Sunday, September 18, 2011

Salty flow into Florida rivers blamed on sea level rise, not overpumping

Craig Pittman in Tampa The folks who live along the Chassahowitzka and Homosassa rivers have noticed a lot of changes lately. Saltwater fish swimming in what used to be mostly freshwater, as freshwater fish disappear. Trees on the riverbanks toppling over, killed by an increase in salt. Barnacles growing where they never did before.

To them, the cause seems obvious: pumping too much freshwater out of the underground aquifer so people can keep their St. Augustine grass green. Overpumping cuts the flow of freshwater from the local springs into the rivers, allowing salty water from the Gulf of Mexico to begin pushing upstream.

So they were outraged when they found out the Southwest Florida Water Management District may let pumping cut back the rivers' flow even more. According to the agency commonly known as Swiftmud, the Homosassa's flow can be cut by another 5 percent and the Chassahowitzka by 11 percent before causing any "significant harm" to the environment.

...The clash turns on an unusual argument. Swiftmud's experts say the increased saltiness of the rivers is not due to overpumping. They contend it's due to climate change. That means it's not a sufficient reason to block more pumping.

"The increased salinity that has occurred is partly the result of sea level rise, and partly due to recent drought conditions that caused the flow to decline," said Marty Kelly, who is in charge of the river flow project for Swiftmud....

Winslow Homer's 1904 watercolor of the Homosassa River

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