November 2012

What’s Happening with Great Lakes Water Levels?

The Ups and Downs of Great Lakes Water Levels
Water levels in the Great Lakes have always been highly variable. They fluctuate over different spans of time — from hours to millennia — in response to wind, storms, precipitation, snowmelt, evaporation from the lakes’ surfaces and runoff, climate and geology.

Seasonal variation occurs every year as the lake levels rise an average of 12-18 inches from winter to early summer. Long-term fluctuations lasting many years (decades or longer) are visible in the historical record.

Lake levels may move irregularly over the course of any given year. We saw some irregularity this past spring when the winter low levels were not followed by a typical rise into summer.

What Happened?
In addition to the usual influences of normal weather conditions, extreme weather conditions can cause annual irregularities like this, and last winter was unusually warm in the Great Lakes region. Warm weather led to a reduced winter snow pack, which meant less runoff into the lake, contributing to a lower summer peak in 2012.

Combined with short-term and long-term cycles, this lack of rebound has contributed to near-record low lake levels this fall, with Lakes Huron and Michigan showing the most pronounced differences from long-term averages. Models and history seem to indicate that this trend will continue with low water levels falling to near-record or record levels this winter and early spring.

Many have wondered if the low levels are related to climate change. While the variations could be related, they are not necessarily an indicator or a result of climate change; they may be part of a natural cycle of variability. After three decades of water levels above the long-term average, levels have been trending downward, however, scientists have not been able to tie this trend definitively to climate change.

Graphic: Interact with Great Lakes water levels through the decades (NOAA Great Lakes Environmental Research Lab)

Why Do Lake Levels Matter?
With more than 3,000 miles of Great Lakes shoreline, lake levels have a huge impact on Michigan’s coastal communities and economies. When levels fluctuate much above or below the long-term average, the impacts can be significant, especially in highly developed areas that were not designed to withstand changing levels.

Lake levels affect coastal properties and infrastructure, as well as shipping, recreation and manufacturing. They also affect plant and wildlife habitat.

Want to learn more about lake levels, climate change and weather patterns in the Great Lakes? Check out:

• A two-part series by Michigan Sea Grant’s Steve Stewart on lake levels
  Part 1: Short-term lake level changes
  Part 2: Long-term lake level fluctuations

• Overview of lake levels, climate and preparing for extremes
  A set of Michigan Sea Grant fact sheets that explore climate-related concepts. They provide information to help teachers, residents and decision makers understand climate terms and issues, and prepare for potential changes in the Great Lakes region.
  Weather and Climate: What is the difference? (PDF)
  Climate Variability and Climate Change: What is the difference? (PDF)
  Preparing for Variable Lake Levels (PDF)
  Preparing for Extremes (PDF)

The Dirt on Dredging: Help for Marinas

Marina owners and operators can get help navigating the dredging permit process during the annual Recreational Boating Education Conference Dec. 5-6.

On Dec. 5, representatives from the Army Corps of Engineers, Michigan Department of Environmental Quality, Michigan Sea Grant and Michigan State University Extension will hold consultations to discuss the permitting process and provide feedback for projects being considered.

Registration for the conference is required. To learn more, see: Details

News in Brief

Salmon Revelation
Anglers in Michigan rivers know that Chinook and coho salmon will bite on eggs and egg imitations, but it was assumed that the fish hit strictly out of aggression or some feeding reflex left over from time spent in the big lake or ocean.Aside from this reflex, most people assumed that Pacific salmon would not bite once they entered rivers near the end of their life cycle. Snagging was legal for decades, in part, because of this assumption. But recent research suggests this isn’t always the case. See: Article

Netting an Education
This fall, teacher Holly Wirgau and her Rogers City Middle School students took a voyage on Lake Huron. Their mission was to explore Great Lakes water quality, fisheries and aquatic ecosystems, maritime heritage and how people connect with Michigan’s water resources.The on-the-water experience launched a yearlong, place-based watershed study centered on their local Trout River Watershed. During the year, students will raise salmon, wade in the Trout River, and make Great Lakes connections through their inland water study. See: Article

Planning for Change
Laura Holladay, Michigan Sea Grant Climate Specialist, recently teamed up with several other climate specialists to host a climate adaptation presentation during the Michigan Association of Planning Annual Conference in Traverse City. The talk was part of a 75-minute panel presentation on climate change in the Great Lakes and its implications for the planning community, as well as examples of climate adaptation planning. Laura focused on the general climate trends for the region and how to approach decision making under uncertainty.

Dive into this New Poster! Dabblers and Divers: Great Lakes Waterfowl

What makes a duck a duck? This new Dabblers and Divers: Great Lakes Waterfowl poster provides a look at the different characteristics of native Great Lakes ducks. The poster is a perfect resource for educators, nature enthusiasts, avid or novice birders — or anyone interested in learning more about the Great Lakes and the great species that call the region home. Cost is $8 per poster, available throughout our online bookstore. Bulk and education discounts available; email msgpubs@umich.edu for details.

Poster Details: High-quality, full-color poster that measures 26 inches wide by 37 inches tall. Printed on 100% recycled, chlorine-free paper with vegetable-based ink. 

Bonus: Each poster order receives a free healthy wetlands brochure.