UD engineer keeps eye on ocean's motion
By MOLLY MURRAY / The News Journal
01/10/2005
Last week, as the rest of the world struggled to understand the tsunami that left a swath of death and destruction around the Indian Ocean, James T. Kirby was busy explaining what makes waves like those such killers.
For Kirby, waves and the way they change the shoreline are an everyday part of his work.
"The tsunami stuff, to me, is basically a hobby," he said.
Though tsunamis are unlikely along the Delaware coast, waves are of special interest here because of the way they shape the shoreline.
Along the Delaware coast, it is hard to predict what waves will do because there isn't a good wave monitoring system in place, Kirby said.
State environmental officials are working toward installation of a wave monitor in Bethany Beach and a second one in Rehoboth Beach to get a better look at what waves are doing, he said. In addition, there are plans to install cameras at beaches along the coast.
Waves can wash away sand, causing erosion and contributing to potentially deadly conditions such as the formation of rip currents.
Kirby's job is to use computers to do mathematical predictions of how waves behave. He likes to study the way waves act near shore, from the area where the water is about 30 feet deep up to the beach.
As waves approach the shore, their height grows and the time between them gets shorter, he said.
Waves in the deep ocean usually are formed and influenced by wind. But as waves get closer to shore, they also can be influenced by currents.
In Indian River Inlet, for instance, waves can create dangerous conditions. The worst problems occur about two to three hours after the highest high tides, Kirby said. Because of currents, waves actually start to break at the entrance to the inlet, he said.
The problem starts when an outgoing tide meets waves coming in the inlet.
"The energy just piles up," he said.
To find out what waves are doing, Kirby plugs into a specialized computer program data such as wind speed and direction. That gives him a picture of wave conditions and the impact they are having along the coast. Once he knows what the waves are doing, he can use that data to figure out how sand is moving along the shoreline.
Kirby, a native of Easton, Md., isn't a surfer or someone who started life with a strong interest in waves.
He said he thought he wanted to be an architect when he started college but realized he was more interested in the structure of buildings than he was in the design. So instead, he studied civil engineering.
He used computers to model air pollution while he was working on his master's degree but was drawn to coastal research when he worked on a project designing a harbor in a port in Guatemala. Although the harbor was never built, Kirby said, he decided he was interested in the way water influences shorelines.
Mathematically, the tools used for ordinary waves are the same as calculations used for tsunami waves, he said, and although scientists understand why tsunamis form, there is much to learn.
"We're still a long way away from being able to characterize the mechanism that generates the waves." he said.
Contact Molly Murray at 856-7372 or mailto:mmurray@delawareonline.com
