“The Matrix” illuminates climate risks to harbors
Mar. 2, 2014 |
Harbors in the Great Lakes are built to last. But bonus rounds of rough weather from more frequent and extreme storms will test the mettle of harbor infrastructure, managers and communities.
Knowing a given port’s vulnerabilities -- from its channels to its slips, piers, pilings and breakwaters -- can be a key to weathering more powerful storms.
Enter “The Matrix,” a new economic impact harbor management tool developed by Gene Clark, a coastal engineering specialist with the UW Sea Grant Institute’s Lake Superior field office and co-chair of the Coastal Communities Working Group in the Wisconsin Initiative on Climate Change Impacts (WICCI).
Officially called The Matrix and Dredging Database, it’s a nuts-and-bolts series of spread sheets detailing each piece of interior and exterior harbor infrastructure and physical characteristics. It itemizes channel and slip depths, which can be run through Clark’s algorithms to generate repair, replacement or dredging costs under different conditions.
“Being an engineer, I looked at climate change implications for ports and harbors and came up with two significant issues,” says Clark. “One is that dredging harbors will have to be done more frequently with increasing storm-generated runoff and wave action, and secondly, with variable water levels and storm action, there will be more damage to infrastructure.”
The Matrix allows managers to consider a range of scenarios. For example, low water levels would make timbers more vulnerable to rot, and cause metals to lose protective coatings. Larger waves, storm surges and seiches – which form when strong prevailing winds push lake water to one side of a lake or the other -- can beat up infrastructure. Silt from storm-churned water and excessive runoff can fill dredged channels and slips.
“The tool provides ranges of cost for repair or rehab of a harbor per foot of structure for a given rise or lowering of water,” explains Clark. Harbor specifics are classified by delineating between 11 different types of entrances, 13 different types of interiors, and shallow, medium and deep water port options.
The Matrix is now included in the Great Lakes Coastal Resilience Planning Guide, an all-encompassing guide to help coastal authorities cope with climate change impacts on the lakes. A multi-partner collaborative effort is being led by the Association of State Floodplain Managers (ASFM).
Aerial view of Port Wing Harbor on Lake Superior. (WDNR photo)
Clark, along with WICCI affiliate David Hart, a senior scientist with UW Sea Grant Institute in Madison, and Jeff Stone, project manager for ASFM, demonstrated the value of Clark’s tool using the Port of Toledo in Ohio, a Great Lakes port that handles over 12 million tons of cargo per year and annually accommodates visits by more than 700 ships.
“The results offer a starting point for port authorities in Toledo and others throughout the Great Lakes to initiate a detailed risk assessment, and help communicate the port’s value to its community and the estimated cost to replace or correct,” says Clark.
That’s critical information for communities along the 2,300-mile stretch of water that connects the Port of Duluth/Superior with the Atlantic Ocean, regularly moving iron ore, salt, sugar, grain, coal, stone, steel and heavy machinery throughout the Great Lakes system. More than 10 percent of all cargo handled by the U.S. and Canadian lake system comes through Wisconsin ports, directly and indirectly employing thousands of Wisconsin workers.
Clark and Hart have also employed The Matrix to analyze risks for the Port of Duluth/Superior, Manitowoc, Green Bay and Milwaukee. Clark plans to modify The Matrix to include smaller structures such as marinas, so managers of smaller harbors can also use the tool to evaluate their infrastructure in the context of climate change projections.
“The seasonal and yearly changes will always trump climate change in people’s minds,” says Clark. “Harbors are often taken for granted, often ignored, but this tool helps shift the focus onto their economic impact—they really are economic engines for the communities they serve, and the impacts are huge when something affects the ports.”