Earth Science Unit 4 Chapter 9

“All streams flow into the sea, yet the sea is never full. To the place the streams come from, there they return again.”

Chapter 9

Gas turning into a liquid

Condensation

Material falling to the ground because of gravity (rain, sleet, snow, etc)

Precipitation

Process of a liquid turning into a gas

Evaporation

Seeping into the ground

Infiltration

Water moving across the surface

Runoff

Water moving through plants

Transpiration

Transpiration when it evaporates from the leaves

Evapotranspiration

Water flowing downhill due to gravity confined to a channel (rivers, creeks, etc)

Stream

Earth as a system; illustrates the circulation of Earth’s water supply

Hydrologic Cycle

Type of stream that meanders through the landscape; soft material

Meandering stream

Type of stream where multiple sections are confined to one channel; glacial or mountain areas

Braided stream

Smaller stream that flows into a larger stream

Tributary

How is water proportioned on earth?

Majority of water is in the ocean, only 1% is liquid freshwater. Majority of freshwater is in glaciers

The bottom of the stream

Stream bed

Where the water is in a stream

Channel

The edges of the stream

Banks

Start of the stream

Head

End of the stream

Mouth

Land area that contributes water to a river system

Drainage basins

A high spot where water flows downhill to a drainage basin (separates them)

Drainage divide

The largest drainage divide in the US and is in the Rocky Mountains

Continental divide

Drainage pattern: many tributaries connecting to a main stream channel; resembles a tree; typical of flatter areas with softer material (easily eroded in any direction)

Dendritic

Drainage pattern: streams originate from one central location; typical of mountain or volcano tops

Radial

Drainage pattern: streams that meet at near right angles; typical of highly fractured rock areas

Rectangular

Drainage pattern: tributaries that form parallel to one another; typical of areas confined by mountain ranges or ridges (streams are in the valleys)

Trellis

Slope of a streamflow

Gradient

Amount of interference on the stream bed/banks - friction slows water

Roughness

Volume of water flowing in the stream

Discharge

Transported material

Stream load

Ions dissolved in the stream; not solid

Dissolved load

Solid particles floating in the stream

Suspended load

Solid material in contact with the stream bed

Bed load

Sediment that skips along the stream bed (sometimes in contact with the bed & sometimes not)

Saltation

Sediment that rolls along the stream bed (always in contact with the stream bed; includes sliding and rolling)

Traction

Maximum particle size

Competence

Maximum load (related to discharge)

Capacity

Sediment that is not being moved (left behind)

Deposition

Lowest point a stream can erode to

Base level

What are the two types of base levels and what do they mean?

1. ultimate base level (sea level)

2. temporary base level (local base level)

Area adjacent to the stream that typically floods

Floodplain

Feature of meandering river; curves in the stream

Meanders

Feature of meandering river; no longer attached to the stream

Cutoff meanders

Feature of meandering river; cutoff meanders filled with water

Oxbow lakes

Feature of meandering river; cutoff meander not filled with water

Meander scar

Outside of bend; where erosion occurs

Cutbank

Inside of bend; where deposition occurs

Pointbar

Sediment deposited when a stream flows into another body of water; in a fan shape; generally sand

Deltas

Sediment deposited when a stream flows onto a flat surface (not in water; flows down a mountain to a valley in a dry climate); in a fan shape

Alluvial fans

Sediment deposited as a stream overflows its channel; form parallel to the stream channel

Natural levees

When a stream overflows its banks; the most common geologic hazard

Flood

What are some ways we can control floods?

• engineering efforts (artificial levees, dams, channelization)

• Nonstructural approach through sound floodplain management (constructed wetlands)

Measures stream flow to help monitor and predict floods

Hydrographs

The average time in years between floods of the same size

Recurrence interval

The largest fraction of liquid freshwater; water within the pores/water beneath the surface

Groundwater

Pore spaces in the soil material are filled mainly with air but can have some water, especially after a rain event (belt of soil moisture)

Zone of aeration/Unsaturated zone

All pore spaces in the material are filled with water

Zone of saturation

The upper limit of the zone of saturation

Water table

Percentage of pore spaces that determines how much groundwater can be stored

Porosity

Spaces between particles, like the space between individual sand grains

Pore spaces

Ability to transmit water through connected pore spaces; the interconnectedness of pore spaces

Permeability

An impermeable layer of material; low permeability and porosity (water does not flow through it; like the blacktop on roads and parking lots) (shale)

Aquitard

A permeable layer of material; high porosity and high permeability (water flows through it) (sandstone, conglomerate, limestone)

Aquifer

Open to the surface that can be refilled by rain events

Unconfined aquifer

Confined between 2 aquitards; very limited area at surface to be refilled by rain events; most water in confined aquifers was put there during the last glacial period

Confined aquifer

Suspended above the water table; also known as a false water table (water will “run out” for wells drilled here)

Perched aquifer

Area at the surface where water infiltrates the aquifer by rain events

Recharge zone

Where water is pumped out of the ground

Wells

Water in the well rises higher than the initial groundwater level (under pressure); occurs with a confined aquifer

Artesian wells

Intermittent hot springs; water beneath the surface turns to steam and erupts due to the pressure from below

Geysers

Caused by groundwater withdrawal (land compacts when it no longer has water and will no longer hold as much water as it did before)

Land subsidence

Explain point source vs nonpoint source pollution

Point source can tie back to a specific place, nonpoint cannot

Freshwater is less dense than saltwater, so it is at the top; a well near the ocean can cause unwanted saltwater to come up into the well

Saltwater Intrusion

Voids in rock, commonly limestone, formed by the dissolution of rock beneath Earth’s surface

Cavern (caves)

Terrain formed by dissolving rock at, or near, Earth’s surface

Karst topography

Surface depressions formed by dissolving bedrock and cavern collapse

Sinkholes

Formed by pumping in the water table due to the drawdown; the larger the well, the larger this is

Cone of depression

Has caused a drop in the water table of up to 70 meters; treating groundwater as a renewable resource

Groundwater overdraft