Missouri

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Missouris Oxbow Lakes

• Georganne Bowman
• Water Protection Program
• DNR
• January 24, 2006

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Oxbow Lakes

• How do oxbows form?
• Missouris oxbows
• Whats the water like?
• What are they good for?
• How should we manage oxbows?

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How Do Oxbows Form?

• Large river flood plains.
• Snake-like meanders.
• Maintains gradient and velocity.

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How Do Oxbows Form?
1) The water on the inside of the loop, travels
slower than the water on the outside edge. This
leads to deposition of sediment in the corners.
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How Do Oxbows Form?
2) Meanwhile, water on the outside of the turn
flows faster, which erodes the banks making the
meander even wider. 3) The neck of the yoke
closes in.
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How Do Oxbows Form?
4) During a high flow event, the meander cuts off
from the main channel. A horseshoe shaped oxbow
lake forms.
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How Do Oxbows Form?

• The new lake is cut off from the river.
• Flooding brings in nutrients and fish.
• Sedimentation occurs with each flood event.
• Short life span.

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Missouris Oxbows

• Missouri and Mississippi floodplains.
• Smaller rivers.
• Approximately 24 classified

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What is the water like?

• Very Shallow.
• most oxbows are less than 3 meters deep.
• High nutrient loads.
• Can Be Very Productive.
• Unless light limited.
• Constantly Mixed.
• Wheres the watershed?

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What is the water like?
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What is the water like?
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What is the water like?

• Four oxbow lakes sampled monthly summers from
  1994-1996.
• Cooley, Sunshine, Teteseau, and Dalton.
• Surface area ranged from 17 323 ha.
• Mean depth at normal elevation for these oxbows
  was lt 1 meter.

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What are they good for?
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What are they good for?

• Big Lake State Park
• Big Lake is the largest remaining oxbow lake in
  Missouri.
• The shallow lake has a long history as a
  recreational area (prior to 1932).
• Created one of the first public recreation areas
  in northwest Missouri.

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How Do We Manage Oxbows?

• Current river management
• Channelization keeps meanders from forming.
• Levees prevent floods from refilling.
• Runoff leads to eutrophication.
• No new oxbows formed.

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How Do We Manage Oxbows?

• Lake Dredging
• As a part of the Page Avenue Extension, MoDOT
  will dredge the main body of the lake. The
  dredging will restore the lake to a minimum depth
  of 10 feet. -Creve Coeur (10,000,000)
• Pumping
• The state will spend up to 2,000 per year to
  ease the costs of pumping at some oxbow
  lakes. - St Joseph News Press
• Water level control for waterfowl hunting.

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How Do We Manage Oxbows?
Oxbow lakes united State officials should
work St. Joseph News-Press (11/20/05) Oxbow
lakes pose a very tricky conundrum for the state
of Missouri and the people who live on the shores
of those lakes. The lakes belong technically to
the state. But when it comes to keeping the lakes
from drying up, the burden lands mainly on local
landowners.
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How Do We Manage Oxbows?

• Blessing and Curse
• High wildlife and recreation value.
• Limited resource.
• Long history.
• BUT
• Will never be high quality H2O.
• Must be maintained - very costly.
• Probably not used for swimming.

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How Do We Manage Oxbows?

• Setting Nutrient Criteria Values.
• Maintain hypereutrophic values?
• Allow these lakes to function as wetlands?
• Other ideas/comments?

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