asymmetric ripple mark
-is a ripple mark structure with a steep, short slope on the downstream side of its crest
and
a low angle, long
slope on the upstream side. Preserved ripple marks of this
type
are indicators of current directions of ancient streams. -asymmetric ripple marks-1 -asymmetric ripple marks-2
bed load
-are the materials that are being dragged along a stream as the stream flows. -bed load-Opal's
Pals
bedrock
-is the solid rock material that underlies loose surface materials.
braided stream
-consists of many parallel and interwoven streams separated by an abundance of
gravel bars.
The gravel bars are deposited as the main stream slows in its flow
due to loss of volume of
water and thus loses its competence and capacity.
buoyancy
-Objects denser than the fluid in which they are placed will sink; objects less
dense than the
luid in which they are placed will float. A dense object placed
within a fluid will have its apparent
weight decreased equal to the weight of an
equal volume of water that it displaces. -density and buoyancy-Opal's Pals
channelization
-is the attempt by humans to straighten out a meandering river.
continental divide
-is a line on a map that separates the collection of drainage basins that empty
into the Pacific
Ocean from those drainage basins that empty into the Atlantic
Ocean.
contour line
-is a line on a map that indicates a constant elevation on the land surface.
contour plowing
-is a form of land conservation; instead of plowing in straight lines, the plowing
in hilly areas follows
contour lines. The furrows left by the plow in contour
plowing act as small terraces which prevent
runoff from carrying soil away.
dam
-is a structure built across a stream or river channel for the purpose of blocking
the flow of water.
delta
-When a stream or river enters into a large body of water, it slows down and
drops its bed and suspended
loads producing a body of land, mostly made of mud. -map, Louisiana-Mississippi Delta
deposition
-occurs when a stream slows down, loses its ability to carry sediments, and
drops its load. -stream
deposition-Opal's Pals
dissolution
-is the process of dissolving a material; the material goes into solution.
dissolved load
-consists of the materials in solution that the stream or river is carrying. -dissolved
load-Opal's Pals
drainage basin
-is an area in which all rainfall is diverted into streams and rivers that feed
into the same main stream or river. -drainage
basin-Opal's Pals
ephemeral stream
-is a stream that only flows part of the year. An ephemeral stream is often called a "dry wash".
erosion
-is the process of carrying away materials in contrast to weathering which
causes the breakdown of materials. -stream
erosion-Opal's Pals
flash flood
-occurs when a dry wash (stream channel) that suddenly fills with water. The water level in
the channel quickly
rises, surge after surge. Often the source of the water may
be a rainstorm in the mountains many miles away.
flood
-occurs when a river overflows its banks
-San Pedro River, Arizona in flood stage:
1
2
flood plain
-is the flat area next to a stream or river that consists of silt that was
deposited when the stream or river
overflowed its channel during flood stage. -Rocky Mountains Park-flood plain
fluvial
-is an adjective that means "related to a river".
fording a river
-is the process of crossing a river and its widest and most shallow point for
safety purposes; the water in the
river moves slower at this location.
Great Salt Lake, Utah
-is a large lake in central Utah that has no river draining it; evaporation of
water from the lake has
concentrated the salt in solution to the point where the
water is saltier than seawater. -geologic map
of the Great Salt Lake
headwaters
-are at the highest elevation of a stream channel. It is the point where a stream just starts to form.
-headwaters-Opal's Pals
hydroelectric power
-is electrical energy created by turbines built into dams.
incised meander
-is a meandering stream that has cut downwards forming a canyon with a meandering
pattern.
It is also called an entrenched meander.
-entrenched meander-Opal's Pals
levee
-is a hill that runs parallel to a river and is created by multiple flooding
events where the flood
waters deposit sediments as the the river overflows its banks. -levee-Opal's
Pals
local base level
-In areas where there has been relatively recent tectonic uplift and faulting, a
stream may not flow
down to its ultimate base level which is sea level. Instead,
the stream ends in a lake at a higher
elevation that has no outlet.
longitudinal profile
-is a graphical plot of the elevation of a stream compared to the distance from its
starting point. -stream
profile-Opal's Pals
meander cutoff
-occurs when the base of a meander loop becomes so narrow that the stream
erodes across it.
The cutoff meander loop becomes an abandoned meander and eventually turns into
an oxbow lake.
-diagram of a cutoff meander
meander loop
-is a pronounced curve or bend in a meandering river.
-meander loop diagram
Mississippi Delta
-is the landform consisting of mud and silt that was deposited in the Gulf of
Mexico at the mouth of the
Mississippi river -map-Louisiana-Mississippi Delta
Nile Delta
-is a large body of sediment deposited where the Nile River enters into the
Mediterranean Sea.
outer bank erosion
-occurs on the outside bank of a meander loop in the river. Water travels
faster on the outside of a turn,
increasing its competence and thereby causing erosion. -outer
bank erosion-Opal's Pals
Oxbow Lake
-is a U-shaped adjacent to a meandering river. The lake forms as a meander loop is
cut off and
abandoned by the flowing river.
-oxbow lake diagram
pot hole
-is a shallow, nearly round hole worn into bedrock in a stream by abrasion from
rocks being moved
by the stream.
radial drainage
-describes a feature on a map where the main drainage channels all radiate either away from or
towards a
central point.
-radial drainage pattern diagram
saltation
-is a form of transportation of materials by rolling and skipping.
-saltation-Opal's Pals
sandbar
-is a ridge of sand in a stream channel.
sheetwash
-After a heavy rain, water flows as a sheet across the land, not confined to
channels.
-sheetwash-Opal's Pals
solution
-is a chemical dissolved in water
stream bed
-is the bottom of the stream channel
stream capacity
-is made up of the total load that the stream or river is capable of carrying.
The capacity is
measured in pounds or tons per hour of the load being carried by the stream or
river.
stream competence
-is the largest object, such as a rock, that the stream is capable of moving. -stream
competence-Opal's Pals
stream cross section
-is a sectional view of the stream channel developed at right angles to the
direction of stream flow.
-stream cross section diagram
stream energy
-A stream obtains its kinetic (moving) energy from dropping in elevation
(gravitational potential
energy) as it travels. -stream
energy-Opal's Pals
stream gradient
-is the rate at which the stream or river drops in elevation per mile traveled. -stream
gradient-Opal's Pals
stream load
-consists of all of the materials being carried by the water in a stream.
Stream
load includes bed load,
suspended load, and dissolved load. -stream
load-Opal's Pals
stream piracy
-By head ward erosion one stream cuts into another stream, thus diverting the
second stream's water
into a different drainage basin.
stream terrace
-is a flat surface above an incised stream channel, formed when the stream went
from a depositional
mode creating valley fill to an erosional mode.
stream velocity
-is a measure of how fast the water in the stream is moving.
traction
-is the pushing or pulling effect of moving water.
trellis drainage
-is a modified dendritic (tree-like) drainage pattern where many of the stream
branches run parallel to a single
direction, influenced by a series of regional
folds or a regional fault system.
-trellis drainage pattern diagram
tributary
-is a smaller stream that feeds into a larger stream; the term may also apply to
rivers that feed into larger
rivers and small valley glaciers that feed into
larger valley glaciers.
V-shaped valley
-indicates a valley recently carved by a river. It is considered to be an
indication of a river in the youthful part
of its cycle of development.
-V-shaped valley, Halemahina volcano, Maui, Hawaii
Chapter 10-Streams, Rivers,
and Lakes