Sudden increase in salinity in Mississippi’s coastal waters

Freshwater no longer seems to be contributing as much to the Mississippi Sound, according to officials

Salinity suddenly increasing in parts of the Mississippi Sound this week

SOUTH MISSISSIPPI (WLOX) - There has been a recent sharp increase in salinity in the coastal waters of Mississippi.

Two United States Geological Survey (USGS) water data sensors located separately in the Mississippi Sound and the Biloxi Bay have both reported a June 11 increase in salinity. Values have doubled or tripled since the beginning of the month from less than five parts per thousandth to now nearly fifteen parts per thousandth.

The combination of locally heavy rain this winter and spring and the opening of the Bonnet Carre Spillway have led to abnormally low salinity levels in the Mississippi Sound in recent weeks.

“One thing I have noticed is that the sharp June 11 increase in salinity occurred right after high tide in Biloxi,” said WLOX First Alert Meteorologist Wesley Williams.

Statement from officials on why:

WLOX contacted the National Weather Service office of New Orleans. And they offered this statement regarding freshwater spilling into the coastal waters of Mississippi. They did not offer an official reason. But, they did say this:

“Based on satellite imagery, we’re constantly monitoring the day to day changes in the behavior of the water as it enters the Gulf. Early on, it contributed quite a bit to the Mississippi Sound. But, that no longer seems to be the case.”

High-resolution satellite picture from June 13 2019... We can see the effects of the Mississippi River draining...

Posted by Meteorologist Wesley Williams on Thursday, June 13, 2019

Here is a list of what is likely not causing the Sound’s salinity to rise rapidly:

South wind

  • The wind has been mainly from the north this week during the time of the salinity increase.

Gulf disturbance

  • The Gulf disturbance occurred last week and this weekend but the salinity increase was on Tuesday after the disturbance was gone.

Ship Island repair

  • The repairs to Ship Island, which connected the west and east portions of the island occurred before this week, too long before the salinity increase.

I have spent all morning investigating why the salinity in the Mississippi Sound went up so much on Tuesday June 11...

Posted by Meteorologist Wesley Williams on Thursday, June 13, 2019

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