State coastal scientists released findings on the best location for two additional sediment diversions along the lower Mississippi River based on cost, highest sediment collection and effectiveness.
Coastal scientists said they will be moving forward with planning of a diversion at Diamond for the Lower Barataria Diversion and at Port Sulphur for the Lower Breton Diversion.
Diversions channel water and sediment from the Mississippi River to coastal wetlands to build land.
The most talked about sediment diversion is Mid-Barataria which is planned to be located in Myrtle Grove. Three other diversions on the lower Mississippi River were included in the state 2012 coastal master plan but were more conceptual and had no location pinned down.
That changed during the state Coastal Protection and Restoration Authority meeting Wednesday in Baton Rouge with the presentation of the best location for two of those other diversions.
Computer modeling of diversions along the lower river should produce results later this year to show the state what diversions should be built.
“This is the year we’re going to be making decisions on diversions,” Kyle Graham, executive director of the Coastal Protection and Restoration Authority, said in an earlier interview.
The models will allow scientists to look at the impacts of a single diversion or a combination of diversions to help officials make decisions on what, if anything, gets built. The decisions on locations for the Lower Barataria and Lower Breton diversion will feed into that overall modeling effort.
To decide on the two locations, scientists started with five alternatives for the Lower Barataria Diversion, which would drain off to the west of the river, and three alternatives for the Lower Breton Diversion, which would drain to the east.
Scientists have already used computer models to help determine the ability of the locations to capture sediment, see what infrastructure already exists as well as the potential cost.
That data was used to narrow down the alternatives to reach the best choices.
For the Lower Barataria Diversion, the five choices were: Magnolia, Diamond, Port Sulphur, Empire and Buras.
“Empire and Buras just don’t build land like the other three do,” said Kent Bollfrass, coastal resource scientist with the state Coastal Protection and Restoration Authority. Computer modeling showed that the Port Sulphur location didn’t capture sediment as well as the remaining two for a western diversion. In addition, there is a lot of infrastructure in the area where a project would have to go around, he explained.
In the choice between Magnolia and Diamond, the Magnolia location had a ship anchorage directly in front of the location and would involve bridging over a four-lane highway.
Diamond, he said, showed up as a better land builder and didn’t have the complications that Magnolia had with the ship anchorage and only would cross a two-lane highway.
Similar criteria were used to narrow down the three choices on the east side of the river — Bass Enterprises, Mardi Gras Pass and Port Sulphur.
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