The Zeeland Water Board protects roughly 380,000 people behind 340 km of flood defence. Since 2024 they have received storm-surge threshold alerts from TIDEWATCH, on average three and a half hours earlier than their previous process.
The system combines three things: forecast surge from the national meteorological model, observed water level from 46 FIELDKIT 400-M gauges distributed along the defence line, and a continuously updated picture of defence condition from ORBIS interferometry and dune volume monitoring.
The gauges matter more than people expect. A forecast is a forecast; a gauge reading is what is happening. The alert logic requires forecast and observation to agree before it escalates, which suppresses a category of false alarm that erodes trust in a warning system faster than anything else.
The limits we stated at the outset, and restate here: this is a decision support tool for a duty officer, not an automated system. It does not close barriers. It does not replace the board's engineering judgement or its statutory inspection regime. And the interferometric settlement monitoring is a screening tool that tells you where to send a levelling crew, not a replacement for one.
It won the 2025 Geospatial Impact Award, which we are pleased about. The three and a half hours is the part that matters.