Is Louisiana falling into the sea, or is the sea inundating Louisiana? It’s actually a bit of both. And to the inhabitants of a tiny island on the bayou, an island getting tinier by the day, it hardly matters. They just know their home is gradually becoming uninhabitable.
A USGS report estimates that Louisiana, which experiences more coastal wetland loss than all other states in the conterminous United States combined, lost 5,197 square kilometers (2,006 square miles) of land from 1932 to 2016. Places are actually being removed from maps—NOAA is deleting labels from its maps for bays, islands, streams, and other features that are now underwater.
A combination of factors is causing this coastal land loss. Marshland, which historically served as protection against storms, has been carved up for oil and gas production activities. The marshland is then open to saltwater intrusion. The low elevation of the region makes it especially vulnerable to sea level rise.
These factors have an immediate effect on the Biloxi-Chitimacha-Choctaw community on Isle de Jean Charles, about 75 miles south of New Orleans. The island has lost 98% of its landmass since the 1950s. Once 5 miles wide and filled with lush cypress groves and cow pastures, barely a half square mile of the island remains above water.
The saltwater intrusion and loss of land have made it impossible for residents to continue the tradition of growing their own produce. They can no longer grow their own herbs for medicine. The increased cost of living from having to shop for food they once provided for themselves is a struggle.
A variety of images from the EROS archive shows how the island, and the surrounding delta, has changed. A combination of different types of imagery is needed in this location to accurately track the changes over time. High resolution is needed to see the small island, but a frequent repeat cycle reveals the larger changes taking place across the delta.
The Biloxi-Chitimacha-Choctaw community began in the early 1800s when Frenchman Jean Marie Naquin married Pauline Verdin, a Native American. Naquin’s family disowned him for this, and the couple moved to the delta region, where his father had traveled many times. Despite being disowned, Naquin named the island where the couple settled after his father Jean Charles Naquin.
Naquin and Verdin, along with the other original inhabitants of the island, had also moved there to escape the Trail of Tears, the forced removal of Native Americans from the southeast in the 1830s to present-day Oklahoma. They sought refuge in the dense forested swamps of the Mississippi Delta, which white settlers thought were uninhabitable.
Most of Jean Marie and Pauline’s children married descendants of the Biloxi-Chitimacha and Choctaw tribes. Other families moved to the island after intermarriage between the families. By 1910, the island population had grown to 16 families, all descendants of the first families to settle there. They lived by fishing, gathering oysters, trapping, and hunting.
By the 1950s, there were around 80 families living in Isle de Jean Charles, and the island spanned 33,000 acres. Today, the island has shrunk to 320 acres and fewer than 30 families remain. Many residents moved elsewhere, fracturing the community. With the people scattered, the heritage and traditions are fading away. Afraid of losing their culture, the community is now planning another resettlement, possibly the only way for them to adapt to the changing Louisiana coast.
The tribe has been planning resettlement since 2000, and in January 2016, the U.S. Department of Housing and Urban Development (HUD) awarded the tribe $48 million to help them move. A possible location has been chosen that would allow the community to regain their culture with traditional hunting, fishing, and agriculture. The site is a 515-acre sugar farm north of Houma. Resettlement, however, is a difficult concept to accept. Tribe members say losing the island is like losing a family member.
Moderate resolution imagery from Landsat (30 meters) and Sentinel (10 meters) shows a broad view of the changes around the island over time. Landsat’s history goes back to 1972, with 60-meter resolution imagery to show a long view of the change.
Imagery from the European Space Agency’s (ESA) Sentinel-2A satellite is distributed by the USGS through EarthExplorer.
High-resolution imagery from the WorldView satellite and aerial photos show details that moderate resolution satellite imagery cannot. The result of the land loss and its effect on Isle de Jean Charles becomes clear in these images.
The loss of land in southern Louisiana has several causes.
- Dams Upriver, dams trap sediment that normally flowed to the delta and built it up.
- Subsidence The land in the Louisiana delta has always sunk naturally. Faults contribute to regional subsidence, and sediments naturally compress over time. Deposits flowing from the Mississippi River continually replenished and built up the land. Much of this sediment is now trapped by upstream dams, taking away the rebuilding process.
- Sea level rise The long-term gradual rise in sea level combined with that subsidence increases the land loss more than either factor alone.
- Canals 10,000 miles of canals dug through the marshland, built for oil and gas production activities, bring saltwater farther inland, which degrades freshwater marshlands.
- Hurricanes Storm surge and waves can propagate farther inland because of land loss, making matters worse. Hurricanes erode the soft land from the coast and can damage both vulnerable and healthy marshlands.
The saltwater that washes farther inland also invades the soil and has made the area no longer good for farming. As the marshland retreats, the saltwater enters bald cypress swamp and kills the trees.
The only road into or out of the island is the 2-mile-long Island Road. When it was built in 1953, land and marsh surrounded it. Tribal members hunted and trapped on the land around the road. It now cuts across open water. It often submerges during high tide, and erosion continues to eat away at the roadbed.
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