Do Now: What is the difference between weather and climate? On Earth why do you think we care about water so much?

Chapter 8 Water :pages 160-165

The Water Cycle why is ground water so important? video Water cycle (hydrologic cycle) – model used to illustrate movement / phase changes of water Driven by solar energy (insolation) Most water on Earth in Oceans Less than 1% of water on Earth is drinkable 97.2% in Salt Water (Oceans) 2.2% Icecaps and Glaciers

Rain and then what? Things that happen to precipitation: Water retention – stored on land as ice or snow, held on leaves Infiltration (seep) – water sinks into the ground Runoff – flow over surface ofland Evapotranspiration – evaporation and transpiration (into atmosphere)

Factors Affecting Infiltration Infiltration: When water seeps into the ground and becomes subsurface water or groundwater Infiltration occurs in the regolith - all loose material at the Earth’s surface 1. Slope steeper slope (gradient) = less infiltration INFILTRATION GRADIENT

2. Porosity- The amount of open space in between sediments The greater the porosity the greater the infiltration INFILTRATION POROSITY

Porosity is determined by: a. Shape - Well rounded particles have greater porosity than angular. ROUND ANGULAR POROSITY ROUNDNESS

b. PACKING- The more closely packed the particles the lower the porosity. UNPACKED PACKED

- If all particles are the same size they are sorted. c. SORTING- - If all particles are the same size they are sorted. - If the particles are different sizes/mixed they are unsorted (poorly sorted) - The more sorted the higher the porosity POROSITY SORTING

Particle Size alone does NOT affect porosity Particle Size alone does NOT affect porosity!!!!! (Shaping, Packing, Sorting does)

Back to factors affecting infiltration…

The more saturated the regolith, the less the infiltration 3. Degree of saturation- how much water seeps into those open pores of the sediment determines how much it can absorb The more saturated the regolith, the less the infiltration INFILTRATION SATURATION

The more permeable the regolith, the greater the infiltration 4. Permeability- The ability of a material to allow fluids to pass through it Impermeable = means water cannot pass through (Ex: clay layers in ground) The more permeable the regolith, the greater the infiltration INFILTRATION PERMEABILITY

Porosity is not the same as permeability!

Capillarity Capillarity increases with a decrease in particle size. Capillarity- Water sticks to the materials that it is passing through. Capillarity increases with a decrease in particle size. *Fine sand has greater capillarity than coarse sand CAPILLARITY PARTICLE SIZE

5. Capillarity- Water sticks to the materials that it is passing through The greater the capillarity, the less the infiltration INFILTRATION CAPILLARITY

Follow up Work: Porosity/Permeability Relationships Packet Time for an activity! Follow up Work: Porosity/Permeability Relationships Packet

Plants slow precipitation down, giving the water more 6. Vegetation- Plants slow precipitation down, giving the water more time to infiltrate into the ground No vegetation = high runoff INFILTRATION VEGETATION

Roads and buildings are impermeable, reducing infiltration 7. Construction – Roads and buildings are impermeable, reducing infiltration INFILTRATION CONSTRUCTION

Factors Affecting Runoff and Stream Discharge 1. Rate of precipitation greater than infiltration or permeability

Runoff and Stream Factors (cont) The pore space of material / rock saturated with water The slope of surface too great Water has not evaporated or sublimated into a gas Stream Discharge = volume of water flowing past a point Greater runoff = greater stream discharge

California Mudslides Identify all factors in the following video to explain why N. California experienced such torrential mudslides

Las Vegas Flash Flood Identify 3 reasons why Las Vegas was prone to flash flooding during this time

Ground Water Zone of Aeration- The pores between particles are mostly filled with air Zone of Saturation- The pores between particles are completely filled with water (Ground Water) Water Table - Where the zone of aeration and zone of saturation meet

More Realistic View

FINE SAND Moderate drainage PERMEABILITY GRAVEL  Rapid drainage  FINE SAND Moderate drainage  CLAY Slow drainage

Porosity and Permeability of Soils Lab

Other Activities Complete Porosity/Permeability/Capillarity worksheet