Chapter 7 Ground water

Question 1

A water table is defined as

Answer 1

the surface on which the fluid pressure in the pores of a porous medium is exactly atmospheric.

Question 2

a ……………………often existed above………………………

Answer 2

saturated capillary fringe

the water table

Question 3

a hydrologic system is often divided into

Answer 3

1. unsaturated zone
2. capillary fringe (sometimes also called tension-saturated zone)
3. saturated zone.

Question 4

The following figure represents

Answer 4

Hydrologic system zones

Question 5

A represents

Answer 5

Unsaturated zone

Question 6

B represents

Answer 6

capillary fringe

Question 7

C represents

Answer 7

Saturated zone

Question 8

D represent

Answer 8

Water table

Question 9

If one places a well a few feet or so below the water table, the water in that well will

Answer 9

rise to the elevation of the water table at the location of the well.

Question 10

The water table often follows

Answer 10

topography

Question 11

although the relief of the water table is ……………….. than the topography, ……………………………. generally flows from topographic ………………….to topographic …………….., and discharges at ……………………………..

Answer 11

less - Groundwater - highs - lows - the topographic low spots.

Question 12

The capillary fringe

Answer 12

subsurface layer in which ground water seeps up from a water table by capillary action to fill pores.

Question 13

Pores at the base of the capillary fringe are……………………………… due to ………………

Answer 13

filled with water due to tension saturation

Question 14

This saturated portion of the capillary fringe is ………………than total capillary rise because of ……………………………………….

Answer 14

less

the presence of a mix in pore size.

Question 15

If pore size is small and relatively uniform, it is …………………………………………..

Answer 15

possible that soils can be completely saturated with water for several feet above the water table.

Question 16

If pore size is small and relatively uniform, it is possible that soils can be completely saturated with water for several feet above the water table. Alternately, the saturated portion will

Answer 16

extend only a few inches above the water table when pore size is large.

Question 17

aquifer

Answer 17

geologic unit that can store and transmit water at sufficient rates to supply wells.

Question 18

Unconfined aquifers

Answer 18

water seeps from the ground surface directly above the aquifer.

Question 19

Confined aquifers

Answer 19

an impermeable dirt/rock layer exists that prevent water from seeping into the aquifer from the ground surface located directly above. Instead, water seeps into confined aquifers from farther away where the impermeable layer doesn’t exist.

Question 20

Confining layers are subdivided into

Answer 20

aquifuges (absolutely impermeable) and aquitards (impermeable relative to the adjacent units).

Question 21

unconfined aquifers

Answer 21

Water table aquifers, those with no confining layer above

Question 22

confined aquifers

Answer 22

Aquifers overlain by a confining layer

Question 23

A represents

Answer 23

Recharge

Question 24

B represents

Answer 24

confined aquifier

Question 25

C represent

Answer 25

confining layer

Question 26

Aquifers are

Answer 26

underground layers of very porous water-bearing soil or sand.

Question 27

Aquitards

Answer 27

compacted layers of clay, silt or rock that retard water flow underground; that is, they act as a barrier for groundwater.

Question 28

Aquitards ………………………………..and ………………………………….

Answer 28

separate aquifers

partially disconnect the flow of water underground.

Question 29

Aquitards separate aquifers and partially disconnect the flow of water underground. Also known as

Answer 29

cap rocks

Question 30

aquitards …………………… and …………………….the surface water which ………………………. and ……………………..

Answer 30

limit and direct

seeps down and replenishes aquifers.

Question 31

aquiclude

Answer 31

geological material through which zero flow occurs.

Question 32

Groundwater flow

Answer 32

part of stream flow that has infiltrated the ground, has entered the phreatic zone, and has been discharged into a stream channel, via springs or seepage water

Question 33

Groundwater is water that is found ……………………… in …………………………….

Answer 33

underground in cracks and spaces in the soil, sand and rocks.

Question 34

Groundwater is water that is found underground in cracks and spaces in the soil, sand and rocks. ………………………………………………….is called a ………………………. or saturated zone.

Answer 34

An area where water fills these spaces

phreatic zone

Question 35

The rate of groundwater flow depends on

Answer 35

1. on the permeability (the size of the spaces in the soil or rocks and how well the spaces are connected)
2. hydraulic head (water pressure).