The Purpose, Design and Benefits of Two Stage and Over Wide Ditches

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The Purpose, Design and Benefits of Two Stage and
Over Wide Ditches
Jessica DAmbrosio and Jon Witter Ohio State
University
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Dan Mecklenburg ODNR
Andy Ward, Erick Powell Ohio State University
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Ohio Headwater Streams

• Facilitate Agricultural Drainage
• Low Gradient
• Deepened and Straightened
• Routinely Maintained

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Quick Facts

• 60,000 miles of streams in Ohio
• 22,500 miles considered drainage ditches
• 4,000 miles under some form of maintenance
  (Sanders, 2000)

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A Recently Maintained Channel
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A Two Stage Channel
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A Constructed Two Stage Channel
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Maintenance Often RemovesFluvial Benches That
Will Rebuild Again
Material Commonly removed during cleanout
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Features due to Bank Failure are not Fluvial
Benches
Bank Failure
Banks that have slumped
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Bank Failure in an Illinois Ditch
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Streams and ditches

• Striking similarities between streams and ditches
• Fluvial Geomorphology
• Fluvial produced by action of a river or stream
• Geomorphology earth change knowledge
• Streams and ditches are predictable

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Rapid Survey
Use A Tape And Rod
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A Rapid Regional Curve Assessment Method
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ODNR Ditch Design Spreadsheet
CUT 2110 square feet
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Bench Characteristics
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Does implementing the two-stage channel concept
in agricultural headwater streams result in water
quality benefits?
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(No Transcript)
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Nitrate Load Percent Reduction
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Total Phosphorus Load Percent Reduction
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Suspended Solids Load Percent Reduction
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Channel Cross Section Measurements
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Thorn Run RM 5.2
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Thorn Run RM 5.2
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Summary

• Two-stage channels, based on geomorphic
  principles, are an alternative channel design to
  traditional trapezoidal channels
• Two-stage channels could be a best management
  practice for agricultural drainage channels
• Of the sampled sites, the two-stage channels had
  better water quality performance than the
  trapezoidal channel
• Two-stage ditch construction has demonstrated
  benefits both for drainage and in-stream habitat.
  In addition to improved substrate habitat, cover
  improves and summer temperatures decrease.

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Tradeoffs

• Potential Disadvantages
• Loss of farmable land
• Increased initial costs
• Potential Benefits
• Improved water quality, ecological function
• Potential long-term reduction of maintenance
  costs
• Improved drainage capacity