CAM-175

The water climbing the steps

Night, after hours of rain. The water is coming down brown and foaming through the lined channel and has covered almost the whole flight of access steps: three treads are still above it. On the wet walkway a small group stands watching, and more people lean over from the bridge. IRIS reads how high the water stands against the stone treads, which have been there for as long as anyone remembers and do not move.

CAM-175 · ACCESS STEPS · LEVEL OVER STEPS

What IRIS understands

What it recognises in this scene

steps under water
access steps
people on the walkway
people on the bridge
floating debris

What this camera measures

An alert says something is happening. The reading says how much.

9 / 12Treads covered
2,10 mHeight above the first tread
+25 cm / 10 minRate of rise
2,40 mLevel at which access closes
8Leaning over the channel
20:30Time of the reading

The figures on this screen are an example from the illustration, not any client's measurement.

The series, not one figure

One number says nothing. A curve does.

The water on the steps, every ten minutes

Height above the first tread
Level at which access closes

The water on the steps, every ten minutes
Slot	Height above the first tread
19:30	0.55 m
19:40	0.7 m
19:50	0.95 m
20:00	1.25 m
20:10	1.55 m
20:20	1.85 m
20:30	2.1 m
Level at which access closes	2.4 m

The figures on this screen are an example from the illustration, not any client's measurement.

The rule

You decide once. IRIS applies it always.

the water covers the tread the council has marked, or rises faster than the rate that has been set

Then

alert the civil protection officer with the camera, the reading and the last hour's curve
say how many people are leaning over the channel at that moment
repeat the alert every ten minutes while the water keeps rising

The instruction that set it up«Tell me which tread of the steps the water has reached, and alert me when it passes the one we have marked.»

What changes

What changes for whoever answers for the site

"The water is 2.10 m above the first tread" tells nobody anything. It may have been like that all afternoon. What decides whether the access gets closed is not the height: it is the rate. The first ten minutes it rose fifteen centimetres; the last ten, twenty-five. That slope is visible at a glance on the chart and does not fit in a single number. The person on duty looks at the curve, sees where the level the council set sits, and decides to close the steps before anyone has to be pulled off them. IRIS closes nothing and predicts nothing: it reads a height against a stone that is standing there, and draws it as it changes.

What people usually ask

Does this replace the catchment sensors?

No, and it is worth being blunt about it. This is a reading against a visible reference — a flight of stone steps — taken with a camera, and it is only good for the stretch of channel that camera sees. It is not a hydrological warning system: it does not measure discharge, it does not know what is happening kilometres upstream and it does not announce a flood wave. The catchment sensors and the emergency service go on doing their job exactly as before, and this camera takes no function away from them. What it adds is the thing they lack: what is happening at this precise spot, and whether anyone is standing in front of it.

Does IRIS warn that a flood is coming?

No. IRIS does not predict. The chart only has data to the left of now: there is no curve drawn into the future, because IRIS does not know whether in ten minutes the water will go up, go down or stay where it is. What it shows is what the water has done up to this moment against a reference that does not move. With that, a person decides. Without it, they decide anyway — blind.

And at night, or with the water running very dirty?

The reading is not about the colour of the water: it is about where the waterline sits against the treads, and that shows up just as well at night under the walkway lights. When the camera cannot read the reference — thick fog, rain on the lens, a dirty housing — IRIS says so and stops giving the reading, rather than giving an invented number. A reading that fails silently is worse than no reading at all. And as for the people leaning over, IRIS counts bodies and nothing else: it does not identify anyone, it does not recognise faces and it does not read number plates.

Other cameras

Demo · IRIS at work

Watch what happens. Then watch what IRIS does with it.

Not a recorded video and not a drawing: it is a summary of the real tool, with a different case each time round. The whole tool does not fit in a box.