Environmental Atlas of the Lake Pontchartrain Basin

Environmental Status and Trends - Status and Trends of the Lake Pontchartrain Basin

• Environmental Status and Trends
• Pleistocene Terraces Region
• Marginal Deltaic Basin Region
  • Maurepas Swamp Area
  • Manchac Land Bridge Area
  • South West Pontchartrain Area
  • Lake Pontchartrain Area
  • North Shore Marsh Area
  • Bayou Sauvage Area
  • East Orleans Land Bridge Area
  • Pearl River Mouth Area
• Mississippi River Deltaic Plain Region

Dramatic habitat changes took place in the BSA during the latter half of the Twentieth Century. In 1949, this unit was largely brackish marsh with some intermediate marshes on the southwest corner and saline marsh near Point aux Herbes. Between 1949 and 1978, the entire area was brackish. Completion of the hurricane protection levee by the 1970's essentially impounded much of the area. Breaks in the Maxent Canal levee drained the southern portions of the unit, causing oxidation and subsidence of the marsh. Later, repairs to the levees and improved water controls led to impoundment and excessive water levels. This resulted in conversion of brackish marsh to fresh marsh and open water.

Figure 10: Measured marsh loss in the Bayou Sauvage Area between 1932 and 1990 projected to 2050 (Coast 2050, 1998). Refer to Table 5 for comparison.

Figure 10 shows the steady loss of marsh in the BSA. Between 1932 and 1990, impoundment, flooding and dredging led to the loss of approximately 3,525 acres or 35% of land in this area. Additional wetlands have been buried under fill from the construction of Interstate 10, Lake Pontchartrain Hurricane Protection Levee and maintenance of the Gulf Intracoastal Waterway (GIWW).

By 2050, a further 3,550 acres or 55% of the 1990 acreage could be lost (Table 5). However, two recently constructed hydrological restoration projects funded under CWPPRA are predicted to reduce this loss rate from 55% to 14%.

A large portion of this area is in the Bayou Sauvage National Wildlife Refuge, which is extremely important to wintering waterfowl, migratory songbirds, wading birds and other water birds. Bald eagles have nested in cypress trees within the Area, while examples of several state-ranked rare plants, animals and communities such as coastal live oak forest also occur here. The USFWS manages the Refuge as a predominantly fresh marsh habitat, encouraging the winter visitation by the migratory waterfowl. The Refuge is also very important as the largest urban wildlife refuge in the country. As such, it is a resource for the population of New Orleans and is of great educational importance.

Population trends for a selection of species are shown in Tables 2, 3 and 4. Generally, the fish and wildlife populations in the BSA are stable or increasing.