The Army Corps of Engineers will begin to construct an underwater sill across the bed of the Mississippi River to help prevent upriver progression of saltwater from the Gulf. According to the Army Corps of Engineers, the Mississippi River's volume of water has fallen to a level that allows saltwater to intrude upstream. Saltwater from the Gulf moves upriver in a wedge shape that may stretch up approximately 20 miles from the bottom to the surface of the river, according to the Army Corps of Engineers.River conditions project that the toe of the saltwater wedge is expected to reach River Mile 80 above Head of Passes within the next 28 days. The sill will take 28 days to create and will be constructed near Myrtle Grove. The Corps constructed a similar underwater sill in 1988, 1999, 2012, 2022, 2023, and 2024 at River Mile 64, near Myrtle Grove, Louisiana, to arrest the progression of saltwater intrusion. According to the Corps, the sill will be maintained until the river flows increase and push the saltwater downstream. What is saltwater intrusion? Drought conditions exist not only in Southeast Louisiana but also in the central and northern Mississippi Valley, increasing the saltwater intrusion threat.Most of the lakes and tributaries that drain into the Mississippi are in areas that are currently experiencing drought conditions similar to what we are experiencing now.Because of those drought conditions, the water flow into the Mississippi is much lower than usual, which results in the low water level and slow southerly flow of the river through Southeast Louisiana. With the low water level and low flow, the pressure from the Gulf overcomes the southerly flow, forcing the salty Gulf water north, upstream.Salty Gulf water being more dense than the fresh Mississippi water means the saltwater intrusion or wedge is moving along the river bottom while the fresh water at the surface is slowly moving south.
The Army Corps of Engineers will begin to construct an underwater sill across the bed of the Mississippi River to help prevent upriver progression of saltwater from the Gulf.
According to the Army Corps of Engineers, the Mississippi River's volume of water has fallen to a level that allows saltwater to intrude upstream.
Saltwater from the Gulf moves upriver in a wedge shape that may stretch up approximately 20 miles from the bottom to the surface of the river, according to the Army Corps of Engineers.
River conditions project that the toe of the saltwater wedge is expected to reach River Mile 80 above Head of Passes within the next 28 days.
The sill will take 28 days to create and will be constructed near Myrtle Grove.
The Corps constructed a similar underwater sill in 1988, 1999, 2012, 2022, 2023, and 2024 at River Mile 64, near Myrtle Grove, Louisiana, to arrest the progression of saltwater intrusion.
According to the Corps, the sill will be maintained until the river flows increase and push the saltwater downstream.
What is saltwater intrusion?
Drought conditions exist not only in Southeast Louisiana but also in the central and northern Mississippi Valley, increasing the saltwater intrusion threat.
Most of the lakes and tributaries that drain into the Mississippi are in areas that are currently experiencing drought conditions similar to what we are experiencing now.
Because of those drought conditions, the water flow into the Mississippi is much lower than usual, which results in the low water level and slow southerly flow of the river through Southeast Louisiana.
With the low water level and low flow, the pressure from the Gulf overcomes the southerly flow, forcing the salty Gulf water north, upstream.
Salty Gulf water being more dense than the fresh Mississippi water means the saltwater intrusion or wedge is moving along the river bottom while the fresh water at the surface is slowly moving south.