Study: Mo. River projects won’t affect ‘dead zone’

Study: Mo. River projects won’t affect ‘dead zone’

JEFFERSON CITY, Mo. —

A study released Tuesday concludes that a U.S. Army Corps of Engineers plan to dump sediment into the Missouri River while improving wildlife habitats would not significantly increase the size of the "dead zone" in the Gulf of Mexico.

Responsible for managing the Missouri River, the Corps’ plan calls for dredging miles of side channels and chutes and dumping tons of soil into the river. The projects are designed to help fish and other wildlife by creating shallow, slow-moving water habitats. Those channels then are designed to allow further erosion over time to simulate natural river erosion.

But federal officials and the Missouri Clean Water Commission have tussled over the idea, which prompted the Corps to request the scientific study two years ago.

State officials were concerned that the sediment contained high levels of nitrogen and phosphorous and could cause pollution in the river and in the Gulf of Mexico. State officials also feared that the proposal could worsen a low-oxygen "dead zone" in the Gulf of Mexico.

The National Academy of Sciences, in its study, concluded that the Corps’ plans to dump more soil into the river would not significantly affect the oxygen-depleted "dead zone" in the northern Gulf of Mexico.

Furthermore, the report found that sediment in the river had decreased by more than half since 1900 as less soil moved downstream because of developments like dams and bank stabilization projects. It estimated that the Corps’ plan would add 34 million tons of sediment more per year into the Missouri River, which would boost sediment flowing to the Louisiana coast by 10 to 20 percent.

Corps officials have continued working on river habitat projects in Iowa, Kansas and Nebraska but halted efforts in Missouri while awaiting the study.

Corps officials said Tuesday that the study’s findings backed up what they had been doing but were still being analyzed. Federal officials said they would work with Missouri but that there are no plans to restart projects there for at least a year.

Col. Anthony J. Hofmann, the Kansas City district commander, said the study’s findings would be used to "help determine a path forward" with state officials on the habitat projects.

The Missouri Clean Water Commission is a seven-member board appointed by the governor that is supported by staff from the Department of Natural Resources.