groundwater

Question 1

aquifer

Answer 1

underground geological formations that hold and transmit water

Question 2

aquitard / aquilude / confining layer

Answer 2

rock or sediment that is non permeable, cannot transmit water, block groundwater flow

Question 3

water table

Answer 3

boundary line between saturated and unsaturated zones, equal pressure to the atmosphere

Question 4

saturated zone

Answer 4

area in the sediment where its pores are filled with water

Question 5

unsaturated zones

Answer 5

area in the sediment where the pores are filled with mainly air and water vapor

Question 6

capillary fringe

Answer 6

small area of saturation above water table, sucked up by capillary forces

Question 7

unconfined aquifer

Answer 7

open to infiltration, no confining layers above

Question 8

confined aquifers

Answer 8

closed by an aquitard, water underneath is under high pressure, so when opened up to surface it can naturally flow all the way up

Question 9

perched aquifer

Answer 9

above the water table, perched on a confining layer

Question 10

porosity

Answer 10

proportion of empty space in a substance, expressed as percent

Question 11

specific yield

Answer 11

the amount of water that drains out of an unconfined aquifer under gravity if the water table were to lower expressed as a percent

Question 12

specific retention

Answer 12

the opposite of specific yield, the amount of water that is not pulled out by gravity, stays due to molecular attraction with sediment

Question 13

transmission

Answer 13

an aquifers ability to allow water to flow away and into it or an aquitards ability to block the flow of water, dependent on hydraulic conductivity and permeability

Question 14

permeability

Answer 14

a substances ability to allow any form of liquid pass though, dependent on the sediment

Question 15

hydraulic conductivity

Answer 15

a substances ability to allow a specific liquid to pass through, dependent on the sediment and the liquid

Question 16

molecular attraction

Answer 16

attraction between molecules due to poles, water is polar because of the way its electrons are oriented giving it a negative and positive side

Question 17

viscosity

Answer 17

viscosity is a measure of thickness in a liquid

Question 18

density

Answer 18

mass per unit of volume

Question 19

viscosity and density relation to groundwater flow

Answer 19

more viscous liquids will have slower groundwater flow, if temperature increases the density decreases because its molecule get farther apart, this in turn decreases viscosity and increases groundwater flow

Question 20

fractures

Answer 20

cracks in low porosity sediment, allow for high permeability by giving the water cracks to flow through, also allows for pollution because of the faster flow rate due to larger more interconnected cracks

Question 21

what drives groundwater flow

Answer 21

pressure and gravity, gravity pulls the water down and pressure causes the water to move from low pressure to high pressure

Question 22

why does groundwater not go above the water table?

Answer 22

its reached the equilibrium of pressure and doesn’t need to go up anymore

Question 23

how does pumping water from well affect groundwater flow?

Answer 23

it sucks water up towards the well, causing groundwater to flow towards the well instead of natural places like streams and lakes and oceans

Question 24

cone of depression

Answer 24

a funnel shape in the water table made by wells, because the well is sucking water up it decreases pressure and lowers the water table in that area

Question 25

compressibility

Answer 25

how much a confined aquifer can change in shape, more compressibility results in more water storage and more water extraction

Question 26

interconnectivity

Answer 26

how connected the pores in a substance are

Question 27

turtuosity

Answer 27

how straight of a path there is in a sediment

Question 28

recharge

Answer 28

refilling of an aquifer, usually from rain

Question 28

infiltration

Answer 28

water moving into a sediment, water on the surface infiltrates into the sediment

Question 29

percolation

Answer 29

after infiltration, the actual movement of water through the sediment

Question 30

what areas tend to have higher and lower pressure?

Answer 30

valleys have lower pressure because there is less sediment stacked up
hills and mountains have higher pressure because there is more sediment stacked up

Question 31

what is packing and how does it affect permeability, porosity, and retention?

Answer 31

packing is how compressed together the sediment particles are
as packing increases, permeability and porosity decrease and retention increases

Question 32

what is angularity/sediment shape and how does it affect permeability, porosity, and retention?

Answer 32

angularity is how cornered or rounded the sediment particles are
as angularity increases, permeability and porosity decreases and retention increases

Question 33

what is sorting and how does it affect permeability, porosity, and retention?

Answer 33

sorting is how well sorted the particles are in a sediment. low sorting means that different sediments types and sizes are mixed together
as sorting increases, permeability and porosity increase and retention decreases

Question 34

what is the vadose zone?

Answer 34

same as the unsaturated zone

Question 35

what are some things that affect the porosity of an aquifer?

Answer 35

sorting: how sorted sediment is, bad sorting results in smaller particles filling pores, decreasing porosity
cementation: minerals dissolved in water act as a glue connecting sediment particles together
overburden stress: pressure caused by weight of rocks and fluids, increases packing and therefore decreases porosity
grain shape: more angular sediments have lower porosity
physical weathering: cracks and disintegration, creates fractures and widens them
chemical weathering: decomposition, increases size of cracks and pores