Groundwater Quality And Wells

Front 1

Groundwater is not as vulnerable to direct pollution and contamination as

Back 1

Surface Water

Front 2

What can cause contamination in groundwater?

Back 2

Leaky underground tanks, chemical spills, failure of on site waste treatment systems, underground injection of wastes, inadequate well protection, leaching from landfills, overfertilization of crops.

Front 3

Wells at what depth are generally free of harmful organisms?

Back 3

50ft+

Front 4

What conditions can cause a well that is 50ft+ depth to be contaminated?

Back 4

Aquifers with large voids in fractured rock or aquifers with conduits (improperly abandoned wells) that provide a pathway for contaminants to reach the aquifers.

Front 5

The most common cases of ground water contamination is from what?

Back 5

Poor well construction or poor waste disposal practices on the land overlaying the aquifer.

Front 6

Othe sources of aquifer contamination includes

Back 6

Recharging from nearby surface waters or excessive pumping near costal areas, resulting in saltwater intrusion onto the groundwater.

Front 7

The movement of water in the ___________ cant treat water naturally

Back 7

Ground

many water supply systems, especially European countries, employ riverbank-filtered water as their source supply

Front 8

What are the two ways that groundwater aquires its chemical characteristics?

Back 8

From contact with soil and rock underground and from incorparation from surface water that leaches into the aquifers

Front 9

What are commonly found contaminants in wells that are nearby agricultural areas ?

Back 9

Nitrates, herbicides, or pesticides

Front 10

What is the main cause of saltwater intrusion of freshwater aquifers near costal areas?

Back 10

Over pumping of the aquifers

Front 11

Several ___________ contaminants affect the potability of groundwater

Back 11

Natural

Front 12

Some natural elements and compounds are beneficial or harmless in _______ concentrations.

Back 12

Low

Front 13

What naturally occurring contaminants are harmful at very low concentrations?

Back 13

Barium, Arsenic, and various radionuclides

Front 14

What type of gases are undesirable in groundwater?

Back 14

Hydrogen sulfide, methane, and radon

Front 15

List some naturally occurring Inorganic Constituents

Back 15

Arsenic, Fluoride, Hydrogen sulfide, Iron, Manganese, Nitrate, Radons, Sodium, Sulfate, TDS

Front 16

Name some organic constituent contaminants

Back 16

Pesticides and herbicides, Solvents

Front 17

Name some Microbiological constituent contaminants

Back 17

Fecal contamination (indicator organisms), Iron bacteria (contamination from the surface) sulfate-reducing bacteria (contamination from the surface)

Front 18

What type of chemical contaminant are of very serious concern

Back 18

Synthetic organic compounds

Front 19

What is a very common synthetic organic compound contaminant?

Back 19

Gasoline

Front 20

If chemical contamination is detected in a well, what is the best move to make?

Back 20

Abandoned the well ans use a new uncontaminated source.

Front 21

True or False

Most chemical contaminants can be removed from aeration and carbon Adsorption?

Back 21

True,

But is is much more desirable to prevent groundwater contamination then to have to treat it

Front 22

What feature of a well prevents contamination from entering the casing?

Back 22

The Sanitary Seal

Front 23

Define well casing

Back 23

The metal pipe used to line the borehole of a well

Front 24

What is the sanitary seal made from

Back 24

Generally its a metal plate with a rubber gasket around its perimeter that fits snugly into the top of the well casing. Its has openings into the well for the discharge pipe, pump power cable and air vent to let air into the casing as the water level drops

Front 25

What material is used to fill the gap between the casing and the borehole and why?

Back 25

Grout, to help prevent water from traveling the outside of the casing and to add support to the casing. Where a well penetrates several aquifers, the grout also keeps water from flowing between aquifers along the outside of the well casing

Front 26

What is a well screen?

Back 26

A well feature that prevents rock and soil from entering the well while letting water in

Front 27

For a well that is screened in soil, what is done to help prevent unwanted sediment out.

Back 27

Sand is packed between the screen and the soil to fill the area.

Front 28

When a well is drilled into solid rock the water may enter the well through fractured rock, in this case what can be done from preventing rock chips and fragments from entering the well?

Back 28

Screens can be placed on the fractured rock zones