Presentation on theme: "As ground saturates the water table rises. If you dig a well below the water table you can access the water!"— Presentation transcript:
As ground saturates the water table rises. If you dig a well below the water table you can access the water!
If water table rises or falls, surface water also changes.
Base your answers to questions below on the diagram, which shows a model of the water cycle. Letters A through F represent some processes of the water cycle. Letter X indicates the top of the underground zone that is saturated with water.
Different ground has different porosity.
If water cannot infiltrate it will runoff on the surface.
Less pores, but bigger = More pores, but smaller
Packing of Grains Shape of Grains Mixed Sizes of Grains More porous Less porous Flatter sediments are less porous
Which beaker has the largest sized pores? Which beaker can HOLD the most water? THEY HAVE EQUAL POROSITY! (more small pores = less big pores)
The diagrams below represent three containers, A, B, and C, which were filled with equal volumes of uniformly sorted plastic beads. Water was poured into each container to determine porosity and infiltration time.
1.The mixture of sand clay and pebbles holds the most water. 2.The cup of sand holds more water than the cup of silt. 3.All cups hold the same amount of water. 4.The cups of pebbles and silt hold the same volume of water.
Assuming equal amounts of precipitation and saturation, which soil could rain infiltrate the most readily? Greater Porosity = Faster Infiltration
Desert soil is often impermeable. Even small amounts of rain will run-off, causing flash floods. Only a few seconds have passed!
As a rule, the slower water infiltrates, the slower it drains. Easy in easy out!
Capillarity Water is so sticky it can “climb” soil particles, moving up against gravity. Larger particles have less capillarity. Smaller particles have more capillarity.
The diagram represents four identical columns filled with sediments of uniform shape and packing. They are placed over empty glass beakers.
The diagram shows a laboratory setup. The rubber band holds filter paper across the base of the open tube to hold the soil sample. The tube was placed in the water as shown. The upward movement of water is represented by arrows. Results with different size particles lead to the conclusion that (1)capillarity is greater in soils with larger particles (2) capillarity is greater in soils with smaller particles (3) permeability is greater in soils with larger particles (4) permeability is greater in soils with smaller particles