Alligator Bayou Update – March 26, 2009


Parish Councils must let the Corps of Engineers undertake any restoration project.

Dear Supporter,

Wow, the outpouring of support for the Spanish Lake Basin has really made people wake up and listen. Thank you.

There has been a lot of talk about hydrology so I thought I might address that.

Hydrology is a very important issue in the Mississippi River Delta. The building of levees to control flood waters and the construction of canals for access for oil and gas exploration have made dramatic changes to the hydrology in South Louisiana and are components of coastal land loss and habitat loss.

The Spanish Lake Basin is surrounded by dramatic changes in the historic hydrology. Bayou Manchac has been cut off from the Mississippi River allowing it to silt in and reducing its size signifigantly. Levees have been built along parts of Bayou Manchac and Alligator Bayou. The point at which Alligator Bayou historically met Bayou Manchac was filled in and Alligator Bayou is now connected to Bayou Manchac by a control structure (a pipe with a valve in it) that was built and then connected to Alligator Bayou by a short “L” shaped canal.

So the current “natural” hydrology in the system is no longer the same as the historical hydrology which created the Spanish Lake Basin.

Yes, there have been challenges with maintaing the Spanish Lake Basin at a healthy water level and in the past it was held at too high a level. This caused a swampy area now known as Cypress Flats to become permenantly flooded and unable to regenerate. In the last few years water levels have been kept lower and this situation is improving. You will now find vegetation growing on Cypress Flats and there are plans to replant and restore Cypress Flats back to a healthy Cypress Tupelo habitat.

I also do not understand how reducing water levels will address Black Willow and Cutgrass. I would expect more of these two plants to grow if larger margins are opened up on the banks of the bayou.

It seems clear that a certain level of water needs to be maintained in the Alligator Bayou system. We believe that the four-foot water level (at the Alligator Bayou control Structure) is a healthy low water level for the Spanish Lake Basin.

The Corps of Engineers has already begun a project with the intention of fixing many of these problems. This project is entitled “Bayou Braud, Spanish Lake, and Alligator Bayou, LA Ecosystem Restoration Project.” This project is still in the planning stages and still needs to go through public comment and other Corps permitting procedures. We hope that the Corps project will use sound science to preserve the ecological and cultural integrity of the Spanish Lake Basin and continue to cooperate and partner with all of the stakeholders involved, including the public.

The existing control structure at Alligator Bayou and Bayou Manchac is old, small and inadequate. The answer is to replace it, not just leave it open. And replacing it is part of the Corps project.

It is not appropriate for the Iberville Parish Council or any Parish Council to step in and attempt to implement a “restoration project” while the Corps of Engineers is developing a science-based project in full accordance with their public oversight policies in the same area.

We, Louisiana Environmental Action Network and Lower Mississippi RIVERKEEPER, ask the Iberville Parish Council and the Ascension Parish Council to leave the area as it is while the Corps of Engineers develops its project. With the participation of all of us I hope that the Corps can develop a plan that will once-and-for-all protect this precious area.

Thank YOU for all that you have done and continue to do!

Paul Orr
Lower Mississippi Riverkeeper

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