Surface Water SG

groundwater, glaciers, oceans

3 largest reservoirs of water on Earth

groundwater

largest source of readily available drinking water

glacial ice

largest freshwater reservoir of water

ocean

largest reservoir of water by far

downcutting

Why do mountain streams form V-shaped valleys?

angle of repose

maximum angle a slope (gradient) can have and remain stable

decreases

Slope (gradient) ______ as you move downstream.

decreases

Downcutting ______ as you move downstream. (V shape is disappearing.)

increase

River width, depth, volume of water all ____ as downcutting increases.

tributaries

River width depth, and volume of water all increase as down cutting increases because new ____ joint the main stream.

increases

Drainage basin ____ as you move downstream.

discharge

the volume of water that passes a give point in a given amount of time

A x V (area x velocity)

How to calculate discharge:

Q =

decreases

When area is increased, velocity ____.

increases

When area is decreased, velocity _____.

braided rivers

What type of river forms a flood plain?

Oxbow

a cutoff meander when two cutbanks join

when two cutbanks join

How is an oxbow formed?

slows, deposited

The river becomes braided at a delta because water ___ down as it enters the ocean. When a river reaches a standing water body, sediment is ______. This creates multiple channels.

semi-arid regions, outwash plains (front of a glacier)

Braided rivers are located in deltas, ___ - ___ _____, _____ ____.

river drainage basins (watersheds)

the area that a river drains

increases

The size of the drainage basin ____ along a river profile.

hydrograph

plots of discharge over time

levees, dams, floodways, floodwalls, retention ponds, zoning maps

5 ways to reduce flooding hazards

levees

create higher banks restricting the flow of water (reduces flooding hazards)

dams

effectively prevent floods by storing water and releasing it in controlled amounts (reduces flooding hazards)

floodways

special artificial channels (we dug it) to divert floodwaters (reduces flooding hazards)

floodwalls

have gates that can be closed to protect communities from flooding (reduces flooding hazards)

retention ponds

DELAY THE ENTRY OF ADDITIONAL WATER INTO A RIVER; capture storm runoff (reduces flooding hazards)

zoning maps

avoid building on floodplain!(reduces flooding hazards)

lower

The BIGGER the flood, the ___ the frequency of occurrence.

smaller

The _____ the flood, the higher the frequency of occurrence.

larger

The larger the flood, the ____ the recurrence intervals.

smaller

The smaller the flood, the ____ the recurrence intervals.

area is reduced

Velocity increases in a channelized river flow because the ___ __ _____. (shorter distance)

flooding, hydroelectric, water, revenue

Pros of Dams:

• Controls _____

• ______ power

• Source of ___ and ____

sediment, sand/silt, lower, flood deposits, migration

Cons of Dams:

• ____ buildup in the lake, pay to remove the sediment.

• Loss of ___/___ in delta

• ____ profile downstream from the dam

• Lack of fertile cropland due to lack of ____ ______ (mud)

• Fish _____

Meandering river

river type is typical of lower gradient areas; bend in river

outside bank

Greatest amount of erosion occurs in the ____ ___ of a meandering river. Occurs because water flows faster. CUTBANK

inside bank

Deposition occurs in the ____ bank of a meandering river. Occurs because water flow is slower. POINTBAR

cutbank

outside bank, area where faster flow, erosion dominates

pointbar

inside bank, area where water is slower, deposition dominates

sinuosity

amount of curves

river distance/straighline distance

How is sinuosity calculated?

braided stream

River or a stream that has wayyy too much sediment in it

sediment

Braided shape in a braided stream is because it has so much ____ that there’s several river channels that tend to crisscross.

trapping

Sediment accumulate on the upstream side of a river because it causes a slower-moving reservoir area behind it, causing suspended sediment to settle out of the water and deposit on the bottom, essentially _____ it in the reservoir.

radial, trellis, rectangular, dendritic, deranged

5 types of river drainage patterns

radial

radiates out in all directions from a central point.

• controlled by a central high point (looks like a mountain)

trellis

controlled by rock types that are tilted, ends up being a ridge where water is stuck flowing between them

rectangular

taking right angled turns

• fractured rock is controlling it

dendritic

tree

deranged

doesn’t know where its going.

• occurs when there is an extremely low grade