Tideline

The problem

Port Ellery had four websites about flooding, each run by a different team. During a storm, residents saw a gauge reading of “4.62 m” and had no idea whether to move the car.

The council phone line took the questions the websites could not answer, at the exact moment staff were needed elsewhere.

What people actually asked

We read two winters of call logs. Almost nobody asked how high the water was. They asked what to do, when, and whether their street was affected.

Interviews with residents of the harbour streets added a second finding: people trusted forecasts more when they were told how uncertain they were.

Action first, then the numbers

Every warning leads with a single action word: Watch, Prepare, Act or Leave. The tide forecast is drawn as a range with a likely band, never as a falsely exact line.

Flood zones are hatched as well as coloured, so they read in greyscale, for colour-blind residents and on the library’s black-and-white printer.

For the first time our residents were a step ahead of the water, not a step behind the phone queue.

Fast, plain and printable

The service is static HTML regenerated every five minutes, so it stays up when traffic spikes. Every map has a table alternative listing streets and their risk, which also became the most-used view on phones.

What changed

Alert sign-ups tripled in the first winter and calls to the council during warnings fell by forty-one per cent. Three old sites were switched off.

What I’d do differently

I underestimated paper. The printed summary pinned up in the harbour café was read by more people in the first storm than the website was. Next time I would design the poster first.

Sample case study: the client, team, figures and quote are fictional.