GEOLOGY
CMU
Bill Palmer
Lecture 14
Streams and Rivers
GEOLOGY
 Johnstown
Flood-A famous flood!
 Johnstown,
Pennsylvania
 Recreational area for Pittsburgh
 Mud and gravel dam across the Conemaugh River
 May 31, 1889-Torrential rain
 Dam collapses
 60foot tall wall of water slammed into Johnstown
 2,300 people dead
GEOLOGY
 Jamestown
PA focus of national sympathy
 Years to recover-first Red Cross relief program
 Flood-an event when volume of water in a stream
or river becomes so great that water covers areas
outside the normal limits of the stream
 Rivers > streams
 Earth is only planet with streams of running water
GEOLOGY
GEOLOGY
 Falling
water may rush off the land in sheetsSheetwash
GEOLOGY
 Types
of Drainage Patterns:
 Dendritic-Tree branches (Ozarks)
 Radial-Flow out like spokes of a wheel (St.
Francois Mtns.)
 Rectangular-form at right angles
 Trellis- like a garden trellis (N. Missouri)
GEOLOGY
GEOLOGY
 Watershed-the
entire area drained by a river or
stream system
 Divide-The
high area or ridge that separates one
drainage area from another
GEOLOGY
GEOLOGY
 Permanent
Streams-Streams that contain water
year round
 Ephemeral
Streams-Streams that contain water
only after a heavy rain (dry wash, arroyo, or wadi)
GEOLOGY
 Discharge-The
volume of water a stream
discharges in a given period
Amazon discharges 200,00 cubic meters/second
this is 15% of all runoff of the earth’s total
Mississippi River = 17,000 cubic meters/second
GEOLOGY
Amazon
River Delta
GEOLOGY
Mississippi River Delta
GEOLOGY
 Discharge
is difficult-Depends on cross-section of
stream, head pressure, and friction of stream bed
GEOLOGY
 Running
water causes four types of Erosion:
 Scouring-removal
of loose fragments
 Breaking and lifting-Moving water lifts sediments
 Abrasion-Sand and silt water is like a sandblaster and
abraids channels
 Dissolution-Water dissolves minerals chemically
GEOLOGY
 Sediment
 Dissolved
Load-three types
load-Chemically dissolved soluble minerals
 Suspended load-Tiny grains of material that swirl
along with water
 Bed load-The big chunkers that move along the bottom
(the faster the stream the bigger the chunkers)
GEOLOGY
 Deposition-
When a stream dumps its sediment
load=Deposition
 Alluvium-sediments
transported by a stream
Alluvium-Copper River, Alaska
GEOLOGY
 Stream
Characteristics-
 Valleys-The
V-shaped canyon created by a downcutting river (Colorado)
 The same type of rock creates a V-shape
 Hard and soft rock create a stair-step pattern
 Rapids-when river flows over boulders or other
obstructions
 Waterfalls-when rivers free-fall down the stream-bed
GEOLOGY
 Stream
Characteristics-Streams are classified as
young, mature, or old age.
 Young-Mountain
Stream
 Mature-Cedar Creek
 Old age-Missouri and Mississippi
GEOLOGY
 Stream
 Old
Characteristics-
Streams have meanders, oxbow lakes, and few
waterfalls. Wide valleys with flood plain (MO and MS
rivers)
 Young streams are straight, flow fast, rapids and
waterfalls, and narrow V-shaped valleys
 Mature streams are in the middle
GEOLOGY
Youthful
Youthful
Mature
Old Age
GEOLOGY
Youthful-waterfalls and
narrow canyons
Old age-Meanders and
oxbow lakes
GEOLOGY
What are these?
GEOLOGY
 Alluvial
Fan-When a relative fast moving stream
or river emerges into a slow moving body of water
and drops its sediment load.
GEOLOGY
 Braided
Stream-when a stream weaves back and
forth creating a braided look.
GEOLOGY
 Meanders-when
a river snakes back and forth,
usually a sign of an old age river.
GEOLOGY
 Delta-where
running water enters a slow or
stationary body of water and dumps its sediments
load
GEOLOGY
Nile R. Delta
Yangtze
R. Delta
Mekong R. Delta
GEOLOGY
 Stream
piracy-When erosion of one stream
captures the water of another stream
GEOLOGY
 Rejuvenation-When
a stream that has meandering
traits is uplifted and given increased down cutting
strength. Most of Missouri’s Ozark rivers and
streams have this characteristic.
Current River
GEOLOGY
 Floods-Two
 Seasonal
Types
Floods-Gradually submerge a floodplain;
usually during rainy season; last for days or weeks
(Missouri River floods of 1993 and 1995)
 Flash Floods-Happen very quickly; people can’t
escape; more of a problem in narrow canyons or
deserts; (flash floods of Big Thompson River Canyon
[1976] and Jamestown flood)
GEOLOGY
Seasonal Flood
Flash Flood
GEOLOGY
 Problems
of Rivers in America
River caught on fire; can’t eat fish
from MO River due to Chlordane (termite poison)
 Dam Construction-5,000 dams over 15 m high;
sometimes flood more land than they protect
 Overuse of water-Colorado River never reaches ocean
 Pollution-Cuyahoga
 65%=agriculture
 25%=industry
 5%=human
drinking
 5%=evaporation loss
 0%=water that reaches ocean
GEOLOGY
Cuyahoga River
catches on fire
GEOLOGY
Chlordane
catfish from
MO river
GEOLOGY
Truman Dam
Hoover Dam
Bagnell Dam
and Spoonbill
Catfish
GEOLOGY
Water from the Colorado
River is “used up” before it
reaches the Gulf of Baja.
GEOLOGY-Wrap-Ups
 1.
What and when was the Johnstown flood?
 2. Sketch and label four types of drainage patterns.
 3. What is a watersheds?
 4. What are ephemeral streams?
 5. What are four types of erosion from streams?
GEOLOGY-Wrap-Ups
 6.
What is the difference between rapids and
waterfalls?
 7. What is a rejuvenated stream?
 8. What type of floods do we have on the Missouri
River?
 9. List three general problems with rivers and
streams in USA.
 10. What is your favorite stream or river in MO?