On May 9, 2011, the Corps began opening the Bonnet Carré Spillway to relieve flood waters on the Mississippi River. This river water quickly spread across Lake Pontchartrain as is evident on the image below. LPBF will add regular updates to show the progression of the river water in Lake Pontchartrain on our website.  LPBF will continue to monitor water quality in the Lake at its 10 weekly sites plus 3 additional sites on the Causeway bridge throughout the summer.  Bacteria counts have been below levels of concern. 

LPBF actions regarding the Bonnet Carré Spillway opening:

• Collaborating with state and federal agencies on monitoring the lake water quality.
• Expanding our water quality monitoring to assess impacts to lake.
• Conducting on the water reconnaissance to monitor flow.
• Conducting satellite image analyses.
• Monitoring flood fight efforts.
• Providing a Bonnet Carré Spillway display at Back to the Beach.

Anticipated impacts of 2011 Bonnet Carré Spillway opening:

• Up to 316,000 cfs (cubic feet per second) may be allowed to flow through the Bonnet Carré spillway and into
  Lake Pontchartrain.  This amount of water would fill the Superdome every 8 ½ minutes.
• The lake water will be displaced within 10-14 days with brown, turbid river water. 
• Most marine species (example, speckled trout and brown shrimp) will move out of the lake through the passes
  and into the sounds. 
• In 1997 the maximum flow was 243,000 cfs. Two-thirds of the lake was covered in an algae bloom for a brief period. 
• In 2008 the maximum flow was 160,000 cfs and there were small algae blooms on the northshore. 
• If you see algae, stay out of the water. 
• 6 to 8 months will be required for salinity to rebound to normal ranges.