The Hydrologic water Cycle The key terms to

The Hydrologic (water) Cycle

The key terms to know here are: • • Groundwater. Runoff. Porosity. Permeability. Infiltration. Saturation. Retention-

Groundwater or Runoff? • Water can infiltrate (enter the ground) if there is space for it. • If there is no space—or if it cannot infiltrate—water will runoff on the surface. • The amount of space is Porosity. • Porosity is the % of a rock's total volume that is open space

Porosity is NOT affected by grain size. = Less pores, but bigger More pores, but smaller

Porosity IS affected by… • Packing of Grains • Shape of Grains • Mixed Sizes of Grains

The amount of runoff is determined by • the saturation of the ground (is the land already full of water). • the permeability of the ground (even if there is space in the ground— porosity—can water infiltrate to these spaces? ) • The rate of infiltration (how fast can water enter the ground? )

• Some soil is already saturated. Small amounts of new rain or melting snow can cause floods. • Desert soil is impermeable. Small amounts of rainwater will run-off, causing flash floods.

Permeability depends upon… • The size of the sediments Which One can water enter faster? • The shape of the sediments Which One can water enter faster?

Retention of Water… • Water not only infiltrates the soil at different rates, it also drains from the soil at different rates. • Smaller sediments retain water better than bigger sediments.

Into which beaker will water infiltrate at the greatest rate? Which beaker will water require the most time to leave?

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.

Which data table best represents the porosity and infiltration time of the beads in the three containers?