The Mississippi River Could Abandon New Orleans. Here's the Data.

CHAPTERS 0:00 Cold Open 0:49 It's Not Wandering 2:12 The River's Old Addresses 4:15 The Door Opens 6:23 The Gate on Old River 8:33 Already Moving 10:15 What the River Is Telling Us DATA IN THIS VIDEO Route lengths: both rivers traced downstream along the USGS national river map (NHDPlus V2, via NLDI). From Old River to the Gulf: about 330 miles down the Mississippi, about 140 down the Atchafalaya. Flow split, 2010-2025: daily flow of the Atchafalaya at Simmesport (USGS 07381490, gaps filled with Army Corps gage 03045Q) and the Mississippi at Tarbert Landing (Army Corps gage 01100Q). Atchafalaya share = Simmesport / (Simmesport + Tarbert), summed by year: 29.4 to 30.7 percent every year. 1973 flood: daily flow, USGS 07265450 Mississippi River near Arkansas City, AR. "Typical year" = median of the same calendar day, 1950-1972. Historic share charts: redrawn from Fisk (1952), Figs. 1 and 5. New land in Atchafalaya Bay: Landsat 5, 8 and 9 Collection 2 (USGS), 7 clear scenes from 1984-86 and 28 from 2023-25. Land = pixels where the modified water index (green vs. shortwave infrared) is below zero. 1980s scenes were compared with 2020s scenes within 30 days of the same calendar date: 22.8 to 37.8 sq mi gained. Images shown: Jan. 13, 1986 and Jan. 14, 2024. Manhattan = Census land area of New York County. Terrain and imagery: USGS 3DEP lidar (1 m) and elevation (1/3 and 1 arc-second), USDA NAIP aerial photos (2023), Copernicus Sentinel-2 (Oct.-Nov. 2023-2025), NASA Blue Marble, USGS NHD and WBD, U.S. Census Bureau boundaries, Natural Earth. Old channel maps: Fisk (1944), U.S. Army Corps of Engineers. SOURCES [1] Fisk, H.N. (1952), Geological Investigation of the Atchafalaya Basin and the Problem of Mississippi River Diversion. U.S. Army Corps of Engineers, Waterways Experiment Station. https://biotech.law.lsu.edu/climate/m... [2] U.S. Army Corps of Engineers, New Orleans District (2009), Old River Control (brochure). https://biotech.law.lsu.edu/blog/OldR... [3] Jones, K.E. et al. (2018), 2016 Old River Control Complex Sedimentation Data. MRG&P Tech Note No. 5, ERDC. https://www.govinfo.gov/content/pkg/G... [4] Roberts, H.H. (1997), "Dynamic Changes of the Holocene Mississippi River Delta Plain: The Delta Cycle." Journal of Coastal Research 13(3), 605-627. https://journals.flvc.org/jcr/article... [5] Public Domain Review, "Ancient Courses: Harold Fisk's Meander Maps of the Mississippi River (1944)." https://publicdomainreview.org/collec... [6] NASA Earth Observatory (2015), "New Land on the Louisiana Coast." https://science.nasa.gov/earth/earth-... [7] National Park Service, "Mississippi River Facts." https://www.nps.gov/miss/riverfacts.htm NOTES The 3D terrain views are vertically exaggerated 15 times. The six delta complexes are simplified outlines redrawn after [4] (from Frazier 1967). Their ages are approximate. The 4 to 19 foot difference in water level across the structures is from the Army Corps' 2009 brochure [2]. CREDITS Contains modified Copernicus Sentinel data 2023-2025 Landsat imagery courtesy of the U.S. Geological Survey WATCH NEXT Why the Grand Canyon Exists (It's Not Just the River)    • Why the Grand Canyon Exists (It's Not Just...   #MississippiRiver #Louisiana #Geology