Catch the Wave

Accurate data on the behavior of storm surges could lead to more intelligent zoning, infrastructure, and land management programs. According to Ben McGee, a supervisory hydrologist with the U.S. Geological Survey (USGS), "storm surge data had always been generated after the storm. We'd basically go into a storm-impacted area . . . and look for high-water marks." Hurricane Katrina got members of the USGS's Ruston, LA, office thinking about how helpful it would be to track surge levels during the storm. Then came Rita, which gave them that chance.

 Collect storm surge data during a hurricane
Collect storm surge data during a hurricane

A number of federal and private agencies are interested in storm surge level data: FEMA for flood zone labeling and building codes, and the USGS for scientific purposes such as understanding the water quality effects of storm surge and its effect on ecosystems. And the affected states apply the data to relief funding and making decisions about where it is safe to rebuild.

As Rita made for land, McGee and his team had 72 hours to secure USGS approval to buy 46 HOBO water-level data loggers from Onset, get them to Louisiana, and install them in protective housings in areas expected to be hit hard. Based on a digital elevation model, that area looked to be ~4000 sq. mi., so judicious selection of monitoring points was essential. The team worked all night to mount the loggers on pilings, bridges, and other Louisiana coast structures likely to survive the hurricane.

The loggers were configured using laptops running HOBOware software, and programmed to measure and record water levels every 30 s around the clock. They were then placed in housings made of 1.25 in. O.D. steel pipe. A week later, about 80% were recovered. The USGS team is off-loading and analyzing the data, which will be stored in a database and displayed in a time-series format to give researchers a visual sense of the flood as it happened.

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