 Runoff  Streams  Rivers

 Water picks up particles of clay, sand, and gravel as it moves along Earth’s surface  Small grooves form – called rills  Gullies form as grooves formed by water become wider and deeper  More rainfall = more/less runoff??  More plant growth = more/less runoff??

 More rainfall = more runoff  More plant growth = less runoff

 Form when gullies meet  Carry large amounts of sediments  Load: soil and rock particles carried by a stream  Large, heavier particles are pushed or rolled downstream  Lighter particles are picked up and carried by force of water  Layers of rock beneath stream can be eroded by abrasion

 Form when streams meet  Drainage system: network of rills, gullies, streams, and rivers in an area › Like the branches of a tree  Tributaries: larger “branches” that connect smaller streams to main river  Drainage basin: area drained by a main river and its channels

 Immature river: young river › Water flows quickly over rocks and produces rapids › Waterfalls are common  Mature river: has been developing for 1000s of years › Continuous erosion has caused rapids and waterfalls to disappear › Broad, flat valley floor › Has curved loops called meanders

 Rivers deposit sediments when they slow down  At curves, they deposit at inside of curve and erode at outer edge of curve  Can form different shapes and landforms as deposits and further erosion take place

 Oxbow lake: U-shaped lake that forms when erosion and deposition cuts off a meander from the river  Alluvial fan: fan-shaped deposit formed at point where river leaves mountains and runs into plain  Delta: triangular formation of sediments deposited at mouth of a large river when it flows into a lake or ocean

 Flood plains: areas of fertile soil on sides of river due to deposits after repeated flooding  Levees: ridgelike deposits formed by large particles deposited in flood plains

 Form where there is a lot of snowfall and the temperature stays cold  Valley glaciers form when snow builds up over time and turns to ice › Move slowly through valleys  Continental glaciers form in polar regions of the world

 Picks away at rocks underneath it as it moves  Carry loads that grind away Earth’s surface as it passes over things

 Some glaciers begin to melt as they reach a warm area › Continue to move forward, but melt away faster than they are moving so it looks like they are moving backward › Called retreating glaciers  Deposit rock and debris as it retreats › Called its till: rock and soil deposited directly by a glacier

 Moraine: ridge of till left behind by a retreating glacier › Terminal moraine: at front of glacier › Lateral moraine: along side of glacier  Drumlin: oval-shaped mound of till › Tip points in direction glacier was moving

 Icebergs: part of a glacier that has broken off and drifted into the sea  Glacial lakes: formed two ways › Glacial till and deposits pile up and keep water from flowing away from an area › Glacial ice blocks are left behind and melt, leaving a depression (hole) that becomes a lake ( kettle lake)

1. What is a glacier, and how does a glacier cause erosion? 2. What is a glacier’s till? 3. Explain what a moraine is and the difference between the two types of moraines. 4. How do icebergs form? 5. Describe the two ways that glaciers can form lakes.