Why Developing?

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Why Developing?

• Restore aquifer, following damage due to drilling
• Reduce head loss by increasing permeability
• Increase well efficiency
• Reduce drawdown and cost of extracting
  groundwater
• Restore/Rehabilitate well due to gradual clogging
  and biofouling.

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How to reduce head loss?
Head loss in aquifer
Head loss near screen
Head loss through screen
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Why is it important?

• Most sensitive area, where flow converges and is
  the fastest
• Where we still have means to modify the aquifer

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Ultimate Goals

• Make the pores as big as possible so water is
  free to flow. Results
• more flow
• lower costs of operation (reduced drawdown less
  energy to lift the water reduced hydro bill)

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Other goals

• Removes fines
• Water quality
• Minimize abrasion on equipment (extend life of
  pumping and piping equipment)
• Creates zone of Autofiltration

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Development Methods

• Overpumping
• Surging
• Air Lift
• Jetting
• Explosive (rock aquifer)

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Overpumping
Drawdown during operation
Increased gradient
Drawdown during development
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Surging
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Air lift
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Jetting
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Overpumping Pros
Cons

• Simple
• No special equiment

• No reverse flow
• No agitation of soil particles
• Low energy impact
• Low efficiency
• Requires removal of fines

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Autofiltration
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Surging Pros
Cons

• Simple technology
• Low Cost

• Flow bypass
• Low level of impact
• Relatively Low efficiency
• Requires removal of fines

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Air Lift Pros
Cons

• Efficient Method
• Combine removal of fines
• Easy to adjust/control energy level

• Requires sophisticated Equipment (e.g.
  compressor)
• Requires good understanding of aquifer conditions
• Does not target specific screened zones

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Jetting Pros
Cons

• Most Efficient Method
• Easy to adjust/control energy level
• Easy to target specific screened zone
• Enhance movement of particles deep into the
  aquifer.
• Screens designed for jetting (V-wire)

• Requires sophisticated Equipment (e.g.
  compressor)
• Requires good understanding of aquifer conditions
• Requires removal of fines

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Wrap Up

• Development is very important
• Immmediately following well completion
• As part of the maintenance of the well
• Development is very complex and need to be
  designed properly to be efficient