An open offer · Isang bukas na alok
A working flood early-warning app, ready to be taken further in the Philippines.
Babala sa baha, mula sa opisyal na datos.
Justin James · The Possible · October 2026 · Experimental — not an official warning service
Project summary
Manila Flood Monitor is a flood early-warning app built for the Marikina watershed by The Possible. It reads official river, dam and rainfall data, works out which homes are affected, and sends a warning in English or Filipino to iPhone and Android, always labelled official or app-derived.
It is free, has no accounts and no ads, and runs on Amazon Web Services for under ₱2,000 a month. The apps are in beta.
This deck offers a copy of the code to a sponsor in the Philippines, government or private, to fork, rebrand and run beyond the pilot. The ask is a small credit and four promises to the people who use it.
Contents
Why it matters
3
The offer in short
4
What it does and how it works
5
Hosting and what it costs
8
Manila: how it behaves
10
Where it stands
14
Bulacan and Cagayan Valley
16
Taking it further
18
Who could take it on
21
Terms and support
22
About
24
Manila Flood Monitor · An open offer for the Philippines · 2
Why it matters
More than 8.8 million people were affected. Closer to home, the water reached my mother-in-law and her neighbourhood. No app can promise it would have saved anyone. A warning that reaches the right phone earlier might.
One life saved, and an app and its sponsor have made a difference to someone's mother or father, son or daughter, wife or husband.
Source: NDRRMC figures, reported 7 September 2026 (43 dead) and 31 August 2026 (8.8 million affected).
The short version
In return: a small credit to the team that built it, and a few promises to the people who use it.
The problem
What the bulletin says
247.42 m³/s
Spill rate at Upper Wawa dam, published as a number in a government post.
What a resident needs at 3 a.m.
What happened?
Where?
Does it affect me?
What do I do now?
Manila Flood Monitor · An open offer for the Philippines · 5
What it does
01
Polls official river gauges, dam bulletins and rainfall every 5–15 minutes. Every raw response is archived unchanged.
02
Turns readings into events: thresholds crossed, rapid rises, dam gates opening, sources going quiet.
03
Works out which saved homes sit downstream, from the watershed map. Nobody has to know their river basin.
04
Pushes a bilingual warning, always labelled as official or app-derived, with a link to the source.
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How it works
River gauges, dams and rainfall, published by government agencies.
Runs on Amazon Web Services. Checks every 5 minutes, spots what has changed, works out who it affects.
An app for iPhone and Android. A warning in your language, with what to do next.
Built: the iPhone and Android apps, from one codebase
Built: cloud templates that set up the whole system in a new account
Manila Flood Monitor · An open offer for the Philippines · 7
How it is hosted
Government gauges, dam and rain bulletins
Scheduled functions, every 5–15 min
Raw responses in locked, versioned storage
Queue, validation, rules engine
Map database, API, push to iOS and Android
AWS, Singapore
The nearest full AWS region to Manila.
About ₱500–1,600 a month
US$8–25 at current scale. No servers to patch.
One codebase for the apps
Expo builds iOS, Android and web. The public site is on Cloudflare Pages.
Infrastructure as code
AWS CDK in TypeScript; redeploys into a new account from the repo.
Manila Flood Monitor · An open offer for the Philippines · 8
What it costs a sponsor
Pilot
up to 1,000 users
₱1,600–3,100 a month
US$25–50
City
around 50,000 users
₱6,300–12,500 a month
US$100–200
Metro
around 500,000 users
₱31,000–63,000 a month
US$500–1,000
At city scale that is about 20 centavos per user a month. Push notifications to iPhone and Android cost nothing to send.
Estimates at AWS list prices, at about ₱62.5 to the US dollar. Hosting only; excludes people's time and app-store fees (Apple ₱6,200 a year, Google ₱1,600 once). · 9
Example: Manila
Upper Wawa
dam, open spillway
Rodriguez
river gauge
San Mateo
river gauge
Marikina
Sto Niño, Tumana
Pasig
downstream
Each gauge against its own published levels · illustrative
Normal
Alert
Alarm
Critical
Thresholds are scraped from PAGASA's own table and stored as versioned rows, never hardcoded. A reading near Critical looks the same at every station.
Manila Flood Monitor · An open offer for the Philippines · 10
Rising water
A rise of 0.5 m in 30 minutes, measured from the low point, raises a warning while the river is still below Alert.
A dam releasing or a gauge climbing upstream reaches downstream homes before the water does.
Dam spill rate is tracked over a sustained window, so a single noisy reading does not set anything off.
Forecasting is deliberately not switched on yet. Every reading is archived, so travel times between gauges can be measured from real storms and added later, presented as history rather than prediction.
Manila Flood Monitor · An open offer for the Philippines · 11
Safety rules
What is shown is the higher of the official status and the app's own reading. Never the lower.
If data stops, the app says so: “latest official reading is 43 minutes old”. No reassuring green screen.
On 9 August 2026 two Manila gauges were frozen above Critical. The app recognised them and sent no false alarm.
Every notification and screen says which is which, and links to the source.
Delays and confirmations apply only to all-clears. An escalation goes out at once.
Rules and official thresholds decide. Residents' reports can confirm, never trigger.
Manila Flood Monitor · An open offer for the Philippines · 12
Where it sits
| National alerting | This app | |
|---|---|---|
| Issued by | Government: NDRRMC, PAGASA, the LGU | Relays and labels official warnings |
| Scope | A province or district | A saved home and its river |
| Says | The instruction: prepare, evacuate | The reading behind it, the trend, upstream |
| Reaches | Every phone in an area | People who install it and save a place |
It never issues an evacuation order of its own and always points back to the official source first.
Manila Flood Monitor · An open offer for the Philippines · 13
Where it stands
410
automated tests
16
river gauges read live
9
dams tracked
2
languages, English and Filipino
iOS
TestFlight public beta
Android
Google Play internal testing
Backend
Live on AWS, polling every 5 minutes
Push
Switched on; first handset delivery not yet confirmed
Manila Flood Monitor · An open offer for the Philippines · 14
See it for yourself
The public site for the Philippine pilot, in English and Filipino.
Why it was built: “It is free, it is experimental, and if anyone with the mandate wants it, it is theirs.”
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Example: Bulacan and Pampanga
Angat Dam
Norzagaray; gated spillway
Ipo Dam
diverts water to Metro Manila
Bustos Dam
Angat River, mid-reach
Calumpit and Hagonoy
where the Angat meets the Pampanga
Angat is one of the nine dams the app reads from PAGASA's bulletin, gates and outflow included.
A gate opening upstream reaches the lowland towns hours later. The app passes it down the river to every saved home in its path.
[Sponsor] Flood
FIL | EN
Not an official warning
Angat Dam has opened its gates. Water is being released downstream.
Home · Calumpit
ALARM · OFFICIAL
Angat releasing; river rising downstream
Upstream
Angat Dam · 2 gates open
Ipo Dam · spilling
Rain here · heavy, 3 h
● Data current · 4 min old
Illustrative mock-up — not a live reading. Downstream gauges and catchment maps still to add.
Example: Cagayan Valley
Magat Dam
Isabela; gated spillway
Magat River
to the Cagayan
Cagayan River
flows north through the valley
Tuguegarao
Buntun Bridge reference gauge
After Typhoon Ulysses, Cagayan and Isabela saw their worst flooding in decades while Magat was releasing water.
Knowing when a dam opens, and what that means downstream, is exactly what the app is for.
[Sponsor] Flood
FIL | EN
Not an official warning
Magat Dam has opened its gates wider. More water is coming downstream.
Home · Tuguegarao
CRITICAL · OFFICIAL
Cagayan at Buntun Bridge above critical
Upstream
Magat Dam · gates opened wider
Cagayan River · rising quickly
Rain here · heavy, 3 h
● Data current · 4 min old
Illustrative mock-up — not a live reading. Cagayan basin adapter and thresholds to confirm with PAGASA.
Taking it further
Manila Flood Monitor · An open offer for the Philippines · 18
Integration points
| Source | Provides | Status |
|---|---|---|
| PAGASA Pasig–Marikina–Tullahan gauges | River levels, thresholds, declared status | Built, verified live |
| PAGASA dam bulletins | Nine dams: level, gates open, outflow | Built |
| PAGASA rainfall stations | 25 stations, six time windows | Built |
| PAGASA warning posts | Official Alert, Alarm, Critical | Built |
| OCD CALABARZON bulletins | Upper Wawa spill status and rate | Built; no live feed |
| Other PAGASA basin centres | Pampanga, Cagayan, Agno, Bicol | Planned |
| NOAH and GeoRiskPH | Hazard maps and catchments | Planned |
| LGU notices | Evacuation orders | Planned |
An unverified source runs below full confidence and can never originate a critical warning. The unofficial PAGASA Marikina API is never used.
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Language
ENGLISH
Marikina is rising quickly
The river rose 0.6 m in 30 minutes. This is our own reading of official gauges, not an official warning.
FILIPINO
Mabilis na tumataas ang Marikina
Tumaas ang ilog ng 0.6 m sa loob ng 30 minuto. Ito ay sarili naming pagbasa ng opisyal na gauge, hindi opisyal na babala.
NEXT
Cebuano, Ilocano, Hiligaynon
Each is another column in the same catalogue. Safety copy is reviewed by a native speaker, never shipped from machine translation.
One shared catalogue feeds the app, the site and every push. The build fails if a string is missing in any language.
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Who could take it on
NDRRMC or OCD, MMDA, a provincial DRRM office, or an LGU such as Marikina.
Street-level context beside the national alerts, owned outright and run under your name.
A telco, bank, insurer, utility, property developer or corporate foundation.
A free safety app carrying your name and logo, and nobody else’s. Useful to residents, good for your reputation.
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The offer
Manila Flood Monitor · An open offer for the Philippines · 22
Support
You have your own engineers
The code, docs and tests are yours, and the handover walkthrough is included. Your team takes it from there.
You want our help
Specific customisation and ongoing support are charged, because they come out of someone's time.
Sponsors can be government or private sector, or both together.
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About
Co-founder, The Possible
I am British. My wife is Filipino, and our son is both Filipino and British. This is my way of saying thank you for the generosity of the people I have met and worked with in the Philippines.
British deep-tech architect, 25 years across silicon, banking, defence and marketing technology. Founded Agencie.io Labs in 2022.
linkedin.com/in/justinjj · thepossible.agencie.io/founders · justin@agencie.io
A not-for-profit build and innovation lab for startups, founders and investors.
Manila Flood Monitor · An open offer for the Philippines · 24
Next step
Let's talk about taking it further in the Philippines.
Justin James
Co-founder, The Possible · justin@agencie.io