Question: Which is longer, the Black River Canal or Gowanus Canal?

Context paragraphs:
Proteus Gowanus: Proteus Gowanus was an interdisciplinary gallery and reading room founded in 2005 in Gowanus, Brooklyn.  The gallery, which curated year-long theme-based shows, took its name from shape-shifting Greek sea god Proteus and the nearby Gowanus Canal.  Proteus Gowanus closed on June 28, 2015.

Red Hook Grain Terminal: The Red Hook Grain Terminal is an abandoned grain elevator in the Red Hook neighborhood of Brooklyn, New York City, adjacent to the mouth of the Gowanus Canal.  It is 12 stories tall, 70 ft wide, and 429 ft long, containing fifty-four 120 ft cement silos.  As the neighborhood's tallest structure, it is highly visible from the elevated Gowanus Expressway and New York City Subway IND Culver Line viaducts over the Gowanus Canal.

New River (Broward County, Florida): The New River is a tidal estuary in South Florida, United States.  The river is connected to the Everglades through a series of man made canals.  After passing through Fort Lauderdale, the river connects to the Atlantic Ocean at Port Everglades cut.  The river is entirely within Broward County and is composed from the junction of three main canals which originate in the Everglades, splitting off from the Miami Canal.  They are the North New River Canal, which flows on the north side of State Road 84 / Interstate 595; the South New River Canal, which flows on the north side of Griffin Road and the south side of Orange Drive; and a canal which flows south of Sunrise Boulevard.

Gowanus Canal: The Gowanus Canal is a canal in the New York City borough of Brooklyn, on the westernmost portion of Long Island.  Connected to Gowanus Bay in Upper New York Bay, the canal borders the neighborhoods of Red Hook, Carroll Gardens, and Gowanus, all within South Brooklyn, to the west; Park Slope to the east; Boerum Hill and Cobble Hill to the north; and Sunset Park to the south.  It is 1.8 mi long.  There are seven bridges over the canal, carrying Union Street, Carroll Street (a landmark), Third Street, Ninth Street, Hamilton Avenue, the Gowanus Expressway, and the IND Culver Line of the New York City Subway.

Black River Canal: The Black River Canal was a canal built in northern New York in the United States to connect the Erie Canal to the Black River.  The canal had 109 locks along its 35 mi length.  Remains of several of the canal's former locks are visible along New York State Route 12 near Boonville.

Brooklyn Community Board 6: Brooklyn Community Board 6 is a New York City community board that encompasses the Brooklyn neighborhoods of Red Hook, Carroll Gardens, Park Slope, Gowanus, and Cobble Hill.  It is delimited by Upper New York Bay and East River on the west, Atlantic Avenue, Court Street, Fourth Avenue, Warren and Pacific Streets on the north, Prospect Park on the east, as well as by the 15th Street, Hamilton Avenue and the Gowanus Canal on the south.  It approximates the 19th century district of South Brooklyn.

Black River Canal Warehouse: Black River Canal Warehouse is a historic canal warehouse building located at Boonville in Oneida County, New York.  It was built in 1850 and is a 1 ⁄ -story, rectangular, wood-frame building, 28 feet by 40 feet with a gable roof.  It was built as a warehouse on the Black River Canal and used as such until the canal was abandoned in 1924.

Bob Zuckerman: Bob Zuckerman (born December 19, 1960) is an American community activist, progressive reformer and former small business owner who has advocated for the cleaning of the Gowanus Canal through environmentally sound strategies, and the creation of new parks along the waterfront.  He is on leave as the Executive Director of the Gowanus Canal Community Development Corporation and Gowanus Canal Conservancy.

Black River (St. Clair County): Black River is an 81.0 mi river in the U.S. state of Michigan, flowing into the St. Clair River in the city of Port Huron.  The Black River Canal in northern Port Huron extends east into Lake Huron near Krafft Road.

Gowanus Canal Conservancy: The Gowanus Canal Conservancy is a nonprofit conservancy founded in 2009 that serves as a community-based environmental steward of the Gowanus Canal.  Partnering with the EPA, the city Department of Environmental Protection (NYCDEP), groups like Riverkeeper and universities as diverse as Brooklyn Law School, SUNY Environmental Science and Forestry at Syracuse, and Rutgers, it seeks to improve the canal's water quality while promoting local green spaces and building habitats for the fauna that live in or near the waterway.

Supporting paragraphs: Black River Canal Gowanus Canal
Answer: Black River Canal