2,617 articles
Northern Outfall Sewer
The Northern Outfall Sewer is a major brick sewer in east London, built between 1860 and 1865 under engineer Sir Joseph Bazalgette as part of London's Main Drainage.
Northumbrian Water
Northumbrian Water is a privately owned water and sewerage company serving 2.7 million customers in north east England and 2 million in Essex and Suffolk as Essex & Suffolk Water.
NRLA
The New Rail Link through the Alps (NRLA), also known as Alptransit, is a Swiss railway project comprising the Lötschberg, Gotthard, and Ceneri base tunnels, completed in 2020.
Nuevo Laredo
Nuevo Laredo is a city in Tamaulipas, Mexico, across the Rio Grande from Laredo, Texas. Founded in 1848, it anchors the busiest commercial crossing on the US–Mexico border.
Nurek Dam
The Nurek Dam, also known as Nurek Hydro-electric Station, is a 300-meter embankment dam on the Vakhsh River in Tajikistan, the tallest embankment dam in the world.
NZS 1170
NZS 1170 is the New Zealand structural design actions standard, a joint Australian/New Zealand series (AS/NZS 1170) specifying loads, wind, snow, and earthquake actions for building design.
NZS 3101
NZS 3101 is New Zealand's joint standard for the design of concrete structures, first issued in the early 1970s and internationally known for its earthquake capacity design provisions.
O'Shaughnessy Dam (California)
O'Shaughnessy Dam, known as the Hetch Hetchy dam, is a 430-foot dam on the Tuolumne River in Yosemite National Park, built by San Francisco for its water supply.
Oahe Dam
Oahe Dam is a large rolled-earth dam on the Missouri River north of Pierre, South Dakota, built by the U.S. Army Corps of Engineers and operating since 1962.
Octávio Frias de Oliveira Bridge
The Octávio Frias de Oliveira Bridge, known locally as the Ponte Estaiada, is a cable-stayed bridge over the Pinheiros River in São Paulo, Brazil, opened in 2008.
Office du Niger
The Office du Niger, a semi-autonomous Malian state agency, administers one of West Africa's largest rice irrigation schemes, in the Ségou region, created by France in 1932.
Ofwat
Ofwat, formally the Water Services Regulation Authority, is the economic regulator of the water and wastewater sectors in England and Wales, established at privatization in 1989. It sets water companies' prices.
Ohio and Erie Canal
The Ohio and Erie Canal was a 308-mile waterway built by Ohio from 1825 to 1832, connecting Lake Erie at Cleveland with the Ohio River at Portsmouth.
Ohio River locks and dams
The Ohio River locks and dams are a chain of 19 navigation structures operated by the U.S. Army Corps of Engineers along 981 miles from Pittsburgh to Cairo, Illinois.
OHL (company)
OHL (Obrascón Huarte Lain, S.A.), known since 2021 as OHLA, is a Spanish construction and infrastructure group based in Madrid, tracing its origins to a Bilbao firm founded in 1911.
Okutadami Dam
Okutadami Dam is a 157 m concrete gravity dam on the Tadami River between Niigata and Fukushima, completed in 1960 and operated by J-POWER for hydropower.
Olarizuko urmaela
Olarizuko urmaela, the Olarizu pond, is a periodically flooded wetland in the Olarizu fields south of Vitoria-Gasteiz, Spain, created as a flood-retention basin in 2014.
Olba Aqueduct
Roman aqueduct of Olba (Ὤλβα), Uğuralanı, Rough Cilicia, Turkey; drew Lamas River water from Kızılgeçit at about 1,175 m and crossed Seytan Deresi on a two-tiered Severan bridge about 150 m long.
Old Alton Bridge
Old Alton Bridge, also known as Goatman's Bridge, is an iron Pratt through-truss bridge built in 1884 over Hickory Creek in Denton County, Texas, now open only to hikers and horseback riders.
Old Bedford River
The Old Bedford River is a straight, 21-mile artificial drainage channel in the Fens of eastern England, cut between Earith and Salter's Lode and completed in 1637.
Old Blenheim Bridge
Old Blenheim Bridge was a wooden covered bridge with a 210-foot single span over Schoharie Creek in North Blenheim, New York, destroyed by flooding in 2011.
Old London Bridge
Old London Bridge was the stone bridge across the Thames between the City of London and Southwark, completed in 1209 and standing for over 600 years until its demolition in 1831.
Old River Control Structure
The Old River Control Structure, also called the Old River Control Complex, is a gated dam complex in Louisiana that keeps the Atchafalaya River from capturing the Mississippi.
Olmsted Locks and Dam
Olmsted Locks and Dam is a US Army Corps navigation complex on the Ohio River near Olmsted, Illinois, opened in 2018 at a cost of about $3 billion.
Oosterscheldekering
The Oosterscheldekering (Eastern Scheldt storm surge barrier) is a 9 km movable flood barrier in Zeeland, the largest of the Netherlands' Delta Works, opened in 1986.
Open (main beam) tunnel boring machine
An open (main beam) tunnel boring machine, or gripper TBM, is a shieldless hard-rock machine that advances by gripping the tunnel walls as its thrust base.
Open-face shield tunnelling
Open-face shield tunnelling is a method in which a rigid steel shield is pushed through soft ground with the tunnel face left unsupported, workers protected by boards, shelves, and hoods.
Operation Stack
Operation Stack is a Kent traffic procedure that closes the M20 to park freight lorries when disruption at Dover or the Channel Tunnel stops cross-Channel departures.
Orange County Groundwater Replenishment System
The Orange County Groundwater Replenishment System (GWRS) is a water purification project in Fountain Valley, California, opened in 2008 to recharge the groundwater basin and block seawater intrusion.
Orapa diamond mine
The Orapa diamond mine is an open-pit mine in Botswana's Central District, opened on 1 July 1971 as the country's first diamond mine, operated by Debswana.