Answer & Explanation:one and half pagescan u do Riparian Ecology paper about river mappingit just one page paper about river mapping and how its done ?there not really any information about it its just research about river mapping on Riparian Ecology how do we do it just about what is river mapping and how it’s done and bit information about iti attached powerpoint it may help with it ?u can use the information in the powerpoint and this website too http://usdasearch.usda.gov/search?utf8=✓&affiliate=nrcs_portal&query=river+mapping
aalectures.pptx
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Riparian Ecology
(Belonging to or relating to the
bank of a river)
TERMS
– Riparian
– Corridor
– Watershed
– Thalweg
– Scarp
– Pool
– Riffle
– Channel
Hydrologic Cycle
Surface Runoff
Runoff dependent on:
– Nature of the Soil
– Degree of slope of the surface
– Development and type of vegetation
– Local climate
– Volume and intensity of experience (ppt)
RESULTS
Erosion
or
Deposition
WATERSHED
Define as:
– An area of land that drains water, sediment, and
dissolved materials to a common outlet at some
point along a stream channel.
Patterns
– Topography and underlying geology
Strahler’s system
Shreve’s system
http://ccl.northwestern.edu/netlogo/models/r
un.cgi?GrandCanyon.854.674
Continental Divide and Mississippi
Drainage
Typical Drainage Patterns
uniform lithology
volcanic or domed uplifts
fractured rocks
alternating strong vs.
weak rocks
Moving Water Ecosystem
Relationship to the motion of the system
– Rate of Flow:
volume of water passing any given point m3/sec
ft3/sec
– Stream Velocity:
Speed at which water moves
m/sec
Stream Discharge Defined
Volume of water that flows past a given point per unit time
Discharge (cfs) = average stream width (ft) •
average depth (ft) •
average velocity (ft/sec)
Example: Stream dimensions are 100 ft wide and 15 ft deep
Flowing at 6 ft/sec (4 mph) has a discharge of 9000 cfs
Humid climates discharge typically increases downstream:
1) Water flows into stream from ground
2) Tributaries are added downstream
Regions of Maximum Velocity
Flow
Types
– Turbulence or irregularity of motion of the water
particles
Laminar flow
– Perfect even
Turbulent flow
– Highly irregular
– http://highered.mcgrawhill.com/sites/0072402466/student_view0/chapt
er10/animations_and_movies.html#
Velocity vs. Grain Size
Giant Boulders; Moved During
Floods
Classification-streams
1. Perennial
– Surface flow throughout the year, only dry
during periods of drought
2. Intermittent
Surface flow only at certain times of the year,
when it receives water from springs, snowmelt,
surface run-off
3. Ephemeral
Surface flow only in direct response to ppt
Channel Formation
Channel Development
Result of:
– Geology
– Fault zones
– Stream flow & sediment load
Channel Roughness
Smooth, semi-circular channel yields highest velocity
Wide, shallow channel increases friction
Rough channel also slows river at base
Channel Width and
Obstructions
Width change due to
Strength change
Channel narrows -> increases stream velocity
Channels
– Most of the time appears that large channels
are overdesigned for their discharge
– Most of the year low half of channel capacity
– Therefore overall stream power that they are
incapable of eroding and transporting much
sediment
Stream Valley Development
Downcutting and Base Level
The Concept of a Graded Stream
Lateral Erosion
Headward Erosion and Stream Piracy
Stream Base Level
Downcutting: Process of deepening a stream valley by erosion
of the stream bed. Evolution from narrow slot to wider V-shaped
valley.
Base Level: Defined as the limit of downcutting for a stream.
Changes in base level alter the dynamic equilibrium of the system.
Ungraded vs. Graded Streams
Graded stream: Balance between transport capacity and sediment load.
Maintained by altering the shape of the channel and stream profile.
Graded Streams
Dynamic equilibrium:
– Balance between sediment load and transport capacity
Increased stream gradient:
– Increases velocity, which allows the stream to carry
more sediment and larger particles. This causes more
erosion lowering the gradient.
Change in sediment load:
– Decrease load, can cause erosion, again tending to
lower the gradient. Common downstream of dams.
Response of system is NOT always predictable!
Lateral Erosion by
Undercutting
Stream Landforms
• Stream Terraces
• Incised Meanders
• Superposed Streams
Stream Terraces – Jackson Hole, WY
Stream Terrace Model
Bankfull Stage
Stage occurs when discharge fills the entire
channel cross section without significant
inundation of the adjacent floodplain.
Bankfull Stage
Stage occurs when discharge fills the entire
channel cross section without significant
inundation of the adjacent floodplain.
example
Stream Erosion
Hydraulic Action
Stream Transportation of Sediment
– Dissolved Load
– Suspended Load
– Bed Load
Transportation Mechanisms
– Traction
– Saltation
Hydraulic Action
Niagara Falls
Hydraulic Action!
Stream Sediment Loads
Sediment Load Animation
Stream Deposition
Bars
Braided Streams
Meandering Streams and Point Bars
Flood Plains
Deltas
Alluvial Fans
Deposition and Erosion of River Bars
Normal Flow
Flood: Increased
discharge and
erosion!
Post-flood; new
bars deposited
Braided Streams
Gravel Bars
Braided Stream – Petrified Forest
From: http://geoweb.tamu.edu/RGallery/zion2003/six/6c.htm
Placer Deposits
Oxbow Lake Development
INCREASING TIME
Stream Meanders & Oxbow
Lakes
Point Bar Development
Animation
Goosenecks of the San Juan River,
UT
Photo credit: Synaptic Gallery
Incised Meanders
Superposed Streams
Erosion and downcutting
through young
horizontal units
Folded Units
Development of
water gap
Internal Delta Morphology
Alluvial Fans
Photo credit: National Park Service
Badwater Canyon Alluvial Fan
Death Valley, CA
Flooding
Urban Flooding
Flash Floods
Controlling Floods
The Great Flood of 1993
1997 Flood Floated House
Effect of Urbanization on
Discharge
Levee Break – Cosumnes
River
Flash Floods in Colorado
Flash Flood Effects
Big Thompson Canyon, CO – 1976
Flash Flood Effects
Spring Creek – 1997 Fort Collins, CO
…
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