Question: What river flows through the capital city of Oklahoma?

full_context: Document 1: Oklahoma City: Oklahoma City is the capital and largest city of the state of Oklahoma. The county seat of Oklahoma County, the city ranks 27th among United States cities in population. The population grew following the 2010 Census, with the population estimated to have increased to 620,602 as of July 2014. As of 2014, the Oklahoma City metropolitan area had a population of 1,322,429, and the Oklahoma City-Shawnee Combined Statistical Area had a population of 1,459,758 (Chamber of Commerce) residents, making it Oklahoma's largest metropolitan area. Oklahoma City's city limits extend into Canadian, Cleveland, and Pottawatomie counties, though much of those areas outside of the core Oklahoma County area are suburban or rural (watershed). The city ranks as the eighth-largest city in the United States by land area (including consolidated city-counties; it is the largest city in the United States by land area whose government is not consolidated with that of a county or borough).
Document 2: Palermo: Today both the Papireto river and the Kemonia are covered up by buildings. However, the shape of the former watercourses can still be recognised today, because the streets that were built on them follow their shapes. Today the only waterway not drained yet is the Oreto river that divides the downtown of the city from the western uptown and the industrial districts. In the basins there were, though, many seasonal torrents that helped formed swampy plains, reclaimed during history; a good example of which can be found in the borough of Mondello.
Document 3: Oklahoma City: According to the United States Census Bureau, the city has a total area of 620.34 square miles (1,606.7 km2), of which, 601.11 square miles (1,556.9 km2) of it is land and 19.23 square miles (49.8 km2) of it is water. The total area is 3.09 percent water.
Document 4: Mexico City: Originally much of the valley laid beneath the waters of Lake Texcoco, a system of interconnected salt and freshwater lakes. The Aztecs built dikes to separate the fresh water used to raise crops in chinampas and to prevent recurrent floods. These dikes were destroyed during the siege of Tenochtitlan, and during colonial times the Spanish regularly drained the lake to prevent floods. Only a small section of the original lake remains, located outside the Federal District, in the municipality of Atenco, State of Mexico.
Document 5: Oklahoma City: Oklahoma City has a major park in each quadrant of the city, going back to the first parks masterplan. Will Rogers Park, Lincoln Park, Trosper Park, and Woodson Park were once connected by the Grand Boulevard loop, some sections of which no longer exist. Martin Park Nature Center is a natural habitat in far northwest Oklahoma City. Will Rogers Park is home to the Lycan Conservatory, the Rose Garden, and Butterfly Garden, all built in the WPA era. Oklahoma City is home to the American Banjo Museum, which houses a large collection of highly decorated banjos from the early 20th century and exhibits on the history of the banjo and its place in American history. Concerts and lectures are also held there.
Document 6: Oklahoma City: Walking trails line Lake Hefner and Lake Overholser in the northwest part of the city and downtown at the canal and the Oklahoma River. The majority of the east shore area is taken up by parks and trails, including a new leashless dog park and the postwar-era Stars and Stripes Park. Lake Stanley Draper is the city's largest and most remote lake.
Document 7: Oklahoma City: In 1993, the city passed a massive redevelopment package known as the Metropolitan Area Projects (MAPS), intended to rebuild the city's core with civic projects to establish more activities and life to downtown. The city added a new baseball park; central library; renovations to the civic center, convention center and fairgrounds; and a water canal in the Bricktown entertainment district. Water taxis transport passengers within the district, adding color and activity along the canal. MAPS has become one of the most successful public-private partnerships undertaken in the U.S., exceeding $3 billion in private investment as of 2010. As a result of MAPS, the population living in downtown housing has exponentially increased, together with demand for additional residential and retail amenities, such as grocery, services, and shops.
Document 8: Dammam: Having been built from the ground up, the Dammam Area was designed from the outset on the principles of modern urban planning. Residential areas are separate from commercial sections, roads are broad and straight and buildings conform to a master plan. One of the main features of the development of the area is land reclamation. Vast stretches of the shallow Persian Gulf waters have been filled, with hotels and office buildings occupying what were once marshes. Water for household, urban and industrial use is provided by desalination plants that supply approximately seven million cubic feet of treated water to the area each day. The availability of water underpins the urban and industrial growth of the Dammam Area, and provisions have been made for expanding existing desalination facilities to meet future growth.
Document 9: Oklahoma City: The city is roughly bisected by the North Canadian River (recently renamed the Oklahoma River inside city limits). The North Canadian once had sufficient flow to flood every year, wreaking destruction on surrounding areas, including the central business district and the original Oklahoma City Zoo. In the 1940s, a dam was built on the river to manage the flood control and reduced its level. In the 1990s, as part of the citywide revitalization project known as MAPS, the city built a series of low-water dams, returning water to the portion of the river flowing near downtown. The city has three large lakes: Lake Hefner and Lake Overholser, in the northwestern quarter of the city; and the largest, Lake Stanley Draper, in the sparsely populated far southeast portion of the city.
Document 10: Midwest City, Oklahoma: Midwest City is a city in Oklahoma County, Oklahoma, United States, and a part of the Oklahoma City metropolitan area. As of the 2010 census, the population was 54,371, making it the eighth largest city in the state.
Document 11: Oklahoma: In descending order of population, Oklahoma's largest cities in 2010 were: Oklahoma City (579,999, +14.6%), Tulsa (391,906, −0.3%), Norman (110,925, +15.9%), Broken Arrow (98,850, +32.0%), Lawton (96,867, +4.4%), Edmond (81,405, +19.2%), Moore (55,081, +33.9%), Midwest City (54,371, +0.5%), Enid (49,379, +5.0%), and Stillwater (45,688, +17.0%). Of the state's ten largest cities, three are outside the metropolitan areas of Oklahoma City and Tulsa, and only Lawton has a metropolitan statistical area of its own as designated by the United States Census Bureau, though the metropolitan statistical area of Fort Smith, Arkansas extends into the state.
Document 12: Oklahoma: Oklahoma had 598 incorporated places in 2010, including four cities over 100,000 in population and 43 over 10,000. Two of the fifty largest cities in the United States are located in Oklahoma, Oklahoma City and Tulsa, and 65 percent of Oklahomans live within their metropolitan areas, or spheres of economic and social influence defined by the United States Census Bureau as a metropolitan statistical area. Oklahoma City, the state's capital and largest city, had the largest metropolitan area in the state in 2010, with 1,252,987 people, and the metropolitan area of Tulsa had 937,478 residents. Between 2000 and 2010, the cities that led the state in population growth were Blanchard (172.4%), Elgin (78.2%), Jenks (77.0%), Piedmont (56.7%), Bixby (56.6%), and Owasso (56.3%).
Document 13: Oklahoma City: Oklahoma City has experienced significant population increases since the late 1990s. In May 2014, the U.S. Census announced Oklahoma City had an estimated population of 620,602 in 2014 and that it had grown 5.3 percent between April 2010 and June 2013. Since the official Census in 2000, Oklahoma City had grown 21 percent (a 114,470 raw increase) according to the Bureau estimates. The 2014 estimate of 620,602 is the largest population Oklahoma City has ever recorded. It is the first city in the state to record a population greater than 600,000 residents and the largest municipal population of the Great Plains region (OK, KS, NE, SD, ND).
Document 14: Lake Texcoco: Tenochtitlan was founded on an islet in the western part of the lake in the year 1325. Around it, the Aztecs created a large artificial island using a system similar to the creation of chinampas. To overcome the problems of drinking water, the Aztecs built a system of dams to separate the salty waters of the lake from the rain water of the effluents. It also permitted them to control the level of the lake. The city also had an inner system of channels that helped to control the water.
Document 15: Oklahoma City: Oklahoma City is the principal city of the eight-county Oklahoma City Metropolitan Statistical Area in Central Oklahoma and is the state's largest urbanized area. Based on population rank, the metropolitan area was the 42nd largest in the nation as of 2012.
ground_truth: North Canadian River
sub_queries: What is the capital of Oklahoma? Answer: Oklahoma City
What river flows through Oklahoma City ? Answer: North Canadian River