NOAA’s national water level observation network (NWLON)

ABSTRACT The National Oceanographic and Atmospheric Administration National Water Level Observation Network (NWLON) is the foundation of a comprehensive system for observing, communicating, and assessing the impact of changing water levels nationwide. The network also measures other oceanographic parameters in addition to water levels, including meteorological parameters. Although initially established to support navigation, NWLON is a ‘go to’ source for data and products to support coastal community decision making. Real-time water level information available 24/7 is critical to emergency managers and planners monitoring changing water levels and contributes to NOAA’s forecast model for tsunami and storm surge warnings. This article also discusses the role of NWLON in terms of addressing emerging observational needs around emergency management, tracking changes in sea level rise through persistent changes in high tide flooding, establishing new regional sea level scenarios and projections, and restoring tidally influenced habitats. Sea level trends have been computed at 142 water level stations using a minimum span of 30 years of observations at each location. Coupling present trends with projected future scenarios supports decisions that will remain relevant into the future.