Running Water

Evaporation

Precipitation

Infiltration

Runoff

Transpiration

Components of the hydrological cycle.

Infiltration

Process wherein precipitation falls on land and soaks it.

Runoff

Process wherein water flows over the surface.

Transpiration

Process wherein water is absorbed by plants and later released in the atmosphere.

Stream

Flow in a channel regardless of size.

River

Type of stream that carry substantial amounts of water and have numerous tributaries.

Divide

A ridge that divide each drainage basin. An imaginary line.

Outlet

Where streams exit drainage basin. Has lower elevation compared to the rest of the basin.

Trunk streams

Where sediment acquired is transported through the channel along streams.

Sediment production

Sediment transport

Sediment deposition

3 zones of river systems

Sediment production zone

Water and sediment are derived. Located in the headwater. Features included weathering of bedrock and erosion of banks.

Sediment transport zone

Characterized by trunk streams.

Sediment deposition zone

Where river enters larger body of water. Energy and velocity of transport greatly reduced.

Laminar flow

Slow. Water moves in straight lines parallel to stream channel.

Turbulent flow

Erratic and fast. Series of vertical and horizontal swinging. Characterized by whirlpools, eddies, and rapids.

Effluent stream

Type of stream where flow is maintained during the dry season by groundwater seepage into the channel.

Influent stream

Type of stream that is everywhere above the groundwater table and flows in direct response to precipitation. Water from the channel moves down to the water table, forming a recharge mound. Loses water.

Gradient

Slope of the stream channel. Vertical drop of stream over specified distance. Varies along the length of the channel.

Wetted parameter

Amount of flow in contact with the bed and banks. Dictates efficiency of stream.

Bankfull

The maximum discharge that a river channel is capable of carrying without flooding.

Discharge

Amount of water supplied from drainage basin. Volume flowing past a certain point in a given unit of time.

Discharge

Cross section x Velocity

Increase in stream width, depth, and flow velocity is a result of?

Increased river discharge.

Longitudinal profile

A cross section of a stream channel along its descending course from the head to the mouth.

Stream velocity and discharge is greater at the mouth.

True.

Stream erosion

Removal of material from the floor and sides of a channel.

Rivers with silty banks are wider that those with sandy banks.

False.

Quarrying

Removal of blocks from bed of channel. Aided by fracturing and weathering. Result from impact forces of flowing water.

Abrasion

Bed and bank continuously bombarded by particles. Smooths and rounds abrading particles. Reduces sediment size.

Potholes

Holes carved into rock at the base of river with a whirlpool action.

Dissolved load

Acquired soluble soil compounds which seeps through cracks and pores in bedrock. Brought to stream by groundwater.

Suspended load

Carry the largest part of the load. Showed by the muddy appearance of water. Mainly fine sand, silt, and clay. Amount increases with increasing stream velocity.

Settling velocity

Speed at which particles fall on still fluid. Affected by size, shape, and specific gravity.

Bed load

Composed of coarse materials like coarse sand, gravel, and boulders. Moved by rolling, sliding, and saltation. Movement is less rapid and localized.

Capacity

Maximum load of solid particles a stream can support per unit time.

Greater discharge = greater capacity

True.

Competence

a measure of the stream's ability to transport particles based on size rather than quantity. Increases proportionally to the square of the velocity.

Sorting

Separation of solid particles by size.

Alluvium

Sediment deposited by streams.

Bedrock channel

Streams cutting across solid rock. Potholes and waterfalls common.

Alluvium channel

Streams cutting across unconsolidated sediment. Characterized by floodplains.

Pools

Relatively flat segments where alluvium accumulates.

Steps

Exposed bedrock in bedrock channels.

Bedrock channel

Characterized by pools and steps. Have winding irregular patterns.

Meandering channel

Stream channel with broadly sinuous banks that curve back and forth in sweeping bends. Deep and smooth.

Meandering channel

Generally transports mud, sand, and occasionally fine gravel. Bends migrate over floodplain.

Where are point bars deposited?

Inner bank of meander.

In a meandering stream, erosion happens where?

Outer bank of meander.

Point bar

A crescent-shaped accumulation of sand and gravel deposited on the inside of a meander.

Cut bank

The steep bank feature that forms on the outside of a river bank due to erosion.

Meanders migrate laterally.

True.

Oxbow lake

A crescent-shaped lake (often temporary) that is formed when a meander of a river is cut off from the main channel.

Braided channel

A network of converging and diverging channels that thread among numerous islands or gravel bars. Mainly bed load. Common on ends of glaciers.

Bars

Segments of braided channels that are composed of coarse sediments and causes the flow to split.

Base level

Downward limit to stream erosion. Lowest elevation to which a stream can erode. Can be a lake, ocean, or trunk stream.

The ultimate base level

Sea level

Local base level

The level of a lake, resistant rock layer, or any other base level that stands above sea level.

Graded stream

A stream that has the correct channel characteristics to maintain exactly the velocity required to transport the material supplied to it. Neither erode nor deposit.

Stream valley

The channel and the surrounding terrain that directs water to the stream.

Valley floor

Lower, flatter area that is partially or totally occupied by the stream channel.

Valley wall

Sloping "walls" that rise above the valley floor.

Wide valley floor (U-shaped)

Common distinguishing parameter of alluvial channels.

V-shaped valley

Common distinguishing parameter of bedrock channels.

Valley deepening

Steep gradient + channel above sea level. Produce V-shaped valleys. Features are rapids and waterfalls.

Resistant beds

Creates rapids in bedrock channels. Acts as temporary base level.

Knickpoint

A sharp irregularity (such as a waterfall, rapid, or cascade) in a stream-channel profile. Made of resistant rock.

Valley widening

Graded condition = downcutting less dominant. Produces meandering patterns and floodplain.

Floodplain

Broad, flat, valley floor covered with alluvium. Carved by a meandering stream.

Erosional floodplain

Forms when a river erodes laterally and creates a floodplain.

Depositional floodplain

Produced by major fluctuations in base level or climate conditions.

Incised meanders

Meandering channels that flow in steep, narrow, valleys. May initially form in a floodplain then change in base level occurred (base level drop or uplift).

Stream terraces

Remnants of a former floodplain present as relatively flat surface. Formed when stream downcuts deposited alluvium.

Delta

Sediment-choked stream. Grows outward at entry of lakes, inland sea, or ocean. Triangular in shape. Sediment supply > erosion.

Distributaries

The fan of small streams formed where a river spreads out over its delta.

Natural levee

A deposit of sand or mud built by floods up along, and sloping away from, either side of the flood plain of a river or stream. By meandering rivers with broad floodplains.

Back swamps

A poorly drained area on a flood-plain resulting when natural levees are present.

Yazoo tributary

A tributary that flows parallel to the main stream because a natural levee is present.

Alluvial fan

Fan-shaped deposits. Accumulate along steep mountain-fronts. Common in arid and humid regions. Fan-shaped due to main flow swinging back and forth between tributaries.

Debris flow deposits interbedded with coarse alluvium

Deposits found at alluvial fans.

Dendritic pattern

Irregular branching that resembles tree branches. Uniform bedrock. Patter determined by slope of land.

Radial pattern

Diverges from central area like isolated volcanic cones or domal uplifts.

Rectangular pattern

Pattern of joints guides the direction of streams. Bedrock is crisscrossed series of joints.

Trellis pattern

Nearly parallel streams. Alternating bands of resistant and less resistant rocks. Common in folded regions.

Flood

Great stream flow that exceeds channel capacity causing water to overflow.

The larger the flood, the more it is expected.

False.

Regional flood

Seasonal. Due to rapid melting of snow or heavy rains.

Flash flood

Little warning, deadly. Dictated by rainfall intensity, duration, surface conditions, and topography. Urban areas susceptible.

Ice-jam flood

A flood, usually in the spring, that results from broken pieces of river ice blocking the flow of a river, thereby flooding areas adjacent to the river.

Dam failure flood

Due to failure of artificial dam or artificial levee. Like flash flood but different in terms of cause.

Artificial levee

Earthen mounds built on river banks to increase the volume of water the channel can hold. Most common stream-containment structure.

Dam

Built to store floodwater and release it slowly. Temporary solution to flooding. Damages river ecosystem. Volume of reservoir diminished by sedimentation.

Channelization

Altering a stream channel to speed the flow of water to prevent it from reaching flood height. Channel clearing or dredging.

Avulsion

Sudden change of the course of a stream