Soils role in filtration of groundwater

1
Soils role in filtration of groundwater

• Jaden Boren
• Jessica Helm

2
How soil filters

• The soil acts like a big strainer trapping
  particles as the water moves through the soil
• Soil can trap particles as small as 1 micron
  which includes harmful parasitic protozoans
• Vegetation trapped dissolved metals like iron and
  zinc
• Clay has an electrochemical attraction to water
  and can lock up chemicals on their surface

3
Water-bearing rocks

• Sedimentary deposits (sand and gravel)
• Channels in carbonate rocks (limestone)
• Lava tubes or cooling fractures in igneous rocks
• Fractures in hard rocks

4
The importance of groundwater

• Groundwater accounts for more than 95 of all
  fresh water available for use
• 50 of Americans obtain all or part of their
  drinking water from groundwater
• About half of irrigated cropland uses groundwater
• About 40 of river flow nationwide (on average)
  depends on groundwater

5
Types of aquifers

• Aquifer underground layers of porous rock that
  are saturated from above or from structures, its
  capacity is determined by the porosity of the
  subsurface material and its area.
• Confined aquifers are (known as artesian or
  pressure aquifers) exist where groundwater system
  is between layers of clay, dense rock and other
  materials with low permeability
• Unconfined aquifers water in unconfined
  aquifers may have arrived recently by percolating
  through the land surface

6
The Making of Ground Water

• Some water evaporates from the earths surface
  into the air or is returned to the earths
  atmosphere
• Some infiltrates into the ground. There it
  follows various pathways to the surface as
  springs, move into surface water, or recharge
  ground water deeper in the earth
• Ground water can move into large underground
  natural storage areas known as aquifers and
  artesian wells

7
Groundwater misconceptions

• It is a common misconception that groundwater is
  like an underground river like those that form
  limestone caverns.
• In reality groundwater is more like the water in
  a sponge, held within the tiny pores of the
  surrounding aquifer material
• For water to move freely through a rock, the
  pores and/or fractures must be large enough and
  connected enough so that the friction from the
  water moving past the rock particles does not
  impede flow

8
Groundwater Management Practices

• Zoning Districts
• Groundwater recharge
• Pollutant reduction
• Pollution prevention

• Management Practices
• Artificial wetlands, Grass lined channels, Ponds,
  Subsurface drains, Infiltration trenches.
• Buffer strips, Filter strips, Riparian zones.
• Soil nitrate testing, integrated pest management,
  manure testing ,abandoned wells closure