COASTAL FLOODING & SOLUTIONS, Workshop July 2020
Tidewatch Maps tidal water level predictor for flood resiliency
Assistant Research Faculty
Tidewatch Maps is a visual water level predictor for Virginia’s coastal plain. It was developed in response to stakeholder observations from the Hampton Roads Adaptation Forum that graph-based water predictors were not useful unless you knew the elevation of your current location and/or all roadways on which you planned to travel. Stakeholders specifically requested a map-based predictor, with water depths depicted as depths above ground (rather than tied to a tidal datum). Development of Tidewatch Maps was supported by the Commonwealth Center for Recurrent Flooding Resiliency, which provides responsive scientific and technical support to the Commonwealth, state agencies, and localities. Tidewatch Maps is based on a robust hydrodynamic model, SCHISM, which uses a large domain (US East and Gulf Coasts) combined with atmospheric wind and pressure forecasts to automatically compute hourly tide simulations at 220 sub-basins of Virginia’s coastal plain. Sub-basin water levels are translated to depth-over-land using a high resolution topo-bathy surface. Forecasts are updated every 12 hours and extend up to 36-hours into the future. Tidewatch Maps spatial flood coverage was validated using >100,000 GPS-reported high water marks collected by citizen scientists during two king tide flooding events occurring in 2017 and 2018.
The key success of the project is the development of a stake-holder requested tool using a model process that is efficient enough to run twice daily and to maintain indefinitely.
Validation of the geographic flood coverage has only been done in areas where citizen scientist were operating, this coverage needs to be expanded.