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David Beckman’s Blog

Solutions for Shrinking the Dead Zone in the Aftermath of the Great Flood of 2011

David Beckman

Posted May 24, 2011 in Curbing Pollution, Reviving the World's Oceans

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The Mississippi River Flood of 2011 has upended thousands of lives. Residents have seen their homes destroyed and farmers have seen their crops inundated. But the damage done by this flood isn’t limited to the length of the river.

As flood waters scoured the farmlands of the Midwest, they picked up enormous amounts of nitrogen and phosphorus and funneled them down river into the Gulf of Mexico. The massive influx of these two pollutants is expected to create a “Dead Zone” of lifeless water, perhaps the largest ever recorded in the Gulf.

The wave of water moving down the Mississippi this month was clearly an extreme event, but it shines a spotlight on a process that is happening all the time.

When it rains, runoff pulls nitrogen, phosphorus, and other chemicals off of farmlands and city streets, dumps them into the river, and sends them down into the Gulf.  There, nitrogen and phosphorus feed the algae that makes the Dead Zone.

The Flood of 2011 temporarily accelerated this cycle, but the forces that created the Dead Zone are a flood in slow motion.

They build up slowly but their prolonged impact on marine life, on coastal communities, and on the Louisiana fishermen who depend on crab, shrimp, lobster, and other species to make a living, can be as devastating as a flood or hurricane.

We humans can’t prevent extreme weather events from descending upon us, but we can stop the floods of our own making. Solutions exist that can cut down on the amount of pollution that we dump into rivers and reduce the Dead Zones that force marine life to either flee or die. 

Nitrogen and phosphorus come from a variety of sources, including animal feedlots, agricultural fertilization, urban runoff, and sewage treatment plants. The following solutions would allow farmers and municipalities to thrive while cutting down on pollution.

Preserve Wetlands and Headwater Streams

Mother Nature has already designed an excellent system for reducing nutrient pollution: wetlands and small streams. They filter out pollution before it reaches major waterways. As my colleague Jon Devine pointed out, even the George W. Bush White House concluded that wetlands along the Mississippi “retain nitrates and phosphates that would otherwise drain from adjacent farmlands.”

The trouble is that, following a pair of Supreme Court decisions, the Bush administration also adopted policies that went far beyond those decisions in undermining legal protections against polluting many streams and wetlands. These resources became vulnerable to developers, mining companies, and other industrial interests. The Obama administration has proposed restoring Clean Water Act protections to many of these natural filters, and NRDC wholeheartedly supports this move. You can too, by submitting comments in support of the administration’s push to protect these resources.

Stop the Rain Where It Falls

Rainwater is the vehicle that transports pollution off of farmlands and city streets. If we can capture rainwater where it falls, then we can cut down the amount of dirty chemicals it can carry into our waterways.

Green infrastructure—things like porous pavement, green roofs, grassy swales, parks and pocket gardens—give rainfall a chance to soak back into the ground. Most conventional drainage systems rely on concrete pipes and canals, but adding more spongy unpaved ground along a waterway or throughout a watershed will allow more rain to get absorbed where it falls, before being shunted through storm sewers and into our streams.

This also reduces overflows at sewage treatment plants, because it reduces the amount of incoming water they need to process.

Clean Up Sewage Plants

That’s right, runoff isn’t the only source of nutrient pollution: sewage treatment plants also release nitrogen and phosphorus contained in human waste. And yet there is no federal standard governing how much nutrient pollution these plants can dump into our waterways.

Public health and environmental groups have asked the EPA to set such standards for more than 15 years without result. The Gulf Dead Zone, which is now sometimes larger than New Jersey, should be reason enough for the agency to finally take action.

Promote Farming Practices that Reduce Runoff

We recognize that controlling Dead Zone pollution will not be free.  Just as society rewards farmers for conserving wildlife habitat, it should also reward them for preserving wetlands and other natural barriers that prevent agricultural fertilizer from leaving farms.

Likewise, we should broadly institute best practices on farms, as highlighted in a great report by the Environmental Law & Policy Center and the Mississippi River Collaborative, with which NRDC works closely on nitrogen and phosphorus pollution in the basin.

At the end of the day, however, it is going to take federal leadership to get these programs implemented widely enough and strategically enough to solve the problem of Dead Zone pollution. That’s going to take quantifiable targets and enforceable cleanup strategies, as Jon Devine discussed in an earlier post.

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Switchboard is the staff blog of the Natural Resources Defense Council, the nation’s most effective environmental group. For more about our work, including in-depth policy documents, action alerts and ways you can contribute, visit NRDC.org.

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