Saltwater Intrusion on the Mississippi River

By Jay Grymes

Louisiana State Climatologist

An overly-simplified perspective on the problem...

Today’s issuance of the U.S. Drought Monitor will show that drought continues to dominate most of the greater Mississippi River Basin, although a large portion of the drainage area could see 2" to 5" of rain over the next several days thanks to a return of frontal weather.  

Unfortunately, the frontal activity will come with a significant severe weather threat for a number of states.

While those rains will be locally beneficial, run-off feeding into the Mississippi may be limited due to absorption by unusually-dry landscapes, low-flows along many rivers throughout the region, and regional capture for reservoir recharge.  In addition, while some areas may deal with localized flooding over the next couple of days, rain totals will trend much lower in the all-important Ohio River Valley (which contributes ~70% of the Lower Mississippi River flow, on average).

As a result, NWS forecasts for the Lower Mississippi show little improvement (increase) in river flow at New Orleans through the next 2 weeks.  Significant rises are unlikely through the next 4 weeks or more.

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Opinions are mine ... the NWS, the USGS, and the USACE are the experts.