Historic Markers Across Tennessee

Bonnet Carre Spillway/Lake Pontchartrain

Marker ID:  10
Location: Mud Island River Park, 125 N Front Street, Memphis, TN
County: Shelby
Coordinates: N 35° 8.968    W 090° 3.507
  35.14946666    -90.05845
Waymark: None


Bonnet Carre Spillway/Lake Pontchartrain
Panel #10 Mississippi Riverwalk

A) Bonnet Carre Spillway

Mile 128.0 AHP

Completed in 1935, the Bonnet Carre Spillway protects New Orleans, LA and the levees around it by diverting flood waters into Lake Pontchartrain. The one and a half mile long concrete structure consist of 350 bays which hold 7,000 large timbers called “needles”. These needles can be independently raised and lowered by a crane running alongside it to provide an adjustable opening. Water entering the spillway is channeled by guide levees to the lake. When not in use, the floodway is a game and fish preserve, and home to a herd of goats which keeps the vegetation closely clipped. The spillway’s first test came during the flood of 1937. Responding to a warning from upriver, a few bays were opened each day until the spillways poured a mile wide stream of floodwater into Lake Pontchartrain. Terrible flooding occurred upriver but the water level at New Orleans stayed almost stationary. The effectiveness of the Bonnet Carre Spillway and the Morganza Floodway, upriver, have made the New Orleans area virtually flood proof.

B) Lake Pontchartrain

Mile 128.5 AHP

Lake Pontchartrain, which forms the northern boundary of New Orleans is actually a lagoon, a land-locked bay of the Gulf of Mexico. Its waters rise and fall slightly with the tides. A five and a half mile Industrial Canal links the lake to the Mississippi River, and Pontchartrain connects eastward to the Gulf through the narrow Rigolets passage into Lake Borgne. The lake is 45 miles long and 25 miles wide. Its semi-salty waters teem with fish and the 112-mile shoreline is a major recreational area. The Pontchartrain Causeway crosses the lake north from New Orleans. The 24-mile long concrete highway is one of the world’s longest causeways over water.

Photo Credit:(1) Lake Pontchartrain Coastline, Louisiana Office of Tourism (2) Bonnet Carre Spillway, courtesy of USACE, (3) Lake Pontchartrain Causeway, Louisiana Office of Tourism

A photo of this marker can be found on HMDB.org


AHP - Above Head of Passes, this is the distance from the mouth of a river when measured along the course (navigable channel) starting at zero.