The Flow of Water

The Water Cycle

http://observe.arc.nasa.gov/nasa/earth/hydrocycle/hydro3.html

What is Water Budget?• balance in the water cycle means the

average annual precipitation over Earth equals the amount of water that evaporates

• the worlds water budget is in balance because precipitation = evaporation

• local water budgets (that of a particular area) are NOT balanced due to temperature, presence of vegetation, wind, and amount and duration of rainfall

Water Conservation

•each person in the U.S. uses 575 liters of water each day on average–bathing, washing clothes, dishes, brushing teeth, watering lawn, carrying waste away, drinking

Agriculture and industry use the greatest amount of water

90% of this used water is returned to rivers, lakes,

oceans, etc.

http://wwwga.usgs.gov/edu/wwvisit.html

What are the 2 ways to ensure water is there

tomorrow?•conserve, conserve, conserve!

•desalination (removing salt from the ocean water)

Desalination Plant in Key West, FL

What are the parts of a River

Systems?

watershed•land from which water runs off into streams (drainage basin)

Surf your watershed

http://www.epa.gov/surf/

Know your watershed

http://ctic.purdue.edu/kyw/kyw.html

tributaries•feeder streams that flow into a main river

divide•ridges or elevated regions of high ground that separate watersheds

headwaters•beginning of a stream

Stream Erosion

channel•the path that a stream follows

bank

bed

headward erosion

•process of lengthening and branching of a stream

What is stream piracy?

•the capture of a stream in one watershed by a stream with a higher rate of erosion in another watershed

Stage 1 - Beaverdam Creek, Gap Run, and Goose Creek flow eastward through the Blue Ridge and enter the Potomac.

Stage 2 - As the land is eroded downward, the three east flowing creeks do not have the power to erode as far through the Blue Ridge as the Shenandoah, Potomac system. The Shenandoah extends itself southward by headward erosion through the relatively high land west of the Blue Ridge. It eventually captures Beaverdam Creek.

Stage 3 - The capture of Beaverdam Creek added more discharge to the Shenandoah which was able to therefore erode more. Headward erosion leads to the capture of Gap Run. The water gaps where Beaverdam Creek and Gap Run used to flow through the Blue Ridge are left as wind gaps.

Stage 4 - Eventually Goose Creek is captured as well. Snicker's Gap, Ashby Gap, and Manassas Gap are left as wind gaps. As the land on either side of the ridge is eroded down together with the ridge summit, the relative elevation of the wind gaps becomes higher and higher.

What are the types of channel erosion?

stream load:

material carried

by a stream

dissolved load: mineral matter transported in liquid solution

suspended load: particles of fine grains and silt suspended in the water

bed load: large, coarser sand, gravel, and pebbles that move along the bottom

Bed

discharge• volume of water moved by a stream

within a given time

gradient•steepness of a stream’s slope

• distance the water travels in a period of time

velocity

What factors affect stream erosion?

River Systems

What are the features of a Youthful river?

•straight •erodes rapidly•V-shaped•few tributaries•has waterfalls and rapids

What are the features of a Mature river?

•meandering (winding)•slow erosion•U-shaped •lots of tributaries •holds lots of water

What are the features of an Old river?

•gradient and velocity decreases

•no more erosion•more meandering

What is a water gap?

•notch formed where the stream has eroded its channel

What is Stream Deposition?

as the velocity of a stream decreases, it drops the sediment it was carrying

What are deposition features created by

rivers?

1. delta•underwater deposit of sediment at the mouth of a stream into a lake or ocean

2. alluvial fan

•fan-shaped deposit at the base of a slope on land

3. floodplain

•part of the valley floor that may be covered with water during a flood

4. natural levee

•raised riverbank that results when a river deposits its load at the river’s edge

Flood Control

artificial levee

dams

Ohio River Flooding

What is Groundwater? underground water that

fills almost all the pores in rock and sediment

• -makes up 90% of the Earth’s liquid freshwater

What is Porosity? refers to the

percentage of open spaces in rock or

sediment

What affects Porosity? 1. sorting: amount of uniformity in size of particle in a rock or sediment-same size particles=large porosity

-different size particles= small porosity

• 2. way particles are packed together – packed loosely= high porosity- packed tightly= low porosity

What is Permeability?

how freely water passes through open spaces in

rock or sediment

• -open spaces must be connected to be permeable !

Impermeable: rock or sediment that

water cannot flow through

Groundwater Vocabulary Terms

• zone of saturation: layer of groundwater where all pores are full

• aquifer: underground body of water (underground lake); can have sediments and rock in it

•water table: upper surface of the zone of saturation

capillary fringe: where water is drawn up by capillary action from zone of saturation

•zone of aeration: zone that lies between water table and surface (remains dry except during rainfall)

•soil-water region: space around soil accumulates water

Ground water flow depends on permeability of aquifer and gradient of

its water table.• Gradient increase = velocity of

ground water increaseGradient decrease = velocity of ground water decrease

What affects groundwater flow?

• well: a hole that is dug below the water table and fills with groundwater

• cone of depression: cone-shaped depression in water table around a well

• artesian well: well in which water flows freely with no pumping necessary

• cap rock: top layer of impermeable rock

Cone of Depression

•spring: flow of groundwater that emerges naturally at the ground surface

•artesian spring: natural flow of water to the surface from an artesian formation

•hot spring: hot groundwater that rises tosurface before cooling

•geysers: hot springs that erupt periodically

•Conserving Groundwater:Sources of pollution – water dumps, underground storage tanks, agriculture and lawn fertilizers, pesticides, leaking sewage

Groundwater Contamination

•Conservation – monitor levels of water tables, discourage uses of excess water, recycle, purifying used water

Results of Weathering by Groundwater

•hard water: water that contains large amounts of dissolved minerals–has metallic taste, soap won’t make suds, damages appliances that use water

•caverns: large cave with connecting chambers

Observe an animation of cave formation.

•sinkhole: depression formed when the roof of a cavern collapses

stalactite: cone-shaped calcite deposit suspended from the ceiling of a cavern

stalagmite: cone-shaped calcite deposit built up from the floor of a cavern