water

Question 1

porosity

Answer 1

the percentage of pore space that a rock contains

Question 2

permeability

Answer 2

a measure of the rate at which a fluid will flow through the rock

Question 3

primary porosity

Answer 3

the pore space at the time the sediment was deposited

Question 4

secondary porosity

Answer 4

develops after in the rock, and includes cavities or fractures that have formed

Question 5

effective porosity

Answer 5

the total porosity minus any cement and this contributes to fluid flow through the rock

Question 6

capillary pressure

Answer 6

the force which exists across the interface which separates two immiscible fluids

Question 7

connate water

Answer 7

trapped in the pores of a rock as the rock formed

Question 8

groundwater

Answer 8

water occupying pore and other spaces in rocks and sediments which is derived mostly from rainfall percolating into the underlying rock

Question 9

water table

Answer 9

the surface separating unsaturated rock above from the saturated rock below

Question 10

hydrostatic pressure

Answer 10

the pressure at a point in a body of water due to the mass of the overlying column of water

Question 11

hydrostatic gradient

Answer 11

the difference in the hydrostatic pressure between two points divided by the distance between them

Question 12

aquifer

Answer 12

a body of porous and permeable rock capable of storing and yielding significant amounts of water

Question 13

recharge zone

Answer 13

the area of an aquifer open to the atmosphere, allowing replenishment of water

Question 14

artesian basin

Answer 14

a large, synclinal confined aquifer under hydrostatic pressure

Question 15

artesian well

Answer 15

holds water under hydrostatic pressure, which rises up the well to the piezometric surface on release

Question 16

piezometric surface

Answer 16

an imaginary surface to which groundwater rises under hydrostatic pressure, to produce springs

Question 17

abstraction

Answer 17

the removal of water from any source

Question 18

cone of depression

Answer 18

occurs when there is a lowering of the water table in the vicinity of a well, usually due to abstraction of water

Question 19

acid mine drainage

Answer 19

water containing toxic metals such as lead and cadmium from abandoned coal and metal mines

Question 20

what are the 3 types of aquifer?

Answer 20

unconfined, confined, perched

Question 21

perched aquifer

Answer 21

sits above the natural water table but is underlain by e lens of impermeable rock

Question 22

spring

Answer 22

occurs where the water table intersects the surface

Question 23

lithological spring

Answer 23

Result of a change in rock type. Where a permeable rock overlays an impermeable rock. A spring will occur at the boundary.

Question 24

springs at faults

Answer 24

Forms if a fault brings a permeable and impermeable rock together. Pressure causes water to rise up fault line to surface

Question 25

seeps

Answer 25

low density hydrocarbons can seep naturally to the surface

Question 26

what are the problems caused by groundwater extraction? x4

Answer 26

lowering of the water - cone of depression subsidence + reduced porosity- water taken out of rock causing it to collapse downwards saltwater encroachment

Question 27

saltwater encroachment

Answer 27

where aquifers are near the coast fresh water sits on top of see water as it less dense. Pumping can disturb this and cause them to mix

Question 28

what are the 2 main threats to groundwater supply?

Answer 28

over pumping | pollution

Question 29

why does some groundwater not need treatment?

Answer 29

pore space acts as a natural filter to groundwater, removing chemical impurities

Question 30

name 4 sources of pollution

Answer 30

nitrates and pesticides hydrocarbons and solvents toxic fluids from landfill waste Acid Mine Drainage

Question 31

factors affecting porosity x4

Answer 31

degree of sorting amount of diagenesis grain shape packing of grains

Question 32

factors affecting permeability

Answer 32

porosity temperature secondary permeability capillary pressures