Question: Which canal is the largest and most important drainage canal in the city of New Orleans, the 17th Street Canal or Champlain Canal?

Context paragraphs:
17th Street Canal: The 17th Street Canal is the largest and most important drainage canal in the city of New Orleans.  Operating with Pump Station 6, It moves water into Lake Pontchartrain.  The canal, along with the Orleans Canal and the London Avenue Canal, form the New Orleans Outfall Canals.  The 17th Street Canal forms a significant portion of the boundary between the city of New Orleans and Metairie, Louisiana.  The canal has also been known as the Metairie Outlet Canal and the Upperline Canal.

Orleans Canal: The Orleans Canal is a drainage canal in New Orleans, Louisiana.  The canal, along with the 17th Street Canal and the London Avenue Canal, form the New Orleans Outfall Canals.  The current version of the canal is about 2 km long, running along the up-river side of City Park, through the Lakeview and Lakeshore neighborhood, and into Lake Pontchartrain.  It is part of the system used to pump rain water out of the streets of the city into the Lake.  The Canal has also been known as the Orleans Avenue Canal, the Orleans Outfall Canal, the Orleans Tail Race, and early on, the Girod Canal,

Champlain Canal: The Champlain Canal is a 60 mi canal that connects the south end of Lake Champlain to the Hudson River in New York.  It was simultaneously constructed with the Erie Canal and is now part of the New York State Canal System and the Lakes to Locks Passage.

Lakewood, New Orleans: Lakewood is a neighborhood of the city of New Orleans.  A subdistrict of the Lakeview District Area, its boundaries as defined by the City Planning Commission are: Veterans Memorial Boulevard to the north, Pontchartrain Boulevard and the Pontchartrain Expressway to the east, Last, Quince, Hamilton, Peach, Mistletoe, Dixon, Cherry and Palmetto Streets to the south and the 17th Street Canal to the west.

London Avenue Canal: The London Avenue Canal is a drainage canal in New Orleans, Louisiana, used for pumping rain water into Lake Pontchartrain.  The Canal runs through the 7th Ward of New Orleans from the Gentilly area to the Lakefront.  It is one of the three main drainage canals responsible for draining rainwater from the main basin of the city of New Orleans.  The London Avenue Canal's flood walls built atop earthen levees breached on both sides during Hurricane Katrina in 2005.

Veterans Memorial Boulevard: Veterans Memorial Boulevard, formerly Veterans Highway (locally referred to as Vets or Veterans), is a 6-lane thoroughfare in Jefferson Parish, Louisiana, running west-east mostly parallel to Interstate 10.  The western terminus is at Belleview Boulevard in Kenner just north of the Louis Armstrong New Orleans International Airport and just east of the St. Charles Parish line.  Veterans than proceeds in an easterly direction across the Jefferson Parish communities of Kenner and Metairie before crossing the 17th Street Canal into New Orleans and terminating at West End Boulevard approximately 1/2 mile east of the Orleans Parish line.

Lakeview, New Orleans: Lakeview is a neighborhood of the city of New Orleans.  A subdistrict of the Lakeview District Area, its boundaries as defined by the City Planning Commission are: Robert E. Lee Boulevard to the north, Orleans Avenue to the east, Florida Boulevard, Canal Boulevard and I-610 to the south and Pontchartrain Boulevard to the west.  Lakeview is sometimes used to describe the entire area bounded by Lake Pontchartrain to the north, the Orleans Avenue Canal to the east, City Park Avenue to the south and the 17th Street Canal to the west.  This larger definition includes the West End, Lakewood and Navarre neighborhoods, as well as the Lakefront neighborhoods of Lakeshore and Lake Vista.

Union Bay Natural Area: The Union Bay Natural Area (UBNA) in Seattle, Washington, also known as Union Bay Marsh, is the restored remainder of the filled former Union Bay and Union Bay Marsh after University Village Shopping Center, the University of Washington (UW) athletic facilities, buildings, and main parking area (E1).  It is located at the east end of the main UW campus, south of NE 45th Street and west of Laurelhurst.  Ravenna Creek is connected to University Slough (Drainage Canal), thence to Union Bay, and Lake Washington.  Drainage Canal is one of three or four areas of open water connected with Lake Washington around Union Bay Marsh.  The canal extends from NE 45th Street, between the driving range and IMA Sports Field 1, south to the bay, ending southeast of the Husky Ballpark baseball grandstand (northeast of the IMA Building).  The Drainage Canal that carries Ravenna Creek past UBNA to Union Bay is locally sometimes called University Slough, though that is something of a misnomer in that "slough" is both used in the eastern and southeastern U.S. meaning, rather than the western U.S. meaning, and it is no longer a natural watercourse in that it is a canal that replaced bay and marsh, both now filled.

West End, New Orleans: West End (also referred to as West Lakeview) is a neighborhood of the city of New Orleans.  A subdistrict of the Lakeview District Area, its boundaries as defined by the City Planning Commission are: Lake Pontchartrain to the north, the New Basin Canal and Pontchartrain Boulevard to the east, Veterans Boulevard to the south, and the 17th Street Canal to the west.  The area was largely built on land reclaimed from Lake Pontchartrain.  It is a commercial seafood and recreational boating hub for the city and has been known for its seafood restaurants.  In recent years, the area has seen large condominium-complex developments built which overlook the Lake, marinas, and centrally located 30 acre West End Park.

New Orleans Outfall Canals: There are three outfall canals in New Orleans, Louisiana – the 17th Street, Orleans Avenue and London Avenue canals.  These canals are a critical element of New Orleans’ flood control system, serving as drainage conduits for much of the city.  There are 13 mi of levees and floodwalls that line the sides of the canals.  The 17th Street Canal is the largest and most important drainage canal and is capable of conveying more water than the Orleans Avenue and London Avenue Canals combined.

Supporting paragraphs: 17th Street Canal Champlain Canal
Answer: 17th Street Canal