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Commercial Navigation

Given the economic impact of commercial navigation, is it reasonable to consider reversing all hydrologic modifications? What responsibility does commercial navigation have to preserving water quality?

Many hydrologic modifications made to rivers in order to support commercial navigation have affected the functions of natural river systems. Dams were constructed to even out the seasonal changes in water flows, creating vast lakes behind them. Curves and meanders removed to straighten rivers have cut wetland areas off from nourishing river waters. Channels and wing dams, constructed to accommodate barges and boats have narrowed riverbeds and increased the speed of the water’s flow.

Areas "starved" of the river’s water, died off, eliminating important habitat. Wetlands have traditionally served not only as habitat, but also as living sponges, soaking up excess water. They are also natural filters, preventing pollutants from dumping directly into waterways.

Creating Fake Lakes

Areas flooded with river water suddenly become lakes. These lakes bury farmland underwater and change the types and number of animals in the area. Now many communities around these artificial lakes rely on the water for their livelihood as they cater to boaters, anglers (fishermen and women), and other water recreationists.

Why Modify?

All these changes were made to make navigation faster and less dangerous. Commercial navigation is a multi-billion dollar business, providing national and international distribution of goods and services. Does it make sense to reverse the changes that were made? Is it even possible to reverse? Can water quality and navigation co-exist?

Boats & Bargess

The commercial activity on working rivers can also pose a threat to water quality.

  • The cargo hauled by boats and barges ranges from rubber tires to toxic chemicals. Accidents can spill dangerous chemicals or petroleum products into water, seriously impairing water quality.
  • The volume of traffic on a working river can also threaten its water quality. The more boats and barges moving up and down, the greater the risk of a spill or accident. There’s also more potential from pollution and dirt the vessels carry with them.
  • The increased traffic also increases the rate of erosion, contributing sediment to the waterways.

 

 


Explore More: Water Quality
Copyright 2004, Iowa Public Television
The Explore More project is supported by funds from the
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and the USDE Star Schools Program.