90 likes | 204 Views
Active River. Objectives Describe how moving water shapes the surface of the Earth by the process of erosion. Explain how water moves through the water cycle. Describe a watershed. Explain the 3 factors that affect the rate of stream erosion. Identify four ways that rivers are described.
E N D
Active River Objectives • Describe how moving water shapes the surface of the Earth by the process of erosion. • Explain how water moves through the water cycle. • Describe a watershed. • Explain the 3 factors that affect the rate of stream erosion. • Identify four ways that rivers are described.
Vocabulary For the section • Water cycle • Evaporation • Condensation • Precipitation • Runoff • Tributary • Divide • Erosion • Discharge • Rejuvenation
Rivers: Agents of Erosion • Erosion- process that wind, water, ice, or gravity transports soil and sediment from 1 location to another. • What process created the grand canyon?
The water cycle • Water cycle – the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean • Precipitation- rain, snow, or hail • Percolation- downward movement of water through pores and spaces due to gravity.
Water Cycle cont. • Runoff-precipitation that flows to streams and rivers which ends up in the ocean. • Evaporation- water changes into vapor caused by the sun and gains energy. • Condensation- water vapor cools an changes into water droplets that form clouds and loses energy • Transpiration-Process by which water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere
River Systems • Tributary- Stream that flows to large stream or lake. • Watershed- area of land that is drained by a water system. • Divide- Boundary between drainage areas that have streams that flow in opposite directions
Stream Erosion • Channel- path that a stream follows • River- wider and larger streams.
Stream Erosion cont. • Gradient- change in elevation over a distance. High gradient more erosive energy. • Discharge- Amount of water a stream or river carries over time. Discharge increases with a storm or snow melt and erosive energy increases • Load- materials carried by the stream or river. Faster moving = more load.
Stages of a river • Youthful River • Mature River • Old River • Erodes deeper not wider, flows quickly because of its steep gradient few tributaries • Erodes Wider not deeper not as steep of a gradient fed with many tributaries. • Low gradient little erosive energy, deposits rock and soil along the channel, few tributaries