Freshwater and Society Module 1, part B

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s2 Watersheds

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s3 Hydrological cycle of a watershed

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s4 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

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s5 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 xecmgmt/lyout2.htm

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s6 Watersheds

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s7 Watershed components  Latitude, albedo & climate  Geology  Topography  Land Use:  Vegetation and impervious surfaces

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s8 Watershed components: Latitude  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  January 21, Seattle solar altitude at noon is

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s9 Watershed components: Albedo Albedo is the reflectance of a surface. The higher the reflectance the less energy input into a watershed. Surface CoverAlbedo (%) Water5-10 Bare soil (light colored, dry)20-35 Marsh and Bogs15-20 Forest (dense spruce)5-10 Forest (hardwoods in leaf)15-20 Snow (fresh)80-95 Snow (old)40-70

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s10  Temperature regime  Relative humidity  Precipitation patterns Watershed components: Climate

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s11 Watershed components: Climate  Precipitation  Temperature  Relative humidity (RH)  Wind

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s12 Watersheds: Average annual precipitation

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s13 Watersheds: Potential evapotranspiration

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s14 Watersheds: Water surplus or deficit

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s15  Bedrock  Type and distribution of soils Watershed components: Geology doc/s2chap5.htm

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s16  The ease with which water penetrate or pass through a bulk mass of soil or a layer of soil Geology: Soil permeability Domino/vro/vroimages.nsf/Images/g loss-ferr/

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s17  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 Geology: soil pore space and water content 168/Pp-limestone.jpg

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s18 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

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s19 Geology: moisture content of various soils

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s20  Infiltration is the flow of water downward through the upper layers of soil Geology: Infiltration

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s21 Geology: infiltration capacity during a storm

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s22 Geology: soil moisture profile after a rain event 1)Before Storm 2)End of Storm 3)One day after 4)Two days after 5)Three days after Adopted from: vro/vroimages.nsf/Ima ges/gloss-ferr/

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s23 Geology: seasonal infiltration trends

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s24 Geology: seasonal variation in watershed runoff

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s25 Geology: Saturation and runoff generation

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s26  Topography  Slope  Aspect Watershed components: Topography

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s27 Watershed components: Topographic interactions

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s28 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

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s29 Land use: Stormwater discharge vs. land use

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s30 Land uses: Effects upon hydrology/water quality  Natural Events  Fires  Wind storms  Disease outbreaks  Floods  Volcanoes  Climate change  Land Uses  Flood control  Timber production  Urban development  Hydroelectric  Agriculture  Mining Water quality Watershed hydrology

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s31 Watershed components: land Use

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s32 Organization of a watershed

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s33  Water budget  Evaluation of sources of supply vs. discharges with respect to a drainage basin Watershed: Water budgets Potlatch, Idaho Spearfish, South Dakota

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s34  Annual water budget for Lawrence Lake, Michigan, and Mirror Lake, New Hampshire Watershed: Water budgets

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s35 Watershed: Water budgets  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

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s36 Watershed water budget: Pacific Northwest

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s37 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

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s38 Aquatic Ecoregions of North America

Developed by: Munson, Richards, Svendsen Updated: Dec. 30, 2003 U1-m1b-s39 Geomorphology Climate Land uses Vegetation Watershed hydrology Albedo Watershed components