Groundwater Notes

                

                                                 

                                                                                     

Porous or Porosity

Amount of empty space or voids in a solid material

Measured as a percentage

Examples:

Permeable or Permeability

• Ability to allow fluids to pass through

• Groundwater moves very slowly

• Measured as a distance / time– feet / second– feet / hour– feet / year

– Examples

The Water Cycle

•

Hydrologic Cycle

•

• GLOBAL WATER SOURCE AND VOLUME• Water Source Water volume (in cubic miles) Percent of

total water 1. Oceans 317,000,000 97.24%2. Icecaps, glaciers 7,000,000 2.14% 3. Groundwater 2,000,000 0.61% 4. Fresh-water lakes 30,000 0.009% 5. Inland seas 25,000 0.008% 6. Soil moisture 16,000 0.005% 7. Atmosphere 3,100 0.001% 8. Rivers 300 0.0001%9. Total 326,000,000 100%

• SOURCE: USGS, 1984, The Hydrologic Cycle- Pamphlet

Period of Renewal (residence times)

• World Ocean 2500 years• Ground water 1400 years• Polar ice 9700 years• Mountain glaciers 1600 years• Ground ice 10000 years• Lakes 17 years• Bogs 5 years• Soil moisture 1 years• Channel network 16 days• Atmospheric moisture 8 days• Biological water several hours

Water Budget

• Income– PRECIPITATION

• Rain, snow, condensation….

• Outgo:– EVAPOTRANSPIRATION

• Evaporation and Transpiration

• infiltration, runoff

Water Budget

•

Water Budget

• Surplus:– More income than outgo

• During rainy season, lots of rain and humidity

• During winter, not much evaporation or transpiration

• Deficit:– More outgo than income

• During dry season, lots of evaporation

• During summer, lots of plants

Watersheds of US

                                  

                       

Which watersheds are we in?

GroundwaterIn which direction does

groundwater move?

Rate of Groundwater Flow

Water Well

Groundwater pump

• Aquifer• Zone of Aeration• Water Table• Zone of Saturation• Cone of Depression

Cone of Depression

Water Quality

• Water is cleaned or filtered as it moves through the aquifer, therefore groundwater is generally clean.

• The deeper the well the farther from a pollution, therefore cleaner.

• Groundwater moves very slowly, therefore pollution can take many years to flush out.

NaturalWater Problems

• Hard Water

• Salty Water

• No Water

• Stinky Water

In which direction does groundwater move?

• Like surface water, groundwater moves down hill, not downward.

How does water leave the ground?

• Evapotranspiration– Evaporation– Transpiration

• Springs

• Geysers

• Wells

• Artesian Wells

Artesian Well

What is our groundwater like here in Hopewell Valley?

• Fractured Shale

• The water table is not very deep.

Groundwater Pollution

Why is vegetation good?• Splash Erosion

– The drop impacts loosen the soil

• Sheet Erosion– Water running over

the surface carries away the topsoil

• Less Infiltration– More runoff means

less groundwater recharge

Gullying

Who uses the water?

Result of Excess Water Withdraw

Forced Recharge of the Aquifer

• Retention Basin– The runoff from

the roads and parking lots is allowed to soak back into the aquifer.

Credits

• www.unesco.org/science/waterday2000/Cycle.htm

• http://physics.uwstout.edu/geo/sect5.htm

• http://geobytesgcse.blogspot.com/2006/11/rivers-source-to-mouth.html