(VA) (Friends of Dyke Marsh) Help us map Potomac River tides October 10 to 12 during the highest tides of the year, called “king tides.” Participants will use a mobile app that collects location-based data points along the water’s edge. Sponsors will hold a training before the mapping event. This data can help researchers develop models that simulate tidal dynamics and sea level rise. To participate, email Stacy Langsdale, at [email protected].