Post on 05-Jan-2016
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Hydrologic Cycle
Pat Ellsworth, ITEP
&
Robert K. HallUSEPA Region IX
hall.robertk@epa.gov
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Hydrologic Cycle “Hydrologic cycle”—circulation and conservation of
earth's water
Begins with evaporation of water from earth (20%) and ocean (80%) surface
As moist air rises, it cools, and water vapor condenses to form clouds
Moisture is transported around globe via oceanic gyres (N and S hemispheres) until it returns to surface as precipitation
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Once water reaches the groundEvaporates back into atmosphereRuns off into streams and lakes,
eventually back to oceanPenetrates surface, becomes groundwater
Groundwater willSeep into lakes, rivers, streamsReturn to atmosphere through
transpiration
Hydrologic Cycle (cont.)
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Earth’s Water Budget
Diagram adapted from: Peixoto and Kettani (1973). http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/home.rxml
(97.5%)
(2.4%)
(0.001%)
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Evaporation 80%
Eva
pora
tion
20%
(inla
nd w
ater
and
veg
etat
ion)
Adapted from The Hydrologic Cycle. Illustration by Tom Schultz
Condensation
Condensation
Convection
Transport
(rain, hail, sleet, snow, freezing rain)
Zone of AerationZone of Saturation
Surface Layer
Ground water flow
Eva
pora
tion
10%
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Hyporheic ZoneRegion beneath and lateral/adjacent to stream
bed
Mixing of shallow groundwater and surface water
Hyporheic flow is important for Surface water/groundwater interactions Fish spawning Benthic macroinvertebrate distribution and community
structure
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Hyporheic Zone (cont.)
Adapted from National park Service (http://www.nps.gov/archive/sitk/Natural%20Resources/Stream%20Ecology/Stream/hyporheic.htm)
HyporheicFlow
RHEIC Z
ONE
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Ecological FunctionNatural riparian-wetland areas characterized by
interactions of vegetation, soils, hydrology
Riparian-wetland areas function properly with adequate vegetation, landform, or large woody debris Dissipates stream energy associated with high waterflows
Reduces erosion, improves water quality….
Changes in ecological function result from alterations (e.g., fire, invasive species, anthropogenic activity)
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Ecological Function (cont.)
Human influences accelerate changes in ecosystem character
Over time, ecosystems develop spatial patterns characteristic of human disturbance and alterations
Necessary to recognize Different geographic patterns and How they respond to alterations and
resource-management activities
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Illustration by Tom Schultz www.buffer.forestry.iastate.edu/Photogallery/...
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Riparian Function
Functional Nonfunctional
Functional at Risk
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Impacts: Watershed Morphology and Invasive Species Classification:
Humboldt River, NV
Area shown is part of the Special Recreation Management Area Near Elko, NVSource: BLM Nevada State Office and BAE Systems Advanced Technologies Inc.
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ConclusionHydrologic Cycle
Impacts to the Hydrologic Cycle
PreservationTribal-oriented Best Management Practices
(BMPs) to achieve ecological function