1. The Water Planet and Hydrology Movement of Water Underground USGS

2. The Water Planet Why is Earth unique?

3. Water Planet There is an enormous amount of water on Earth – most of it is in the oceans. There is an enormous amount of water on Earth – most of it is in the oceans. The remainder is distributed among ice sheets and glaciers, groundwater, lakes, streams, and the atmosphere. The remainder is distributed among ice sheets and glaciers, groundwater, lakes, streams, and the atmosphere.

4. Water Planet There are constant exchanges of water among the oceans, the atmosphere, and the continents. There are constant exchanges of water among the oceans, the atmosphere, and the continents. This unending circulation of Earth ’ s water is called the – This unending circulation of Earth ’ s water is called the – Hydrologic Cycle Hydrologic Cycle

5. The Hydrologic Cycle Water enters the atmosphere by evaporation. Water enters the atmosphere by evaporation. Precipitation returns liquid water to the surface. Precipitation returns liquid water to the surface. A portion soaks into the ground – infiltrates. A portion soaks into the ground – infiltrates. This is groundwater. This is groundwater.

6. Runoff Water that does not soak in will flow across surface as runoff. Water that does not soak in will flow across surface as runoff. Most reenters the atmosphere due to evaporation. Most reenters the atmosphere due to evaporation. Some by transpiration Some by transpiration Winter thaw run off

7. Groundwater Any water that is below the surface Any water that is below the surface May be in soils or porous rocks May be in soils or porous rocks Can be tapped for wells or supply artesian springs Can be tapped for wells or supply artesian springs Click on image to view a groundwater animation http://earthguide.ucsd.edu/earthguide/diagrams/groundwater/index.html

8. Ground water Zones Color in accordingly Color in accordingly

9. Zone of aeration: Zone of aeration: Zone where most of the interconnected pores are filled with air. Zone where most of the interconnected pores are filled with air. Water table: Water table: The surface below which, the ground is saturated with water The surface below which, the ground is saturated with water Zone of saturation: Zone of saturation: Layer of soil where pores are filled with groundwater (below the water table) Layer of soil where pores are filled with groundwater (below the water table) Impermeable Rock: Impermeable Rock: The layer where water cannot penetrate The layer where water cannot penetrate Factors that determine whether water infiltrates: 1. Slope of the land 2. Porosity of surface/ground 3. Permeable or not 4. Gravitational pull

10. Physical Properties of Sediments and Water Flow – Pore Space Unoccupied or void space between sediment particles Unoccupied or void space between sediment particles Can be filled with air or water Can be filled with air or water Measured by packing solid in a container to measure the total volume; water is added just to the surface filling the empty space Measured by packing solid in a container to measure the total volume; water is added just to the surface filling the empty space added water = pore space

11. Porosity (ability to hold groundwater) = Percentage of Pore Space (ability to hold groundwater) = Percentage of Pore Space Depends on: - Shape – round is more porous than angular - Packing – loosely packed is more porous than tightly packed - Mixture – sorted is more porous than unsorted

12. Physical Properties of Sediments and Water Flow – Pore Space If particles are round and the same size they will pack a certain way leaving a regular pore space. If particles are round and the same size they will pack a certain way leaving a regular pore space. If this is the case, the pore space does not depend on the particle size. The larger the particles, the larger but fewer the spaces. For smaller particles, there are more but smaller spaces. If this is the case, the pore space does not depend on the particle size. The larger the particles, the larger but fewer the spaces. For smaller particles, there are more but smaller spaces.

13. 256 cm Boulder 64 cmCobble 2 mm Pebble Gravel 0.0062 mmSand 0.0039 mmSilt Mud Clay Clay Sediment Size Classifications

14. Physical Properties of Sediments and Water Flow – Pore Space More but smaller spaces Larger but fewer spaces Mixed – less empty space http://techalive.mtu.edu/meec/module06/Packing.htm

15. Physical Properties of Sediments and Water Flow – Pore Space Larger but fewer spaces Mixed – less empty space Most sediments are not regular in shape and pack more tightly. This reduces the pore space even more and reduces the connectivity of the space.

16. Physical Properties of Sediments and Water Flow- Permeability To determine permeability you can measure : To determine permeability you can measure : flow time:time for a set amount of water to flow through the sediment (minutes/100 mL) or flow rate: volume of water that flows through a given amount of sediment in a set amount of time (mL/minute)

17. Physical Properties of Sediments and Water Flow- Permeability Measurement Measurement Value Flow Time (min/100 mL) Flow Rate (mL/min) High Low P High P Medium Medium P Low High P Low P P = relative permeability

18. Physical Properties of Sediments and Water Flow- Permeability Measure of the flow of water through ground material Measure of the flow of water through ground material Depends on the size of sediment particles because it is controlled by the connectivity of pore space and surface area Depends on the size of sediment particles because it is controlled by the connectivity of pore space and surface area Comparison animation-play http://techalive.mtu.edu/meec/module06/Permeability.htm

19. Runoff Rainfall exceeds permeability rate of the soil Rainfall exceeds permeability rate of the soil Occurs when: - slope is too steep, - temperature is below 0°C - soil is saturated

20. Physical Properties of Sediments and Water Flow – Water Retention Amount of water that is retained as water flows through sediments Amount of water that is retained as water flows through sediments Water is retained on the surface so the greater the surface area, the higher the water retention Water is retained on the surface so the greater the surface area, the higher the water retention Which will have more retention for the same volume - gravel or sand? Which will have more retention for the same volume - gravel or sand?

21. Physical Properties of Sediments and Water Flow – Water Retention For the same volume, smaller particles will have more surface area, and therefore, greater water retention. Sand will have higher water retention.

22. Water Retention is due to Capillarity Ability of a substance to draw another substance into it – Ability of a substance to draw another substance into it – Movement of water within spaces due to properties of water: A: adhesion = stickiness B: cohesion = attaching itself to other water molecules large pore space => lower capillary action small pore space => higher capillary action

23. Groundwater Animation for Kids Try the animation about the importance of groundwater. It runs about 4 minutes and requires Macromedia Flash 5 (or newer version). http://www.kingcounty.gov/environment/waterandland/groundwater/education/animation.aspx Click on image to view a groundwater animation