Human Alterations of the Hydrologic Cycle

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Human Alterations of the Hydrologic Cycle

• Chris Welcker, PhD Candidate
• University of Idaho--Boise
• Center for Ecohydraulics Research

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Hydrologic Cycle
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Why do we care?
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Land Use Urbanization
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Green river
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Land Use Urbanization
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Land Use Urbanization
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Land Use Agriculture
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Land Use Agriculture

• More efficient drainage
• Extended stream network
• Tiling or underground drains
• Less groundwater recharge
• More or less evapotranspiration

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Land Use Agriculture
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Land Use Agriculture
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Land Use Logging
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Land Use Logging
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Logging Storm hydrograph
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Logging Annual hydropgraph
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Land Use Forest Fire
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Land Use Forest Fire

• Soil changes hydrophobicity, surface sealing
• Dead vegetation
• Altered local weather patterns

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Land Use Forest Fire
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(No Transcript)
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Groundwater Pumping
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Ogallala Aquifer

• Fossil aquifer
• 225,000 mi3 of water
• Started pumping in 1900
• Dropping 2-3 feet per year

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ID Water

• "We are seeking - we always have been and we
  always will - the ways and means of developing
  every drop of water that tumbles from the snow
  packs of the Snake River watershed. And when we
  have used that water, whether to help grow a
  potato or turn a turbine, or both, then, and only
  then, will we willingly send it flowing into the
  canyons below Weiser
• --Former ID Governor Robert Smylie 1955

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ID Water Use

• We use 8.1 trillion gallons of water each year
• This is second only to California
• 97 of this is used for agriculture
• Source (High Country News February 20, 1995 (Vol.
  27, No. 3)

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ID Water Law

• 1963 Groundwater irrigators first required to get
  permits
• 1986 IDWR allowed to enforce this law
• 1994 groundwater irrigators to measure their
  consumpton for the 1st time
• Source (High Country News February 20, 1995 (Vol.
  27, No. 3)

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Hagerman, ID
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Irrigation Diversion
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Irrigation Diversion
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Dams
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Dams
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DAMS vs dams
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Dams Size Matters

• Reservoir size
• Flow volumes
• Can it hold 1 storms flow?
• Can it hold 1 years flow?

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Dams
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Dams on the Boise River
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Boise River
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Boise River

• Average flow at Glenwood 1,285 cfs
• Annual flow volume 40,527,005,847 ft3
• Storage 1,079,800 acre feet
• Storage 47,035,720,868 ft3

What does this mean?
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Turning on/off the spigot

• What should the peak flow be?
• When should it occur?
• Should things be different each year?
• How high is baseflow?
• What variability is needed in baseflow?
• How much flooding is acceptable?

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When, Where, How Much?
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Boise River 1938-40 and 2000-2003at Glenwood
Street Bridge
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Boise River
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Channel Alterations

• Straightening channels and diking changes the
  shape of hydrograph
• For better or worse?

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Channel Alteration
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Climate Change
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Climate Change

• Spatial Complexity
• Complicated Interactions

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(No Transcript)
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Spatial Complexity of Climate Change
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Gulf Stream Sea Surface Temp
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Gulf Stream
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Gulf Stream
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Questions
Questions