1. Water 1: Processes

2. Water: Celebrated Throughout History "When the well is dry, you know the value of water.” - Benjamin Franklin Water, water, everywhere, And all the boards did shrink. Water, water everywhere, Nor any drop to drink. -Samuel Taylor Coleridge (1772-1834), "The Rime of the Ancient Mariner" 1798 "Whiskey is for drinking; water is for fighting over." - Attributed to Mark Twain

3. Water Cycle –Abundance is not a problem –Distribution and time of occurrence are the problems; needs to be in the right place at the right time –As water moves from one reservoir to another, it carries sediment, chemicals, waste, nutrients, etc. –1 is balanced by 2 & 3 –3 is balanced by 6 –3 & 4 are balanced by 5 –60% of terrestrial precip evaporates (4), whereas 40% returns to ocean (6)

4. World’s Water Supply LocationPercentResidence Time Oceans97.210 3 years Ice caps and glaciers2.1510 5 + years Shallow groundwater 0.3110 2 -10 3 years Lakes0.00910 years Atmosphere0.0019 days Streams0.00012 weeks Source: U.S.G.S.

5. Water: Unique Liquid (H-O-H) General Properties –Covalently bonded – electron sharing –Dipolar – charge distribution leads to … –Cohesion vs. adhesion (hydration of clay particles) –Triple point on phase diagram (s-l-v) – transfers easily between water cycle reservoirs on Earth –Specific heat – great capacity to store and absorb heat –Only common substance with a solid form lighter than its liquid form – why ice floats

6. Surface Runoff and Sediment Yield Effect of underlying geology (rock type) on surface run-off within a watershed or drainage basin Large drainage basins are divided into smaller basins Rain falling on either side of a divide may end up in very different places

7. Drainage Basins of the World

8. Factors Affecting Runoff –Geologic factors (drainage density) –Physiographic factors Basin shape Relief and slope Orientation of stream basin –Climatic factors Timing and magnitude of precipitation –Biologic factors Vegetation – interception/transpiration efficiency Animals – burrowing/grazing Soil organisms – opening of macropores to enhance infiltration capacity of landscape

9. Surface Runoff Runoff Paths –Throughflow – shallow subsurface flow above water table –Overland flow – when precip. Intensity exceeds infiltration capacity –Groundwater flow – movement through the saturated zone

10. Sediment Yield RiverSediment Load (t/km 2 ) Amazon63 Mississippi97 Nile37 Missouri159 Yangtze257 Colorado212 Lo7,300