Sunday, June 02, 2019

How all this river flooding will affect fishing

Bonnet Carre Spillway. Photo from USACE.
The Mississippi and Red Rivers drain over two-thirds of the United States. Since 1831, when steamboat captain Henry Miller Shreve cut a shortcut in the Mississippi at Turnbull's Bend, the Mississippi and Red / Atchafalaya have been separated. The Mississippi wants to take the shorter route through the Atchafalaya, which is why in 1950 the Army Corps of Engineers began construction of the Old River Control Structure.

The longer path of the river has its own consequences. In years of extreme high water, the Mississippi gets bottled up - the water simply cannot exit fast enough into the Gulf of Mexico. The levees built to contain the river were meant to withstand weeks - not months - of inundation.

Despite the Bonnet Carre Spillway having been opened twice (and still open) along with other diversions, the Ol' Muddy is beyond stressed. Some flow is also being diverted through the Old River Control Structure into the Atchafalaya. But the Red River that feeds the Atchafalaya is itself at the highest level in many years.

That leaves one option left - opening the Morganza Spillway. The Spillway has only been opened twice in history, and was scheduled to open today but has been postponed to this Thursday. The Morganza diverts water into a broad plain containing forests, fields, camps and some homes. The delay will allow extra time for landowners to move livestock and belongings.

The water that flows into the Morganza eventually empties into the Atchafalaya Basin, putting more stress on Morgan City where the basin flushes back into the river. A barge will be sunk on Bayou Chene as a dam to prevent back-flooding in the Lake Verret, Belle River and Stephensville areas - although that will also result in higher water in those waters because water levels will be raised by the "dam".

So everyone is asking, "What will be the impact on fishing in areas affected by the rivers?".  The following is speculation, based on past situations.  Nobody really knows what the weather - and rivers - will do.

The live oxbows such as Old River Morganza, Old River Vidalia, Yucatan, Mary Crawford and Deer Park Lake will be a waste of time until the Mississippi gets down to under 25 feet on the Baton Rouge gauge.  But then expect a brief spurt of outstanding fishing! 

The Pontchartrain Basin has already seen a large impact from the Bonnet Carre. Freshwater fishing across the basin - from Highway 51 canals all the way to Shell Beach near Lake Borgne - is the best in many years. Redfish and sheepshead - which don't mind freshwater - continue to be fairly good. Speckled trout fishing has taken a big hit in Pontchartrain itself, but the edges of Lake Borgne and beyond have been very good as the trout have congregated eastward in avoidance of the river water.

Once the water starts to go down, we should see outstanding catches of bass, bream, and crappie in the Atchafalaya Basin. And also in the Verret Basin. Probably late June through July.

One area that will be a bust this summer will be Cypremont Point. It typically takes 2-4 weeks after the Atchafalaya hits it's summer low mark before the Point begins producing decent numbers of speckled trout. That could well be as late as August.

The worst fear on every anglers mind in south Louisiana is that once the rivers get down, we'll get a hurricane that will knock the fishing prospects back further.