A water supply network or water supply system is a system of engineered hydrologic and hydraulic components that provide water supply . A water supply system typically includes the following:
69-684: The Croton Aqueduct or Old Croton Aqueduct was a large and complex water distribution system constructed for New York City between 1837 and 1842. The great aqueducts , which were among the first in the United States , carried water by gravity 41 miles (66 km) from the Croton River in Westchester County to reservoirs in Manhattan . It was built because local water resources had become polluted and inadequate for
138-483: A fountain of water that spouted to a height of 50 feet (15 m) from the beautifully decorated cast iron Croton Fountain in City Hall Park . Water started flowing through the aqueduct on June 22, 1842, taking 22 hours for gravity to take the water the 41 miles (66 km) (at a velocity of 1.86 miles per hour [2.99 km/h; 2.73 ft/s]) to reach Manhattan. Even though only 6,175 houses had been connected to
207-415: A layer of calcium carbonate . Corrosion inhibitors are often added to reduce release of metals into the water. Common corrosion inhibitors added to the water are phosphates and silicates . Maintenance of a biologically safe drinking water is another goal in water distribution. Typically, a chlorine based disinfectant , such as sodium hypochlorite or monochloramine is added to the water as it leaves
276-521: A left onto Ashburton Avenue going east. At Palisades Avenue, it makes a right and the trail bed restarts. Remnants of the aqueduct still exist and can be seen along the trail, including 21 stone ventilators, three stone weirs (chambers which were used to empty the aqueduct for maintenance), and one "Keeper's House" located in Dobbs Ferry . The Keeper's House in Dobbs Ferry was built in 1857 and
345-421: A long term, due to the uncertainty of the future demand”. It is preferable to provide extra pipe capacity to cope with unexpected demand growth and with water outages. The problem changes from a single objective optimization problem (minimizing cost), to a multi-objective optimization problem (minimizing cost and maximizing flow capacity). To solve a multi-objective optimization problem, it is necessary to convert
414-453: A metallic taste. Release of lead can occur from the solder used to join copper pipe together or from brass fixtures . Copper and lead levels at the consumer's tap are regulated to protect consumer health. Utilities will often adjust the chemistry of the water before distribution to minimize its corrosiveness. The simplest adjustment involves control of pH and alkalinity to produce a water that tends to passivate corrosion by depositing
483-472: A price in the market; water often becomes a business for private companies, which earn a profit by putting a higher price on water, which imposes a barrier for lower-income people. The Millennium Development Goals propose the changes required. Goal 6 of the United Nations' Sustainable Development Goals is to "Ensure availability and sustainable management of water and sanitation for all". This
552-492: A rise in the water table, which flooded many cellars. To address this problem, the city built sewers in many residential streets. By 1852, 148 miles (238 km) of sewers had already been constructed. About this time the German cockroach attracted attention and was called the "Croton bug" in the mistaken belief that the aqueduct brought the insects into the homes being connected to the new water supply system. Despite its size,
621-538: A set of rules and policies to overcome expected future problems. There are many international documents with interesting, but not very specific, ideas and therefore they are not put into practice. Recommendations have been made by the United Nations , such as the Dublin Statement on Water and Sustainable Development . The yield of a system can be measured by either its value or its net benefit. For
690-461: A system is governed by multiple criteria, one being cost. If the benefit is fixed , the least cost design results in maximum benefit. However, the least cost approach normally results in a minimum capacity for a water supply network. A minimum cost model usually searches for the least cost solution (in pipe sizes), while satisfying the hydraulic constraints such as: required output pressures, maximum pipe flow rate and pipe flow velocities. The cost
759-399: A water supply system, the true value or the net benefit is a reliable water supply service having adequate quantity and good quality of the product. For example, if the existing water supply of a city needs to be extended to supply a new municipality , the impact of the new branch of the system must be designed to supply the new needs, while maintaining supply to the old system. The design of
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#1732772292422828-409: A “Municipal Water Reuse System” which is a current approach to manage the rainwater. It applies a water reuse scheme for treated wastewater, on a municipal scale, to provide non-potable water for industry, household and municipal uses. This technology consists in separating the urine fraction of sanitary wastewater, and collecting it for recycling its nutrients . The feces and graywater fraction
897-411: Is a function of pipe diameters; therefore the optimization problem consists of finding a minimum cost solution by optimising pipe sizes to provide the minimum acceptable capacity. However, according to the authors of the paper entitled, “Method for optimizing design and rehabilitation of water distribution systems”, “the least capacity is not a desirable solution to a sustainable water supply network in
966-539: Is accessible from numerous stations on that line. The trail briefly parallels the Rockefeller State Park Preserve and its trails. Access to the trail is easiest where it crosses Route 9 , known variously as Albany Post Road, Broadway, or Highland Avenue. Heading southbound into downtown Yonkers, the trail goes on-street at Bishop William J. Walls Place and N. Broadway, where it follows the sidewalk on N. Broadway for one block, and then makes
1035-553: Is an integrated system including water intake, water utilization, wastewater discharge and treatment and water environmental protection . It requires reducing freshwater and groundwater usage in all sectors of consumption. Developing sustainable water supply systems is a growing trend, because it serves people's long-term interests. There are several ways to reuse and recycle the water, in order to achieve long-term sustainability, such as: Other possible approaches to scoping models for water supply, applicable to any urban area, include
1104-404: Is called potable water if it meets the water quality standards required for human consumption. The water in the supply network is maintained at positive pressure to ensure that water reaches all parts of the network, that a sufficient flow is available at every take-off point and to ensure that untreated water in the ground cannot enter the network. The water is typically pressurised by pumping
1173-685: Is collected, together with organic wastes from the households, using a gravity sewer system , continuously flushed with non-potable water. The water is treated anaerobically and the biogas is used for energy production . One effective way to achieve sustainable water management is to shift emphasis towards decentralized water projects, such as drip irrigation diffusion in India. This project covers large spatial areas while relying on individual technological adoption decisions, offering scalable solutions that can mitigate water scarcity and enhance agricultural productivity. Another method that can be utilized
1242-703: Is in recognition of the human right to water and sanitation, which was formally acknowledged at the United Nations General Assembly in 2010, that "clean drinking water and sanitation are essential to the recognition of all human rights". Sustainable water supply includes ensuring availability, accessibility, affordability and quality of water for all individuals. In advanced economies, the problems are about optimising existing supply networks. These economies have usually had continuing evolution, which allowed them to construct infrastructure to supply water to people. The European Union has developed
1311-489: Is increasing, so less water must be wasted and actions must be taken to prevent pipeline leakage. Shutting down the supply service to fix leaks is less and less tolerated by consumers. A sustainable water supply network must monitor the freshwater consumption rate and the waste-water generation rate. Many of the urban water supply networks in developing countries face problems related to population increase , water scarcity , and environmental pollution . In 1900 just 13% of
1380-489: Is insufficient maintenance of the water networks, especially in the major pipe lines in urban areas. The system deteriorates and then needs rehabilitation or renewal. Householders and sewage treatment plants can both make the water supply networks more efficient and sustainable. Major improvements in eco-efficiency are gained through systematic separation of rainfall and wastewater. Membrane technology can be used for recycling wastewater. The municipal government can develop
1449-551: Is not well distributed in the world. 1.8 million deaths are attributed to unsafe water supplies every year, according to the WHO . Many people do not have any access, or do not have access to quality and quantity of potable water, though water itself is abundant. Poor people in developing countries can be close to major rivers, or be in high rainfall areas, yet not have access to potable water at all. There are also people living where lack of water creates millions of deaths every year. Where
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#17327722924221518-503: Is the amount of time needed to achieve the transformation. More specifically, transformation must be implemented by municipal legislation bodies, which always need short-term solutions too. Another obstacle to achieving sustainability in water supply systems is the insufficient practical experience with the technologies required, and the missing know-how about the organization and the transition process. Croton Distributing Reservoir The Croton Distributing Reservoir , also known as
1587-603: Is the only remaining of four Keeper's Houses that is both on the aqueduct and open to the public. The only other remaining Keeper's House is located in Ossining, but it was moved off the aqueduct, is privately owned, and is not open to visitors. A portion of the Old Croton Aqueduct, running from the Croton River to Manhattan, was listed as a National Historic Landmark in 1992. The Croton Water Supply System
1656-786: Is through the promoting of community engagement and resistance against unsustainable water infrastructure projects. Grassroots movements, as observed in anti-dam protests in various countries, play a crucial role in challenging dominant development narratives and advocating for more socially and ecologically just water management practices. Municipalities and other forms of local governments should also invest in innovative technologies, such as membrane technology for wastewater recycling, and develop policy frameworks that incentivize eco-efficient practices. Municipal water reuse systems, as demonstrated in implementation, offer promising avenues for integrating wastewater treatment and resource recovery into urban water networks. The sustainable water supply system
1725-627: The Croton Reservoir , a similar fortified tank located on Fifth Avenue between 40th Street and 42nd Street , where the New York Public Library Main Branch and Bryant Park are located today. This reservoir was built to resemble ancient Egyptian architecture . New Yorkers came uptown for the fine view of the city obtained from atop its walls. The aqueduct opened to public use with great fanfare on October 14, 1842. The day-long celebration culminated in
1794-535: The European Commission is a good example of what has been created there out of former policies. There is great need for a more sustainable water supply systems. To achieve sustainability several factors must be tackled at the same time: climate change, rising energy cost, and rising populations. All of these factors provoke change and put pressure on management of available water resources. An obstacle to transforming conventional water supply systems,
1863-762: The Fifth Avenue station on the New York City Subway 's IRT Flushing Line ( 7 and <7> trains) and the 42nd Street–Bryant Park station on the IND Sixth Avenue Line ( B , D , F , <F> , and M trains). A few years before the reservoir was torn down, there were two tablets affixed to the Reservoir. The inscription was: HISTORICAL AND DESCRIPTIVE ACCOUNT OF THE CROTON AQUEDUCT – The Law authorizing
1932-618: The Great Lawn and Turtle Pond in Central Park . The old aqueduct remained in service until 1955. In 1987 the northernmost portion was reopened to provide water to Ossining . The Old Croton Trail extends for 26.2 miles (42.2 km) in Westchester County , providing public access along all but four segments — in the Getty Square neighborhood of downtown Yonkers , Tarrytown , Scarborough and Ossining — along
2001-580: The Murray Hill Reservoir , was an above-ground reservoir at 42nd Street and Fifth Avenue in the New York City borough of Manhattan . Covering 4-acre (16,000 m ) and holding 20 million US gallons (76,000 m ), it supplied the city with drinking water during the 19th century. Its massive 50-foot-high (15 m) granite walls, which presented a vaguely Egyptian-style facade , were 25 feet (7.6 m) thick. Atop
2070-460: The water industry . Raw water (untreated) is from a surface water source (such as an intake on a lake or a river ) or from a groundwater source (such as a water well drawing from an underground aquifer ) within the watershed that provides the water resource . The raw water is transferred to the water purification facilities using uncovered aqueducts, covered tunnels or underground water pipes . Virtually all large systems must treat
2139-523: The Commissioners to proceed with the work." David B. Douglass was employed as Chief Engineer until October, 1836; when he was succeeded by John B. Jervis . In March, 1837, Benjamin M. Brown resigned, and was succeeded by Thomas T. Woodruff. In March, 1840, the before mentioned Commissioners were succeeded by Samuel Stevens, John D. Ward, Zevedee Ring, Benjamin Birdsall and Samuel R. Childs. The work
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2208-595: The South Court at the Main Branch. Today water is primarily supplied to New York City via its three city water tunnels. The decommissioned Central Park Reservoir still remains, but has not operated as part of the Croton Aqueduct system since 1993. Subway commuters can see historical photographs showing the former reservoir. The display is located on the wall in the underground passageway that connects
2277-503: The adoption of appropriate technology coupled with effective strategies for operation and maintenance. These strategies must include effective management models, technical support to the householders and industries, sustainable financing mechanisms, and development of reliable supply chains . All these measures must ensure the following: system working lifespan; maintenance cycle; continuity of functioning; down time for repairs; water yield and water quality. In an unsustainable system there
2346-523: The aqueduct was constructed, residents of New York obtained water from cisterns , wells, natural springs, and other bodies of water. Rapid population growth in the 19th century and encroachment on these areas as Manhattan moved further north of Wall Street , led to the pollution of many local fresh water sources. Below Grand Street , a small number of well-off customers of the Manhattan Company had fresh water delivered to them, but that company
2415-480: The best combination. Returning to the cost objective function, it cannot violate any of the operational constraints. Generally this cost is dominated by the energy cost for pumping. “The operational constraints include the standards of customer service , such as: the minimum delivered pressure, in addition to the physical constraints such as the maximum and the minimum water levels in storage tanks to prevent overtopping and emptying respectively.” In order to optimize
2484-560: The capacity of the Old Croton Aqueduct could not keep up with the growth of New York City, and construction on a New Croton Aqueduct began in 1885 a few miles east. The new aqueduct, buried much deeper than the old one, went into service in 1890, with three times the capacity of the Old Croton Aqueduct. It currently supplies 10 percent of New York City's water. The Croton Receiving Reservoir continued to supply New York City with drinking water until 1940, when Commissioner of Parks and Recreation Robert Moses ordered it drained and filled to create
2553-446: The chances of the water becoming contaminated after treatment. Traditional surface water treatment plants generally consists of three steps: clarification, filtration and disinfection. Clarification refers to the separation of particles (dirt, organic matter, etc.) from the water stream. Chemical addition (i.e. alum, ferric chloride) destabilizes the particle charges and prepares them for clarification either by settling or floating out of
2622-412: The city. A polluted aquifer, overcrowded housing, the lack of sewers, public ignorance of basic sanitary conditions, and the existence of polluting industries near wells and residential areas contributed to an unprecedented mortality rate of 2.6% (1 death per 39 inhabitants) in 1830. Then in 1832 cholera first reached New York in the deadliest epidemic to that date. The need for a new supply of fresh water
2691-590: The construction of the work, passed May 2nd, 1834. Stephen Allen, William W. Fox, Saul Alley, Charles Dusenberry and Benjamin M. Brown were appointed Commissioners. During the year 1834, two surveys were made—one by DAVID B. DOUGLASS and the other by JOHN MARTINEAU. In April, 1835, a majority of the Electors of the City voted in favour of constructing the Aqueduct. On the 7th May following, the _Common Council_ "instructed
2760-452: The costs and benefits resulting in a set of solutions that can be used for sensitivity analysis and tested in different scenarios. But there is no single optimal solution that will satisfy the global optimality of both objectives. As both objectives are to some extent contradictory, it is not possible to improve one objective without sacrificing the other. It is necessary in some cases use a different approach. (e.g. Pareto Analysis ), and choose
2829-451: The distribution system, the water quality can degrade by chemical reactions and biological processes. Corrosion of metal pipe materials in the distribution system can cause the release of metals into the water with undesirable aesthetic and health effects. Release of iron from unlined iron pipes can result in customer reports of "red water" at the tap. Release of copper from copper pipes can result in customer reports of "blue water" and/or
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2898-569: The following: The Dublin Statement on Water and Sustainable Development is a good example of the new trend to overcome water supply problems. This statement, suggested by advanced economies, has come up with some principles that are of great significance to urban water supply. These are: From these statements, developed in 1992, several policies have been created to give importance to water and to move urban water system management towards sustainable development. The Water Framework Directive by
2967-607: The global population lived in cities. By 2005, 49% of the global population lived in urban areas. In 2030 it is predicted that this statistic will rise to 60%. Attempts to expand water supply by governments are costly and often not sufficient. The building of new illegal settlements makes it hard to map, and make connections to, the water supply, and leads to inadequate water management. In 2002, there were 158 million people with inadequate water supply . An increasing number of people live in slums , in inadequate sanitary conditions, and are therefore at risk of disease . Potable water
3036-584: The growing population of the city. Although the aqueduct was largely superseded by the New Croton Aqueduct , which was built in 1890, the Old Croton Aqueduct remained in service until 1955. The island of Manhattan, surrounded by brackish rivers, had a limited supply of freshwater available. It dwindled as the city grew rapidly after the American Revolutionary War , and freshwater sources became polluted by effluent . Before
3105-603: The majority of assets of a water utility. Systematic documentation of maintenance works using a computerized maintenance management system (CMMS) is a key to a successful operation of a water utility. A sustainable urban water supply network covers all the activities related to provision of potable water. Sustainable development is of increasing importance for the water supply to urban areas. Incorporating innovative water technologies into water supply systems improves water supply from sustainable perspectives. The development of innovative water technologies provides flexibility to
3174-541: The network. Most systems are divided into zones. Factors determining the extent or size of a zone can include hydraulics, telemetry systems, history, and population density. Sometimes systems are designed for a specific area then are modified to accommodate development. Terrain affects hydraulics and some forms of telemetry. While each zone may operate as a stand-alone system, there is usually some arrangement to interconnect zones in order to manage equipment failures or system failures. Water supply networks usually represent
3243-698: The northernmost 26 miles (42 km) of the aqueduct and its right-of-way , from Croton Gorge Park to the Yonkers-New York City line. It lies wholly within Westchester County but is under the jurisdiction of the Taconic Region of the New York State Office of Parks, Recreation and Historic Preservation . The trail runs roughly parallel to Metro North's Hudson Line from northern Yonkers to Scarborough and
3312-401: The operational performance of the water supply network, at the same time as minimizing the energy costs, it is necessary to predict the consequences of different pump and valve settings on the behavior of the network. Apart from Linear and Non-linear Programming, there are other methods and approaches to design, to manage and operate a water supply network to achieve sustainability—for instance,
3381-411: The optimal solution for all the original objectives. The second approach (the constraint method), chooses one of the objective functions as the single objective, and the other objective functions are treated as constraints with a limited value. However, the optimal solution depends on the pre-defined constraint limits. The multiple objective optimization problems involve computing the tradeoff between
3450-467: The problem into a single objective optimization problem, by using adjustments, such as a weighted sum of objectives , or an ε-constraint method. The weighted sum approach gives a certain weight to the different objectives, and then factors in all these weights to form a single objective function that can be solved by single factor optimization. This method is not entirely satisfactory, because the weights cannot be correctly chosen, so this approach cannot find
3519-579: The route of the aqueduct. It crosses the lawn of Lyndhurst , following the aqueduct's easement. The trail enters New York City on the eastern side of Van Cortlandt Park and runs through the Bronx alongside Aqueduct Avenue, and the trail continues under the southern part of University Avenue. Both the trail and the tunnel are part of the Old Croton Aqueduct State Historic Park , which was created in 1968 and encompasses
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#17327722924223588-483: The steel industry, and for several operations in food processing facilities. It is necessary to adopt a new approach to design urban water supply networks; water shortages are expected in the forthcoming decades and environmental regulations for water utilization and waste-water disposal are increasingly stringent. To achieve a sustainable water supply network, new sources of water are needed to be developed, and to reduce environmental pollution. The price of water
3657-456: The system by 1844, the Croton water had already dramatically improved both domestic hygiene and interior design. Baths and running water were being built in the private homes of wealthy New Yorkers, and public bathing facilities were constructed for the masses. The water system had another inadvertent consequence. The decline in the number of residents drawing water from the city's wells resulted in
3726-517: The treatment plant. Booster stations can be placed within the distribution system to ensure that all areas of the distribution system have adequate sustained levels of disinfection . Like electric power lines, roads, and microwave radio networks, water systems may have a loop or branch network topology, or a combination of both. The piping networks are circular or rectangular. If any one section of water distribution main fails or needs repair, that section can be isolated without disrupting all users on
3795-491: The walls was a public promenade offering panoramic views; Edgar Allan Poe enjoyed walking there. The Croton Aqueduct was New York City's foremost water source when it was established. Construction began in May 1837, and filling began July 4, 1842, amidst great fanfare. Prior to the aqueduct's construction, water had been obtained from cisterns , wells and barrels from rain. The aqueduct and reservoir obtained their names from
3864-404: The water into storage tanks constructed at the highest local point in the network. One network may have several such service reservoirs . In small domestic systems, the water may be pressurised by a pressure vessel or even by an underground cistern (the latter however does need additional pressurizing). This eliminates the need of a water tower or any other heightened water reserve to supply
3933-632: The water pressure. These systems are usually owned and maintained by local governments such as cities or other public entities, but are occasionally operated by a commercial enterprise (see water privatization ). Water supply networks are part of the master planning of communities, counties, and municipalities. Their planning and design requires the expertise of city planners and civil engineers , who must consider many factors, such as location, current demand, future growth, leakage, pressure, pipe size, pressure loss, fire fighting flows, etc.—using pipe network analysis and other tools. As water passes through
4002-402: The water stream. Sand, anthracite or activated carbon filters refine the water stream, removing smaller particulate matter. While other methods of disinfection exist, the preferred method is via chlorine addition. Chlorine effectively kills bacteria and most viruses and maintains a residual to protect the water supply through the supply network. The product, delivered to the point of consumption,
4071-866: The water supply system cannot reach the slums, people manage to use hand pumps , to reach the pit wells, rivers , canals , swamps and any other source of water. In most cases the water quality is unfit for human consumption. The principal cause of water scarcity is the growth in demand. Water is taken from remote areas to satisfy the needs of urban areas. Another reason for water scarcity is climate change : precipitation patterns have changed; rivers have decreased their flow; lakes are drying up; and aquifers are being emptied. In developing countries many governments are corrupt and poor and they respond to these problems with frequently changing policies and non clear agreements. Water demand exceeds supply, and household and industrial water supplies are prioritised over other uses, which leads to water stress . Potable water has
4140-408: The water supply system, generating a fundamental and effective means of sustainability based on an integrated real options approach. Water is an essential natural resource for human existence. It is needed in every industrial and natural process, for example, it is used for oil refining , for liquid-liquid extraction in hydro-metallurgical processes, for cooling, for scrubbing in the iron and
4209-541: The water's source, a series of mostly underground conduits that brought water from the Croton River in northern Westchester County to New York City's spigots. The reservoir was torn down in the 1890s. Today, the Main Branch of the New York Public Library , located in the eastern portion of Bryant Park , stands at that location. Some of the reservoir's original foundation can still be found in
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#17327722924224278-582: The water; a fact that is tightly regulated by global, state and federal agencies, such as the World Health Organization (WHO) or the United States Environmental Protection Agency (EPA). Water treatment must occur before the product reaches the consumer and afterwards (when it is discharged again). Water purification usually occurs close to the final delivery points to reduce pumping costs and
4347-563: Was a rectangular tank within fortress-like rusticated retaining walls, 1,826 feet (557 m) long and 836 feet (255 m) wide; it held up to 180 million US gallons (680,000 m) of water. 35 million US gallons (130,000 m) flowed into it daily from northern Westchester. From the Receiving Reservoir, water flowed down to the Croton Distributing Reservoir , better known simply as
4416-498: Was actually more focused on banking—it eventually became Chase Manhattan —and only paid as much attention to its water activities as it needed to avoid losing the state charter that allowed it to bank. The poor and the rest of the city were forced to rely on well water, often made palatable by adding alcoholic spirits, prompting temperance campaigners to call for the municipal provision of water. The unsanitary conditions caused an increase in disease. Epidemics of yellow fever ravaged
4485-738: Was added where the aqueduct crossed rivers. It extended from the Old Croton Dam in northern Westchester County to the Harlem River , where it continued over the High Bridge at 173rd Street and down the West Side of Manhattan and finally into a Receiving Reservoir located between 79th and 86th streets and Sixth and Seventh Avenues; the site is now the Great Lawn and Turtle Pond in Central Park . The Receiving Reservoir
4554-661: Was also designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers in 1975. The interior of the Old Croton Aqueduct has been documented by explorers including Miru Kim and historian Steve Duncan. Aqueduct Walk is a community park in the Bronx , New York City, running between Kingsbridge Road and Tremont Avenue . Aqueduct Walk is designated as an official New York City scenic landmark . Water supply network Water supply networks are often run by public utilities of
4623-558: Was commenced in May, 1837. On the 22nd June, 1842, the Aqueduct was so far completed that it received the Water from the Croton River Lake; on the 27th the Water entered the Receiving Reservoir and was admitted into this Reservoir on the succeeding 4th of July. The DAM at the Croton River is 40 feet high, and the overfall 251 feet in length. The CROTON RIVER LAKE is five miles long, and covers an area of 400 acres. The AQUEDUCT, from
4692-401: Was crucial. In March 1833, Major David Bates Douglass , engineering professor at West Point Military Academy , was appointed to survey and estimate the proposed route. In 1837, construction began on a massive engineering project, to divert water from sources upstate, following a route surveyed by Douglass and supervised by Douglass' successor, Chief Engineer John B. Jervis . The Croton River
4761-414: Was dammed, aqueducts were built, tunnels dug, piping laid, and reservoirs created. The gravity-fed aqueduct dropped 13 inches per mile, 1/4" per 100' (~0.02%). An elliptical tube, 8.5 feet (2.6m) high by 7.5 feet (2.3m) wide, of iron piping encased in brick masonry was laid, sometimes in cuts, with conical ventilating towers every mile or so, to relieve pressure and keep the water fresh. Hydraulic cement
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