BROADCASTS.com

Host Dan Zehner talks with scientists whose jobs are forecasting and planning for stormsurge and flooding. Coastal engineer Cheryl Ann Blain works in the oceanography division in the Office of Naval Research. David Johnson is a professor of engineering and political science at Purdue University. At the Naval Research Lab in Mississippi, Blain develops storm surge models and forecasts with the ADCIRC tool. She discusses the history and importance of ADCIRC, one of the first hurricane modeling tools developed. It is used around the nation for regional forecasting and predicting local storm surge. ADCIRC makes relatively accurate predictions, usually within three days of the event. Blain discusses data that is used to build a forecast, including wind and topography data. She explains the trend for using ensembles of data, different groupings of info, which produce the \u201cspaghetti plots\u201d we see in hurricane forecasts. David Johnson agrees with Blain that some things, such as storm direction, are hard to predict because we don\u2019t fully understand how hurricanes form. As a result, we still make guesses about what sorts of data should go into our models. One of projects Johnson works on is Louisiana\u2019s coastal master plan project. Louisiana seeks to reduce flood risk and land loss, so policy-makers and scientists are trying to determine how factors like changing climate, population and ground subsidence will affect the region. To plan, they develop multiple scenarios and estimate risk, depending on various strategies, such as building levies or wetlands. Planners weigh priorities, which are often in conflict. For example, building a levee takes years; so should the state first dedicate itself to elevating houses? Such planning is not limited to the Gulf Coast. New Jersey and New York, after Superstorm Sandy, are making similar plans. Johnson and Blain discuss how national infrastructure is affected by storm surge affects, including NASA, which has many coastal installations. They discuss how levees prevent river flooding but then prevent natural distribution of river sediments \u2013 a natural process that creates protective coastal wetlands. In Louisiana, planners must manage river flooding as well as stormstorm flooding. Johnson and Blain discuss why it is not possible for the US to replicate the success of the Netherlands, when it comes to preventing flooding and sea inundation.