Inches can have a crucial impact on shorelines, river flow
Written by The Palladium Times   
Sunday, 26 November 2006 18:51

Lake Ontario is about two inches above the average water level for this time of the year. In a lake with an average depth of about 283 feet, a difference of inches can have an impact on the shorelines.

The International St. Lawrence River Board of Control is responsible for regulating the flow of water out of Lake Ontario by way of the St. Lawrence River, the lake's outlet to the Atlantic Ocean. This regulates the level of the lake, which is kept within a four-foot range throughout the year.

“With a couple of inches, most people wouldn't think much of it,” said Dave White, the Great Lakes Program coordinator for New York State Sea Grant. “But then you throw a storm on top of that and that is where you can really get into a critical issue, and that's why a lot of folks in the Eastern Basin were heavily impacted by the October storm.”

White said that the level of the lake is on a cycle that fluctuates throughout the year by about a two-foot range. White explained that a balance must be struck between slowing the flow of water out of the lake while allowing enough water out so that Lake Ontario is not “holding water” going into the spring. “It's a real balancing act based on years of modeling,” White noted.

“If you're higher than average going into the winter and that gets maintained all winter, come spring it's going to be above, and that is when you have the worst storm systems,” he continued.

Holding water is where the lake has a higher than normal water level. This impacts areas where the beach or shore has a gradual slope more than steep shorelines. In a sloping shoreline, an increase of two inches in the level of the lake could mean that water actually moves up the shore by feet. As a result, even with only two more inches of water on the lake, the shoreline might move closer to a person's lakefront property by a foot or more, creating a potentially dangerous situation if a storm should strike.

On the other hand, if too much water is allowed out of the lake, it will prevent an ice cover from forming on the St. Lawrence River. Without a good ice cover on the St. Lawrence River, the ice forming could break-up, causing ice jams at the dam, impeding water progress. A good ice cover means that water can freely flow under the ice.

According to a press release from the International St. Lawrence River Board of Control, since this is the second consecutive month of wet conditions, flow of water out of the lake will be increased, bringing the highest outflows for this time of year since 1997.

“Throughout the Great Lakes Basin, we've gotten a tremendous amount of precipitation,“ said White, “and that's all coming into the system so they have to be cognizant of trying to maintain that balance.”

A member of the International St. Lawrence River Board of Control said at a teleconference in September that the outflow of the lake could be increased by as much as 300 cubic meters of water per second and it would only change the lake by about a centimeter over the course of a week. White said that the amount of time that the lake would take to drain entirely, given current conditions, is into the hundreds of years.

He also said that the process is complicated by weather conditions. “A lot of people think the lake changes very quickly,” said White, “its not a bathtub where the lake is sitting flat. You have storms somewhere in the lake system or wind coming through and that changes it because it's taking water and moving it somewhere.”

“If you have strong winds coming out of the west, it's pushing water to the east. Well, the water level in the east is going to go up.” This event is known as a seiche.

“So when people say ‘Gee, the lake went up a foot yesterday,' they're not completely wrong,” said White. “The lake in their area rose by a foot based on weather conditions coming in, but the lake level itself didn't change.”

The New York State Sea Grant program is focused on the coordination of information across the state between coastal user groups. They provide information to businesses and industries, government entities at the local, state and federal levels including agencies and legislators, and to the public. They also coordinate funding for research, education and outreach programs involving New York's waters. Sea Grant covers the area from Lake Ontario and Lake Erie to the Atlantic Ocean, as well as the St. Lawrence and Hudson rivers, and many other bodies of water across the state.
 
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