An observation post (commonly abbreviated OP ), temporary or fixed, is a position from which soldiers can watch enemy movements, to warn of approaching soldiers (such as in trench warfare ), or to direct fire. In strict military terminology, an observation post is any preselected position from which observations are to be made - this may include very temporary installations such as a vehicle parked as a roadside checkpoint, or even an airborne aircraft.
41-398: When selecting a (temporary) observation post, trained troops are to avoid obvious and conspicuous locations such as hilltops, water towers or other isolated terrain features, and to ensure that the observation post can be reached via a concealed route. This is especially important as the observer in the post should be rotated every 20–30 minutes, as vigilance decreases markedly after such
82-654: A large ivy -covered trellis or they can be simply painted. Some city water towers have the name of the city painted in large letters on the roof, as a navigational aid to aviators and motorists . Sometimes the decoration can be humorous. An example of this are water towers built side by side, labeled HOT and COLD . Cities in the United States possessing side-by-side water towers labeled HOT and COLD include Granger, Iowa ; Canton, Kansas ; Pratt, Kansas , and St. Clair, Missouri . Eveleth, Minnesota at one time had two such towers, but no longer does. Many small towns in
123-464: A longer time, an observation post (or ground observation post ) may develop into a bunker -like installation. It is not unusual for soldiers to occupy a 'hide' for long periods of time. To avoid detection they have to remove all their own waste. This is achieved with the aid of clingfilm, plastic bags and empty water bottles. This military -related article is a stub . You can help Misplaced Pages by expanding it . Water tower A water tower
164-471: A narrower pipe leading to and from the ground. There were originally over 400 standpipe water towers in the United States, but very few remain today, including: Tankhouse A tankhouse (also spelled tank house or tank-house) is a water tower enclosed by siding . Tankhouses were part of a self-contained domestic water system supplying the house and garden, developed before the advent of electricity and municipal water mains. The system consisted of
205-416: A public water supply. Water towers are able to supply water even during power outages , because they rely on hydrostatic pressure produced by elevation of water (due to gravity ) to push the water into domestic and industrial water distribution systems; however, they cannot supply the water for a long time without power, because a pump is typically required to refill the tower. A water tower also serves as
246-510: A pulsing flow, while the pressurized water distribution system required constant pressure. Standpipes also provided a convenient fixed location to measure flow rates. Designers typically enclosed the riser pipes in decorative masonry or wooden structures. By the late 19th century, standpipes grew to include storage tanks to meet the ever-increasing demands of growing cities. Many early water towers are now considered historically significant and have been included in various heritage listings around
287-422: A reservoir to help with water needs during peak usage times. The water level in the tower typically falls during the peak usage hours of the day, and then a pump fills it back up during the night. This process also keeps the water from freezing in cold weather, since the tower is constantly being drained and refilled. Although the use of elevated water storage tanks has existed since ancient times in various forms,
328-541: A time. Observation posts should be garrisoned with at least two personnel (more, for defense and observer rotation, if the post is to be retained for longer durations), and should be provided a means of communication with their chain of command , preferably by phone instead of by radio. Often being positioned in secret very close to the enemy, an observation post is usually a small construct, often consisting largely of camouflage materials and possibly weather cover. However, where frontlines are expected to be stable for
369-487: A water tower present, pumps can be sized for average demand, not peak demand; the water tower can provide water pressure during the day and pumps will refill the water tower when demands are lower. Using wireless sensor networks to monitor water levels inside the tower allows municipalities to automatically monitor and control pumps without installing and maintaining expensive data cables. The adjacent image shows three architectural approaches to incorporating these tanks in
410-405: A windmill, a hand-dug well and the tankhouse. The windmill pumped water from the well up into the tank at the top of the tankhouse, from where it flowed down under gravity pressure to the house and garden. The system used no fuel or electricity . The tankhouse is sometimes called a pump-house, a well-house, a well-tower or just a water tower. But whatever it is called, it is a water tower that
451-665: Is a water tower topped with a sphere-shaped water tank in Union, New Jersey , and characterized as the World's Tallest Water Sphere . A Star Ledger article suggested a water tower in Erwin, North Carolina completed in early 2012, 219.75 ft (66.98 m) tall and holding 500,000 US gallons (1,900 m ), had become the World's Tallest Water Sphere. However, photographs of the Erwin water tower revealed
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#1732858198827492-459: Is also possible that the early German immigrants conceived the idea themselves or brought it with them from Germany. The cypress tanks, sometimes called cisterns in Texas, were always exposed on top of the limestone towers, and the windmills stood on separate towers over the nearby well. Later, tankhouses in the same area were built of concrete with steel or concrete tanks, and a few were built of wood in
533-502: Is an elevated structure supporting a water tank constructed at a height sufficient to pressurize a distribution system for potable water , and to provide emergency storage for fire protection. Water towers often operate in conjunction with underground or surface service reservoirs , which store treated water close to where it will be used. Other types of water towers may only store raw (non-potable) water for fire protection or industrial purposes, and may not necessarily be connected to
574-426: Is enclosed by siding. The siding is what makes it a "house", with usable interior space. Ordinary water towers, with a tank on top of an open tower, are not tankhouses. The term is also used for an unrelated structure in the copper-refining industry. Tankhouses are an important part of California 's historical heritage and the state's early material culture . Many thousands were built in both town and country from
615-414: Is enough pressure to operate and provide for most domestic water pressure and distribution system requirements. The height of the tower provides the pressure for the water supply system, and it may be supplemented with a pump . The volume of the reservoir and diameter of the piping provide and sustain flow rate. However, relying on a pump to provide pressure is expensive; to keep up with varying demand,
656-947: Is located in Edmond . The Earthoid , a perfectly spherical tank located in Germantown, Maryland is 100 ft (30 m) tall and holds 2,000,000 US gallons (7,600 m ) of water. The name is taken from it being painted to resemble a globe of the world. The golf ball-shaped tank of the water tower at Gonzales, California is supported by three tubular legs and reaches about 125 ft (38 m) high. The Watertoren (or Water Towers) in Eindhoven , Netherlands contain three spherical tanks, each 10 m (33 ft) in diameter and capable of holding 500 cubic metres (130,000 US gal) of water, on three 43.45 m (142.6 ft) spires were completed in 1970. Water towers can be surrounded by ornate coverings including fancy brickwork ,
697-467: Is tall. A spheroid looks like a round pillow that is somewhat flattened. A cross section of a spheroid in two directions (east-west or north-south) is an ellipse, but in only one direction (top-bottom) is it a perfect circle. Both spheres and spheroids are special-case ellipsoids: spheres have symmetry in 3 directions, spheroids have symmetry in 2 directions. Scalene ellipsoids have 3 unequal length axes and three unequal cross sections. The Union Watersphere
738-407: Is used to hold the water in. The wooden walls of the water tower are held together with steel cables or straps, but water leaks through the gaps when first filled. As the water saturates the wood, it swells, the gaps close and become impermeable. The rooftop water towers store 250,000 to 50,000 litres (55,000 to 11,000 imp gal; 66,000 to 13,000 US gal) of water until it is needed in
779-622: The Goldbergturm in Sindelfingen , Germany, or the second of the three Kuwait Towers , in the State of Kuwait . It is also common to use water towers as the location of transmission mechanisms in the UHF range with small power, for instance for closed rural broadcasting service, amateur radio , or cellular telephone service. In hilly regions, local topography can be substituted for structures to elevate
820-419: The 1850s to the 1930s, almost exclusively of redwood — tower, water tank, siding and roof shingles — at a time when the state's abundant redwood forests seemed inexhaustible. The windmill , which stood over the well, was usually attached to the tower, but sometimes stood on a separate tower. Tankhouses became obsolete with the coming of deep, drilled wells and electric pumps in the countryside and water mains in
861-490: The 19th century, and for a long time New York City required that all buildings higher than six stories be equipped with a rooftop water tower. Two companies in New York build water towers, both of which are family businesses in operation since the 19th century. The original water tower builders were barrel makers who expanded their craft to meet a modern need as buildings in the city grew taller in height. Even today, no sealant
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#1732858198827902-448: The 19th century. Cooper illustrates four early examples with octagonal towers. Pitman includes drawings of six types, one of which is now rare, with the supporting structure wider than the tankroom. Manning includes drawings of five types, including the same rare type. Thorsheim also illustrates five types. Many tankhouses have lost the top (tank) level, making it hard to know the original design. Windmills were usually attached to
943-562: The California style. In Texas the windmill always stood on a separate tower. In California, several types of tankhouse can be seen today. The supporting tower may have vertical or sloping sides. The tankroom (top floor) may also have vertical or sloping sides, and may or may not overhang the tower. On many tankhouses the redwood tank is not enclosed by siding but exposed, with or without a roof above it. In some areas one type predominates. Other variants occur, particularly among those built in
984-459: The United States use their water towers to advertise local tourism, their local high school sports teams, or other locally notable facts. A "mushroom" water tower was built in Örebro , Sweden and holds almost two million gallons of water. Alternatives to water towers are simple pumps mounted on top of the water pipes to increase the water pressure. This new approach is more straightforward, but also more subject to potential public health risks; if
1025-588: The Wieża Ciśnień ( Wrocław water tower ) in Wrocław , Poland which is today a restaurant complex. Others have been converted to residential use. Historically, railroads that used steam locomotives required a means of replenishing the locomotive's tenders. Water towers were common along the railroad. The tenders were usually replenished by water cranes , which were fed by a water tower. Some water towers are also used as observation towers, and some restaurants, such as
1066-421: The building below. The upper portion of water is skimmed off the top for everyday use while the water in the bottom of the tower is held in reserve to fight fire. When the water drops below a certain level, a pressure switch, level switch or float valve will activate a pump or open a public water line to refill the water tower. Architects and builders have taken varied approaches to incorporating water towers into
1107-475: The design of a building, one on East 57th Street in New York City. From left to right, a fully enclosed and ornately decorated brick structure, a simple unadorned roofless brick structure hiding most of the tank but revealing the top of the tank, and a simple utilitarian structure that makes no effort to hide the tanks or otherwise incorporate them into the design of the building. The technology dates to at least
1148-565: The design of their buildings. On many large commercial buildings, water towers are completely hidden behind an extension of the facade of the building. For cosmetic reasons, apartment buildings often enclose their tanks in rooftop structures, either simple unadorned rooftop boxes, or ornately decorated structures intended to enhance the visual appeal of the building. Many buildings, however, leave their water towers in plain view atop utilitarian framework structures. Water towers are common in India , where
1189-406: The distinction between a water sphere and water spheroid thus: A water sphere is a type of water tower that has a large sphere at the top of its post. The sphere looks like a golf ball sitting on a tee or a round lollipop. A cross section of a sphere in any direction (east-west, north-south, or top-bottom) is a perfect circle. A water spheroid looks like a water sphere, but the top is wider than it
1230-454: The east. There is an interesting but as yet not well documented cluster of tankhouses in the Texas hill country west of Austin, where German immigrants settled in the last half of the 19th century. They found no redwood, but there was plenty of limestone, and cypress trees along the creeks: they built their towers of limestone and their tanks out of cypress wood. It is possible that the tankhouse idea traveled from California to Texas , but it
1271-476: The electricity supply is erratic in most places. If the pumps fail (such as during a power outage), then water pressure will be lost, causing potential public health concerns. Many U.S. states require a " boil-water advisory " to be issued if water pressure drops below 20 pounds per square inch (140 kPa). This advisory presumes that the lower pressure might allow pathogens to enter the system. Some have been converted to serve modern purposes, as for example,
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1312-464: The modern use of water towers for pressurized public water systems developed during the mid-19th century, as steam-pumping became more common, and better pipes that could handle higher pressures were developed. In the United Kingdom, standpipes consisted of tall, exposed, N-shaped pipes, used for pressure relief and to provide a fixed elevation for steam-driven pumping engines which tended to produce
1353-674: The new tower to be a water spheroid. The water tower in Braman, Oklahoma , built by the Kaw Nation and completed in 2010, is 220.6 ft (67.2 m) tall and can hold 350,000 US gallons (1,300 m ). Slightly taller than the Union Watersphere, it is also a spheroid. Another tower in Oklahoma, built in 1986 and billed as the "largest water tower in the country", is 218 ft (66 m) tall, can hold 500,000 US gallons (1,900 m ), and
1394-454: The pump would have to be sized to meet peak demands. During periods of low demand, jockey pumps are used to meet these lower water flow requirements. The water tower reduces the need for electrical consumption of cycling pumps and thus the need for an expensive pump control system, as this system would have to be sized sufficiently to give the same pressure at high flow rates. Very high volumes and flow rates are needed when fighting fires. With
1435-506: The pumps fail, then loss of water pressure may result in entry of contaminants into the water system. Most large water utilities do not use this approach, given the potential risks. Kuwait Towers , which include two water reservoirs, and Kuwait Water Towers (Mushroom towers in Kuwait City . A standpipe is a water tower which is cylindrical (or nearly cylindrical) throughout its whole height, rather than an elevated tank on supports with
1476-435: The tank in New York. Water towers were used to supply water stops for steam locomotives on railroad lines. Early steam locomotives required water stops every 7 to 10 miles (11 to 16 km). A variety of materials can be used to construct a typical water tower; steel and reinforced or prestressed concrete are most often used (with wood, fiberglass , or brick also in use), incorporating an interior coating to protect
1517-430: The tanks. These tanks are often nothing more than concrete cisterns terraced into the sides of local hills or mountains, but function identically to the traditional water tower. The tops of these tanks can be landscaped or used as park space, if desired. The Chicago Bridge and Iron Company has built many of the water spheres and spheroids found in the United States. The website World's Tallest Water Sphere describes
1558-500: The towns. Almost all of the hand-dug wells have been filled in now, and most of the windmills have disappeared. The remaining tankhouses are an endangered species, threatened by constant commercial, residential, industrial and agricultural development. Their numbers dwindle with each passing year, and of those that remain, many suffer from lack of maintenance. There are far more tankhouses in California than in any other state, and they most probably originated in California. A tankhouse
1599-631: The water from any effects from the lining material. The reservoir in the tower may be spherical , cylindrical , or an ellipsoid , with a minimum height of approximately 6 metres (20 ft) and a minimum of 4 m (13 ft) in diameter. A standard water tower typically has a height of approximately 40 m (130 ft). Pressurization occurs through the hydrostatic pressure of the elevation of water; for every 102 millimetres (4.016 in) of elevation, it produces 1 kilopascal (0.145 psi ) of pressure. 30 m (98.43 ft) of elevation produces roughly 300 kPa (43.511 psi), which
1640-404: The world. Some are converted to apartments or exclusive penthouses . In certain areas, such as New York City in the United States, smaller water towers are constructed for individual buildings. In California and some other states, domestic water towers enclosed by siding ( tankhouses ) were once built (1850s–1930s) to supply individual homes; windmills pumped water from hand-dug wells up into
1681-451: Was built in Mendocino, California, in 1857 and many tankhouses in a variety of designs are still standing in that village. Tankhouses can be found in most of the state's 58 counties, wherever there was water not more than 50 feet or so below the surface. Probably after transcontinental and branch railroads were completed, tankhouses were built in other western states, the midwest, and even in