DG Puts Eyes on a Crumbling Coastline
But storms on large, deep lakes such as the Great Lakes can have equally dramatic and tragic effects. The results can be lost lives, lost property and thousands of acres of lost shoreline. Shoreline erosion is especially dangerous, because it leads to more and more damage with each successive storm. In Ohio, academic and government researchers are seeking ways to model the erosion-driven evolution of what the Lake Erie shoreline is likely to look like in order to give government officials more data and IT-based tools for public policy decisions.
Erie was dubbed by the native Erie Indians, "Lake of the Cat." Some think the name derives from the panthers native to the area. Others, like Don Guy, a geologist with the Ohio Department of Natural Resources, suggest it may be a poetic way of evoking the claw-like waves of Erie's fierce storms. Given the lake's orientation and its relatively shallow depth, Erie experiences significant storm surges at its east and west ends, "I've seen 20 or 30 feet [of shoreline] disappear in as many seconds," says Darrell Webster, Director of the Lake County Planning Commission.
These conditions make Erie especially prone to erosion damage, which makes the ability to predict shoreline changes of critical importance when planning housing and infrastructure. Both Webster and Guy have collected data on the area for many years, information which they shared with Rongxing (Ron) Li, professor in civil and environmental engineering and geodetic science at Ohio State University. In addition to showing historical surveys and aerial maps, they took Li and his lab members on a grim walking tour of the worst areas, where, says Li, "You see roads that break off at the shoreline."
As part of his NSF-funded Digital Government grant, Li and his students are trying to create a dynamic software model of what areas of the Lake Erie coast will look like in the future. The model, which takes into account variables like water level oscillations, tide motion and atmospheric changes, will serve as a template for similar work in other coastal areas. They will be applying next it to Tampa Bay, Florida, where the sandy shoreline erodes in different ways over a different timescale from the cohesive clay bluffs of the Great Lakes.
When completed, the project will provide a tool that can help a government body approve or deny a permit application for coastal structures, by giving an estimate of the likelihood of erosion. "The system can help judge whether a barrier will do more harm than good," says Li, "The Ohio Department of Natural Resources will look at the proposed design of a protection structure, and test it against different criteria. So far, we can implement five out of twelve criteria in our system." In addition, for the general public, they will provide a Web page, where coastal residents can see where their property is relation to the shoreline over time.
Li's team is also modifying off-the-shelf hardware to create a PDA/GPS/wireless combination that can update survey information in real-time, thus giving professional geologists and coastal engineers another tool in their arsenal for field inspection and decision making.
Li is using satellite and aerial images to collect data to feed into the model. In Tampa, Li's team was able to get one-centimeter accuracy on a GPS survey and 0.6-meter resolution QuickBird satellite images, while in Ohio, the IKONOS satellite images of 1-meter resolution were acquired. Guy cautions that a finer resolution is needed for an accurate picture of the sort of erosion that occurs on Erie's bluffs, where water insidiously carves away at the base, until an entire chunk of hillside falls. Still, academic research has an especially helpful side: It's a good workaround for a regulatory constraint that limits official mapping of coastal change to only the most recent timescales.
"I'm hoping Ron's work could lead not only to where not to build, but where to safely reclaim land," says Webster. "There need to be additional safe harbors created on the lake, given how violent the storms can get in just a matter of minutes."
Webster has faith in the science, "I think when [Li and his students] get done, they'll have a pretty good model of the lakeshore." Guy may believe in science too, but despite the best efforts of his department and Li's lab, he says he's not taking any chances. "I've decided I don't want to live by the lake," he says. "I just want to live a little farther back."
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