Lake Erie

Long ago, glaciers covered this land.

As they melted, lakes filled the low ground. Over time, they became Lake Erie.

Lake Erie's basin has held many different lakes. Charles Herdendorf of Ohio State University sorts them into three phases. From 14,400 to 12,000 years ago, glaciers still sat in the basin, and the lakes stood higher than Lake Erie does today.

From 12,000 to 4,700 years ago, during a drier time, the lakes were cut off from the water of the upper Great Lakes and sat lower than today. Since 4,700 years ago, water from the upper lakes has flowed through again, and the lake reached its present level as its outlet wore down.

Herdendorf (Ohio Journal of Science, 2013) reviews the Holocene history of the Lake Erie basin using newer bathymetric data that reveal drowned former shorelines on the lake floor. He groups its lakes into three phases: 14,400 to 12,000 years ago, ice-associated lake stages higher than present Lake Erie; 12,000 to 4,700 years ago, stages isolated from Upper Lakes drainage during a drier climatic period and below the present level; and from 4,700 years ago, renewed Upper Lakes drainage, a rise to a slightly higher stage, and the present elevation set by outlet erosion. The Wisconsinan ice sheet retreated some 12,000 years ago.

Water flows into Lake Erie from Lake Huron and many rivers.

It flows out through the Niagara River toward Lake Ontario.

Water enters Lake Erie from Lake Huron and from many rivers, and leaves through the Niagara River toward Lake Ontario. Water passes through it quickly: on average, it stays only about 2.6 years, compared with about 191 years in Lake Superior.

The lakewide plan says Lake Erie gives drinking water to more than 12 million people.

Water enters from Lake Huron and numerous rivers (the lakewide plan also covers the St. Clair River, Lake St. Clair and the Detroit River) and leaves through the Niagara River; NOAA's table names the Niagara River and the Welland Canal as outlets. Its retention time is about 2.6 years, the shortest of the five lakes (Superior 191, Michigan 99, Huron 22, Ontario 6).

The plan says Lake Erie provides drinking water to more than 12 million people, and the 2022 State of the Great Lakes assessment it cites rated treated drinking water from the lake as Good.

Fishers catch lots of fish in Lake Erie.

In summer, green blooms of tiny living things can grow on parts of the lake.

The lakewide plan says Lake Erie's warm, shallow water grows lots of underwater plants that fish need, and that it has the most productive fishery in the Great Lakes. Its shores have bluffs, sandy beaches and four sand spits, including Point Pelee and Long Point, which are important stopovers for migrating birds.

The same warmth has a downside. In the western part of the lake, too much phosphorus from rivers feeds blooms of cyanobacteria, also called blue-green algae, which NOAA forecasts each year from about July to October.

The lakewide plan credits Lake Erie's warm, shallow waters with extensive aquatic vegetation and the most productive fishery in the Great Lakes, including one of the world's largest freshwater commercial fisheries. Its coasts include over 335 km of bluffs, 403 km of sand beaches and four sand spits (Point Pelee, Rondeau, Long Point and Presque Isle), stopovers for waterfowl, shorebirds and landbirds recognized as Important Bird Areas, biosphere reserves or Ramsar wetlands.

In the western basin, the plan explains, shallow depths, warm summer temperatures and high phosphorus loads from the Detroit and Maumee rivers contribute to recurring cyanobacterial blooms, with severity tied to spring nutrient loads and rainfall, as in the record 2011 bloom. NOAA's National Centers for Coastal Ocean Science forecast the blooms, typically from July to October.

Stay out of water that looks green, scummy or smelly.

Swim only where a grown-up says it is safe.

The US Centers for Disease Control and Prevention (CDC) says some algal blooms make toxins that can make people and animals sick. Its advice: stay out of water that looks discolored, has scum or smells bad, keep pets away from it, and follow swimming and fishing advisories.

NOAA warns that rip currents happen along the shores of the Great Lakes too. If one pulls you, swim parallel to the shore, not straight back against it.

The CDC notes that cyanobacteria are the most common cause of harmful algal blooms in fresh water, that blooms can look like foam, scum, mats or paint, or hide below the surface, and that some produce toxins. It advises staying out of discolored, scummy or smelly water, keeping pets away and following swimming, fishing and shellfish advisories. NOAA's National Ocean Service adds that rip currents occur along Great Lakes shores, move at up to eight feet per second, and are escaped by swimming parallel to the shore.

PlayOwl's own advice: check the local beach advisory before swimming.