S

Storage and Movement of Groundwater

Unit 9

What determines how water flows through soil?

Porosity: percent of pore space available or the amount of pore space compared with the volume of material

Porosity is affected by shape of particles, packing of particles and mixing of particles

Shape of particles

Flat particles will have a lower porosity than round particles

Ex: clay particles have a very low porosity because they are flat and angular and fit together leaving very little pore space

Packing

Well packed particles or soil will have a lower porosity than loosely packed soil

Sorted particles

Equal samples of sorted particles will have the same porosity

Mixing

Mixed particles will have a lower porosity than sorted particles

Permeability

This is the ability of a soil to transmit water or the rate of flow of water through the soil

Water will flow faster if: The pores are connected The pores are large (large size partilcles)

Runoff

Water will runoff if it cannot infiltrate-if the rate of permeability is lower than the rate of precipitation (rainfall exceeds the rate of permeability)

Water will runoff going down a steep slope

Capillary Water

This is the water moving up ward from the ground Water will move up faster the smaller the pore

space

Water for Stream Flow

During times when rainfall is low, water for streams comes from the groundwater ---the water table

Watershed

This is the geographic area around stream

It is important to know your watershed because usually our drinking water comes from this area

We need to protect and preserve our watersheds