Watersheds/Stream Drainage

Patterns

WATERSHEDS / DRAINAGE BASINS• Watershed: The area of land drained by any one

stream• REMEMBER: a stream is running water that’s

confined to a channel---this channel can be any size:

SMALL

MEDIUM

LARGE

Q:Where does water go once it hits the surface of the earth?A: Some gets absorbed into the ground (infiltration) some flows along the surface (runoff)

Topic 11D.1 -- Running Water - An Erosional-Depositional System I

A. Watershed or Drainage Basin = the entire area of land from which a stream and its tributaries receive water.

B. Divide = Imaginary line which separates the drainage basins of two separate streams.

Q:Where does water go once it hits the surface of the earth?

A: Some gets absorbed into the ground (infiltration) some flows along the surface (runoff)

Water always flows from HIGH elevation to LOW elevation.

Along the way, this water combines with other water, so the size of the stream gets bigger and bigger.

A

B

The smaller streams are called tributaries.

These watershed regions are pretty small because the streams they feed into are pretty small

The rivers of New York State obtain their water from very distinct regions. The state is divided into the following

DRAINAGE BASINS (WATERSHEDS):

In what drainage basin is Valhalla?

The Continental Divide

This side, all water flows to

PACIFIC OCEAN

This side, all water flows to

ATLANTIC OCEAN

The UNITED STATES is split into

two LARGE drainage basins

Stream Drainage Pattern:

-The shape of a stream’s course in an area as viewed from the sky

or

-what the pattern of stream flow is when looking from above

*The formation of the pattern a stream creates is determined by the shape of the underlying bedrock structure

a)dendritic: homogeneous rock

b)trellised pattern: alternating weak and strong rock

c)radial: dome uplift or volcano.

d) centripetal: converging to a central basin e) rectangular: intersecting fractures in bedrockf) deranged: retreat of glaciers

Dendritic Drainage-Consists of many tributaries flowing into one river

-Occurs in a humid climate

-Looks like branching tree roots

Trellis Drainage - Looks like a trellis.

- WHAT IS A TRELLIS???

Trellis drainage-occurs when tributaries flow at right

angles to rivers

Rectangular drainage -Occurs in regions of faulting

-Water flows along path of least resistance

-Right angles form from the offsetting of faults (land is shifting left/right up/down at right angles)

Radial Drainage

-develops around a central elevated point (Mountain Peak)

-Tributary “roots” start at the high elevation

Centripetal Drainage

- Opposite of Radial Drainage

- Streams flow to a central depression or basin

Deranged Drainage-No apparent pattern

-Streams flow with the landscape left behind from a glacier

-Water is from the retreat of the glacier

• Question:– What determines the shape of a

stream drainage pattern????

The landscape of the underlying bedrock