Conservation Guardians of Northwest Illinois

More Field Notes Previous Next

Home  •  Field Notes  • The Health of the Mississippi

The Health of the Mississippi

Winter 2000 Newsletter

After measuring the ecological health of the Upper Mississippi River system for about 10 years, ecologists from the U.S. Geological Survey have discovered that some areas within the system are healthier than others.

Now they are encouraging the public to insist that the system's health be maintained or improved.

The healthiest is the area referred to as the Upper Impounded Reach, which flows from the Twin Cities to Bellevue, Iowa. Even this area has suffered from commercial navigation, non-point source pollution — such as agricultural runoff — and flood plain development, according to Ken Lubinski, an ecologist from the geological survey.

Lubinski spoke on a recent Saturday to about 40 people at the Jo-Carroll Electric Cooperative in Elizabeth in a meeting sponsored by the Natural Area Guardians.

Lubinski said that if the Mississippi River system is to remain healthy or to become healthier, the public must insist that government agencies take action.

People should not allow the U.S. Army Corps of Engineers to retain total control of the river, he said. The corps' primary objective is to keep the river navigable. Navigation must be balanced with ecological health, he said.

Lubinski recommended that people become involved with the National Audubon Society or the Upper Mississippi River Conservation Community, which are most active in river ecology.

In addition to the Upper Impounded Reach, other areas of the system are the Lower Impounded Reach from Bellevue to St. Louis, the Unimpounded Reach from St. Louis to the southern tip of Illinois, and the Illinois River Lower Reach from Goose Lake in Illinois to the confluence with the Mississippi. The Illinois River Lower Reach has suffered most, Lubinski said.

He said there are six ways to measure a river system's health:

• By the number of viable populations of native species.
  
  With 485 species of fish, mussels, birds, mammals, amphibians and reptiles, the upper reach enjoys good health, according to Lubinski.
   
• By the ability of aquatic species to recover from disturbances, such as floods, navigation and spills.
  
  To recover, a species must live throughout the system so that it can repopulate an area in which it has been destroyed. The upper reach is in fairly good shape but has experienced some negative impacts. For example, the zebra mussel, which is not native, has destroyed some native species of mussels.
   
• By the sustainability of the ecosystem.
  
  Ecosystems should remain relatively unchanged over time, Lubinski said. However, habitats have changed gradually over the past two centuries, especially since the dams were built. A change in habitat disturbs the ecosystem. So far the upper reach ecosystem remains in reasonably good shape.
  
  "Now the question is: How long will it take to lose these habitats and how many ecosystems will be affected?" Lubinski asked.

• By its capacity to function as part of a healthy basin.
  
  "The river is not an ecosystem itself," Lubinski said. It is part of a large watershed that is affected by what happens to surrounding land.
  
  The functioning in the upper reach is relatively good but could be better, as evidenced by higher flood heights in recent decades and the accumulation of sediment in side channels and backwaters.
   
• By the connection between the main channel and the flood plain.
  
  Frequent, moderate flooding enhances the system's health, Lubinski said. But the addition of levees has caused less flooding in some areas and more in others. The upper reach is relatively healthy because only * [sic] percent of it has levees.
   
• By the ecological value of floods when they do occur.
  
  Digging the 9-foot channel in the river reduced the value of floods throughout the system, including in the upper reach.
  
  "The question is: How often do huge floods occur and can we restore the variability of aquatic life when they do?" Lubinski asked.

— Becky Cisco