The fish-killing “dead zone” in the Gulf of Mexico this summer covers 6,952 square miles, midway in size between Connecticut and New Jersey, said researchers on Thursday. It is the eighth-largest dead zone in 33 years of keeping records.
A spillway on the Mississippi River designed to prevent the river from overflowing its levees and inundating towns and cities in Louisiana will likely be opened for only the third time in history this Sunday, flooding 25,000 acres of farmland in the Atchafalaya basin and all but guaranteeing a total crop loss for farmers in the area.
Spring rains and melting snow are helping to create the potential for major or moderate flooding in 25 states, with the greatest threat in the northern Plains and the upper Mississippi River basin, said NOAA in a spring outlook issued on Thursday.
This past spring, Louisiana-based professor Dr. Nancy Rabalais, perhaps the world’s most renowned researcher on marine dead zones, predicted that the summer of 2017 would see the largest hypoxic area in the Gulf of Mexico in recorded history. Last month she was proven right.
Marine scientists estimate the low-oxygen "dead zone" in the Gulf of Mexico covers a record 8,776 square miles, or one-seventh of the basin. "This large dead zone size shows that nutrient pollution, primarily from agriculture and developed land runoff in the Mississippi River watershed, is continuing to affect the nation’s coastal resources and habitats in the Gulf," said NOAA.
A mandated interstate "pollution diet" intended to reduce nutrient runoff into the Chesapeake Bay is paying off, while voluntary measures to reduce nitrogen levels in Mississippi River have failed, writes a University of Michigan professor at the site The Conversation. "From my perspective, when we compare these two approaches it is clear that voluntary measures are not even making modest dents in nutrient pollution," says professor Donald Scavia, who has worked on the issue of "dead zones" for four decades.
The Mississippi River, rising from Lake Istasca in northern Minnesota to flow 2,340 miles to the Gulf of Mexico, "is heading toward an ecological precipice," says the Minneapolis Star Tribune in a special report. In five years, 400 square miles of forests, marshes and grasslands in the upper Mississippi have been converted to agriculture and urban development, "endangering the cleanest stretch of America’s greatest river with farm chemicals, depleted groundwater and urban runoff."
The Mississippi River basin got an overall grade of D+ in a report card from America’s Watershed Initiative, which looked at six areas – flood control, transportation, water supply, economy, recreation and ecosystems. The lowest mark, a D-, was for transportation, said St Louis Public Radio. …
Researchers know that a comparatively small share of cropland accounts for a disproportionate amount of erosion and nutrient runoff, writes economist Marc Ribaudo in Choices, the ag econ journal.