Record low water levels in the Upper Great Lakes are tough on recreation, property values, habitat diversity, and commercial navigation.
Precipitation and evaporation drive the lake levels and the past 10 years have been particularly hard on Lakes Michigan and Huron which are 15 inches below average. Lake Superior was nine inches below average in January 2009, according to NOAA.
The International Joint Commission is addressing this by asking the Army Corps of Engineers and Environment Canada to examine six core areas of concern related to low water levels in the Upper Great Lakes. The information will be used to further discussions on lake levels regulated by the Soo Locks at Sault St. Marie. Currently, flow from Lake Superior into Michigan-Huron is 75,200 cubic feet per second.
NRRI was asked to use knowledge gained during the Great Lakes Environmental Indicators project and other published information to prepare a report on “Ecosystem Responses to Regulation-based Water Level Changes in the Upper Great Lakes.”
“This is going to be a big issue over the coming years,” said NRRI scientist Jerry Niemi who is co-lead investigator on the project. “The water levels have been going down for a number of years and with the projections from climate change models, the water levels may decrease even more.” Jan Cibrowski from the University of Windsor, Ontario, is the other co-lead investigator.
The 40-plus page report has already been well received by regulatory agencies that need to understand the responses of a variety of bio-indicators—endangered/threatened species, birds, amphibians, fish, water quality, and invasive species—to water level changes. Water level fluctuations also affect nitrogen and metal cycling, and the microbiology in the ecosystems.
“This report brings together the science of what’s known about water level changes with respect to these important indicators that should be measured and examined,” said Niemi.
A copy of the complete white paper can be downloaded from NRRI’s Web site at www.nrri.umn.edu/cwe.