Ridge and swale, or in dunal areas dune and swale, is a landform consisting of regular, parallel ridges alternating with marshy depressions. Ridge-and-swale landscapes are most commonly formed by the gradual movement of a

beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc sh ...

, for example as a result of gradually fluctuating water levels, or the shifting

meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex ba ...

s of a river. In the river context, ridge-and-swale landscapes are commonly formed by

scroll bar A scrollbar is an interaction technique or widget in which continuous text, pictures, or any other content can be scrolled in a predetermined direction (up, down, left, or right) on a computer display, window, or viewport so that all of the c ...

s. They are also found along ocean coasts, for example on the

Outer Banks The Outer Banks (frequently abbreviated OBX) are a string of barrier islands and spits off the coast of North Carolina and southeastern Virginia, on the east coast of the United States. They line most of the North Carolina coastline, separating ...

of North Carolina.

Great Lakes ridge and swale

Freshwater ridge-and-swale ecosystems are globally rare and found only in parts of the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lak ...

of North America. They were formed as a result of the gradual retreat of beaches due to falling water levels and

post-glacial rebound Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound ...

. The swales and the adjoining lake or river commonly form a single hydrological unit, so that rising or falling lake levels will cause water levels in the swales to rise or fall as well. Most ridge-and-swale landscapes have been destroyed as a result of the massive industrial development found in many former ridge-and-swale areas, such as the

Calumet Region The Calumet Region is the geographic area drained by the Grand Calumet River and the Little Calumet River of northeastern Illinois and northwestern Indiana in the United States. It is part of the Great Lakes Basin, which eventually reaches the ...

of Northwest Indiana. However, some extensive dune-and-swale complexes persist in Michigan, such as at the Michigan Wilderness State Park. The remaining dune-and-swale complexes along the Great Lakes are often home to extremely rare plants and animals, such as the endangered Karner Blue butterfly. In the Calumet Region, the difficulty of moving equipment through dune-and-swale topography greatly slowed industrial development, but could not stop it after the turn of the 20th century. The few remnants are preserved as

nature preserves A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, or features of geological or ...

, including the Gibson Woods county park in

Hessville, Indiana Hessville is a neighborhood of Hammond, Indiana. Located in the southeast corner of Hammond, it adjoins the Hammond neighborhood of Woodmar to the west, the East Chicago neighborhood of Calumet to the north, the Gary neighborhoods of Westside ...

, the

Miller Woods Miller Woods is the far western unit of Indiana Dunes National Park in the lakefront community of Miller Beach, Indiana. Miller Woods is home to the federally endangered Karner Blue butterfly and the federally threatened Pitcher's thistle. Mil ...

section of the

Indiana Dunes National Park Indiana Dunes National Park is a United States national park located in northwestern Indiana managed by the National Park Service. It was authorized by Congress in 1966 as the Indiana Dunes National Lakeshore and was redesignated as the nation ...

, and additional preserves operated by The Nature Conservancy and Shirley Heinze Land Trust.

Great Lakes ridge and swale

Works cited

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