Water Cycle, Rivers, Flooding

Water Cycle – Driven by Sun’s Energy and is recycled Water Budget

Distribution of Water 97% 2% 1%

The Water Cycle

Evaporation – Water changes from liquid to gas

Transpiration – water escapes from plants during photosynthesis Guard Cells - Stomata

Condensation – Water vapor (gas) changes to liquid - Clouds

Precipitation -When the water in clouds gets too heavy

Run-Off - Water that collects in rivers, streams, and oceans Infiltration – When water seeps in ground

Summary: Condensation The Clouds form Transpiration The movement through plants Precipitation The rain falls Evaporation The vapor rises

How can water be conserved? Household Uses…? Agriculture/Industry….? Pollution…? Desalination….?

Watersheds & River Basins

Watershed Land that drains water to a particular stream, lake, or river.

The high land that separates one watershed from the next. Divide The high land that separates one watershed from the next.

River basin The land drained by a river and its tributaries.

Tributary – Feeder Streams

Other Terms - Meandering

Other Terms – Channel Erosion

Other Terms – Discharge = Velocity Gradient = How Steep the Slope

Other Terms – Water Gap- carved in Mountain Wind Gap- when no more water

Stages of a River Youthful – V-shaped valley, few tributaries, little water, lots of waterfalls Mature – Lots of tributaries, starts to meander, Oxbow Lake Old – Few tributaries, lots of meandering

Youthful

These young streams typically have V-shaped valleys.

The rivers tend to move fast in their upstream portions,

The young mountain streams tend to have a steep slope or gradient.

Mature/Old - Meandering Rivers

To view an animation of this process click on this web site. http://www.school-portal.co.uk/GroupDownloadFile.asp?file=21606

Mature to Old River – click fast

Maximum deposition Maximum erosion

Meander scars Oxbow Lake Oxbow cuttoff

Delta- Fan Shaped Deposit Made in Water Made of Mud Flat land

The deposit is formed on land Alluvial Fans The deposit is formed on land Sand and Gravel Land is Sloped

Question – Why would people live in flood-prone areas? Flooding Causes Spring Floods Deforestation Weather/Flash Floods Solutions Risk Mapping (GIS) Levees/Dams Sandbags Channelization Wetlands Question – Why would people live in flood-prone areas?

Anatomy of a Flood Prone Area Soggy soil Heavy rain Steep slopes Impermeable rock Loss of trees Built up areas Flat flood plain The flood plain is flat land around the river that the river floods naturally when it gets too full. If you live on a river’s flood plain you are at risk of flooding.

Ecological evidence of flooding

Wetlands Help Protect From Floods

1993 Mississippi Flood

More Pictures

What’s Wrong With This Picture?

Flash Flood

Deforestation

Risk Mapping

Artificial Levees

Sand Bags

Channelization

Flood Risk Simulation https://www.floodsmart.gov/floodsmart/pages/flooding_flood_risks/flood_scenarios.jsp

Review Questions What is….Evaporation? Precipitation? Condensation? Transpiration? Run-Off? Infiltration? Name 2 ways water can be conserved. What is a…River basin? Divide? Meandering? Name one characteristic of a Youthful River… Mature River… Old River. What is the difference between a Delta and Alluvial Fan? Name some causes of Floods. Describe some solutions to Flooding.