Upper Mississippi is faring better, worse, study says

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Upper Mississippi is faring better, worse, study says

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DENNIS LIEN STAFF WRITER

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Constrained by an elaborate lock-and-dam system, the Upper Mississippi River

is choking from a steady diet of sediment, chemicals and nutrients, an

exhaustive report released Wednesday said.

But in other ways, the river is a healthier place than it was decades ago,

when unchecked pollution from large industries made it a hostile place for

many insects and invertebrates, the report's senior editor said.

The study, ``Ecological Status and Trends of the Upper Mississippi River

System 1998,'' is the product of more than a decade of research by

scientists from two federal agencies and five states including Minnesota. It

documents how the river has been altered by human activity.

The report breaks 800 miles of the Mississippi River into three zones, from

the Twin Cities to Rock Island, Ill., there to St. Louis, and finally, St.

Louis to Cairo, Ill. The study also covers the 400-mile Illinois River,

which connects the Mississippi to Lake Michigan.

The report grades each segment on the basis of ecological indicators. The

northernmost stretch gets the highest ranking.

That portion, between the Twin Cities and Rock Island, is rated as

``moderately impacted'' in five of six categories: native populations of

fish and aquatic vegetation, ability to recover from disturbances, long-term

sustainibility, amount of land changes and amount of flood plain where no

levees have been built. In a sixth category, ecological value of floods, the

upper section was rated as ``degraded.''

Downstream stretches -- along the borders of southern Iowa, Missouri and

Illinois -- were generally rated as ``highly impacted'' and ``degraded'' in

nearly all categories.

The report cites an elaborate system of locks and dams and its capacity to

rob the river of its ability to periodically flush itself of sediment. The

river also has been hurt by construction in flood plains, conversion of

prairies and forests to farmland dominated by row crops, and pesticides and

sewage from farms and municipalities, according to the report.

Lubinski, a U.S. Geological Survey ecologist and the report's senior

editor, said the river is slowly deteriorating and will continue to do so

unless sediment and nutrients from those varied sources is reduced.

But for all the river's problems, there have been improvements, including

reductions in pollution from industries and wastewater treatment plants, he

said.

``From an environmental point of view, the biggest concern we have that we

need to pay attention to are the changes that have taken place since the

lock and dam system was put in,'' Lubinski said.

Those navigation pools are filling with sediment, leading to loss of aquatic

and plant diversity and the insects, fish, birds and waterfowl that depend

on them, he said.

No one is suggesting the lock and dam system be eliminated, but it may be

possible to regulate water levels to mimic floods to improve floodplain

vegetation, he said.

``That's being proposed now,'' he said. ``Twenty years ago, you couldn't get

anyone to talk about a change like that.''

The report initiates an assessment process that will clarify which actions

are the most urgent. It was released by the U.S. Geological Survey, the U.S.

Army Corps of Engineers and five upper Midwestern states, Minnesota,

Illinois, Iowa, Missouri, and Wisconsin.

The Upper Mississippi River report is available on the Internet at

www.umesc.usgs.gov

***Dennis Lien can be reached at dlien@... or at (651)

228-5588.

TO LEARN MORE

The Upper Mississippi River report is available on the Internet at

www.umesc. usgs.gov