Water Resources Groundwater

Key definitions Zone of aeration – soil and rock are less saturated (some pores contain air) Zone of saturation- pores contain only water Porosity- dependant on size, shape, and degree of compaction Permeable/impermeable- permit or obstruct water flow

Key definitions Aquifer- a rock layer that is permeable to groundwater flow Aquiclude- body of rock that does not conduct water

Water table Water table- the upper limit of the water that collects in the zone of saturation Basically just the border between the saturation zone and the aeration zone

Groundwater Characteristics

Worlds largest aquifer High Plains Aquifer How did it form?

Water Withdrawal by Sector

Global Water Scarcity

Well issues…

GROUND WATER POLLUTION

Water Resources Surface Water

Surface Water has two primary pathways once it falls onto Earth: -overflow  RUNOFF! -movement into ground (infiltration and percolation) Places with large amounts of rainfall typically have large amounts of runoff

Annual Global River Runoff

Drainage Basin Drainage divide- ridges or mountains that separate where precipitation drains –The Appalachian Mountains separate the East from the Central US

A Drainage Basin

Watershed Watershed- The water receiving area of a drainage basin

Drainage Basins

Streamflow Characteristics Stream Discharge Q (quantity of H 2 O produced) = width x depth x velocity

Stream Transport Streams transport sediment in several ways—all depend on the velocity of stream: –Dissolved load (solution): water appears clear but contains dissolved salts or other substances –Suspended load: water carries material along—usually brown muddy looking water –Bed load: large and heavy particles are pushed along the bottom (bed)

Fluvial Transport

Three Types of rivers Braided—lots of excess sand and sediment Straight—generally flow downhill and have little curve Meandering—large curvatures, snake like appearance that is constantly changing

Braided River Channel

Meandering Stream Profile

OXBOW LAKE

Oxbow lakes How do these lakes form? –SHORTEST PATH TO THE OCEAN!

Meandering Stream Development

Itkillik River, Alaska

Carter Lake, Iowa

Floodplains Floodplain- the flat, low-lying area flanking a stream channel that is subjected to recurrent flooding

Floodplain Features

River Deltas River delta- the mouth of a river is where it reaches base level, at this point the river slows and the depositional plain that forms is known as the delta Called ‘delta’ because of its shape

Ganges River Delta

Nile River Delta

Mississippi River Delta