1973 Morganza 007.JPG

Advocate file photo

The last time water was as high as it is today in the Mississippi River and in the forebay at the Morganza Spillway floodgates was in 1973 when this photo was taken shortly after the Corps of Engineers opened the spillway. With water in the Mississippi River, and threatening the Old River Control Structure, the corps is planning a Sunday opening of the Morganza Spilllway. the Old River Control Structure allows a percentage of Mississippi River water into the Atchafalaya River. If the control structure fails, the Atchafalaya River would capture the Mississippi River and send floodwaters throughout the Atchafalaya Spillway threatening populated area in St. Mary Parish and other upriver locales.

Come Sunday, when the first pins are pulled from the Morganza Spillway gates, the entire 60 miles of our country’s largest overflow swamp will change.

For how long and the how much effect it will have on the fauna and flora of this incredible area are the biggest questions.

A first memory of the full rush of water through the Morganza Spillway is 1973, a record flood then, and one only exceeded by this year’s rising waters during the past nine months.

Former Advocate Outdoors writer Mike Cook, God rest his soul, documented 1973’s efforts of state Wildlife and Fisheries biologists and staff along with dozens of volunteers who spent hours on end attempting rescue of whitetail deer from the rising waters in the Atchafalaya Basin.

Lessons learned then prompted state Wildlife Division biologists to come up with something along the order of a “leave deer alone” policy, believing deer can better fend for themselves in the rising water when the floodgates were opened in 2011.

Truth is, the 1973 venture didn’t produce the kind of results the LDWF staff intended. Very few deer were captured and brought to the safety of wooded areas outside the basin’s east and west guide levees. And from witnessing those efforts firsthand, it was a struggle to get even the smallest of whitetails into a boat and headed for a safer place.

And lots of deer did cross the levees in 2011. Herds could be seen munching grasses atop the levees, and, when approached, almost seemed to know where to dash to escape human encroachment.

The biggest problem, it appeared, was poachers, who took advantage of this exodus to kill or maim whitetails.

A further examination of the situation can be broken down into several segments for what’s expected to happen in the next months.

Land animals

Deer are the most visible among the quadrupeds, but there are many others, some which can adapt to the water and some which can’t.

Deer can’t, although in 2011 we observed five whitetails nestled on a raft of timber and debris and riding the current like folks snuggled in an inner-tube floating down the Amite River. Those deer disappeared behind a row of willows and we don’t know what happened to them.

Yet, others by the hundreds, escaped, but it’s clear in the intervening years a lower number of whitetails returned to the basin after the spillway’s gates were closed and the water receded.

Moreover, by some strange twist from Mother Nature, the deer breeding cycle is extra late across the major rivers’ basins and the fawn “drop” is late in this area, maybe into late August, long after however many females have left the basin.

Rabbits have been known to swim the Mississippi River, so this event shouldn’t be a problem for their populations.

Squirrels live in trees — except for the buggers who like to steal tomatoes from backyards these days — and most will survive.

Alligators will be gators and go where they darned well please, and otters and nutria will swim their way out.

Feral hogs are in the mix, too, and they should be given a wide berth when they’re moving from the basin.

And, there are enough black bears throughout the area that folks could come in contact with them. The LDWF asks anyone encountering bears in a rural or urban setting to call (337) 262-2080.

Birds, except for turkeys, should be OK. A flood like that which is coming cripples turkey numbers, if only because the nesting season is just about over and whatever chicks hatched certainly won’t have the ability to fly from their rearing grounds.

A bigger problem for all land animals is habitat. Sheet-water flooding destroys lots of understory, the plants most of these animals need to survive. With the Mississippi River carrying water enough for a prediciton of “normal” waterflow well into July, there might not be enough time for plants to re-establish by the fall to carry animal populations through the winter.

There is a benefit to all this water: it comes from new silt deposits, which will stimulate new plant growth in the coming years.

Fish

OK, so it’s water and fish live in it, and can thrive amidst all the food — crawfish and the like — sheet-water flooding brings to the basin.

The problem here comes much later than the spillway’s opening and the volume of water moving heavy loads of detritus into the waterways when the water goes down.

The leaves, twigs, branches and other dead plants usually get washed into basin canals and bayous, and, during summer’s heat, begin to decompose.

Worse yet is all this newly introduced organic matter needs oxygen to begin decomposition, and this causes even large waterbodies to become anoxic, or devoid of dissolved oxygen.

So, as with most all south Louisiana waters, and under summer’s heat, no dissolved oxygen leads to fish kills, certainly not the kind we saw in 1993’s aftermath of Hurricane Andrew in the Atchafalaya Basin — remember the estimated 175 million fish killed from that storm — but there will be dead fish.

Worst of all, we could see this event repeat over and over again in other flooded areas, like the Verret Basin and some areas south of U.S 90 in the Atchafalaya Delta, although fish in that latter area are less prone to encounter anoxic conditions.

So, for the thousands of anglers who are expecting a windfall of action after the water is out, there is peril at the end of the flood. It’s something that’s happened before, and sometimes happens annually, but it will come, so don’t be shocked when you see thousands of baitfish, even a few gamefish, floating on both east and west sides of the basin.

A note for fishermen: when water gets low enough, there will be a procession to the launches on the basin’s east and west sides. There will be enough water and enough silt to create new sandbars and cuts.

Just know the topography of the basin will change, and change dramatically in some areas, and you will need to be cautious when running a boat even in areas you know “like the back of your hand.”

Snakes

If you live in or around the basin, experiences with past floods have taught many of us to be wary of where you walk on the levees and surrounding areas.

Snakes move with the water, too, and if you spend enough time in these places in the next weeks you could see any number of poisonous critters, including rattlesnakes, cottonmouths, copperheads and coral snakes.

Those pretty little coral snakes have a way of getting into the tightest places in the back of sheds and in boats and can deliver a pretty tough punch, not at first, but wait and, well, you don’t want to find out.

The coast

Move this volume of water from the two major rivers in the southern U.S. and it’s bound to affect coastal fishing.

A couple of weeks after the spillway’s opening, folks will begin to see rafts of dead water hyacinths in coastal waters – and a lot of dirty water moving to the beaches even as far east (from the Atchafalaya) as Last Island chain and whatever beaches remain in Timbalier Bay.

The slug of freshwater will move lots of species, including shrimp and pogeys, and when you move these two forage species, speckled trout and other recreational fishing targets will move, too.

In past openings, or in other heavy floods, the rafts of dead hyacinths can be a bonus. Tripletail find them and hide under the mats and can be a target for catching one of the most delectable fish there is swimming in coastal Louisiana.

There have been times when the freshwater push sends trout to the beaches and other shallow-reef spots and this provides a bonanza for anglers.

Know, too, that freshwater is lighter than saltwater, and just because you see a lot of muddy river water on the surface idoesn’t mean the trout have moved from the shallows of bays and coastal lakes. Try your favorite places first, and if it doesn't pan out, then go hunting specks.

Just get ready. The Morganza Spillway is opening Sunday.