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 Know your watershed http://www.epa.gov/surf/ 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 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

velocity discharge gradient What factors affect stream erosion? distance the water travels in a period of time discharge volume of water moved by a stream within a given time gradient steepness of a stream’s slope

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