Soil and groundwater pulse check

Soil

Made of loose, weathered rock and organic material

Three sizes of sediment

Sand, silt, clay

Components of soil

45% mineral, 25% water, 25% air, 5% organic matter

Five factors of soil formation

1. Parent Material

2. Climate

3. Living Organisms

4. Topography

5. Time

Parent Material

The minerals and organic materials at soil formation. Materials from volcanoes, sediment transported are examples.

Climate

Can have a major influence on the rate of soil formation. Weathering processes like the cycles of freezing and thawing, along with wetting and drying vary with each region. Influences include weathering types, living things, and seasonal changes.

How does climate affect A horizon as latitude increases

The A horizon is thicker with increased latitude and temperate climate. Topsoil size increases as you move away from equator.

Living Organisms

As they die, organic matter incorporates with weathered parent material and becomes part of the soil. Actions of moles earth/roundworms, bacteria, and fungi mix and enrich the soil.

Topography

Slope and hilliness of a region can have influence on moisture and erosion of soils. Moist, poorly drained soils are located in low areas, and drier, well drained soils are often found in sloping hillsides.

Time

Takes hundreds of years to form one inch of soil from parent material. Only top few centimeters are able to sustain plant growth

Why is soil conservation important

It takes a long time for soil to form, only top few cm of soil can sustain plant growth

Steps of bedrock becoming soil

1. Bedrock begins to disintegrate

2. Organic materials facilitate disintegration

3. Horizons form

4. Bedrock soil supports thick vegetation

O horizon (organic layer)

It consists of leaf litter and other organic materials lying on the surface of the soil (humus)

A horizon (topsoil)

It is usually loose and crumbly with varying amounts of organic matter. Generally most productive layer of soil (cons. efforts focused)

B layer (subsoils)

Are usually lighter in color, dense and low in organic matter

C layer (transition/parent material)

Layer of transitistion is almost completely void of organic material and is made up of partially weathered parent material. Below C is bedrock (Layer R?)

Leaching

Compounds on the surface of minerals can be become dissolved. In addition, the water can dislodge and move particles. Leaching can transport chemical compounds like dissolved substances or larger materials such as decomposing plant materials, fine rock fragments, and microbes throughout the soil horizons. It is chemical interactions with surfaces and physical movement of water.

Porosity

How much space you have around sediment particles and is a factor of the particle size

Permeability

How easily water can soak through

Relationship with porosity, permeability and sediment size

In well sorted (same size) sediments, large and small sediments have the same porosity. However, well sorted small sediments have low permeability, whereas well sorted large sediments have high permeability.

Watershed

An area or ridge of land that separates waters flowing to different rivers, basins, seas

Water filtered and stored into the ground (aquifers) becomes part of watershed

Aquifer

An area where groundwater may be stored

Relationship between porosity and groundwater

The greater the porosity, the more water we find stored in the ground. Porosity is improved when sediment is well sorted

What is needed for rock to be permeable?

Pores or fractures must be connected for good permeability

Zone of Aeration

Found above the water table…does not store water

Zone of Saturation

Below the water table…where we find stored water

How is groundwater a resource?

Groundwater is continuously used and replaced by the water cycle—it is necessary for life

How can water quality in a watershed affect the quality of groundwater?

Groundwater may come from a watershed—so water quality can transfer to grounwater

Ways that pollution can enter an aquifer

Waste dumps, underground chemical storage, fertilizers, pesticides, leaking sewer systems

Ordinary Well

Penetrate the water table through highly permeable sediment or rock

Cone of Depression

Indication of water being pumped from a well

Artesian well

Different from ordinary well, as water is under pressure, so pumping it is not required

Features created by groundwater

• Caverns

• Stalactites/Stalagmites

• Sinkholes

• Natural Bridges

• *Groundwater creates chemical weathering

How is Karst topography different from normal types of weathering and erosion by groundwater?

Results from chemical weathering (carbonation) of limestone…makes it unique

Large caverns/caves prevent water from being purified naturally