Dyke

Revision as of 06:14, 31 May 2021

Introduction

As an engineering term, a dyke is a form of flood protection designed to keep water from overrunning land adjacent to it. In North America, the standard spelling is dike; in other English speaking countries, the common spelling is dyke. Both spellings are widely used and accepted.

Outside of engineering applications, the terms levee and dyke are sometimes used interchangeably.

NB In geology, a dyke is a sheet of rock within the cut surface of another type of rock.

Related terms and usage

Levee

This type of artificial structure is similar to a dyke (sometimes referred to as a floodbank or stopbank). Both types of embankments can be used to control water levels. However, levees are generally associated with rivers and are designed to protect areas that would otherwise be dry. Dykes control both sea and river levels in areas that are below sea level and would otherwise be flooded.

Levees can can be permanent structures, such as those built from cement, or temporary structures which might be made from stone, earth or sandbags.

In Ancient Egypt, levees were used along the Nile to protect the surrounding valleys. They were also used in other Ancient cultures.

Gully

A gully can be a form of dyke, since a structure does not need to be a wall in order for it to serve the same water control purposes. Earthen gullies, stone lined ditches or naturally occurring rock formations that run parallel to the water source can serve as dykes.

See Gully.

Berm

Defined as a shelf or raised barrier separating two areas, a berm is another term that is sometimes used interchangeably with dyke. Since a berm is not always associated with flood control, it is not the same thing as a dyke. However, a dyke can be a type of berm, depending on its construction.

See Berm.

History

In many cases, the usage of these terms is regionally influenced. For example, in the state of Louisiana (which is vulnerable to hurricanes), levee is the term that is most frequently used. In the lowlands of the Netherlands, dyke is the common term.

It is believed that the term dyke originates from the Dutch word dijk, which was used to describe both the ditch and the walls created to support it. Early references to the term dijk were found in Northern European records in the 11th century, but there are other references that appear even earlier - perhaps as far back as 500 BC.

During that period, the population grew in the northwestern region of what is now the Netherlands. Although much of the land was below sea level, engineers set about to make it suitable for human habitation through an extensive hydraulic engineering effort.

The construction of simple dykes was a central part of the land reclamation process which began in the 13th century. This effort increased through the centuries and has resulted in the creation of reclaimed land referred to as polders.

See Polders.

Dykes in England

The term dick was used instead of dyke in Northern England. In this part of the country, the term dyke may be associated with a dry stone field wall. This is the case in Scotland as well, where the term dry stane (or drystane) dyke is also associated with a dry stone wall or dyke. These constructions are often used to establish boundaries for fields. The professionals who build these structures are sometimes referred to as dykers.

In the Midlands and East Anglia, the term dyke was used while ditch was used in Southern England. In addition to referring to a drainage channel, these terms are also associated with property boundary markers - as they are in Scotland. When used to control the flow of water (as a dyke or ditch), they are sometimes referred to as running dykes.

Associated terms include soak dyke (in The Fens) and sock dyke (in Lincolnshire).

There are also spur dykes, which are built to protect the land from erosion. They are commonly found near coastlines and can be constructed either perpendicular or at an angle to the bank. Spur dykes can be permeable or impermeable. They are generally man-made from material such as loose stones or bricks and contained by wire. Longer spur dykes are sometimes referred to as groynes.

See Groynes

Temporary dykes

Like temporary levees, temporary dykes can be used to divert water from areas that have been disturbed as a result of natural or human activity. These structures serve to direct water to a more suitable location. They can also help to reduce the flow of water to control additional issues associated with erosion.

Related articles on Designing Buildings Wiki

• Coastal defences.
• Flood.
• Flood plain.
• River engineering.
• Traditional construction materials on the Isle of Man.
• Water engineering.