Freshwater and Society

1. Freshwater and Society Module 1, part B

2. http://www.epa.gov/owow/watershed/whatis.html Watersheds

3. Hydrological cycle of a watershed

4. Watershed definition • Watershed: • An area of land that drains water, sediment and dissolved materials to a common receiving body or outlet • The term is not restricted to surface water runoff and includes interactions with subsurface water • Watersheds vary from the largest river basins to just acres or less in size

5. http://www.epa.gov/watertrain/execmgmt/lyout2.htm Organization of watersheds: • A divide represents the boundary of a watershed • Larger watersheds can often be divided into smaller units called subbasins, drainage areas, or water resource inventory areas

6. Watersheds

7. http://vathena.arc.nasa.gov/curric/weather/storm.html Watershed components • Latitude, albedo & climate • Geology • Topography • Land Use: • Vegetation and impervious surfaces

8. Energy input into a watershed depends on solar height and length of daylight hours Determined by the latitude and season May 21, Seattle, WA solar altitude at noon is 62.500 January 21, Seattle solar altitude at noon is 22.500 Watershed components: Latitude

9. Watershed components: Albedo

10. Watershed components: Climate http://www.eia.doe.gov/emeu/recs/origin/climzone.gif • Temperature regime • Relative humidity • Precipitation patterns http://www.epa.gov/ceisweb1/ceishome/atlas/nationalatlas/climatezones.htm

11. http://www.hanford.gov/docs/annualrp00/sumoverview.stm http://www.habitat.fws.gov/images/river.jpg Watershed components: Climate • Precipitation • Temperature • Relative humidity (RH) • Wind

12. Watersheds: Average annual precipitation

13. Watersheds: Potential evapotranspiration

14. Watersheds: Water surplus or deficit

15. http://www.soils.umn.edu/academics/classes/soil2125/doc/s2chap5.htmhttp://www.soils.umn.edu/academics/classes/soil2125/doc/s2chap5.htm http://geohazards.cr.usgs.gov/wa/lsphotos1/photos4.html Watershed components: Geology • Bedrock • Type and distribution of soils

16. http://soils.usda.gov/gallery/state_soils/ http://soils.usda.gov/gallery/state_soils/ http://www.nre.vic.gov.au/web/root/Domino/vro/vroimages.nsf/Images/gloss-ferr/ Geology: Soil permeability • The ease with which water penetrate or pass through a bulk mass of soil or a layer of soil

17. Geology: soil pore space and water content • Total porosity of a soil determines maximum water content at saturation; soils within zone of aeration are seldom saturated. • Textural (primary) porosity: voids between aggregates. • Structural (secondary) porosity: voids within aggregates – fracture or poor zones http://wrgis.wr.usgs.gov/open-file/of99-168/Pp-limestone.jpg

18. Geology: Groundwater vs. soil moisture • Groundwater: • Subsurface water in the zone of saturation that is free to move under the influence of gravity, often horizontally to stream channels • Soil Moisture: • Subsurface water in the unsaturated zone held in place by capillary forces or osmotic pressure

19. Geology: moisture content of various soils

20. Geology: Infiltration • Infiltration is the flow of water downward through the upper layers of soil

21. Geology: infiltration capacity during a storm

22. Before Storm • End of Storm • One day after • Two days after • Three days after Adopted from: http://www.nre.vic.gov.au/web/root/Domino/vro/vroimages.nsf/Images/gloss-ferr/ Geology: soil moisture profile after a rain event

23. Geology: seasonal infiltration trends

24. Geology: seasonal variation in watershed runoff

25. Geology: Saturation and runoff generation

26. http://volcanoes.usgs.gov/Hazards/What/PF/PFUnzen.html http://www.pes.poquoson.k12.va.us/images/marsh.jpg http://www.cce.cornell.edu/onondaga/watersheds/images/fallcolor2.jpg Watershed components: Topography • Topography • Slope • Aspect

27. http://www.nrmsc.usgs.gov/research/glacier_model.htm Watershed components: Topographic interactions

28. http://www.nature.nps.gov/pubs/I&M1998/Peer-01.htm http://www.cce.cornell.edu/onondaga/watersheds/images/fallcolor2.jpg Watershed components: Land use and vegetation • Vegetation • Slows runoff • Reduces soil compaction • Prevents soil erosion • Reduces pace of raindrop splash • Reduce soil material moving downslope • Influences timing of snowmelt runoff • Influences water yield

29. Land use: Stormwater discharge vs. land use

30. Natural Events Fires Wind storms Disease outbreaks Floods Volcanoes Climate change Land Uses Flood control Timber production Urban development Hydroelectric Agriculture Mining Watershedhydrology Water quality Land uses: Effects upon hydrology/water quality

31. Watershed components: land Use

32. Organization of a watershed

33. Potlatch, Idaho Spearfish, South Dakota Watershed: Water budgets • Water budget • Evaluation of sources of supply vs. discharges with respect to a drainage basin

34. Watershed: Water budgets • Annual water budget for Lawrence Lake, Michigan, and Mirror Lake, New Hampshire

35. Water budgets provide a graphic depiction of the distribution of moisture throughout the year in any given area An idealized budget, however, is rarely achieved Examples from Los Angles, CA and Pullman, WA, illustrate the range of potential deviation from the “ideal” water budget Fig. 8.4 Watershed: Water budgets

36. Watershed water budget: Pacific Northwest

37. Watershed: Aquatic ecoregions • North America has been divided into eight major aquatic ecoregions: • Arctic rivers and lakes • Large temperate lakes • Temperate headwaters and lakes • Large temperate rivers • Endorheic rivers, lakes, and springs • Xeric-region rivers, lakes, and springs • Temperate coastal rivers and lakes • Subtropical coastal rivers and lakes

38. Aquatic Ecoregions of North America

39. Climate Geomorphology Vegetation Land uses Albedo Watershed hydrology Watershed components