Saltwater Intrusion/Saltwater Barrier/Weirs

[Duck Butter]

Gonna go ahead and start a new thread on this because the other got off-track but the gist is the same

The take home message is that saltwater intrusion is a problem, will be a problem, and has been a problem for over 50 years it appears. The Ship Channel is the life blood of Lake Charles industry, but when it was dug that allowed saltwater a direct route into an area that didn't normally get saline water for long periods of time.

Saltwater Barrier

This seems to be the 'elephant in the room', no one has addressed this structure in the other discussions about weirs. The entire reason this was put there is to keep saltwater from getting where its not supposed to be (exactly the same concept as Grand Bayou Weir). This structure was put in over 50 years ago with the same reasoning (keep saltwater out of places its not wanted - i.e rice fields). Keep in mind this is over 30 MILES from the Gulf. Here is a link
http://www.mvn.usace.army.mil/Portal...lcasieuSWB.pdf
per page 2 of this document:

The Problem
While the deeper channel brought increased shipping and greater prosperity to the area, it also allowed saltwater from the Gulf to migrate further inland. The intruding saltwater threatened the upper Calcasieu River, which provides water for irrigating the region's rice fields. The saltwater which kills many types of vegetation, began to destroy some of the sensitive wetlands of the Calcasieu River Basin.

The Solution
To solve the saltwater intrusion problem, in 1962 Congress modified the existing authorization for the Calcasieu River Project to include construction of a dam upstream of Lake Charles. The structure, commonly referred to as the Calcasieu River Saltwater Barrier, was designed to keep the saltwater from traveling north, yet not to hinder commercial navigation of the river.

Weirs
The purpose of the weirs are exactly the same as the saltwater barrier (essentially it is a saltwater barrier). These are 10 miles? from the Gulf of Mexico whereas the saltwater barrier is over 30 miles from the Gulf so it makes sense that the salinity here is going to rise faster than the salinity by the saltwater barrier and probably be more saline for longer periods of the year, so for the same reason (protecting ag land) is why they were put in. There are rice farms back there, just like the rice farms the saltwater barrier was trying to protect 50 years ago. Rice farms DO produce ducks, and YES people get to hunt them and are benefitting from saltwater NOT getting back there, but I feel like we are all benefitting from it as well. That are keeps ducks in the area for us all to ultimately shoot. There is also a National Wildlife Refuge there that is negatively influenced by saltwater
http://www.fws.gov/swlarefugecomplex/cameronprairie/

The main focus of Sabine and Cameron Prairie are for waterfowl. Waterfowl that we all get to hunt and they manage specifically for these and saltwater has a negative effect on waterfowl foods.

Per the above document
Cameron Prairie National Wildlife Refuge was established to preserve and protect wintering waterfowl and their habitat. It was the first refuge established under the auspices of the North American Waterfowl Management Plan. The refuge is located approximately 25 miles southeast of Lake Charles, Louisiana, in north central Cameron Parish. It contains 9,621 acres that include fresh marsh, coastal prairie, and old rice fields (currently moist soil units). Located at the convergence of two major flyways, the refuge has an important role in management for migratory birds.

Marshes

4 types in Louisiana - freshwater, intermediate, brackish, and salt and here is a link to what is there
http://pubs.usgs.gov/of/2008/1224/pdf/OFR2008-1224.pdf

They are completely different from one another. They share a common name (marsh) but that is it, they function totally different, just like other things that share common names are not the same. Trout (speckled trout and white trout are different), forest (bottomland hardwood forest is not the same as longleaf pine forest) snapper (red snapper are not mangrove snapper). Behind Grand Bayou weirs you will find brackish marsh which is totally different from salt marsh. It can not handle highly saline water for very long periods. It dies. We have seen that.