Geography Chapter 15 - Groundwater & Karst Topography

Inputs vs Outputs

• Inputs = water added to the system

  • Example: Precipitation

• Outputs = water is lost from the system

  • Example: Evapotransportation

What is evaporation?

• moisture is lost to the atmosphere through the wind and sunlight

• rates are affected by temperature, wind speed, humidity

What is Transpiration?

• biological process by which water is lost from a plant

• Rates depend on time of year, type + amount of vegetation, availability of moisture, and the length of the growing season

What is Groundwater?

• fresh water (from raining or melting ice and snow) that soaks into the soil and is stored in the tiny spaces between rock

• can stay underground for hundreds to thousands of years

What is Groundwater? pt. 2

• can come to the surface and help fill rivers, streams, lakes, etc.

• can also come to the surface as a spring or be pumped from a well

What is Porosity?

• In order for groundwater to exist, there has to be porous layers

• These are spaces within the soil which allows water to flow through them and be stored

What is Permeability?

• Permeable = the ability for water to pass through rock layers

• Impermeable = the inability for water to pass through rock layers

What is the Importance of Groundwater?

• In the prairies groundwater is used extensively for crop irrigation

• Areas with no mountain ranges with no rain rely on groundwater as their water source

What are Groundwater zones?

• When water infiltrates the ground a section of rock becomes saturated (zone of saturation)

• The top of the saturated rock/soil is the water table

• The portion of the rock that is not 100% saturated is called the zone aeration

What is an aquifer?

• Rock layer that can store and yield water

• In dry areas aquifers provide clean water for drinking and irrigation by drilling a well

Recharge vs Discharge Diagram

Aquifers: Ordinary Wells

• Ordinary Wells are located in-between permeable rock

• Water is not under pressure and is forced to rise with a pump

Aquifers: Artesian Well

• Artesian Well is drilled through the ground

• Confined between two impermeable rock layers which causes a build up of pressure which causes the water to rise on its own

What are some potential threats to our Groundwater?

• contamination + Overuse and depletion

How do Karst Landforms form?

• Process is called: Carbonation

• Limestone and Dolostone

Landforms created by groundwater

• Travertine Terraces:

  • Found in areas in where there is an abundant amount of hot groundwater

  • Hot water carries dissolved material and when it reaches the surface it quickly cools and deposits minerals on existing rock

Karst Landscapes

• Caves or Caverns

  • Found in areas with highly soluble rock such as limestone

  • Water moves through the rock, dissolving limestone

Sinkholes

• As caverns increase in size the support decreases and the ground collapses

• Forms a depression (sinkhole)

Why does Florida have so many sinkholes?

• Most of Florida peninsula is made up of limestone and dolostone overlain by sand and clay

• Carbonate rocks may dissolve (solution) forming karst terrain