Term
| what percentage of Earth's water is in the ocean? |
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Definition
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Term
| What percentage of Earth's water is in ice sheets/glaciers? |
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| what percentage of water is divided among lakes, streams, subsurface water, and the atmosphere? |
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Definition
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Term
| water is constantly moving among the... |
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Definition
| hydrosphere, atmosphere, geosphere, and biosphere. |
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Definition
| a portion of water soaks into the ground. moving downward, then laterally, and finally seeping into lakes, streams, or directly into the ocean. |
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Definition
| when the rate of rainfall is greater than the land's ability to absorb it, the additional water flows over the surface into lakes and streams. |
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Definition
| some of the water that infiltrates the ground is absorbed by plants, which later release it into the atmosphere. |
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Definition
| refers to the loss of water from land areas through the combined effect of evaporation and transpiration. |
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Definition
| the volume of water that passes through each part of the cycle annually |
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Term
| what would happen if present-day glaciers were to melt and release their stored water? |
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Definition
| sea level would rise by several tens of meters worldwide and submerge many heavily populated coastal areas. |
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Term
| is the hydrologic cycle balanced? |
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Definition
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Term
| because the total water vapor in the atmosphere remains about the same, average annual precipitation over Earth must... |
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Definition
| be equal to the quantity of water evaporated. |
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Term
| for all the continents taken together... |
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Definition
| precipitation exceeds evaporation |
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Term
| over the oceans, evaporation... |
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Definition
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Term
| what is the single most important agent sculpturing Earth's land surface? |
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Definition
| running water. even though only a small percentage of the energy of running water is used to erode the surface. |
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Definition
| runoff initially flows in broad, thin sheets across the ground. |
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Term
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Definition
| how much water the ground soaks in. determines the amount of water that runs off. |
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Term
| there are 5 factors that control infiltration capacity. what are they? |
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Definition
| 1. the intensity and duration of the rainfall. 2.the prior wetted condition of the soil. 3. the soil texture. 4. the slope of the land. 5. the nature of the vegetative cover. |
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Definition
| tiny channels that develop from threads of current in sheet flow. |
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Term
| how big is the sheet flow when it begins? |
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Definition
| it begins as a layer only a few millimeters thick. |
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Definition
| the land area that contributes water to a river system. |
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Definition
| an imaginary line that separates one drainage basin from another. |
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Term
| what has the largest drainage basin in North America? |
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Definition
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Term
| River and streams can simply be defined as... |
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Definition
| water flowing in a channel. |
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Term
| rivers and streams have three important roles in the formation of a landscape: |
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Definition
| they erode the channels in which they flow, they transport materials provided by weathering and slope processes, and they produce a wide variety of erosional and depositional landforms. |
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Term
| a river system consists of three main zones.. |
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Definition
| a zone of erosion, a zone of sediment transport, and a zone of sediment deposition. |
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Term
| the parts of a river system are.. |
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Definition
| interdependent, so that the processes occurring in one part influence the others. |
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Term
| In large river systems, what is the dominant process in the upstream area? |
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Definition
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Term
| where is the region located within a river system that is dominated by deposition? |
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Definition
| it is usually located where the stream enters a large body of water. |
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Term
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Definition
| it is between the zones of erosion and deposition and serves to transport sediments. |
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Term
| water can flow in one of two ways... |
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Definition
| laminar flow or turbulent flow |
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Term
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Definition
| in very slow moving streams the flow is often laminar and the water particles move in roughly straight-line paths that parallel the stream channel. |
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Term
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Definition
| streamflow is usually turbulent, with the water moving in an erratic fashion that can be characterized as a swirling motion. may exhibit whirlpools and eddies, as well as rolling whitewater rapids. |
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Term
| where do the highest velocities occur in a channel? |
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Definition
| when the channel is straight, the highest velocities occur in the center just below the surface. friction is the least here. |
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Term
| where do minimum velocities occur in a channel? |
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Definition
| along the sides and bottom of the channel where friction is always greatest. |
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Term
| when a stream channel is crooked or curved, what happens to the zone of maximum velocity? |
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Definition
| it shifts toward the outside of each bend. this shift plays an important part in eroding the stream's channel on that side. |
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Term
| the ability of a stream to erode and transport material is directly related to... |
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Definition
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Term
| what three factors determine the velocity of a stream? |
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Definition
| 1. the gradient 2. the shape, size, and roughness of the channel and 3. the discharge. |
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Term
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Definition
| the slope of a stream channel expressed as the vertical drop of a stream over a specified distance. |
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Term
| the steeper the gradient... |
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Definition
| the more energy available for streamflow. |
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Term
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Definition
| determines the amount of water in contact with the channel and hence affects the frictional drag. |
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Term
| the most efficient channel is... |
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Definition
| one with the least perimeter for its cross-sectional area |
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Term
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Definition
| the volume of water flowing past a certain point in a given unit of time. usually measured in cubic meters per second or cubic feet per second. |
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Term
| how is discharge determined? |
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Definition
| by multiplying a stream's cross-sectional area by its velocity. channel width(meters) x channel depth(meters) x velocity (meters/second) |
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Term
| what is north america's largest river in terms of discharge? world's? |
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Definition
| Mississippi River & Amazon River |
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Definition
| a cross-sectional view of a stream from its source area called the head or headwaters to its mouth. |
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Term
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Definition
| the point downstream where the river empties into another water body. |
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Term
| although many local irregularities may exist, the overall profile is... |
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Definition
| a relatively smooth concave-upward curve. |
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Term
| can rainfall infiltrate when the ground is saturated? |
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Definition
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Term
| when the ground is saturated and the rainwater cannot infiltrate, what does it do? |
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Definition
| it flows downslope, transporting some of the material it has dis-lodged. |
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Term
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Definition
| rounded depressions that are created by the abrasive action of particles swirling in fast-moving eddies. |
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Term
| streams transport their load of sediment in three ways |
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Definition
| 1. in solution 2. in suspension and 3. sliding or rolling along the bottom |
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Term
| most streams carry the largest part of their load in |
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Definition
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Term
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Definition
| the speed at which a particle falls through a still fluid. |
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Term
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Definition
| the sediment moving by saltation appears to jump or skip along the stream bed. |
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Term
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Definition
| the greater the amount of water flowing in a stream, the greater the stream's capacity for hauling sediment. |
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Term
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Definition
| indicates the maximum particle size that a stream can transport. |
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Term
| it is a general rule that the competence of a stream increases as... |
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Definition
| the square of its velocity. |
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Term
| critical settling velocity |
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Definition
| as streamflow drops below the critical setting velocity of a certain particle size, sediment in that category begins to settle out. |
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Term
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Definition
| stream transport provides a mechanism by which solid particles of various sizes are separated. |
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Definition
| the material deposited by a stream. |
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Term
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Definition
| the streams are actively cutting into solid rock. |
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Term
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Definition
| a channel in which the bed and banks are composed mainly of unconsolidated sediment. |
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Term
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Definition
| these streams flow in relatively deep, smooth channels and transport mainly mud. |
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Term
| when the river eventually erodes through the narrow neck of land to the next loop, what is the new, shorter channel segment called? |
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Definition
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Term
| the abandoned bend is called |
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Definition
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Term
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Definition
| channels with an interwoven appearance. they are wide and shallow. |
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Term
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Definition
| a downward limit to stream erosion |
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Definition
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Term
| local or temporary base levels |
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Definition
| include lakes, resistant layers of rock, and main streams that act as base levels for their tributaries. |
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Term
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Definition
| has the correct slope and other channel characterisitics necessary to maintain just the velocity required to transport the material supplied to it. |
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Term
| what book did John Playfair write in 1802? |
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Definition
| Illustrations of the Huttonian Theory of the Earth |
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Term
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Definition
| consists not only of the channel but also the surrounding terrain that directly contributes water to the stream. |
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