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As Hurricane Michael rapidly approached the Florida coastline, USGS scientists used a new storm-tide sensor network along the Gulf Coast to quickly install more than 30 storm-tide sensors that will provide important information about the storm’s effects.

This was the first time the USGS used the Gulf of Mexico predefined network of pre-positioned storm-tide sensor receiving brackets, which was intended for just such a purpose: to quickly deploy scientific instruments in advance of a major hurricane or coastal storm. The network consists of more than 130 pre-surveyed receiving brackets installed along the coast from Texas to the Florida Keys.

“This new network of pre-positioned receiving brackets, which holds storm-tide sensors during storms, allows the USGS to collect important information about how storm tides affect coastal communities and deliver this data to emergency managers and responders faster than we could before,” said Athena Clark, USGS Coastal Storm Response Team leader. “This relevant storm data will allow decision makers to better track flood impacts, assess flood damage and get much needed assistance to flooded communities as fast as possible.” 

The coastal storm-tide information collected by the sensors can be used to help guide storm response efforts following major storms like Hurricane Michael. The Gulf of Mexico network has only been fully operational for a few weeks and Hurricane Michael will be the first test of the system’s effectiveness, USGS experts said.

“Michael was a short notice hurricane that quickly strengthened. We only had a small window to safely install storm-tide sensors, and the predefined bracket network allowed us to do just that,” said Richard Kane, associate director of the USGS’ Caribbean-Florida Water Science Center.

The USGS field crews were able to get into Michael’s projected path, install the sensors, and get out very quickly, which is one of the network’s main purposes, Clark said.

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Why Does USGS Collect Storm-Tide Sensor Data?

Storm tide is the hurricane-driven increase in water levels above normal tides. These rising waters are responsible for upwards of 40 percent of deaths associated with hurricanes and, together with waves, typically cause a major portion of coastal flood damage. During a hurricane, the USGS sensors record the precise time the storm tide arrives, the changing water depths throughout the event, the height and frequency of storm-driven waves, and the time when the water recedes.

The information is immediately useful to agencies responding to storm surge and coastal flooding. Used in conjunction with storm-surge models, the USGS data can help emergency mangers delineate the precise boundaries of maximum flood depth and extent, identify flood damaged areas, and help decipher the cause of the damage – wind versus water. It also helps scientists develop more accurate storm-tide models, which can lead to better flood predictions and better simulations of long-term flood patterns and trends.

This information in turn will help engineers as they design flood-hardened structures and assess the effectiveness of engineered dunes and wetlands at reducing storm damage. It will help community leaders prepare for storm-tide flooding and inform land use practices and building codes. Ultimately, the information helps those building more resilient coastal communities.

Making Time-Tested Technology More Efficient

Installing sensors before a storm to measure storm-tide surge is not new to the USGS; temporary sensors were first deployed for Hurricane Rita in 2005 and have been deployed for every major storm making landfall in the United States since then. The USGS’ first predefined sensor network - the Surge, Waves, and Tidal Hydrodynamics network - was installed along the Atlantic coast from Maine to North Carolina after Hurricane Sandy.

In the early years, this work involved waiting until there was a fair degree of confidence on where a storm was most likely to make landfall, then quickly deploying crews to install the sensors at sites that seemed likely to withstand extreme conditions. The number of miles of coastline the sensors were deployed and number of sensors installed depended on the area forecast to receive the greatest surge, and the same sites might or might not be used in more than one storm.

Following a storm, crews returned to the sites to retrieve the sensors, determined their elevations using tools such as GPS surveys to measure the storm-tide elevation and flood extent. The crews also documented highwater marks and conditions at each site. With numerous sites to survey, it could take months before the final report was complete.

Installing the network

With the new Gulf network of pre-surveyed locations and pre-installed brackets, the time required to install and retrieve the sensors and process their data can be cut to days.

This summer, dozens of USGS specialists selected more than 400 potential bracket sites along the Gulf Coast. They chose the best locations to install the permanent receiving brackets that hold the sophisticated sensors and surveyed those locations to get elevation information in advance.

These brackets allow the sensors to be installed days to hours before a coastal storm makes landfall. “They also pay dividends after the storm has passed since the sites are already surveyed and this can save hours of work for each sensor,” Kane said.

The new USGS network configuration also includes locations that cross some barrier islands, wetlands, and urban areas. This will enable scientists to measure the effect of topography, vegetation, and structures on wave height and frequency – important influences on storm-tide heights.

In addition to monitoring the coastal impact of storms, the USGS continuously monitors water levels and discharge at more than 8,200 stream gauges across the Nation on a real-time basis. Information on water levels throughout the country can be accessed at the USGS Current Streamflow Conditions web page. The USGS also has a “push” system called WaterAlert that texts or emails real-time information to subscribers on when waters are rising in rivers or streams near them.

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