Lab 7

Question 1

What do rivers do to the earth’s geography

Answer 1

Rivers are a major influence on the shape of the earth’s surface. They transport sediment and water over vast distances. They carve out canyons, dissolve bedrock, and create numerous deltas, wetlands and floodplains

Question 2

How do rivers act for erosion and transportation

Answer 2

they move water and sediment supplied to them from the land surface to the oceans. Must expend energy provided from 2 sources:
- The topographic gradient (slope)
- Stream discharge (amount of water moving through the stream per unit time in m3/s)

Question 3

What is the structure of a river

Answer 3

rivers can develop a wide range of network and channels that reflect the energy expenditure. The usually have well defined boundaries, and can be technically regarded as open systems for energy and matter.

Question 4

What do the properties and behaviours of the fluvial system reflect

Answer 4

The properties and behaviour of the fluvial system at any particular location then reflect the combined results of various upstream controls (climate, geology, land use, basin physiography) and downstream controls (base level of outlet) as the river strives to reach grade.

Question 5

What is base level

Answer 5

the lowest point to which a river can flow and erode

Question 6

what is stream gradient

Answer 6

the measure of a stream’s downhill slope, calculated as the vertical drop in elevation divided by the horizontal distance traveled along the stream

Question 7

what is stream profile

Answer 7

a two-dimensional side view that shows its elevation from the source (headwaters) to the mouth

Question 8

what is a levee

Answer 8

a man-made embankment, often made of compacted earth or concrete, built alongside a river, coastline, or other waterway to control or divert the flow of water and protect adjacent land from flooding

Question 9

what is a stream channel

Answer 9

the physical pathway of a stream, defined by a bed and banks, that contains a body of flowing water

Question 10

what is erosion

Answer 10

the process of wearing away and transporting Earth materials like soil, rock, and sediment from one location to another through natural forces such as water, wind, ice, and gravity

Question 11

what is turbulent flow

Answer 11

chaotic, irregular, and swirling movement of water particles, creating eddies and whirlpools

Question 12

what is an Alluvium

Answer 12

loose clay, silt, sand, and gravel deposited by running water, such as in a riverbed, floodplain, or delta

Question 13

What is an Alluvial fan

Answer 13

a fan-shaped landform made of sediment and debris deposited by a stream or creek as it flows from a steep mountain or canyon onto a flat valley floor

Question 14

What is a delta

Answer 14

a landform created where a river deposits sediment as it enters a larger body of water

Question 15

What is a floodplain

Answer 15

a flat, low-lying area of land adjacent to a river, stream, or coast that is subject to flooding during high-water events

Question 16

What is a cutoff

Answer 16

new channel that forms when a river erodes a path across the narrow neck of a meander bend, shortening the overall course of the river

Question 17

What is a meander

Answer 17

a bend or curve in a river, like a snake-like path across a relatively flat landscape

Question 18

what is a braided stream

Answer 18

a river that consists of multiple, shifting channels separated by sand and gravel bars

Question 19

what is a flood

Answer 19

the overflow of a body of water onto normally dry land, a natural disaster that can be caused by heavy rainfall, rapid snowmelt, coastal storms, or the failure of man-made structures like dams or levees

Question 20

what is an oxbow lake

Answer 20

a U-shaped or crescent-shaped lake that forms when a wide meander of a river is cut off from the main flow, becoming a separate body of water

Question 21

what is deposition

Answer 21

the process where a river drops sediment it has been carrying, which happens when the water’s energy decreases

Question 22

what is a cut bank

Answer 22

an erosional landform found on the outer curve of a river’s meander, where fast-flowing water cuts into the riverbank, often forming a steep bank or cliff