Hurricane Gustav hit Louisiana's coast Monday September 1, 2008 as a strong
category 2 storm (1 mph below category 3). Like Hurricane Andrew that hit Louisiana's
coast in August 1992 as a category 2 storm, Hurricane Gustav caused extensive fish kills
in the Atchafalaya Basin in and out of the levee system.
The following is a report of the effects of Hurricane Gustav on the water and fish in
the Eastern part of the Atchafalaya Basin.
Timeline:
- Monday September 1st. Hurricane Gustav hits the area in the afternoon
dumping huge amounts of green leaves into the waterways and forests.
- Tuesday September 2nd. I return to the Bayou Sorrel area. Very heavy
rains hit the Atchafalaya Basin and the Northern part of the Basin between
the Atchafalaya Basin levee and the Mississippi River (Point Coupee, West Baton Rouge and
Iberville Parishes). No fish kills or signs of fish stress are seen or reported
in the area. Thousands of acres of forests go under water.
- Wednesday September 4th. Water levels increase dramatically between the
Atchafalaya Basin levee and the Mississippi River levee. My yard floods. First
signs of fish stress are documented with lots of fish activity in the upper column
of the water. Fish are moving fast and no dead or weak fish are reported.
- Thursday September 5th. The water in the woods starts to smell like raw
sewage (I will call it the green manure effect). The effect of green leaves
in water is very different from dry brown autumn leaves rotting in the water.
Fish are coming to the surface with signs of acute stress and some catfish can
be scooped easily from the top of the water.
- Friday September 6th. Fish outside the Atchafalaya Basin levee system are
dying or dead, especially small shad. Water levels in the woods are dropping
with millions of gallons of water contaminated by the rotting green leaves going
into the system. I got reports of massive fish kills inside the Atchafalaya Basin
in the Bayou Sorrel Shell Field area and Little and Big Bayou Pigeon areas. A trip
to the Atchafalaya Basin is scheduled for tomorrow and boat is ready.
- Saturday September 7th. Water levels continue to drop outside the Atchafalaya
Basin levee. Lots of fish mortality: shad, catfish, carp, buffalo, white drum, perch
(all types), bass (all types), german carp, and silver carp. The only species not
reported as dying are all species of garfish, bowfin and most minnows.
Boat trailer breaks and trip to the Atchafalaya Basin has to be cancelled.
Dead fish pile up at one of the island bridges at Bayou Sorrel.
- Sunday September 8th. Last fish died in the Pat's Bay system with 100% of most
species of fish (excluding garfish, bowfin, and minnows) either dead or migrated out
of the area. Horrible smell. The only place with no fish kills is the pond by the
house that is covered with duckweed and the lake by my horse pen that does not have
any rotten water from the flooded forest draining into it.
- Wednesday September 10th. Traveled into the Atchafalaya Basin by boat
with Dr. Paul Kemp and Cara Leverett. Many small shad along the Intracoastal
Waterway are dying or dead. South of the Bayou Sorrel public landing toward
the Bayou Sorrel locks more small shad are dead or dying.
North of the
landing toward Bayou Sorrel more fish are surviving with fewer dead small shad.
Huge amounts of dead fish are floating down the levee, most likely from Bayou
Maringouin.
We turn left into Bayou Sorrel. The water is coming out of the Bayou
Sorrel Shell Field black and rotten with the rotten black water mixing with the
clean muddy water from Bayou Sorrel. Water levels are dropping so fast that black
rotten water pushes all muddy water to a small strip on the south bank of Bayou
Sorrel and many egrets concentrate on that bank to catch sick fish.
Rotten water from the Shell Field overwhelms fresh muddy water from Bayou Sorrel.
A small strip of good, fresh muddy water on the south bank of Bayou Sorrel.
Black water looks black and thick and smells like raw sewage. In the Shell
Field there is no fish activity except for minnows, which suggests that all
fish have either died or migrated out of the Shell Field. In the flooded swamps
the water is cooler under the water hyacinths and water in that slough smells
more like rotten swamp bottom instead of the sewage smell of the other flooded
forests. Flooded broad-leaved forests have way worse water quality problems than
cypress-willow-tupelo swamps.
In the Mound's Bayou location canal, there are a huge amount of feeding birds
including egrets, ibises, wood storks, great blue herons, little blue herons,
spoonbills and anhingas. There is so much fish activity that the water sounds
like it is boiling from the hundreds of moving fish; no mortality reported.
It is obvious that many fish are taking refuge in the canal.
Egrets, herons, wood storks, and anhingas feeding on the high concentrations
of live fish in the good water of the Mounds Bayou location canal.
The only two dead fish are at the mouth of canal and were most likely pushed
by the wind into the canal. The main difference between that canal and the areas
with many dead fish is that the spoil banks are very high and there is no discharge
of "green sewage" water from the swamps except for a small trickle at the end of
the canal. The phytoplankton was somewhat affected in Mound's Bayou canal (most
likely by the green leaves that fell into the canal), but is present throughout
the canal. This is the only place that we found any phytoplankton in the water.
This shows that keeping water out of the forests is critical to managing the
Basin to avoid another massive fish kill caused by a future hurricane.
- Saturday September 13th. Hurricane Ike makes landfall in the North coast
of Texas. Very strong southern winds push bad water north making water quality worse.
- Tuesday September 16th. Left the Bayou Sorrel landing 9-16-08 in the Intracoastal
Canal on the land side of the Atchafalaya Basin levee toward the Port Allen Locks.
Total miles between the landing and the Port Allen locks are 26.7.
The destruction caused by Hurricane Gustav can be seen along the banks
traveling north toward the Plaquemine locks in the Intracoastal Waterway.
From the Port Allen Locks, going south back toward the landing, the water
quality is excellent for about 8 miles, to the mouth of Bayou Choctaw. Water in the
canal on the east bank of the Intracoastal before Bayou Choctaw was good and full of fish.
No flooded forests along that canal and the banks are high.
Water has live phytoplankton on the East bank for about half a mile from Bayou
Choctaw to the railroad bridge over the Intracoastal Waterway. Lots of egrets feeding
along that bank show that it is an area where fish are struggling for air.
High concentrations of egrets and other fish-eating birds shows where fish are struggling for oxygen.
First very fresh dead fish (died early today) were found right before the railroad bridge.
First fresh dead fish were 9 miles before the Port Allen Locks.
Local landowner claims that no fish were dying last Saturday September 13 which
suggests that Hurricane Ike made water quality worse, probably by blowing bad water
up the Intracoastal Waterway.
Bayou Choctaw has terrible water quality and is dumping bad water into the Intracoastal Waterway.
Bad water from Bayou Choctaw mixes with good water from the Intracoastal Canal.
Coming back South on the Intracoastal Waterway, the last live shad was seen in
front of Trinity Marine about 9 miles from Locks. Many dead fish about 24 hours
old found in the area. We need to remember that big winds from Ike pushed lots of
water north into the Intracoastal Friday September 12, Saturday September 13, and
Sunday September 14.
Signs that the water levels overflowed the banks, flooding the forest can be
found about 12 miles from the Locks and about 3 miles from where the last fish
was seen alive.
Water overflowed and flooded forests 12.2 miles from locks.
Some fish (look like yellow bullhead catfish or pollywogs) seen alive
on the way to the landing, but all the water is rotten with a terrible smell.
- Wednesday September 17. We left north from the Grand River landing on
the land side along the Atchafalaya Basin levee. Most fish are dead and we only
saw two instances of fish moving (again I think they were yellow bullhead catfish).
Fish died all the way North of Interstate 10.
Next, we went to the Atchafalaya Basin all the way to the mouth of Bayou
Maringouin at Grand River. Water from Bayou Maringouin is dead and rotten. Water from
Grand River is poor but good enough for fish to live in.
Mixing waters, Grand River and bad water from Bayou Maringouin (black).
Many swamps along the Work Canal and the Interstate 10 canal empty upriver into
Grand River and I assume all the water coming from that canal is rotten. Again
great numbers of egrets and ibises were along the west bank of Grand River south
of Bayou Maringouin, showing the area where fish are struggling for air.
- Thursday September 18. We made the same trip that we did with Dr. Kemp.
Water along levee has improved and a great number of egrets, little blue herons, ibises
and great blue herons feed along western bank, with a few wood storks and even few spoonbills.
This indicates that the better water is along that bank, but also that fish are struggling
for air along that bank. Water coming from Bayou Sorrel completely overtakes water coming
from the Shell Field.
Water in the Shell Field is still very bad; the only fish activity was from three what appear
to be yellow bullhead catfish (pollywogs).
Conclusions/ Recommendations:
Our observations suggest that massive fish kills following hurricanes are caused
by green leaves falling into the water and decaying, causing a drastic reduction in
water quality, particularly reduced oxygen levels.
In areas where water levels cannot be managed by dams or locks, little can be
done to avoid massive fish kills caused by hurricanes. In inland areas like the ones
we observed in the eastern part of the Atchafalaya Basin, locks and dams can be managed to
control water levels, which allows us to prevent or minimize hurricane-related fish kills.
As soon as we know that a hurricane is coming, the following strategy should be implemented to
achieve that goal. In an effort to minimize the amount of water that floods into the woods,
we should lower water levels as much as possible before, during and just after the storm so
that our main canals, bayous, rivers and lakes can accommodate water from torrential rains that
are expected during a hurricane without overflowing into the woods. All efforts should be focused
on draining flooded swamps and forests before the fallen green leaves start affecting the quality
of the water. After water quality deteriorates we should not increase water levels in the flooded
swamps and forests under any circumstance. Water should be flushed into the system to slow drainage
of rotten water from the swamps and forests and to freshen up the system. If forests are not flooded,
the system should be flushed out such that water does not go into any swamp or forest. The only
exception would be if water levels in the Mississippi River are high and water levels in the
Atchafalaya Basin can be kept fairly high until water quality in the flooded forests improves
(a scenario that would be most likely to happen when water temperatures decrease in the fall).
Another thing we learned is that egrets and little blue herons do feed on rotten fish.
Snowy egrets, great egrets and juvenile little blue herons, feeding on two week old rotten fish
carcasses at the second Island
bridge in Bayou Sorrel, fly away scared by our truck.
|