The High Bridge (originally the Aqueduct Bridge) is a steel arch bridge connecting Manhattan and the Bronx in New York City, New York, United States. Rising over the Harlem River, it is the city's oldest major bridge, having opened as part of the Croton Aqueduct in 1848. The eastern end is located in the Highbridge section of the Bronx, near the intersection of University Avenue and 170th Street, and the western end is located in Highbridge Park in Manhattan, near the intersection of Amsterdam Avenue and 172nd Street. Operated and maintained by the New York City Department of Parks and Recreation, the bridge is a New York City designated landmark and is listed on the National Register of Historic Places.
The High Bridge, measuring long, spans a valley that contains the Harlem River. The original bridge had fifteen stone round arches, each measuring either long. The five arches over the Harlem River were replaced by a single steel arch between 1926 and 1928. The bridge originally carried water pipes, and gatehouses at both ends controlled the flow of water in these pipes. In addition, the High Bridge Water Tower (which is still extant) pumped water to the Highbridge Reservoir at the Manhattan end.
The High Bridge was proposed in 1839 in lieu of a low-level bridge or a tunnel carrying water across the Harlem River, and water began flowing across the bridge in May 1848. The bridge originally carried two water tubes; a third tube and a walkway were added in the early 1860s. The bridge was proposed for demolition in the 1910s and 1920s, as it posed a hazard to navigation on the Harlem River. The city government approved the demolition in 1923 before instead ratifying a separate proposal to reconstruct only the central arch. Water stopped flowing across the bridge in 1958, and the bridge was closed to all traffic by the early 1970s due to safety concerns. A restoration began in 2013, following several years of planning, and the bridge was reopened to pedestrians and bicycles on June 9, 2015.
Site The High Bridge is an arch bridge between Manhattan and the Bronx in New York City, New York, U.S.. It carries pedestrians, bicycles, and the Old Croton Aqueduct over the Harlem River. Within the bridge's vicinity, the Harlem River is in a valley between Manhattan to the west and the Bronx to the east. The valley floor (which includes the riverbed) is made of Inwood marble, which erodes more easily than either the Manhattan schist on the Manhattan side or the Fordham gneiss on the Bronx side. The terrain on the Manhattan side is steeper than on the Bronx side, and the slope in the Bronx was originally forested. The river measures about wide at this location. New York City Department of Parks and Recreation (NYC Parks) owns the land at both ends of the bridge. Approximately north is the Washington Bridge, and between the two spans is the newer Alexander Hamilton Bridge. To the south is the Macombs Dam Bridge.
The bridge's Manhattan terminus is accessed via Highbridge Park in Washington Heights. The nearest park entrance is at the intersection of Amsterdam Avenue and 172nd Street, and there originally were steps leading to the former Highbridge Reservoir and a trail running south to 155th Street. Within Manhattan, the High Bridge crosses over ramps leading to the Trans-Manhattan Expressway, as well as Harlem River Drive along the western shore of the Harlem River. East of the river, the bridge crosses the Metro-North Railroad's Hudson Line, the Major Deegan Expressway (carrying Interstate 87), and Sedgwick Avenue. The Bronx terminus contains a seating area with tables. The bridge's walkway continues east to University Avenue and 170th Street in Highbridge. A set of 168 steps descends from that intersection; the staircase is divided into staggered flights, rising over a run of .
Design Built in 1848, the High Bridge is the oldest surviving major bridge in New York City and is sometimes cited as the city's oldest extant bridge of any kind. It is also the oldest of the bridges leading into Manhattan, and it was the last bridge constructed across the Harlem River before the Bronx was annexed into New York City in 1874. The High Bridge was originally part of the Old Croton Aqueduct, which carried water from the Croton River watershed to supply the then-burgeoning city of New York (now part of Manhattan). Sources disagree on whether the bridge has a height of or above the Harlem River, with a total length of . The central arch provides of vertical clearance at mean high water.
The design was led by Croton Aqueduct engineer John B. Jervis, who replaced David Bates Douglass, the aqueduct's original engineer. James Renwick Jr., who went on to design St. Patrick's Cathedral in Midtown Manhattan, participated in the design. The bridge is owned and operated by various agencies of the New York City government. The New York City Department of Parks and Recreation (NYC Parks) owns the physical structure and oversees its operations and long-term maintenance. The New York City Department of Environmental Protection owns the pipes carrying the Croton Aqueduct over the bridge, and the New York City Department of Transportation assists with the bridge's maintenance.
Arches The bridge was constructed with fifteen semicircular arches. The design bears similarities to ancient Roman aqueducts; one source cites the Pont du Gard in France as a particular inspiration. There were originally eight wide arches, measuring long, and seven narrow arches, measuring long. The wide arches, most of which have been replaced, originally spanned the river; the narrow arches, which still exist, spanned the shoreline on either side. The stonework for the arches is made of Maine granite, supplied by at least ten quarries in New York and New England. Gneiss is also used for the arches' interiors.
The arches are supported by piers measuring across at ground level. There were originally ten piers on the shoreline (including the abutments at either end) and six within the river. The foundations of each pier consist of oak pilings, with concrete poured into the gaps between the pilings. The mid-river piers were built on mud; workers constructed cofferdams to surround the pilings and concrete, and a series of wooden grillages were built atop the pilings. For the piers on the shoreline, the pilings were inserted into pits; concrete was then poured around each piling, and stones were laid atop the concrete. The springers—where the lowest sections of the arches curve outward from the piers—are placed about above mean high water. Above the springers (between the spandrel panels at the top corners of each arch), the interiors of the piers were made as hollow as possible. Excess water from the deck drained into the side walls of the piers. Each pair of adjacent arches served as counterweights, holding up the piers beneath them. The Bronx abutments have a pair of arched doors for maintenance.
Due to the fast-moving waters of the Harlem River, the piers in the middle of the river originally created a navigational hazard, as watercraft were vulnerable to crashing into them. The piers did not run perpendicularly to the river channel, which meant that many barges had less than of horizontal clearance when passing through the arches. In the late 1920s, the five mid-river arches were demolished and replaced with a larger steel arch measuring about long. The existing piers at each end of the steel arch were enlarged to serve as abutments. The remaining stone portions of the bridge mostly retain the original design. The arches are illuminated at night by LEDs.
Deck Pipes Prior to 1861, water from the aqueduct was carried across the bridge via a pair of pipes, variously cited as measuring or in diameter. These tubes were surrounded by a chamber that could accommodate additional pipes in the future, and a earthen embankment surrounded the tubes to protect them from extreme temperatures. The carrying capacity was enlarged in 1861–1862 with a larger tube, made of wrought iron. Measuring about in diameter, it was built above the existing pipes, resting on cast iron pedestals placed between the two original pipes. A brick arch, measuring thick with a radius, surrounds the largest pipe. A manhole provides access to the pipes midway across the bridge, and the largest pipe has two granite ventilators as well.
The pipes are lower than the rest of the aqueduct on both ends of the bridge, forming a siphon. In the Bronx, the aqueduct descends toward the bridge, while in Manhattan, the aqueduct ascends before continuing its southward trajectory. The water tunnels leading to the pipes remain intact in the early 21st century. The pipes also remain in place under the pedestrian walkway, although the interior of the largest pipe had rusted extensively by 2010.
Walkway The top of the deck has a walkway with a brick pavement arranged in a herringbone pattern. The deck has never carried vehicles, and the walkway was originally accessible only by stairs at either end. The original bricks, made of Hudson River clay, had darkened by the early 2010s (before the renovation). The current walkway has been open ; it is ADA-accessible and is open between 7 a.m. and 10 p.m. seven days a week. The brick walkway, which has been restored to its original design, contains embedded plaques depicting the aqueduct's history. There are Victorian-style lampposts along the walkway, as well as brick-and-granite parapets on either side.
History The island of Manhattan, surrounded by brackish rivers, originally had numerous small sources of freshwater, including springs, streams, and lakes. All of these had been polluted or eliminated by the 18th century as modern New York City grew. As such, there were proposals to bring water from outside Manhattan via an aqueduct crossing the Harlem River; the first such plan was made in 1778, when Manhattan residents suggested that water be obtained from Rye Pond in Westchester. As the city was devastated by cholera in 1832 and the Great Fire in 1835, the inadequacy of the water system of wells and cisterns became apparent, and numerous corrective measures were examined. Efforts to bring freshwater from the Croton River watershed in New York's Hudson Valley, north of the city, commenced in the early 1830s. David Bates Douglass was appointed the chief engineer of what would become the Old Croton Aqueduct in 1835; in this capacity, he was tasked with designing the High Bridge. He was replaced the next year by John B. Jervis, who oversaw construction of the entire aqueduct. Work on the Old Croton Aqueduct began in 1837, and it began supplying water in 1842.
The aqueduct measured long, running from Old Croton Dam in Westchester to the modern boroughs of the Bronx and Manhattan in New York City. It used a classic gravity feed, running through an enclosed brick-and-masonry structure for most of its length. University Avenue was later built over the southernmost portion of the aqueduct's Bronx section, leading to the bridge. Between the Bronx and Manhattan, the aqueduct had to cross the Harlem River valley, which was wide. On the Manhattan side, the aqueduct continued south under Amsterdam Avenue, leading to the Central Park and Murray Hill reservoirs. In addition to the High Bridge, the aqueduct had other above-ground structures including gatehouses, reservoirs, ventilators, weirs, and a bridge above the Sing Sing Kill stream in Westchester.
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