Geog 272 post midterm

Flashcards for key terms and concepts related to river systems, sediment transport, and coastal processes.

Alluvium

Material deposited by running water, typically young and not consolidated. Very specially dynamic and unconsolidated

Intermittent Stream

A stream that runs dry during parts of the year.

Permanent Stream

A stream that flows year-round.

Ephemeral Stream

A stream that flows briefly for hours or days, primarily after heavy rainfall.

Hydrological Cycle

Processes driven by water that influence much of the shape of Earth’s surface.

Groundwater

Water that flows below ground, maintaining base flows in rivers and streams.

Drainage Basin

An upslope area draining into a stream, also known as a watershed.

Dendritic Pattern

A drainage pattern that resembles a tree, typical in regions with homogeneous rock.

Bedload transport

River sediment transported along the riverbed by rolling, sliding, or hopping. More for coarse materials

Discharge

How much is flowing. A stream’s volume of flow per unit of time.

Measured by a hydrograph annually, for storms and long-term.

Base Level

The lowest point to which a river can erode.

Delta

Landform that forms at the mouth of a river when sediment carried by the river is deposited as the flow velocity decreases upon entering a standing body of water.

Storm Surge

An abnormal rise in water level during a storm caused by low pressure and onshore winds.

Permafrost

Ground material that remains below 0°C for at least two consecutive years.

Erratics Boulders

Pieces of rock carried by a glacier and left stranded on bedrock of a different composition.

Till

Unsorted, unstratified sediment deposited directly by a glacier. Forming moraines, drumlins and till plains

Lateral Moraine

Ridges of till deposited at the margins of a valley glacier.

Erosion

The process of removing and transporting weathered sediments.

Thermokarst

Process - Terrain instability and subsidence caused by melting ground ice, leading to surface lowering.

Kame Hills

Steep-sided conical hills of stratified drift deposited at the margin of a glacier.

glacier.

A slow-moving mass of ice that forms from compressed snow and flows under its own weight.

coastal processes?

natural processes that shape coastlines, including erosion, sediment transport, and deposition.

watershed?

It is an upslope area like a lake that drains into a stream. 

river erosion.

process by which river water wears away rocks and soil, shaping the landscape.

What are fjords?

deep, narrow inlets of the sea between high cliffs, formed by glacial erosion.

coastal wetlands?

areas where saltwater and freshwater mix, providing important habitats for wildlife and serving as natural buffers against storms.

Explain glacial deposition.

during glacial melt, they release the materials they have carried, depositing them as sediment in various landforms.

sedimentation in rivers

process by which sediments are transported and deposited by river flow, shaping riverbeds and banks.

outlet glacier.

ice stream from an ice cap flows into a valley.  transitional area between ice caps and valley glaciers

erosion in coastal environments.

process occurs due to wave action, tidal forces, and currents, leading to the wearing away of cliffs and beaches.

glacial striations?

scratches or gouges cut into bedrock by glacial abrasion, indicating the direction of ice movement.

estuary.

Partially enclosed coastal area where freshwater from rivers meets and mixes with salty seawater. Has brackish water with a mix of sediment

river meandering?

the winding path a river takes as it flows, resulting in curves or bends called meanders.

'permafrost.'

a layer of permanently frozen subsoil, that has stayed below 0 degrees for more than 2 years. Often found in polar arctic regions, and can affect glacial movements.

coastal cliff

Wave-cut platforms are rock ledges that are eroded at the base of coastal cliffs due to wave action.

Water Balance entails…

Atmosphere, surface and subsurface

Inputs, outputs and storage

Tributary

In river systems, other stream sources connected to a main stream. This effects stream order rank

Treillis Drainage

Drainage pattern with multiple parallel straight streams influenced by rock structure, arrises with folding in the landscape

Rectangular Drainage

Drainage pattern in strongly jointed 90^o patterns

Radial Drainage

Outward drainage pattern that develops from single large peak

suspended load transport

Riverine transportation of finer grained sediment, which is swept through with minimal riverbed contact

Straight river form

Single Thread:Typically confined to valleys. Mostly exist in short distances with control channel structure. 

Meandering river form

Single Thread: Gentle gradient found in wider plains. The curves cause variations in flow velocity/energy and sediment deposition.

Braided river form

Multi-threaded: Unvegitated and mountain-fed, fairly shallow but very wide. Unstable splits

Anastomosing river form

Multi-threaded: Anabranching channels consist of multiple channels separated by vegetated semi-permanent islands.

similar in appearance to braided channels, but the splits are permanent

Bar

An elevated region of sediment (such as sand or gravel) that has been deposited by the flow.

highly mobile deposits in rivers and indicator of disequilibrium because the River cannot hold all the sediment it contains.

Longitudinal bar

elongated, align parallel to direction of flow, excess of sediment

Linguoid bar

in rivers with strong seasonal variability, the bar forms perpendicular to the flow direction due to changing sediment transport capacity

Point bar

Form through slow accumulation of sediment. A low, curved ridge of sand and gravel along the inner bank of a meandering stream

Catchment

area where all surface and groundwater ultimately drains into the same outlet (lake, river, or sea)

Hard engineering

Artificial, man-made structures

Soft engineering

smaller-scale techniques, more natural, sustainable approaches, focusing on aligning and working with natural processes. Often with less impact on the environment.

River adaptation purpose

 Protection of large infrastructure, flood protection and Ensuring drinking water supply

Deposition

Potential energy decreases to zero and drops all sediment with it.

Arcuate Delta

Rounded fan shape with lots of distributaries.

tidal DOMINATED

Birds foot delta

Long, projecting distributary channels branching outwards from the shoreline (like claws of a bird) 

fluvial DOMINATED

Cuspate delta

Pointed Triangular shape and few distributaries 

wave DOMINATED

Subsidence

Lowering of land

Tide

 rise and fall of sea levels caused by gravitational forces and the rotation of the Earth

Costal dominant processes

Waves, Tides and Winds

Process-response system

Longshore currents

 energy parallel to the shoreline due to wave action.

Return flow (undertow)

 Upper parts have onshore flow

Near the bottom flow is seaward 

Rip current

strong narrow currents that flow seaward through the surf zone in channels

These are the little channels heading back

Waves

Coastal erosion and sediment transport = wave action with shortlived changes in water level

wave amplitude

Wave height the vertical distance between the wave's trough and crest. 

Wind waves

forms when: wind speed faster than the transfer of energy from crest to crest.

Swell waves

long-period and rounded series of waves generated at a distance

Shoaling waves

slowed down wave that breaks. Wavelength decreases, but wave period stays the same

Height increases and gets steeper

Wave Swash

water rush up the beach. limited by the slope of the water.

Wave refraction

erodes and smoothes coastlines

Spilling waves

wave breaks gradually over a distance. White water forms at the slight curl of the crest and expands down the face of the wave. flat bottom beach.

Plunging wave (cartoon)

peaks up until it becomes an advancing vertical wall of water. The crest advances faster than the base of the breaker, curls, and then descends violently into the trough.

medium to steep sloping beach, with little wind

Surging wave

uniform advances, it surges up the beach as a wall of water. No white breaks.

Found on very steep beaches.

Spits

Long and narrow accumulation of sand with one end connected to the shore and the other extending into the water. The distal end is a barrier to wave action

High latitude coast

Cliff landform with Ice is present. Glacial ice, sea ice, permafrost, etc.They can be low lying or high relief coast line

Berm

Active ridges parallel to the shoreline formed by swash processes A common midpoint indicator between a mean low and mean high tide.

Beach Ridge

Inactive burm left behind by former shorelines, often elevated above the current beach level, formed during periods of rising sea levels or storm events.

Glaciation

Period when continental ice sheets grow and spread outward over vast areas

Deglaciation

Period when the climate warms or snowfall decreases, ice sheets shrink and even melt completely.

interglacial

A period following deglaciation, but before the next glaciation period. Climate is mild. 

Earth’s temperatures influenced by…

Eccentricity (shape of the ellipse), Axial procession and obliquity (earth’s titl)

Ice sheet

 largest form of glacier They are so thick they completely cover the landscape

Ice cap

Same as ice sheet, but smaller

Ice shelves

Ice on the ocean

Piedmont glacier

 unconfined by topography with glacier flows from a valley into an open plain (where it tends to fan out because it loses confinement of the valley).

Glacial Zones

1) Accumulation zone

2) Ablation zone (losses from glacial surface)

Crevasse

crack in the ice

Moulin

 well-like shaft (nearly vertical) draining meltwater from the glacier top to glacier bottom

Stratified drift

layers of sorted glacial sediment deposited by meltwater

Till

Unsorted glacial sediment mixture of rock fragments, ranging in size deposited by the ice (no water)

Ice wedge

massive ice in permafrost systems. This begins with thermal contractions of the earth, which causes cracking. With freeze thaw cycle, this fills with water and creates a wedge

Active layer

Surface layer of permafrost which seasonally freezes and thaws

Pingo

Perrenial frost mound - Ice cored hills, usually up to 20m high,

Palsa

Perrenial frost mound - Ice lenses formed through ice segregation in wetlands

Permafrost issues for agriculture

• difficulty plowing

• “Drunken” fence posts 

• Seasonal streams emerging and flooding areas

• Row lengths shrink annually

All impacting crop yield

Plucking

Glacial erosion - transport large chunks of rocks. Water seeps into cracks in and/or around the rock fragments. Rock becomes unstable, picked up and eroded

Abraison

Glacial erosion - particles scrape against each other

end moraine

a ridge of till that forms at the Recessional moraines terminus of a stationary glacier

Recessional moraine

series of end moraines formed by a receding glacier that periodically stabilized.  If two lines meet…