1. 1 Hydrologic Cycle Pat Ellsworth, ITEP & Robert K. Hall USEPA Region IX hall.robertk@epa.gov

2. 2 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

3. 3 Once water reaches the ground Evaporates back into atmosphere Runs off into streams and lakes, eventually back to ocean Penetrates surface, becomes groundwater Groundwater will Seep into lakes, rivers, streams Return to atmosphere through transpiration Hydrologic Cycle (cont.)

4. 4 Earth’s Water Budget Diagram adapted from: Peixoto and Kettani (1973). http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/home.rxmlPeixoto and Kettani (97.5%) (2.4%) (0.001%)

5. 5 Evaporation 80% Evaporation 20% (inland water and vegetation) Adapted from The Hydrologic Cycle. Illustration by Tom Schultz Condensation Convection Transport (rain, hail, sleet, snow, freezing rain) Zone of Aeration Zone of Saturation Surface Layer Ground water flow Evaporation 10%

6. 6 Hyporheic Zone Region 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

7. 7 Hyporheic Zone (cont.) Adapted from National park Service (http://www.nps.gov/archive/sitk/Natural%20Resources/Stream%20Ecology/Stream/hyporheic.htm) Hyporheic Flow RHEIC ZONE

8. 8 Ecological Function Natural 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)

9. 9 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

10. 10 Illustration by Tom Schultz www.buffer.forestry.iastate.edu/Photogallery/...www.buffer.forestry.iastate.edu/Photogallery/...

11. 11 Riparian Function Functional Nonfunctional Functional at Risk

12. 12 Impacts: Watershed Morphology and Invasive Species Classification: Humboldt River, NV Area shown is part of the Special Recreation Management Area Near Elko, NV Source: BLM Nevada State Office and BAE Systems Advanced Technologies Inc.

13. 13 Conclusion Hydrologic Cycle Impacts to the Hydrologic Cycle Preservation Tribal-oriented Best Management Practices (BMPs) to achieve ecological function