2Surface water movement: Water (Hydrologic) Cycle Earths water supply is constantly recycled
3The Water Cycle The Sun provides energy for the water cycle. Radiation from the Sun causes water to change to a gas called water vapor.The process of water vapor changing to a fluid is called condensation.
4Precipitation falls to Earth’s surface in the form of rain, snow, sleet, or hail. Water then flows downslope along Earth’s surface which is called Runoff.
5Runoff may reach a stream, river, or lake, may evaporate or may accumulate into puddles and eventually seep intothe ground.
6Water that seeps into the ground becomes groundwater. For water to enter the ground, there has to be large pores or spaces in the ground.
7Fate of water: Run off or Seep Certain characteristics will determine whether not water will either seep into or become runoff1) VegetationVegetation allows for loose soilLoose soil allows water to enter ground
8Fate of water 2) Rate of precipitation Heavy: Light: Water falls too quickly and becomes runoffLight:allows water to gently slide through
9Fate of Water 3) Soil Composition Effects the waters holding capacity Decayed organic matter (humus)Creates the pores in soil which retains waterMineralsClay – fine mineral which clump togetherFew SpacesSand – large pores-allows water to move through it.
10Fate of Water4) SlopesSteep: allows for high runoff & little absorptionLittle: low runoff and high absorption
11Formation of Stream systems Precipitation that does not enter the ground usually runs off the surface quickly.Surface water flows in thin sheets and eventually collects in small channelsRunoff increases, channels widen and become deeper and longerChannels fill up again each time with rainChannel can become a stream
12Streams Some streams flow into lakes and oceans. Tributaries flow into other streams.
13StreamsA large stream = River. All of it’s tributaries make up a stream or river system.Small streams are called brooks or creeks.
14Water sheds (Drainage Basin): Land where all water drains into a streamDivideHigh land area that separates watersheds
15Stream Load All the materials that the stream carries There are 3 ways that a stream carries a load:SolutionSuspensionBed Load
16Stream LoadSolutionMaterial is carried in solution after it becomes dissolved in a stream’s water.
17Stream Load Suspension All particles small enough to be held up by the turbulence of a stream’s moving water are carried in suspension.Silt, Clay, Sand
18Stream LoadBed LoadLarge sediments that are too heavy to be held up by turbulent water.Consists of sand, pebbles, and cobbles that the stream rolls and pushes along the bed of the stream.
19Stream LoadBed LoadAs the particles move, they rub, scrape, and grind against one another or against solid rock of the streambed in a process called abrasion.This causes the rocks to be polished and round.
21Stream velocity and carrying capacity The ability of a stream to transport material is called the carrying capacity.Discharge = The measure of the volume of stream water that flows over a particular location within a given period of time.Expressed in cubic meters per second (m3/s)
22Stream Velocity & Carrying Capacity Discharge = width x depth x velocity (m) (m) (m/s)As discharge increases so does carrying capacity
23FloodplainsFloods occur when water spills over the sides of a stream’s banks onto the adjacent land.Floodplain: broad flat area of land that extends out from streams for excess flooding
25FloodsFlood stage = level where a stream overflows its banks and the crest of the stream is at max heightUpstream flood = the flooding of a small area. They are localized and cause damage within a short period of time.