Urban Flood Nowcasting System (Drainage and Rainfall Coupling)
Ministry of Earth Sciences (MoES) · Disaster Management · Software
The abstraction is elegant and the specification is excellent, but the drainage graph it depends on is not public for any Indian city — if you take it, get a real network from one municipal ward or accept that you are modelling a drainage system you made up.
What it actually is
Knowing how much rain will fall on a city does not tell anyone which junctions will go under, because that depends on the shape of the streets and the state of the drains beneath them. The ask is a system that routes forecast rainfall across the actual terrain and through a model of the storm drain network to say which streets flood, how deep, and within the next three hours.
What to build
A coupled surface-and-network flood nowcaster as the statement specifies: rainfall nowcasts routed across a high-resolution surface terrain model accounting for the imperviousness that makes urban runoff so fast, coupled to a directed graph of the stormwater system with manholes and inlets as nodes and pipes and canals as edges, each edge carrying a hydraulic capacity so the model computes where the network surcharges and water backs up onto the street; outputs as street-level inundation with depth estimates over a zero-to-three-hour window on a live GIS dashboard, plus a routing API returning flood-safe alternatives for emergency vehicles and commuters.
Smallest thing that wins the room
Feed the rainfall from a documented flood day into the coupled model and show your predicted flooded junctions and depths against the locations that were actually reported waterlogged that day.
How crowded this one gets
A guess, projected from the 2025 statements — the last year where both the submission counts and the winners were published.
Quieter than 40% of the 226 · #137 of 226 by expected field
A normal-sized field. Your idea has to be good, not miraculous.
Why: central ministry statements sat below the average.
This is a guess, not a fact
Nobody has published 2026’s numbers yet. This is an analysed estimate from last year’s pattern, so please do not take it as the truth — check the live counter on the SIH portal before you decide anything. The range covers the middle half of likely outcomes, so one statement in two lands outside it. Entry closes at 500 ideas per statement, so no range goes past that — a statement that reaches the cap fills and shuts rather than drawing an unlimited crowd. The model reads only three things a team can see before choosing — software or hardware, the theme, and what kind of body posted it — and those explain about a quarter of the variation in last year’s field sizes (R² 0.25 on held-out statements). Trust the band more than the number, and the ordering more than either. It cannot see how good your idea is, which is the part that actually decides it.
The scores
The number is the shorthand. The line under it is the reason.
Acceptance potential
2/5The drainage graph is the explicit core of this statement and it is not obtainable for any Indian city, so submissions will synthesise the network and then demonstrate a model of a drainage system that does not correspond to the one under the streets — producing authoritative-looking depth maps with no basis.
Feasibility
2/5The statement's central mechanism is a graph of the city's stormwater network with per-pipe hydraulic capacity, and that data is held by municipal corporations and is not published — without it the drainage half is a graph you invented, and the metre-scale terrain the surface routing needs is equally unavailable for Indian cities.
Innovation scope
3/5The coupled architecture, the graph representation of the drain network and the surface routing approach are all specified, leaving the hydraulic solver choice and the coupling scheme between surface and network as the genuinely open decisions.
Clarity
5/5Among the most precisely specified statements in this block — it fixes the lead time, states the output as water depth in centimetres at street level, defines the drainage representation down to what the nodes and edges are, and specifies both the dashboard and the routing API.
Effort
MassiveSurface routing over a fine terrain model, a hydraulic network solver on a city-scale graph, the coupling between them, a live dashboard and a routing API is five components, and coupled surface-network hydraulics is a specialist engineering discipline in its own right.
Demo-ability
MediumPredicted flooded junctions checked against locations actually reported waterlogged on a documented day is honest and persuasive, but the map's credibility rests entirely on the terrain and drainage data beneath it and a judge will ask about both.
In its favour
- Green flag: The graph representation of the drain network is genuinely the right abstraction and is elegantly stated — modelling surcharge and backflow as capacity violations on edges is both correct and computationally tractable
- Green flag: Established open hydraulic modelling engines exist for exactly this coupled surface-network problem, so you can build on validated hydraulics rather than writing a solver
- Green flag: Crowd-reported waterlogging locations from documented flood days are findable, giving you at least a qualitative validation target for which junctions flood even without measured depths
- Green flag: The flood-safe routing API is a concrete, immediately understandable output that makes an abstract hydraulic model useful in the demo
Against it
- Red flag: Stormwater network topology and pipe capacities are held by municipal corporations and are not public, so the graph at the centre of this system has to be invented — and a hydraulic model of a fictional drainage network predicts fiction
- Red flag: Metre-scale urban terrain is equally unavailable, and the freely available elevation data cannot resolve the difference between a road and the drain beside it, which is the entire question
- Red flag: Depth in centimetres is a very precise claim to make from invented inputs, and presenting it that way invites exactly the scrutiny the model cannot survive — grade the risk instead
- Red flag: Coupled surface-network hydraulics is a specialist discipline and a naive implementation will produce plausible-looking but physically wrong results that nobody in the room can check
What you will be writing
- SWMM-style hydraulic network solver
- directed graph drainage model with capacity constraints
- 2D surface routing over high-resolution DEM
- imperviousness-weighted runoff coefficients
- radar rainfall nowcast coupling
- flood-aware routing API over road network
- Urban hydrology
- Flood modelling
- Municipal emergency response
Prior art to read before you start
coupled surface and drainage flood modelling · street-level inundation depth prediction · flood-safe routing for emergency services
Analysed by Claude Opus. Every score above is a judgment call with its reasoning attached — kindly cross-check this against the official statement on the SIH portal before your team commits to it.