Operational Total Water Level and Coastal Change Forecasts
The USGS National Assessment of Coastal Change Hazards project is working with the National Weather Service (NWS) and the National Centers for Environmental Prediction (NCEP) to combine wave predictions from the Nearshore Wave Prediction System (NWPS) with USGS-derived beach morphology to provide regional weather offices detailed forecasts of wave-induced water levels. The interagency operational model is available at select pilot sites and model forecast can be accessed in the Total Water Level and Coastal Change Forecast viewer. The viewer includes predictions of the timing and magnitude of water levels at the shoreline and potential impacts to coastal dunes.
The primary components of total water level elevation along the coast include tides, surge, and wave-induced runup. However, existing operational water level models do not account for wave-driven water levels. The USGS National Assessment of Coastal Change Hazards project is working with the National Weather Service (NWS) and the National Centers for Environmental Prediction (NCEP) to combine wave predictions from the Nearshore Wave Prediction System (NWPS) with USGS-derived beach morphology to provide regional weather offices detailed forecasts of wave-induced water levels. A pilot study is on-going at Duck, North Carolina with additional sites to follow. For each study area, tides and subtidal water levels are provided by the Extratropical Surge and Tide Operations Forecast Systems (ESTOFS) and wave properties (wave height and period) are being provided along the 20-meter isobath by the NWPS. These wave characteristics provide input for the empirical wave runup model developed by Stockdon and others, 2006. Beach slopes and slope uncertainty, also required by the wave runup model, are provided from multiple USGS lidar surveys in the same area. The method for determining average beach slope for U. S. sandy coastlines, along with published datasets, is published in Doran and others (2015). The spatial and temporal uncertainty in total water level due to variability in beach slope and wave height and period is also predicted using the methodology described in Doran and others (2015). Existing and future pilot sites will be instrumented with video remote sensing equipment to provide observations of total water levels for comparison to predicted values. In addition, processes driving extreme water levels and sediment transport under storm conditions will be explored to improve predictions.
Stockdon, H.F., Doran, K.J., Sopkin, K.L., Smith, K.E.L., and Fredericks, Xan, 2013, Coastal topography–Northeast Atlantic coast, post-hurricane Sandy, 2012: U.S. Geological Survey Data Series 765, http://pubs.usgs.gov/ds/765.
Doran, K.S., Long, J.W., and Overbeck, J.R., 2015, A method for determining average beach slope and beach slope variability for U.S. sandy coastlines: U.S. Geological Survey Open-File Report 2015–1053, 5 p., http://dx.doi.org/10.3133/ofr20151053.