Aim: How can we explain the factors affecting infiltration?

Infiltration When water enters the ground When water cannot infiltrate, it becomes RUNOFF

Factors that affect infiltration

Slope of the Land The steeper the slope, the less infiltration

Degree of Saturation The more saturated the loose materials at Earth’s surface, the less the infiltration

Amount of Vegetation The more plants present, the more the infiltration

Porosity The percentage of open space (pores and cracks) in a material compared to its total volume The greater the porosity, the greater the infiltration Porosity depends on shape, packing, and sorting

Round particles have greater porosity than angular particles Shape Round particles have greater porosity than angular particles

Which one is more porous?

How does porosity change as the particle change from round to oval to flat?

The more closely packed the particles, the lower the porosity Packing The more closely packed the particles, the lower the porosity BUT! Porosity is independent of particle size if they are packed the same (each size had the same amount of water)

Which one is more porous?

Which one is more porous?

Sorting Unsorted particles have a lower porosity than sorted particles

Which one is more porous?

Which would be most porous? Which would be less? THINK PAIR SHARE

Permeability The ability of a material to allow fluids such as water to pass through Permeability rate is the speed at which fluids pass through

Particle size and permeability Permeability increases with particle size (the water ran through the largest particles the fastest)

TTYP Compare the porosity and permeability of the two samples

Capillarity The attractive force between water molecules and the surrounding Earth materials Causes water to move upwards – decreases the rate of infiltration The smaller the pores are, the greater the capillary action

Soil Storage Saturation INFILTRATION Infiltration refers to water soaking into the ground: Permeability Infiltration rate Porosity Infiltration rate Infiltration rate Slope Infiltration rate Soil Storage Saturation