The Coastal Crisis and Louisiana’s Response
US Army Corps of Engineers Photo
Broad generalizations seldom have much validity, and that fact is clearly demonstrated by the complex and often contradictory character of Region Three. For example, Terrebonne, one of three basins in the region, endures the second highest land-loss rate in Louisiana, giving up 10.2 square miles per year. On the other hand, a sister basin, the Atchafalaya, ranks as the only basin in all of Louisiana to be naturally gaining land, thanks to the sediment-rich waters of the Atchafalaya River that run within its borders. And yet, even this isn’t without complication. While the Atchafalaya River successfully builds land in the bay, it can also cause serious flooding in the Morgan City area.
Farthest west, the Teche-Vermilion Basin contends with severe shoreline erosion and the disruption of natural water flows caused by canal dredging and energy exploration. Here too, the Atchafalaya River’s influence is diverse and complex. The flow of fresh water may be benefiting the basin’s wetlands and agricultural irrigation, but it’s also changing the salinity levels in the estuaries, causing concern among recreational fishers.
| Region 3 Statistics |
Fresh marsh acres |
Intermediate marsh acres |
Brackish marsh acres |
Saline marsh acres |
Total marsh acres |
|---|---|---|---|---|---|
| Acreage in 1990 | 298,300 | 92,700 | 240,700 | 140,200 | 771,900 |
| Projected acreage in 2050 | 292,330 | 69,100 | 184,800 | 94,900 | 641,130 |
| Net acres lost by 2050* | 5,970 | 23,600 | 55,900 | 45,300 | 130,770 |
| Percent 1990 marsh lost | 2% | 25% | 23% | 32% | 17% |
| *includes acres preserved by Breaux Act Priority Lists 1-6 and Caernarvon and Davis Pond Diversions | |||||
In spite of all the complexities and contradictions, there are some things that we do know for certain. From 1932 to 1990 over 247,000 acres of marsh were lost in Region Three. This is a loss of nearly one-fourth of the region’s total marsh acreage, and even with the acres preserved by the Breaux Act projects on Priority Lists 1 through 6, an additional 17 percent (130,700 acres) of these vital marshes, including 32 percent of the region’s saline marshes, could be lost in the next 50 years.
Louisiana Office of Tourism Photo
The effort to reverse this trend is guided by two broad objectives:
- Maintain present habitats above the Gulf Intracoastal Waterway (GIWW)
- Restore habitats below the GIWW
In response to these broad objectives, Coast 2050 has established 17 strategies that might be employed throughout the coastal areas of the region. These strategies include increasing delta building in Atchafalaya Bay, moving the excess water from the upper Penchant marshes to the south, developing a structure in the Houma Navigation Canal to control salinity, moving fresh water to the central Terrebonne marshes, dedicating delivery of sediment, building land by a conveyance channel from the Mississippi River, maintaining and stabilizing the bay and gulf shorelines, restoring the barrier islands, and resolving salinity and turbidity issues in Vermilion and Cote Blanche bays.
The chart on the next page describes current Breaux Act projects intended to reverse the trend of wetland loss in Region Three.