Running Water Day 1

Mass Movements Recap Rockfalls – A rockfall occurs when rocks or rock fragments _______ freely through the air Slides – In a slide, a _______ of material moves ______________along a flat, inclined surface – Slides that include segments of bedrock are called rockslides Slumps – A slump is the downward movement of a block of material along a ___________surface

Mass Movement Recap Flows – Flows are mass movements of material containing a large amount of _______ – Mudflows move quickly and carry a mixture of soil, rock, and water that has a consistency of wet concrete – Earthflows move relatively slowly and carry clay- rich sediment Creep is the slow, downhill movement of soil and regolith

Running Water The single-most important erosional agent on earth is _____________________. But where does the water come from, and how much of it is running, or moving on our planet?

Water Cycle  Water is EVERYWHERE  About 97.2 % is in the oceans  About 2.15 % is in glaciers and ice sheets  About 0.65 % is _______________ in lakes, streams, groundwater, and the atmosphere  Water constantly moves among the oceans, the atmosphere, the solid Earth, and the biosphere. This unending circulation of Earth’s water supply is the ______________________.

Water Cycle How much of our planets water is fresh? ___________ How does that affect life on our planet?

Water Cycle 1.You are already familiar with the Water Cycle - precipitation, evaporation, infiltration, runoff and transpiration. - Infiltration – the ____________________________________or soil through cracks and pore spaces. - Runoff – excess water that does not permeate into the land and _____________________________________instead Running water starts as precipitation and either infiltrates the surface to flow under ground, or becomes runoff and creates streams and rivers.

Running Water  When water falls to Earth it hits the ground running in the form of ____________and ___________  ______________influences how water makes its way to the sea – or base level.

Streams Water that has become runoff creates streams. The stream channel is the _________that the water in a stream follows. Streams have different features that will determine how much erosion it causes: 1.______________ 2.______________ 3.Stream ________________ 4.______________level Let’s take a closer look at each of these features…

Streams - Gradient Gradient is the _________or steepness of a stream channel. – Expressed as the vertical drop of a stream channel over a certain distance. Which would move at a higher rate: (highlight) – A stream with a high gradient, or – A stream with a low gradient? Why? ______________________________________

Stream Profile  A stream’s ___________is the cross-sectional view of a stream – From ___________(source) to __________. Where would a stream have the steepest gradient – near the head or near the mouth? The stream would have a steeper gradient near the _______________.

Streams - Discharge A streams discharge is ____________________ ______________in the stream at a given point. – Discharge can vary with snowfall, snowmelt or drought. What do you think would happen if a stream’s discharge is increased? – It would go ___________: increased velocity – It would get __________: increased channel width – It would get __________: increased depth

Streams – Base Level A base level is the _________________to which a stream can erode. – the level at which the ____________of the stream enters the ____________, a lake, or another stream Two general types – ultimate— ____________level – temporary, or local

Streams – Base Level What would happen if you lowered the base level? It will cause the stream to ________________. Streams mostly head down slope, ultimately reaching it’s final destination – the sea.

Check In Questions 1.What is the single most important erosional agent on earth? 2.In the water cycle, what is infiltration in your own words? 3.What happens to a streams discharge as it moves from the head to the mouth? 4.Explain what happens when a stream’s discharge increases. 5.At which part of a stream would the gradient be steepest? 6.What would happen if you lowered the base level of a stream?