Corps continues to monitor water quality following Flood of 2011

Published July 28, 2011

NEW ORLEANS – The U.S. Army Corps of Engineers, in close collaboration with approximately 10-15 federal and state partners and non-governmental organizations, continues to assess the water quality of the Mississippi and Atchafalaya Rivers, Lake Pontchartrain Basin and Mississippi Sound in response to the 2011 opening of the Bonnet Carre’ Spillway and the Morganza Floodway. The Corps has conducted weekly conference calls since early May and continues to exchange information and field experiences with the collaborating organizations.

Bonnet Carre’ Spillway
The Bonnet Carre’ Spillway is designed to ensure that a maximum river flow of 1.25 million cubic feet per second (cfs) is passed through the Mississippi River and Tributaries system at New Orleans. The Spillway allows water from the Mississippi River to flow into Lake Pontchartrain.

The diversion of freshwater into Lake Pontchartrain and adjacent waters temporarily alters water quality in the estuary. To better understand and evaluate these changes, the Corps has an agreement in place with the United States Geological Survey (USGS) to collect water quality data. Conditions measured include typical field parameters (e.g. dissolved oxygen, salinity, pH, etc.), nutrients, total suspended solids, chlorophylls, phytoplankton, and herbicides. USGS and Louisiana State University are also collecting samples to assess potential algal blooms in Lake Pontchartrain including blue-green algae, which can be harmful to people and animals.

Morganza Floodway
Intended to operate during emergency flood events, the purpose of the Morganza Floodway is to divert floodwater from the Mississippi River into the Atchafalaya Basin to limit the flow in the Mississippi River below Morganza to 1.5 million cubic feet per second (cfs).
In response to opening the Morganza Floodway, the Corps funded USGS to collect additional water quality samples at four of their routine monitoring stations in the Mississippi and Atchafalaya Rivers as well as a temporary station at the I-10 bridge to evaluate effects in the Atchafalaya Basin. Parameters measured included major inorganic analytes, dissolved organic carbon, alkalinity, nutrients, pesticides, suspended sediment, and parameters associated with potential oil and gas leaks.
To access the monitoring map developed in response to opening the Bonnet Carre’ Spillway and Morganza Floodway, the Corps and USGS created a website available at: http://deltas.usgs.gov/spillway/BonnetCarre2011.aspx<http://distribution.mymediainfo.com/lists/lt.php?id=fB8PBFdUAVMESAECUwdVTgBUVlACBg%3D%3D> .
The website allows users to spatially view data collected and provided by multiple organizations from monitoring stations across southern Louisiana. The Corps continues to coordinate closely with the participating agencies and organizations to monitor water quality effects and identify areas of collaboration between organizations to maximize spatial and temporal coverage of monitoring activities.

Contact
Rachel Rodi
504-862-2587
rachel.rodi@usace.army.mil

Release no. 11-034