Flooding

Question 1

What is the main role of streams and rivers?

Answer 1

Drain the water and transport sediments

Question 2

A stream overflow occurs if its ability to carry water is overwhelmed.

Answer 2

Flood

Question 3

The volume of water moving through a channel over a period of time.

Answer 3

Stream discharge

Question 4

A process where water flows through stream channels.

Answer 4

Runoff

Question 5

Precipitation reaching the land surface moves downslope in thin sheets.

Answer 5

Overland flow

Question 6

Discharge of groundwater into the surface environment.

Answer 6

Groundwater baseflow

Question 7

Provide information about the river or stream by plotting the discharge and time.

Answer 7

Stream hydrographs

Question 8

Amount of time for a water to move across the landscape and into channels.

Answer 8

Lag time

Question 9

Continuous input of groundwater baseflow allows stream in many areas to keep flowing at minimum levels.

Answer 9

Baseflow conditions

Question 10

More water infiltration causes groundwater to be higher than stream channels.

Answer 10

Gaining streams

Question 11

Result of less deep infiltration in arid areas resulting in a water table below the streams.

Answer 11

Losing streams

Question 12

Large streams serve as the principal channel within the drainage system.

Answer 12

River

Question 13

Upper portion of the drainage system.

Answer 13

Headwaters

Question 14

Found in the lower part of the system where a river empties into an ocean.

Answer 14

Mouth

Question 15

Individual system separated from one another by topographic high or crest.

Answer 15

Drainage divide

Question 16

Land area that collects water for an individual stream or river.

Answer 16

Drainage basin/ Watershed

Question 17

Smaller streams that feed larger streams within a drainage basin.

Answer 17

Tributaries

Question 18

A method of classifying or ordering the hierarchy of natural channels

Answer 18

Strahler Stream Order

Question 19

The longitudinal profile reflects a downstream trade-off between discharge and slope in setting transport capacity.

Answer 19

Stream Longitudinal Profile

Question 20

The limiting level below which a stream cannot erode is called _________.

Answer 20

Base level

Question 21

Approximately equals the inverse of the source basin length.

Answer 21

Drainage density

Question 22

True or False. Steep terrain has high drainage density while gentle terrains have low drainage density.

Answer 22

TRUE

Question 23

Drainage pattern that forms horizontally bedded and uniform sediments or on uniformly resistant crystalline rocks.

Answer 23

Dendritic

Question 24

Drainage pattern that develops on moderate to steep slopes, but also where regional structure, such as outcropping resistant rock bands.

Answer 24

Parallel

Question 25

Patterns most commonly on dipping or folded sedimentary or weakly metamorphosed sedimentary rock; also areas of joints and faults which intersect with right angles and old sand dunes with parallel alignment.

Answer 25

Trellis

Question 26

Usually have more or less perpendicular turns mainly caused by crisscrossing fractures.

Answer 26

Rectangular

Question 27

Occurs around domes or cones and is particularly common in volcanic areas.

Answer 27

Radial

Question 28

Patterns also develop around domes, where there exist alternating resistant and weak beds.

Answer 28

Annular

Question 29

Can occur in a variety of conditions where local hummocks and depressions inhibit a continuous channel network.

Answer 29

Multibasinal

Question 30

Incised into rocks with complicated structural patterns. Associated with crystalline metamorphic rocks with a history of intense folding, jointing, intrusion, alterations, and faulting.

Answer 30

Contorted

Question 31

Types flowing streams.

Answer 31

Perennial, intermittent, & ephemeral

Question 32

Types of linearity of river.

Answer 32

Straight, meandering and braided

Question 33

The Cross profile of the river can be described as _______.

Answer 33

Gently and steeply sloping

Question 34

The length of the profile can be described as __________.

Answer 34

Graded or interrupted profile

Question 35

Loose rock particles/sediments deposited on a stream.

Answer 35

Alluvium

Question 36

Key factors in a stream's ability to erode the landscape is _______ .

Answer 36

Velocity of the water

Question 37

_______ unstable overhang located at the outer bank which is produced by the velocity increase.

Answer 37

Cutbanks

Question 38

Inner bank where velocity decreases sediments tends to accumulate and form deposit.

Answer 38

Point bar

Question 39

__________ by streams is not performed by the water itself, but rather by the sediment that wears away rock.

Answer 39

Downcutting

Question 40

Evidence of stream abrasion.

Answer 40

Potholes

Question 41

Swirling motion of water column

Answer 41

eddy current

Question 42

Velocity of a stream segment is controlled by _____.

Answer 42

stream gradient

Question 43

Sea level is referred to as ________________ because oceans represents the low point of most rivers.

Answer 43

ultimate base level

Question 44

___________ describes the fraction of solid particles that is in suspended state.

Answer 44

Suspended load

Question 45

___________ consist of sediments particles that roll, bounces, or remain stationary.

Answer 45

Bed load

Question 46

The process whereby water separates sediment grains based on their size, shape, and density.

Answer 46

Hydraulic sorting

Question 47

Mound-shaped channel deposits consisting of sorted material ranging in size from boulders to coarse gravel to fine sand.

Answer 47

Bars

Question 48

__________ are formed when a rivers enters a lake or ocean.

Answer 48

Deltas

Question 49

________ large fan-shaped deposits that form where steep mountains streams empty out onto valley floors at the mouth of river.

Answer 49

Alluvial fans

Question 50

A channel that is choked with sediments called a ________.

Answer 50

Braided streams

Question 51

Transport considerable amounts of dissolved ion refer to as the ____________.

Answer 51

Dissolved load

Question 52

________ erosion that occurs along the outside of meander bends produces wider valleys over time.

Answer 52

Natural floodplain

Question 53

_________ a pair of ridges that run parallel to the bank which are formed due to the deposition of sediments.

Answer 53

Natural levees

Question 54

Areas on the floodplain that are poorly drained and can remain wet after the flood.

Answer 54

Back swamps

Question 55

Old floodplains are poorly drained and dry as the river migrates.

Answer 55

Stream terraces

Question 56

Normally dry areas of land become inundated.

Answer 56

Flood

Question 57

_______ the height at which a river begins to overflow.

Answer 57

Flood stage

Question 58

The ability of the ground to absorb water is referred to as __________.

Answer 58

Infiltration capacity

Question 59

The actual rate at which water can infiltrate is determined by the ________ of the land surface, _______ and _______ of the material.

Answer 59

Slope; Type of ground material and Moisture content

Question 60

Vegetation intercepts and stores a certain fraction of the rain water.

Answer 60

Vegetation cover

Question 61

Floods that have short duration with relatively high peak discharge.

Answer 61

Flash flood

Question 62

Can be defined as one where a river leaves its channel farther down in its drainage basin, flowing out onto its floodplain and inundating large areas of the valley floor.

Answer 62

Downstream floods

Question 63

Another term for flash flood.

Answer 63

Upstream flood

Question 64

Land-use factors that affect flooding.

Answer 64

Removal of natural vegetation Destruction of wetlands Construction activity Urbanization

Question 65

Flood mitigation measures.

Answer 65

Dams Artificial levees Channelization Erosion controls Flood proofing Education

Question 66

Protecting floods and serving as an important source of freshwater and electrical power.

Answer 66

Dams

Question 67

Constructed of earthen materials, but large concrete panels called floodwalls are sometimes used.

Answer 67

Artificial levees

Question 68

Straightening and deepening a stream channel so that its discharge capacity is increased.

Answer 68

Channelization

Question 69

Temporarily stores some the excesses water in a series of depression which are constructed within the tributary network.

Answer 69

Retention basins

Question 70

Practices that tend to keep soil particles in place so as to minimize the amount of material able to move downslope.

Answer 70

Erosion control

Question 71

Type of barrier in which vegetated strips line the banks of stream channels trapping sediments before it can enter the drainage network.

Answer 71

Stream buffers

Question 72

Synthetic fabric that is fine enough to trap sediments but allow some water to pass.

Answer 72

Silt fences

Question 73

Ponds constructed for the purpose of trapping any sediments.

Answer 73

Silt basin

Question 74

Involves raising the building above the expected flood level.

Answer 74

Flood proofing

Question 75

_____ the public about flooding in a very cost-effective means of reducing the number of fatalities and property damage.

Answer 75

Education

Question 76

Increase the ability of water to flow downslope, which translates into more overland flow and less infiltration.

Answer 76

Removal of natural vegetation

Question 77

Excessive dislodged sediment is moved off the landscape into the drainage systems which causes channels to become filled with sediments.

Answer 77

Sediment pollution

Question 78

The destruction of ________ has reduced the landscape's ability to store water.

Answer 78

destruction of wetlands

Question 79

This activity exacerbates flooding because it increases the overland flow and causes stream channels to fill with sediment.

Answer 79

Construction activity

Question 80

Large pipes called ________ are typically used for small streams that flow intermittently.

Answer 80

Culverts

Question 81

Land covered with an impermeable surface which do not allow water to infiltrate, but rather forces to moved as overland flow.

Answer 81

Urbanization