The Corps is proposing to use the fly ash as part of a lime slurry mixture for some kind of grouting to stabilize the levees according to the article. Environmentalists are concerned about the potential impacts of residual toxins in the fly ash. However, they are drawing comparisons to the TVA coal ash dam failure. From my perspective, this is an unfair comparison since this fly ash would be mixed with lime and in theory any toxins would be bound up in the grout matrix. But it never hurts to be cautious regarding potential contaminants that close to such an important waterway. [Source: bnd.com via ASCE SmartBrief]
In this ENR.com video, a US Army Corps of Engineers (USACE) project to protect Grand Isle Louisiana from the erosional effects of a large storm surge is described. 5.7 miles of sand filled geotextile tubes or geotubes 30-ft in diameter are used to form the core of a dune along with a geotextile erosion apron held in place by anchor tubes. The design is aimed to prevent devastating erosion in the event that a large storm surge overtops the protective dunes. The sand is screened on site and mixed with water to form a slurry that is pumped into the tube. Once the tubes are in place, additional sand will be placed over the top and the dune revegetated. If the topping sand is eroded away, the Corps hopes the fix will be easier to perform with the tubes. Click through for the video.