Lake Pontchartrain

Lake Pontchartrain
Copernicus Sentinel-2, ESA · CC BY-SA 3.0 igo · source
Name	Lake Pontchartrain
Caption	Aerial view of the lake
Location	Southeast Louisiana
Coords	30, 11, 20, N...
Type	Brackish estuary
Inflow	Mississippi River–Gulf Outlet Canal, Tchefuncte River, Tangipahoa River, Tickfaw River, Amite River
Outflow	Rigolets, Chef Menteur Pass
Basin countries	United States
Length	40 mi
Width	24 mi
Area	630 sqmi
Depth	12 ft
Max-depth	20 ft
Cities	New Orleans, Metairie, Kenner, Mandeville, Slidell

Lake Pontchartrain is a large, brackish estuary located in southeastern Louisiana. It is the second-largest inland saltwater body in the United States, after the Great Salt Lake. The lake forms a vital hydrological and ecological component of the Pontchartrain Basin and has played a central role in the development of the New Orleans metropolitan area.

Geography and hydrology

Situated north of New Orleans, its shores touch St. Tammany Parish, Orleans Parish, Jefferson Parish, and St. John the Baptist Parish. The lake connects to the Gulf of Mexico via the Rigolets strait and Chef Menteur Pass, and it receives freshwater from several rivers including the Tchefuncte River, Tangipahoa River, and Amite River. Its shallow average depth, coupled with a surface area of over 600 square miles, makes it particularly susceptible to wind-driven storm surge, a critical factor during events like Hurricane Katrina. The lake is part of the larger Lake Maurepas–Lake Pontchartrain–Lake Borgne estuarine complex.

History

The lake was named in 1699 by French-Canadian explorer Pierre Le Moyne d'Iberville in honor of Louis Phélypeaux, comte de Pontchartrain, the French minister of the marine. For centuries, it served as a crucial transportation corridor for indigenous peoples like the Choctaw and later for European settlers. The Battle of Lake Pontchartrain in 1779 saw American Revolutionary War forces capture a British vessel. In the 19th and 20th centuries, the southern shore became densely populated with the expansion of New Orleans and its suburbs like Metairie. The lake's history is also marked by environmental challenges, notably the construction of the Mississippi River–Gulf Outlet Canal, which exacerbated saltwater intrusion and wetland loss.

Ecology and environmental issues

The lake supports a diverse ecosystem, serving as a nursery for species like blue crab, spotted seatrout, and American oyster. Its surrounding marshes are vital habitat for migratory birds along the Mississippi Flyway. Major environmental stresses have included pollution from New Orleans's urban runoff, historic shell dredging that altered the lakebed, and the lasting impacts of the Mississippi River–Gulf Outlet Canal. A significant victory for conservation was the closure of the Causeway to swimming in the 1970s due to water quality concerns, leading to a multi-decade restoration effort spearheaded by the Lake Pontchartrain Basin Foundation that has dramatically improved conditions.

Infrastructure and crossings

The most prominent crossing is the twin-span Lake Pontchartrain Causeway, a bridge that holds the record as the world's longest continuous bridge over water, connecting Metairie to Mandeville. Other major spans include the I-10 Twin Span Bridge carrying Interstate 10 between New Orleans and Slidell, and the U.S. Route 11 bridge. The lake's southern shore is protected by the Lake Pontchartrain and Vicinity Hurricane Protection Project, a system of levees and floodwalls that was catastrophically tested during Hurricane Katrina in 2005.

Recreation and culture

The lake is a popular recreational destination for sailing, fishing, and crabbing, with public access points at venues like West End Park and Fontainebleau State Park. The New Orleans Yacht Club, founded in 1949, is a hub for sailing activities. Culturally, the lake features prominently in local lore, music, and cuisine, and it is the site of the annual Great Louisiana BirdFest. The scenic Causeway drive and historic lakeside communities like Mandeville contribute to its status as a defining landmark of the Greater New Orleans region.

Category:Lakes of Louisiana Category:Estuaries of the United States Category:Landforms of St. Tammany Parish, Louisiana