A moat is a deep, broad ditch, either dry or filled with water, that is dug and surrounds a castle, fortification, building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive water defences, including natural or artificial lakes,

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...

s and sluices. In older fortifications, such as

hillfort A hillfort is a type of earthwork used as a fortified refuge or defended settlement, located to exploit a rise in elevation for defensive advantage. They are typically European and of the Bronze Age or Iron Age. Some were used in the post-Roma ...

s, they are usually referred to simply as ditches, although the function is similar. In later periods, moats or water defences may be largely ornamental. They could also act as a sewer.

Historical use

Ancient

Some of the earliest evidence of moats has been uncovered around ancient Egyptian castles. One example is at

Buhen Buhen ( grc, Βοὥν ''Bohón'') was an ancient Egyptian settlement situated on the West bank of the Nile below (to the North of) the Second Cataract in what is now Northern State, Sudan. It is now submerged in Lake Nasser, Sudan; as a resu ...

, a castle excavated in Nubia. Other evidence of ancient moats is found in the ruins of Babylon, and in reliefs from ancient Egypt,

Assyria Assyria ( Neo-Assyrian cuneiform: , romanized: ''māt Aššur''; syc, ܐܬܘܪ, ʾāthor) was a major ancient Mesopotamian civilization which existed as a city-state at times controlling regional territories in the indigenous lands of the ...

, and other cultures in the region. Evidence of early moats around settlements has been discovered in many archaeological sites throughout Southeast Asia, including Noen U-Loke, Ban Non Khrua Chut, Ban Makham Thae and Ban Non Wat. The use of the moats could have been either for defensive or agriculture purposes.

Medieval

Moats were excavated around castles and other fortifications as part of the defensive system as an obstacle immediately outside the

walls Walls may refer to: *The plural of wall, a structure *Walls (surname), a list of notable people with the surname Places * Walls, Louisiana, United States * Walls, Mississippi, United States * Walls, Ontario, neighborhood in Perry, Ontario, C ...

. In suitable locations they might be filled with water. A moat made access to the walls difficult for siege weapons such as

siege tower A Roman siege tower or breaching tower (or in the Middle Ages, a belfry''Castle: Stephen Biesty's Cross-Sections''. Dorling Kindersley Pub (T); 1st American edition (September 1994). Siege towers were invented in 300 BC. ) is a specialized siege ...

s and

battering ram A battering ram is a siege engine that originated in ancient times and was designed to break open the masonry walls of fortifications or splinter their wooden gates. In its simplest form, a battering ram is just a large, heavy log carried b ...

s, which needed to be brought up against a wall to be effective. A water-filled moat made the practice of

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic ...

- digging tunnels under the castles in order to effect a collapse of the defences - very difficult as well. ''Segmented moats'' have one dry section and one section filled with water. Dry moats that cut across the narrow part of a spur or peninsula are called ''

neck ditch A neck ditch (german: Halsgraben), sometimes called a throat ditch,
at www.roadstoruins.com. Accessed on 3 Jan 2012. is a dry

es''. Moats separating different elements of a castle, such as the inner and outer wards, are ''cross ditches''. The word was adapted in

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English ...

from the

Old French Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intellig ...

''motte'' "mound, hillock" and was first applied to the central mound on which a castle was erected (see Motte and bailey) and then came to be applied to the excavated ring, a ‘dry moat’. The shared derivation implies that the two features were closely related and possibly constructed at the same time. The term ''moat'' is also applied to natural formations reminiscent of the artificial structure and to similar modern architectural features.

Later western fortification

With the introduction of siege

artillery Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...

, a new style of fortification emerged in the 16th century using low walls and projecting strong points called bastions, which was known as the ''

trace italienne A bastion fort or ''trace italienne'' (a phrase derived from non-standard French, literally meaning ''Italian outline'') is a fortification in a style that evolved during the early modern period of gunpowder when the cannon came to domin ...

''. The walls were further protected from infantry attack by wet or dry moats, sometimes in elaborate systems. When this style of fortification was superseded by lines of

polygonal fort A polygonal fort is a type of fortification originating in France in the late 18th century and fully developed in Germany in the first half of the 19th century. Unlike earlier forts, polygonal forts had no bastions, which had proved to be vulnerabl ...

s in the mid-19th century, moats continued to be used for close protection.

Africa

The Walls of Benin were a combination of ramparts and moats, called Iya, used as a defence of the capital Benin City in present-day Edo State of Nigeria. It was considered the largest man-made structure lengthwise, second only to the Great Wall of China and the largest earthwork in the world. Recent work by Patrick Darling has established it as the largest man-made structure in the world, larger than

Sungbo's Eredo Sungbo's Eredo is a system of defensive walls and ditches that is located to the southwest of the Yoruba town of Ijebu Ode in Ogun State, southwest Nigeria (). It was built in 800–1000 AD in honour of the Ijebu noblewoman Oloye Bilikisu Sungbo. ...

, also in Nigeria. It enclosed 6,500 km² of community lands. Its length was over 16,000 km of earth boundaries. It was estimated that earliest construction began in 800 and continued into the mid-15th century. The walls are built of a ditch and dike structure, the ditch dug to form an inner moat with the excavated earth used to form the exterior rampart. The Benin Walls were ravaged by the British in 1897. Scattered pieces of the walls remain in Edo, with material being used by the locals for building purposes. The walls continue to be torn down for real-estate developments. The Walls of Benin City were the world's largest man-made structure. Fred Pearce wrote in New Scientist: "They extend for some 16,000 kilometres in all, in a mosaic of more than 500 interconnected settlement boundaries. They cover 6,500 square kilometres and were all dug by the Edo people. In all, they are four times longer than the Great Wall of China, and consumed a hundred times more material than the Great Pyramid of Cheops. They took an estimated 150 million hours of digging to construct, and are perhaps the largest single archaeological phenomenon on the planet."

Asia

Japanese castle are fortresses constructed primarily of wood and stone. They evolved from the wooden stockades of earlier centuries, and came into their best-known form in the 16th century. Castles in Japan were built to guard important or strategic sites, such ...

s often have very elaborate moats, with up to three moats laid out in concentric circles around the castle and a host of different patterns engineered around the landscape. The outer moat of a Japanese castle typically protects other support buildings in addition to the castle. As many Japanese castles have historically been a very central part of their cities, the moats have provided a vital waterway to the city. Even in modern times the moat system of the

Tokyo Imperial Palace The is the main residence of the Emperor of Japan. It is a large park-like area located in the Chiyoda district of the Chiyoda ward of Tokyo and contains several buildings including the where the Emperor has his living quarters, the where va ...

consists of a very active body of water, hosting everything from rental boats and fishing ponds to restaurants. Most modern Japanese castles have moats filled with water, but castles in the feudal period more commonly had 'dry moats' , a trench. A is a dry moat dug into a slope. A is a series of parallel trenches running up the sides of the excavated mountain, and the earthen wall, which was also called , was an outer wall made of earth dug out from a moat. Even today it is common for mountain Japanese castles to have dry moats. A is a moat filled with water. Moats were also used in the

Forbidden City The Forbidden City () is a palace complex in Dongcheng District, Beijing, China, at the center of the Imperial City of Beijing. It is surrounded by numerous opulent imperial gardens and temples including the Zhongshan Park, the sacrifi ...

and

Xi'an Xi'an ( , ; ; Chinese: ), frequently spelled as Xian and also known by other names, is the capital of Shaanxi Province. A sub-provincial city on the Guanzhong Plain, the city is the third most populous city in Western China, after Chongqi ...

in China; in Vellore in India;

Hsinchu Hsinchu (, Chinese: 新竹, Pinyin: ''Xīnzhú'', Wade–Giles: ''Hsin¹-chu²'') is a city located in northwestern Taiwan. It is the most populous city in Taiwan Province not among the special municipalities, with estimated 450,655 inhabi ...

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

; and in Southeast Asia, such as at Angkor Wat in

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailan ...

; Mandalay in

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

and Chiang Mai in

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

Australia

The only moated fort ever built in Australia was Fort Lytton in

Brisbane Brisbane ( ) is the capital and most populous city of the Australian state of Queensland, and the third-most populous city in Australia and Oceania, with a population of approximately 2.6 million. Brisbane lies at the centre of the South ...

. As Brisbane was much more vulnerable to attack than either Sydney or Melbourne a series of coastal defences was built throughout

Moreton Bay Moreton Bay is a bay located on the eastern coast of Australia from central Brisbane, Queensland. It is one of Queensland's most important coastal resources. The waters of Moreton Bay are a popular destination for recreational anglers and are ...

, Fort Lytton being the largest. Built between 1880 and 1881 in response to fear of a Russian invasion, it is a pentagonal fortress concealed behind grassy embankments and surrounded by a water-filled moat.

North America

Moats were developed independently by North American

indigenous people Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...

of the Mississippian culture as the outer defence of some fortified villages. The remains of a 16th-century moat are still visible at the

Parkin Archeological State Park Parkin Archeological State Park, also known as Parkin Indian Mound, is an archeological site and state park in Parkin, Cross County, Arkansas. Around 1350–1650 CE an aboriginal palisaded village existed at the site, at the confluence of ...

in eastern

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the O ...

. The

Maya people The Maya peoples () are an ethnolinguistic group of Indigenous peoples of the Americas, indigenous peoples of Mesoamerica. The ancient Maya civilization was formed by members of this group, and today's Maya are generally descended from people ...

also used moats, for example in the city of

Becan Becan (Spanish: Becán) is an archaeological site of the Maya civilization in pre-Columbian Mesoamerica. Becan is located near the center of the Yucatán Peninsula, in the present-day Mexican state of Campeche, about 150 km (93.2 mi ...

. European colonists in the Americas often built dry ditches surrounding forts built to protect important landmarks, harbours or cities (e.g.

Fort Jay Fort Jay is a coastal bastion fort and the name of a former United States Army post on Governors Island in New York Harbor, within New York City. Fort Jay is the oldest existing defensive structure on the island, and was named for John Jay, a memb ...

Governors Island Governors Island is a island in New York Harbor, within the New York City borough of Manhattan. It is located approximately south of Manhattan Island, and is separated from Brooklyn to the east by the Buttermilk Channel. The National Park ...

in New York Harbor).

Photo gallery

Image:Muiderslot september 2007.JPG, Muiderslot,

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

Image:The moat around Fort Pulaski, Savannah, GA IMG 4673.JPG, Moat surrounding

Fort Pulaski National Monument Fort Pulaski National Monument is located on Cockspur Island between Savannah and Tybee Island, Georgia. It preserves Fort Pulaski; during the American Civil War, the Union Army successfully tested rifled cannon in combat in 1862 there, the suc ...

near Savannah,

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

Image:Keep of Matsumoto Castle.JPG, Matsumoto Castle, a Japanese Castle in Nagano Prefecture Image:Bodiam-castle-10My8-1197.jpg, Bodiam Castle, a 14th-century castle near Robertsbridge in East Sussex, England Image:Caerlaverock Castle from the air.jpg, Caerlaverock Castle, a 13th-century castle in southern Scotland Image:Sunset of the Forbidden City 2006.JPG,

The Forbidden City ''The Forbidden City'' is a 1918 American silent drama film starring Norma Talmadge and Thomas Meighan and directed by Sidney Franklin. A copy of the film is in the Library of Congress and other film archives.Beijing } Beijing ( ; ; ), alternatively romanized as Peking ( ), is the capital of the People's Republic of China. It is the center of power and development of the country. Beijing is the world's most populous national capital city, with over 21 ...

: North-western angle Image: Angkor-Wat-from-the-air.JPG, Angkor Wat,

Image:Egeskov Slot 08.jpg,

Egeskov Castle Egeskov Castle ( da, Egeskov Slot) is located near Kværndrup, in the south of the island of Funen, Denmark. The castle is Europe's best preserved Renaissance water castle. History Egeskov was first mentioned in 1405. The castle structure was er ...

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establish ...

Image:LissingenEugenBracht1880BurgLissingen.jpg, Castle of Lissingen Image:Sigiriya moat 2011.jpg, Sigiriya moat, Sri Lanka File:Qufu City Wall - south of the west gate - looking S - P1050985.JPG, Frozen moat of the walled city of

Qufu Qufu ( ; ) is a city in southwestern Shandong province, East China. It is located about south of the provincial capital Jinan and northeast of the prefectural seat at Jining. Qufu has an area of 815 square kilometers, and a total population of ...

, China Image:Fortbourtange.jpg,

Fort Bourtange Fort Bourtange ( nl, Vesting Bourtange) is a fort in the village of Bourtange, Groningen, Netherlands. It was built under orders of William the Silent and completed in 1593. Its original purpose was to control the only road between Germany and the ...

, a late 16th-century star fort in Groningen,

Image:Fort Brockhurst 4-Gosport - geograph.org.uk - 693238.jpg, Fort Brockhurst a mid-19th-century polygonal fort in

Hampshire Hampshire (, ; abbreviated to Hants) is a ceremonial and non-metropolitan county in western South East England on the coast of the English Channel. Home to two major English cities on its south coast, Southampton and Portsmouth, Hampshire ...

, England Image:Castello_esterno.jpg, The

Castello Estense The ' (‘ Este castle’) or ' (‘St. Michael's castle’) is a moated medieval castle in the center of Ferrara, northern Italy. It consists of a large block with four corner towers. History On 3 May 1385, the Ferrarese people, driven to des ...

of Ferrara, Italy Image:Fort-Jefferson Dry-Tortugas.jpg, Fort Jefferson,

Dry Tortugas Dry Tortugas National Park is a national park located about west of Key West in the Gulf of Mexico. The park preserves Fort Jefferson and the seven Dry Tortugas islands, the westernmost and most isolated of the Florida Keys. The archipelago's c ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

Image:Moat Castle Steinfurt.jpg, Moat with civic houses bordering on it in Steinfurt Image:Beijing ancient city gate and moat.jpg,

Beijing } Beijing ( ; ; ), alternatively romanized as Peking ( ), is the capital of the People's Republic of China. It is the center of power and development of the country. Beijing is the world's most populous national capital city, with over 21 ...

ancient city gate and moat Image:Vellorefort.jpg,

Vellore Fort Vellore Fort is a large 16th-century fort situated in heart of the Vellore city, in the States and territories of India, state of Tamil Nadu, India built by Vijayanagara Empire, Vijayanagara kings. The fort was at one time the headquarters of ...

Moat, in

Tamil Nadu Tamil Nadu (; , TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

File:Daalsesingel-Utrecht-2020.jpg, The ''Daalsesingel'', a part of the moat that surrounds the city center of Utrecht, Netherlands File:Hikone-Castle-canal-cherry-blossom-2018-Luka-Peternel.jpg,

Hikone Castle is a Japanese Edo-period Japanese castle located in the city of Hikone, Shiga Prefecture, Japan It is considered the most significant historical building in Shiga. The site has been protected as a National Historic Site since 1951. Hikone is ...

moat File:Gate-of-Divine-Might-Forbidden-City-2018-Luka-Peternel.jpg,

moat File:Landskrona citadell från luften.jpg,

Landskrona Citadel Landskrona Citadel ( sv, Citadellet or ''Landskrona slott'') is situated in Landskrona, Scania, southern Sweden. Much of the original work is intact. Examples remain of all major parts of the fortification, which is uncommon in such an accessible ...

with mid 15th-century dual moat construction

Modern usage

Architectural usage

Dry moats were a key element used in French Classicism and

Beaux-Arts architecture Beaux-Arts architecture ( , ) was the academic architectural style taught at the École des Beaux-Arts in Paris, particularly from the 1830s to the end of the 19th century. It drew upon the principles of French neoclassicism, but also incorp ...

dwellings, both as decorative designs and to provide discreet access for service. Excellent examples of these can be found in Newport, Rhode Island at Miramar (mansion) and The Elms, as well as at

Carolands Carolands Chateau is a , 4.5 floor, 98 room mansion on in Hillsborough, California. An example of American Renaissance and Beaux-Arts design, the building is a California Historical Landmark and is listed on the National Register of Historic P ...

, outside of San Francisco, California, and at

Union Station A union station (also known as a union terminal, a joint station in Europe, and a joint-use station in Japan) is a railway station at which the tracks and facilities are shared by two or more separate railway companies, allowing passengers to ...

Toronto Toronto ( ; or ) is the capital city of the Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the most populous city in Canada and the fourth most populous city in North America. The city is the anch ...

, Ontario, Canada. Additionally, a dry moat can allow light and fresh air to reach basement workspaces, as for example at the James Farley Post Office in

New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...

Anti-terrorist moats

Whilst moats are no longer a significant tool of warfare, modern architectural building design continues to use them as a defence against certain modern threats, such as terrorist attacks from car bombs and

armoured fighting vehicle An armoured fighting vehicle (AFV) is an armed combat vehicle protected by armour, generally combining operational mobility with offensive and defensive capabilities. AFVs can be wheeled or tracked. Examples of AFVs are tanks, armoured cars, ...

s. For example, the new location of the Embassy of the United States in London, opened in 2018, includes a moat among its security features - the first moat built in England for more than a century. Modern moats may also be used for aesthetic or ergonomic purposes. The

Catawba Nuclear Station The Catawba Nuclear Station is a nuclear power plant located on a peninsula, called "Concord Peninsula", that reaches out into Lake Wylie, in York, South Carolina, USA. Catawba utilizes a pair of Westinghouse four-loop pressurized water reacto ...

has a concrete moat around some of the plant. (Other sides of the plant are bordering a lake.) The moat is a part of precautions added to such sites after the September 11, 2001 attacks.

Safety moats

Moats, rather than fences, separate animals from spectators in many modern zoo installations. Moats were first used in this way by Carl Hagenbeck at his Tierpark in

Hamburg (male), (female) en, Hamburger(s), Hamburgian(s) , timezone1 = Central (CET) , utc_offset1 = +1 , timezone1_DST = Central (CEST) , utc_offset1_DST = +2 , postal ...

, Germany. The structure, with a vertical outer retaining wall rising direct from the moat, is an extended usage of the

ha-ha A ha-ha (french: hâ-hâ or ), also known as a sunk fence, blind fence, ditch and fence, deer wall, or foss, is a recessed landscape design element that creates a vertical barrier (particularly on one side) while preserving an uninterrupted view ...

of English landscape gardening.

Border defence moats

In 2004 plans were suggested for a two-mile moat across the southern border of the

Gaza Strip The Gaza Strip (;The New Oxford Dictionary of English (1998) – p.761 "Gaza Strip /'gɑːzə/ a strip of territory under the control of the Palestinian National Authority and Hamas, on the SE Mediterranean coast including the town of Gaza.. ...

to prevent tunnelling from Egyptian territory to the border town of Rafah. In 2008 city officials in

Yuma, Arizona Yuma ( coc, Yuum) is a city in and the county seat of Yuma County, Arizona, United States. The city's population was 93,064 at the 2010 census, up from the 2000 census population of 77,515. Yuma is the principal city of the Yuma, Arizona, M ...

planned to dig out a two-mile stretch of a 180-hectare (440-acre) wetland known as Hunters Hole to control immigrants coming from Mexico.

Pest control moats

Researchers of

jumping spider Jumping spiders are a group of spiders that constitute the family Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described species, making it the largest family of spiders at 13% of all species. Jumping spi ...

s, which have excellent vision and adaptable tactics, built water-filled miniature moats, too wide for the spiders to jump across. Some specimens were rewarded for jumping then swimming and others for swimming only. '' Portia fimbriata'' from

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

generally succeeded, for whichever method they were rewarded. When specimens from two different populations of '' Portia labiata'' were set the same task, members of one population determined which method earned them a reward, whilst members of the other continued to use whichever method they tried first and did not try to adapt. As a basic method of pest control in bonsai, a moat may be used to restrict access of crawling insects to the bonsai.

References

External links

{{Authority control Castle architecture Masonry Water