Surface Water Chapter 9

Surface water movement: Water Cycle Earths water supply is constantly recycled WRITE WRITE

Surface Water Movement 1) Runoff  Water flowing down slope along Earth’s surface or seep into the ground Run off speed determined by slope of the hill  Ends up in a stream or lake, evaporate, or accumulate into puddles WRITE WRITE

Movement Seep into ground  Ground must have large enough pores – loose soil Evaporate WRITE WRITE

Fate of water: Run off or Seep Certain characteristics will determine whether not water will either seep into or become runoff 1) Vegetation  Vegetation allows for loose soil  Loose soil allows water to enter ground  Gardeners do not pack their soil WRITE WRITE

Fate of water 2) Rate of precipitation  Heavy: soil clumps together closing pores Fills up ground to quickly and water becomes runoff  Light: allows water to gently slide through Less erosion WRITE WRITE

Fate of Water 3) Soil Composition  Effects the waters holding capacity  Decayed organic matter (humus) Creates the pores in soil – Increases retain ability  Minerals Clay – fine mineral which clump together Few Spaces Sand – large pores WRITE WRITE

Fate of Water 4) Slopes  Steep: allows for high runoff & little absorption  Little: low runoff and high absorption WRITE WRITE

Formation of Stream systems Runoff Surface water flows in thin sheets and eventually collects in small channels Runoff increases, channels widen and become deeper and longer Channels fill up again each time with rain Channel can become a stream WRITE WRITE

Water sheds:  drainage basin  Land where all water drains into Divide  High land area that separates watersheds WRITE WRITE

Mississippi Watershed

Stream Load All the materials that the stream carries Solution  Material that has been dissolved  Depends on area where the steam runs through  Erosion of rocks and dirt WRITE WRITE

Suspension  Small particles held up by the turbulence of stream  Clay, silt, sand  Depends on volume and velocity of water Bed Load  Turbulence of water pushes heavy things  Pebbles and cobbles  Larger velocity – large objects  B/c of abrasion, rocks are smooth Stream Load WRITE WRITE

Stream Velocity & Carrying Capacity Discharge = width x depth x velocity (m)(m) (m/s) As discharge increases so does carrying capacity WRITE WRITE

Floods Water fills over the sides of a stream banks Floodplain: broad flat area of land that extends out from streams for excess flooding WRITE WRITE

Floods Water fills over the sides of a stream banks Floodplain: broad flat area of land that extends out from streams for excess flooding WRITE WRITE

Chapter 9 Sec. 2 Stream Development

Moving Water Adequate supply of water  What happens to streams in areas of high precipitation?  What happens to streams in areas of low precipitation? The region where water first accumulates is known as what?  Headwaters  Where are common areas for head waters? WRITE WRITE

Stream development As water accumulates in high in small gullies, water starts to move downward Stream channel  narrow pathway into sediment or rock that the moving water carves The moving water is held in by ___________, the ground bordering each side. WRITE WRITE bank

Stream development The process by which small streams erode away soil and rock ahead of the stream is called ______________  What does head ward erosion do to the stream? Lengthens  What is stream capture?  Open Book to page 232.  Explain what Stream Capture is  Figure 9-11 WRITE WRITE Headward Erosion

Stream Valleys As streams erodes – creates a V-shaped valley  Grand Canyon Continues until it reaches a base level: elevation where it enters another stream Lowest base: Sea Level WRITE WRITE

Meandering Stream Streams slope decreases as it reaches base level, as result, the channel gets wider. Why?  Creates build up in the stream and erodes the sides of the channel Starts to bend or wind called a Meander Velocities of the water differ from where it is located within the stream.  Outside – greatest velocity  Inside – slowest velocity  Diagram Diagram WRITE WRITE

Deposition of sediment Streams lose velocity – lose the ability to carry sediment Alluvial Fan:  Sloping depositional features from bases of slopes  Sand or gravel  Death Valley Delta:  Triangular deposit into larger, quieter bodies of water  Silt and clay  Mississippi River WRITE WRITE

Age of streams Youth, Mature, Old Rejuvenation: “to make young again”  Stream actively resumes down cutting towards its base level  Causes the channel to become V-shaped and start over WRITE WRITE

Chapter 9 Section 3 Lakes and Fresh Water Wet lands

Origin of lakes Lake is a depression in the surface materials  Landscape that holds and collects water  Surface materials determine where lakes are formed  Accumulate water from streams, rivers, and precipitation WRITE WRITE

Oxbow lakes: streams cut off meanders and isolate channels Stream flow becomes blocked by sediment from a landslide Lakes… WRITE WRITE

Glacial Lakes Glaciers gouged out land during Ice Ages  Great Lakes in North America Glacial sediments dammed outflow of water WRITE WRITE

Changes in lakes Eutrophication: process by which lakes become rich in nutrients which results in change of organisms in lake  1) P hotosynthesis w/ plants adding oxygen  2) Animals use O 2 and add waste products  3) Increasing nutrients in lake Results in a change of organisms in a lake  Natural process, but can be speed up with fertilizers Addition of Nitrogen and Phosphorous increases algae Appears as green scum Green algae WRITE WRITE

Fresh Water wet lands Wet land: area that is covered w/ water (3 types) Bogs:  Feed only by precipitation  Soil is rich in Sphagnum, peat moss  Break down of pete moss to give acidity to the water Results in unusual plant species: Flytrap and Pincher plants WRITE WRITE

Marshes:  Form along mouths of streams with extensive deltas  Constant supply of water produces lush grasses  A lot of vegetation and wildlife in marshes WRITE WRITE

Swamps:  Low lying areas near streams  May form from marshes that can provide abundant shrubs and trees WRITE WRITE

Swamp Thing

Wet lands continued Improve water quality  Provide excellent filtering systems by trapping pollutants and sediments Provide habitats for wild life  Migratory birds Not very well protected  Peoples desire for land WRITE WRITE