Texas Clipper Trip Report 5/17

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Check out the loop current flow in the Gulf and tell me how water from the Mississippi can make it's way to Port Isabel when the flow south of Aransas is northbound.

The Loop Current

Have no clue myself....not a scientist who studies these fun things--LOL....but I can tell you it is river muck and at times very dense. The muck I have encountered is much farther off shore than 17 miles and much deeper than 130fsw.
 
Check out the loop current flow in the Gulf and tell me how water from the Mississippi can make it's way to Port Isabel when the flow south of Aransas is northbound.

The Loop Current

This website clearly refers to surface current. Last time I checked, the Gulf Of Mexico was fairly three dimensional...

I think its possible that flow can do some crazy things in the gulf at depth.
 
Hi ReefHound,

I can only tell you what the dive op told us, which is that we were experiencing a push from the Mississippi which had a roughly north to south current flowing at the dive site. They even said that the push was strong enough to stop the normal current and more or less reverse it. The link you have shows what appears to be the normal current flow, but the conditions on our day of diving were not normal. Wish I knew enough to explain it better, hopefully someone who knows more about the Gulf can give you a better explaination.

Check out the loop current flow in the Gulf and tell me how water from the Mississippi can make it's way to Port Isabel when the flow south of Aransas is northbound.

The Loop Current
 
Hi ReefHound,

I can only tell you what the dive op told us, which is that we were experiencing a push from the Mississippi which had a roughly north to south current flowing at the dive site. They even said that the push was strong enough to stop the normal current and more or less reverse it. The link you have shows what appears to be the normal current flow, but the conditions on our day of diving were not normal. Wish I knew enough to explain it better, hopefully someone who knows more about the Gulf can give you a better explaination.

This is a correct assessment, I have had several sources explain it to me....the gulf has several layers of current as we all understand.... and they do at times flow sw from the mouth of the Mighty 'M' bringing dark river muck that far south and suspending it in the water.

But if someone can provide information that this is not what many of us agree it is I/we would be happy to read the information and see if the previous explanations are in error.
 
Hi ReefHound,

I can only tell you what the dive op told us, which is that we were experiencing a push from the Mississippi which had a roughly north to south current flowing at the dive site. They even said that the push was strong enough to stop the normal current and more or less reverse it. The link you have shows what appears to be the normal current flow, but the conditions on our day of diving were not normal. Wish I knew enough to explain it better, hopefully someone who knows more about the Gulf can give you a better explaination.

Recently the Bonnet Carre spillway was opened. The spillway bypasses the Mississippi River directly into Lake Ponchartrain. Its sole purpose is to alleviate flooding potential along the river in the spring. This action increases flow from Lake Ponchartrain through the Chef Menteur Pass, and out to the Gulf of Mexico on the east side through Lake Borgne. However, the river is still high, and we have had more rain since the spillway was closed after being open for several weeks.

When the river enters the gulf, from an airplane, and even from a boat, at the surface you can see where the muddy river water ends, and the clear gulf water begins. This is quite a sight to see since it can take place over miles of open water. I am sure that there are currents at depth which move the river water literally all over the gulf at varied concentrations. Higher flows from the river may be contributing to increased sediments and water particulate at greater distances and varying depths. It could also be that increasing the flow into the Gulf increases the amount of dispersion and the distance that water stays at a higher concentration, thus reaching areas that normally would not be affected by the river.

It would not surprise me if, during higher flow situations, river water flowed all the way to the southernmost point in the gulf (but not necessarily at the surface) and then flowed north along the east coast of Mexico and Texas causing higher than normal particulate and lower visibility. This may explain how river water may actually flow from the South at South Padre Island.

Unfortunately the river is more like a pipe than it should be. We have the Army Corps of Engineers to thank for that. All the great rivers form alluvial fans at their distribution points. Hopefully we will see that fixed and restored to normal order in our lifetimes.
 
Does anyone have any hard data to back up all the speculation? So far only one person has provided actual data.

See Figure 8Q-2, the subsurface currents appear to follow the same clockwise flow around the Gulf.
 
The Gulf of Mexico watershed covers almost two million square miles. It borders Mexico and Cuba on all sides. Five states in the United States border the Gulf of Mexico. They are Alabama, Florida, Louisiana, Mississippi, and Texas.

Pollution from these five states runs into the streams, rivers, and eventually the Gulf of Mexico. Litter on the beaches gets washed into the water. Runoff from the Rocky Mountains and the Appalachian Mountains goes into the Gulf of Mexico. Thirty-three rivers in the United States drain into the Gulf of Mexico.

All of the states between the Rocky Mountains and the Appalachian Mountains send their runoff to the Gulf of Mexico. That includes states as far away as Montana and New York. Some 33 major rivers drain into the Gulf of Mexico, as well as many, many small rivers, creeks, and streams.

In all there are 31 states in the Gulf of Mexico watershed.

They are Alabama, Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Virginia, West Virginia, Wisconsin!

Think about it - all of the pollution from all of of the creeks, streams, and rivers from all of these states enters the Gulf of Mexico. The Mississippi River drains almost 40% of the United States and it carries 1.5 million metric tons of nitrogen pollution into the Gulf of Mexico each year.

With that much pollution going out into the Gulf of Mexico, it is no wonder it finds it way everywhere along the Texas Coast at time...
 
The size and volume of the Gulf and the states that border it wasn't the kind of hard data I was asking for. Show me something besides armchair speculation that subsurface currents or any other kind of currents carry water from the Mississippi across the 6000 foot chasm to South Texas.

Keep in mind that subsurface currents flow much slower. For instance, the well known Thermohaline current takes 1000 years to complete it's circuit around the world.
 
OK, after a quick google search I have turned up some interesting information. Apparently the normal discharge flow of the Mississippi river is East to West along the Louisiana and Texas Coasts, so the conditions we encountered are not all that unusual, although the effect being quite that far along the coast is somewhat so. I searched for abnormal currents in the Gulf, and found this link:

AGU Web Site: The Great Flood of Summer 1993: Mississippi River Discharge Studied

Here is a short clip from the article:

"During the 1993 summer, not only was river discharge anomalously high but the direction of flow of river water in the northern Gulf of Mexico was also unusual. Generally, much of the river water discharged into the northern Gulf of Mexico by the Mississippi and Atchafalaya Rivers moves westward along the Louisiana and Texas coasts, driven primarily by the prevailing easterly winds. Freshwater from these rivers has been observed as far as Port Aransas, Tex., 800 km from the Mississippi River delta." (emphasis added)

Again, that the effect reached as far as it did was a little unusual, but the overall direction was not. Now whether what we saw was related to the volume of water coming from the Mississippi or just by the wind is speculative. This does not counter the Loop Current, it just shows that the Loop Current has less of an effect in close to the coast.

Regards,
 

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