Lake levels: can anything be done?
They do not recommend any manmade solutions.
The Corps updated the news media around the Great Lakes by teleconference last Wednesday afternoon. Officials from the Corps' Detroit office answered questions about the low lake levels, particularly for "Lake Michigan-Huron." The Corps considers them one lake because of the connection at the Straits of Mackinaw. They discussed causes, as well the impact of low water.
- What are the primary drivers of low lake levels?
"Rainfall, (snow) runoff and evaporation," stated Keith Kompoltowicz, chief watershed hydrologist at the Detroit office.
"We had an abnormal winter and hot dry summer, which increases evaporation. The average snow runoff is about a foot. It was four inches last year…The drought was wide-spread…We had a stretch of several months with dry conditions that led to the low water levels."
Water levels started going down in the mid-1990s, although precipitation aver- ages were about average Kompoltiwicz said.
"There was one winter with virtually no snow over the Great Lakes region. That one solitary event got the lakes to get below (average levels), and they remained below," he noted.
Water levels vary from lake to lake, depending upon the weather patterns and storm systems for each region, he explained.
Kompoltowicz said dredging the channels does not cause low water levels.
The United States and Canada coordinated a series of dredging projects on the St. Clair River in the 1920s, '30s and '60s for commercial vessels, stated John Allis, the chief Great Lakes Hydrologist at the Detroit office.
"We do not have enough data to know how much impact the dredging had on water levels. But the last deepening was in the '60s and since they we have experienced high water levels, record highs in the '70s," Allis noted.
"The last of those projects was in 1967. Since then there has only been maintenance dredging," he said.
Recent studies indicate the dredging led to a 10-16 inch lowering and some advocate placing structures in the channel to reduce the out flow. However, Allis said many groups do not support more structures because of the problems it will cause when water levels rise again. In addition, he noted approval of new structures would take so long, water levels would have probably gone back up by then.
"We found some erosion between the '60s through 2000. Three to five inches on top of the 16-inch (flow through). We also found since 2000, no erosion in the river. In fact it did the opposite. That is not an immediate reason to engage in remediation," stated John Nevin, Corps public affairs.
- Has the diversion of water from the Lake Michigan-Huron through the Chicago Sanitary and Ship Canal and down the Mississippi impacted water levels?
"No. There is a two-inch lowering, which is balanced by the in-flow from Lake Superior," stated Kompoltowicz.
However, responding to complaints from constituents, U.S. Representative Candice Miller, the co-chair of the House Great Lakes Task Force, has asked the Corps to review of the interbasin diversion to determine the impact on the water levels. The last published review of this kind was conducted in 2009.
Currently the International Joint Commission is completing a study examining the impact of how the upper great lakes regulates the flow of water out of Lake Superior.
"There is not a lot we can do to help Lake Michigan-Huron, really. By climate modeling, (we see) the levels of Michigan-Huron is in the same range as the past. Low levels are not a new normal," stated Nevin.
The commission is finishing the public comment period on the study and will then review the comments and the science before making recommendations to the governments in early 2013, Nevins noted.
- What about the impact of the municipal water withdrawn from the Great Lakes?
"The impact of that is very minimal. There is more taken (through evaporation) in a cool night in the fall than diversions of that sort over many years. That (municipal water) is returned to the same basin. Many communities draw water from the Great Lakes. All those uses add up to a very small impact," stated Kompoltowicz.
• Impact of low lake levels
"The low water impact is spread across many user groups," according to Kompoltowicz. Commercial shipping, the amount (they are able to carry). Recreational boating, not able to access their favorite place. Property owners have much more beach, and marinas, they won't be able to sell all their boat slips."
The Corps sees an increased demand for harbor dredging when lake levels are low.
"We see increased questions about it from Congress, more attention about more dollars for dredging," noted Allis.
However, the Corps budget is fixed and are planned two years out.
"It is impossible to project (lake levels) more than six months out," stated Doug Wilcox.
"The budget is focused on commercial (shipping needs), the smaller harbors get less priority. The budget is lower and there is very little we can do different to address lake levels. Lake levels do not drive the dollars."
• October lake levels
Whether Lake Michigan-Huron hits record lows all depends on the weather over the next six months.
"We've seen very heavy rainfall all over the Great Lakes region, Michigan- Huron especially was impacted with (Super Storm) Sandy, which is a couple inch rise," stated Kompolitowicz.
"The is the time of year with a seasonal decline, the amount coming in versus evaporation. Early in the month we had another significant rain event that caused Michigan-Huron to rise quite a bit, and have kept it higher than it would have been. But we would several months, several seasons in a row to get back to the long term averages."
(Carol Seifferlein is the Features Editor at a “Huron County VIEW” sister newspaper, the “Sanilac County News.”)