Storm-surge early warning for 340 km of coastal defence
The Zeeland Water Board needed surge warnings earlier than tide-gauge networks alone could provide, across a defence system too large to instrument densely.
The challenge
Zeeland's defence system spans 340 km of primary and secondary flood defences protecting roughly 380,000 people. The board's existing tide-gauge network gave excellent point measurements and nothing in between. Dyke condition was surveyed on a six-year cycle by levelling, which is accurate, slow and expensive.
What we did
Terravek deployed 46 FIELDKIT 400-M tide and pressure nodes along the defence line and combined them with TIDEWATCH satellite-derived shoreline and dune volume monitoring, and an ORBIS persistent-scatterer interferometry stack for settlement. Threshold alerts are issued to the board's duty officer within 25 minutes of downlink.
Results
- Surge warnings issued on average 3.5 hours earlier than the previous process
- Dyke settlement now monitored continuously at 2 mm/year sensitivity, replacing the six-year levelling cycle for screening purposes
- Dune volume assessed after every named storm rather than annually
- Awarded the 2025 Geospatial Impact Award for Coastal Resilience
We have not replaced our engineers' judgement. We have given them a picture of the whole system between surveys instead of four points and an assumption.
Programme Manager, Zeeland Water Board