwa, Kaliwa River,
30:33somewhere in Kaliwa low,
30:35that's about 25 kilometers, 26 kilometers.
30:37So I think that's the scheme.
30:40What would this be, Doc?
30:42A tunnel, like a spillway from the watershed,
30:46heading to the Kaliwa River,
30:48and then the exit is already in the Pacific Ocean?
30:51It will be in Kaliwa River.
30:54Kaliwa River goes to Agos,
30:57and then goes to the Pacific Ocean.
31:00So it's like a diversion,
31:02you will divert the floodwaters,
31:04the Agos of water.
31:06Just like Haro, Haro River, we diverted it.
31:08Or the river,
31:12which is the smart tunnel,
31:14stormwater and road tunnel in Kuala Lumpur,
31:17we just diverted it.
31:18We directed it instead of
31:20going through Marikina.
31:22But in our case,
31:23we diverted it on the other side,
31:25instead of on the other side,
31:28just sideways.
31:29In our case, it's the opposite way.
31:31So this proposal,
31:33this idea to divert water
31:36to the Pacific Ocean,
31:38rather than allow that same water
31:40to flood Metro Manila,
31:43is that being discussed now?
31:46Are those kinds of suggestions
31:48being prioritized?
31:50I always thought there was a little bit
31:52of politics behind that.
31:53In 2010, when the World Bank Study
31:57must have been finished,
31:59and then it was approved by the ICC,
32:03the Infracom of the DBWH Zone,
32:06under Secretary Babe Singson.
32:09That was in 2012.
32:11That wasn't in the study.
32:13I was telling Secretary Babe Singson,
32:16he was DBWH then,
32:17and the water czar,
32:18that's a good idea.
32:20He said,
32:21why don't you ask students to do a study?
32:23So I asked students to do the study.
32:25But it was never really picked up
32:27seriously by the government.
32:28A lot of the flood control,
32:30especially in Metro Manila,
32:32it's like dominated by
32:34chayka consultants.
32:37If that's not really their idea,
32:39I hope I'm not controversial here.
32:41Maybe they will not really entertain.
32:43Maybe not that.
32:44So if you want to do that,
32:46you do it your own.
32:47But who am I to be influencing?
32:51You know, there is a chayka office
32:53in DBWH, right?
32:55So maybe that's not really going
32:57to be entertained.
32:58Because they were insisting that,
32:59oh, you have the Paranaque spillway,
33:01where in 2018,
33:03imagine,
33:042018,
33:052014,
33:06or 2012,
33:08I already started talking about this one.
33:102018,
33:12they did another study
33:15on the Paranaque spillway.
33:17I know the details of that.
33:19It's about 60 billion.
33:21And then they put diking in Laguna Lake,
33:23which is another 140 billion.
33:28Because you diverted water from Marikina
33:30to Laguna Lake.
33:32But you could have avoided that
33:35by spending maybe 60 or 40, 60 billion
33:40to put the tunnel that I'm talking about.
33:42And on top of that,
33:43they have another tunnel
33:47from Pakil,
33:48which is lake level in Laguna,
33:50all the way to Pacific Ocean.
33:52That's what's in the 2010 study
33:55of the World Bank.
33:57That is why I mentioned
33:59the Japanese there.
34:03Because it was a Japanese consulting firm
34:06who did the World Bank study.
34:10So you mentioned the Iloilo.
34:12Let's go back.
34:15So would that be an example
34:19of a flood control project
34:21that has been effective
34:24for you?
34:25Definitely, yeah.
34:27It has been working.
34:29I think the Iloilo River
34:31probably not going to go on.
34:34They were able to build
34:38restaurants.
34:40It didn't flood.
34:41It was a good flood.
34:43Imagine if we could divert,
34:45we could have riverbanks
34:47in Marikina,
34:49which was, I think, suggested
34:50by Architect Palapox back then.
34:53It wouldn't have flooded.
34:56Those riverbanks.
34:59Right?
35:00So what would need to happen
35:02in the Marikina River
35:04so it wouldn't flood?
35:07That's my suggestion
35:08in the Marikina River Basin.
35:11Whereas in the other areas
35:12like here in the San Juan River
35:15that joins Pasig in some words
35:17in Pandacan,
35:19where we have this big
35:21big depressed area
35:24around Rodriguez
35:26and Araneta
35:30and then even part of
35:33Quezon Avenue.
35:35In between that,
35:36there's a hospital
35:38in Delos
35:41where Rodriguez is.
35:43The floods are on the first floor.
35:46That's a low-lying area.
35:48So either
35:49you just have to
35:51abandon your lower area
35:53for housing
35:55or anything,
35:57mga tindahan.
35:58So that's a non-structural measure.
36:00You have to remove the people.
36:02Yeah.
36:03We have to abandon low-lying areas.
36:05No.
36:07Do not use it as a housing
36:09or a shelter.
36:11Maybe parking lot or whatever
36:13para pagba.
36:14Pwede umalis doon.
36:16You cannot put a hospital there.
36:18Yes.
36:19What I'm saying is that
36:21those are non-structural measures.
36:23In fact,
36:24in the World Bank study,
36:26again,
36:27there are
36:29priority areas
36:30where about 700,000 people
36:32have to be removed
36:34in those low-lying areas.
36:36Kamanawa,
36:38San Juan River,
36:40some areas in Marikina,
36:42almost
36:45three-fourths of a million people
36:47you remove.
36:49But this was back in 2010.
36:51Yes, 2010.
36:53Siguradong dumami na yung tao doon.
36:55So ang sinasabi niyo, Doc,
36:57no infrastructure project
36:59can save these low-lying areas
37:01dahil nga
37:03babahalang ng babahayan.
37:05I mean, no matter what we do.
37:07Talaga, hindi talaga siya fit
37:09for human habitation.
37:11Yes.
37:12In other words,
37:14if we run simulation models,
37:16again,
37:17I keep on talking about that,
37:19yung sinaryo na ganto,
37:21karina or undoy,
37:23and it could happen again and again,
37:25what will be the
37:27socioeconomics of that?
37:29Do you still want to live there?
37:31In the flood disaster
37:33management,
37:35you have these five or seven
37:37suits
37:39from the government
37:41from
37:43mitigation, prevention,
37:45you have this adaptation, early warning,
37:47response, recovery, and so on.
37:49Ang ginagawa natin,
37:51response, recovery lang, diba?
37:53Can we prevent? Can we
37:55mitigate? Maybe walang
37:57mitigation lang. So we prevent.
37:59Now, kung
38:01ibagoyin natin yung use lang,
38:03hindi sa titira,
38:05or gusto nang tumira, meron bang
38:07adequate flood warning?
38:09Kasi mag-siren ka para tumakbo
38:11na sila, which is what we do in Marikina.
38:13But can
38:15you really
38:17tolerate that?
38:19Pero meron coping mechanism
38:21ng mga tao maybe. Wala sila choice.
38:23Okay lang sa kanila na umalis uli sila.
38:25But you have the risk na meron ayaw
38:27umalis. Di na matay.
38:29And all these
38:31gasto pag-rescue and so on,
38:33is that
38:35economic?
38:37People rescuing people.
38:39Yes, yes. So, balikan natin
38:41itong sinasabing kailangan
38:43ng tanggalin yung population,
38:45ano?
38:47There are areas.
38:49Which areas are these?
38:51Uh,
38:53na banggitin yung E. Rodriguez sa
38:55Quezon City? Oh, that's one. There were
38:57areas in Marikina that I know
38:59na natanggal
39:01even sa may Pasig.
39:03Somewhere
39:05near the
39:07lakeshore,
39:09in Malabon.
39:11It's in the
39:13World Bank study.
39:15Yeah, so those are very densely populated
39:17areas, no?
39:19Itong ilo-ilo na sinasabing
39:21niyo, ano yung ginawado
39:23na pwede nating tularan
39:25dito sa Luzon, dito sa Metro
39:27Manila?
39:29Sabi niyo nga, effective.
39:31Yeah, in this ilo-ilo,
39:33and this like north and then this
39:35south, ito yung city,
39:37instead of yung river
39:39goes this way pa sa city,
39:41they diverted here
39:43towards the
39:45south
39:47east valley.
39:49Instead of going north to south,
39:51it was going down from
39:53north to southeast.
39:55So, based on that,
39:57naghukay sila ng bagong daanan?
39:59Yes, they created a Mangahan floodway
40:01so to speak.
40:03Mangahan floodway is a man-made channel
40:05that connected
40:07that lower Marikina around
40:09Rosario area,
40:11yung Circulo Verde,
40:13all the way to Laguna Lake.
40:15Yeah, so was the Mangahan floodway
40:17effective?
40:19Kasi malaki din yung ginastos don.
40:21Yeah, the idea behind
40:23that is that you move the
40:25waters from, instead of going
40:27down to lower Marikina and passing
40:29sa napinan,
40:31you temporary store sa Laguna Lake.
40:39You transferred the problem to Laguna Lake.
40:41Yung mga towns
40:43ng Santa Cruz or even parts of
40:45Bael, Los Baños, and then
40:47parts dito sa Binongonan
40:49and so on.
40:51Pag yung water elevation
40:53niya, DPWA's
40:55datum, which is 10.4,
40:5710.5 meters
40:59above sea level yung
41:01pinaka zero niya.
41:03Anyway, if you say
41:0514 meters bali,
41:07as opposed to 11.5.
41:09Pag 11.5 minus 10.5,
41:11that's only 1 meter above sea level.
41:13Yan ang meaning no.
41:15Pag 14 minus 10.5, that's 3.5
41:17meters above sea level.
41:19During ang do'y umabot ng 14,
41:21mga 12.5
41:23or more, babayan na yung
41:25and so on.
41:27Ngayon, during ang do'y
41:29umabot ng 14,
41:31it took 90 days,
41:33a little bit over 3 months,
41:35to move the water from 14
41:37back to mga 12.
41:39Pero,
41:41you were able to put
41:43from 12 to 14
41:45during ang do'y lang bali.
41:47Anong kadami yung ulan na yon?
41:49Napuno yung lake.
41:51And it took 3 months
41:53pagun umupas ulit na gano'n.
41:55Because you diverted
41:57water. So, essentially
41:59you transferred the problem
42:01to them.
42:03To the Laguna towns.
42:05You were able to alleviate flooding
42:07in Pasig River along
42:09Pagkati or maybe
42:11along Malacanang
42:13or Pandakan.
42:15Pero, yung nag-suffer
42:17yung mga tagalaguna towns.
42:19Nilipat mo lang sa Laguna Lake, no?
42:21So, pinakamagandang
42:23solusyon, ilipat ang tubig sa dagat
42:25talaga. Sa dagat talaga.
42:27That's the reason why
42:29dapat merong parangyaki spillway
42:31para mabilis tumakbo do'n.
42:33Pero, hindi nga nagawa yan.
42:35Papunta ng Manila Bay.
42:37Papunta ng Manila Bay, ano.
42:39That's the reason why we need a dedicated
42:41body to be able to do
42:43all of this. Yung Department of Water
42:45Resources, part and parcel
42:47of the department,
42:49to look at this problem every day.
42:51Hindi pwede yung after 5 years
42:53after 10 years, may mangyari
42:55na malaki.
42:57You mean a department?
42:59Yeah. The Department
43:01of Water Resources,
43:03it already passed Congress.
43:05Being
43:07entertained by Senate na ngayon.
43:09Big part of that is to look
43:11into yung adaptive
43:13planning na sinasabi ko. And it will
43:15have a division to have
43:17planning, operation studies,
43:19scientific support,
43:21to see all these kinds of
43:23problems on a continuous
43:25basis. Cannot be like
43:27reactive lang tayo parate.
43:29Hindi sapat yung DPWH
43:31ngayon kasi yan ang tinuturo ng
43:33karami. The DPWH,
43:35if you look at the flood control na ginagawa
43:37nila, first of all,
43:39along national
43:41ng mga waterways, highways.
43:43They don't really look at the local
43:45flooding. These are LGU
43:47issue. So meron ng mga
43:49subdivision, magtateyo ka,
43:51meron kang mga supposedly
43:53local na flood studies,
43:55what's the impact of that? Pero
43:57ginagawa ko nila. Walang tumiting
43:59isa nila na gano'n. And then
44:01given na lumabas na subdivision
44:03na yung tubig, papunta doon
44:05sa National Drainage, which is DPWH.
44:07Meron bang National
44:09Drainage na adequate
44:11enough to move all the way to the
44:13rivers, to Manila Bay.
44:15Wala.
44:17And then if you look at flood
44:19control, that's why
44:21holistic manner, dapat
44:23tingnan muna sa watersheds.
44:25If the watershed is done by
44:27DNR, are they
44:29really looking at flood control?
44:31They try to look at flood control
44:33but they're more into
44:35landslides and things like that.
44:37Hindi talaga yung flood
44:39disasters. So walang
44:41coordination. So during the Senate
44:43hearing, they were talking about coordination,
44:45collaboration.
44:47But without the digital twin
44:49I'm talking about, because flooding
44:51is a wicked problem. It's
44:53a large-scale, complex, uncertain,
44:55unpredictable, land
44:57vineyard, and so on. Kailangan ang vehicle
44:59to be able to see this.
45:01You draw a simulation, then visualize.
45:03Anong mangyari kung gawin na ito?
45:05Gawin na din yan. What happens in time?
45:07In space?
45:09For a prolonged storm
45:11as opposed to a sudden onset storm.
45:13Change in land use, change in
45:15mga behavior,
45:17garbage, and so on. All those
45:19things, to be able to see
45:21in a very
45:23big-picture, holistic manner.
45:25You have that kind of digital twin.
45:27Otherwise, yung mga taga
45:29DNR, yung mga
45:31taga DWH, yung mga
45:33LGU, hindi nila makikita yun.
45:35That's what it takes to do these kinds of
45:37to solve problems like this.
45:39And then you have to time the investments.
45:41Investments are really
45:43parang
45:45ang hirap na makakuha ng pera.
45:47So if you're
45:49not able to do this, you're not able to do that,
45:51can you
45:53improvise? Can you retrofit?
45:55You have to do that
45:57kasi walang pera.
45:59Okay, Doc. Andami na na ating
46:01na pag-usapan na napaka
46:03enlightening. So we want to
46:05thank you for
46:07educating us.
46:09We hope more of our policy makers
46:11listen to people like you.
46:13Dr. Guillermo Tabios,
46:15isang expert of flood control
46:17systems. Maraming salamat po
46:19at mabuhay po kayo.
46:21Thank you very much, Howie.
46:23Hi, I'm Howie Severino.
46:25Check out the Howie Severino Podcast.
46:27New episodes will stream every Thursday.
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