Quarter 2 Study Guide - Hydrosphere

Hydrologic CycleThe Hydrosphere is Earth’s water. The hydrosphere includes all the liquid and frozen water of the Earth’s oceans and land (groundwater), as well as water vapor in the atmosphere.The hydrologic cycle is a conceptual model that describes the storage and movement of water between the biosphere, atmosphere, lithosphere, and the hydrosphere. The Sun is the ultimate source of energy that drives the water cycle. Water on our planet can be stored in any one of the following major reservoirs: atmosphere, oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater. Water moves from one reservoir to another by way of processes like the ones depicted in the diagram to the right. Evaporation is a process where liquid water on Earth’s surface gains enough energy from the environment to be transformed into gaseous water in the atmosphere. This gaseous water can then rise high enough in the atmosphere where it cools and condenses into liquid water droplets, forming clouds. When the droplets gain enough mass, they fall to the ground as precipitation. Water that falls back to the Earth can flow as runoff on Earth’s surface, or infiltrate into the ground, where it can be absorbed by the roots of plants. When plants release water vapor through their leaves (transpiration), water is put back into the atmosphere, where the cycle can continue.What is the ultimate source of energy that drives the water cycle? The Sun The Moon Tidal power DNA Match the key vocabulary to the correct definition/ description. Evaporation process by which the surface of liquid water on Earth gains enough energy to vaporize or become a gas Runoff process by which surface water enters the soil; seepage. Precipitation process by which liquid or solid water in earth’s atmosphere falls to Earth’s surface. Condensation process by which water vapor (gaseous water) is cooled enough to transform into a liquid Transpiration process by which plants absorb water and release it in a gaseous form through small openings in their leaves. Runoff process by which water flows due to gravity when the soil is infiltrated to full capacity. Use the paragraph below to fill in the blanksStreamsThe stream gradient is the downhill slope of the channel. For example, a gradient of 10 feet per mile means that the elevation of the channel drops a total of 10 feet over 1 mile of horizontal distance traveled. Gradients are typically the lowest at a river's mouth (end), and highest at its headwaters (start). The higher the gradient, the faster the stream flows.The speed at which a stream flows is called the stream velocity. A fast river moves at a rate of about 5 miles per hour. The water moves most rapidly in the middle of the channel, where the water is deepest and friction is minimal. The water moves at a slower rate along the bed of the channel and the banks, where contact with rock and sediment (and therefore friction) is greatest. The greater the velocity of a stream, the greater its capacity to erode and transport earth materials over longer distances. A streams gradient is the downhill slope of the channel.The velocity of the stream, or how fast the stream is moving, affects the rate of erosion. The water moves more quickly in the middle of the channel, where water is deepest and friction is minimal. The water moves at a slower rate along the bed of the channel and the banks, where contact is greatest. The greater the velocity of a stream, the greater its capacity to erode materials. Use the paragraph below to fill in the blanksA stream's discharge is the amount of water that flows past a certain point in a given amount of time. Discharge is usually expressed in cubic feet per second. Discharge generally increases downstream because of additional water that is contributed from tributaries and groundwater that enter the main channel of flow. Stream discharges vary according to seasonal and precipitation changes. The rates of flow, discharge, erosion, sedimentation, transportation, and deposition increase dramatically during flooding and may be a hundred times greater than normal rates A stream's discharge is the amount of water that flows past a certain point in a given amount of time. Discharge tends to increase when flowing downstream because of additional water that is contributed from tributaries and groundwater. Use the paragraph below to fill in the blanksThe majority of a stream's sediment load is carried in solution (dissolved load) or in suspension. The remainder is called the bed load. Earth material that has been dissolved into ions and carried in solution is the dissolved load. It is usually contributed by groundwater. Common ions are calcium, bicarbonate, potassium, sulfate, and chloride.The suspended load is the fine-grained sediment (like sand, silt, and clay) that remains in the water during transportation. For example, a flooding river is muddy and discolored from the large amounts of sediment suspended in the water. The suspended load is generally made up of lighter-weight, finer-grained particles such as silt and clay. Most of the sediment in a stream is carried as suspended load.The heavier, coarser-grained earth material that travels along the bottom of the stream is the bed load. A stream carries most of its load in solution, or in suspension. The remainder is called the bed load. The suspended load is the fine-grained sediment that remains in the water during transportation, while the bed load is the heavier, coarser-grained material. Use the paragraph below to fill in the blanksStream stagesGeologists characterize streams as youthful, mature, and old. Typically, streams have steep gradients near their sources, or beginnings, and gentle gradients as they approach their mouths, or ends. Discharge increases downstream as more tributaries connect with main streams as they flow toward their base levels (other streams, lakes, etc.). Because of this, stream channels also become deeper and wider downstream. The ocean is a stream’s ultimate base level.Young StreamA youthful stream has a fairly straight channel and a steep gradient. It generally flows in a V-shaped valley in a highland or mountainous area with little shifting of its channel. Its velocity is high, and it is actively lowering its channel through downcutting in order to reach base level. In this stage, a stream has little, if any, floodplain. Rapids and waterfalls may mark its course. Mature StreamA stream in its mature stage has a moderate gradient and velocity because it has eroded its bed downward and is closer to base level. Since it has slowed down, the stream begins to meander. While it is still eroding downward, the stream's main force of erosion is lateral (horizontal) as it begins winding back and forth, carving out a valley floor between valley walls or bluffs. Periodically, the stream will flood all or a part of its valley, depositing alluvium (sediments and minerals) on its developing floodplain.Old StreamAn old age stream has nearly reached its base level, and its gradient and velocity are very low. Because its velocity is low, it has lost its ability to erode downward. In fact, it deposits as much material as it erodes. The stream meanders greatly in its nearly flat valley. It has a wide, well-developed floodplain marked with oxbow lakes that formed from the cutoff of a wide meander. A young stream has a fairly steep gradient and generally flows in a V-shaped valley. Because a young stream has a steep gradient its velocity is high, and it is actively lowering its channel.Young streams tend to have straight channels, high velocity, and little to no floodplains. Old streams tend to have curves, or meander, low velocity, and are often marked with oxbow lakes that formed from the cutoff of a wide meander. Use the paragraph below to fill in the blanksMeandering Streams (Lateral Erosion)Meanders are another very important part of stream erosion. In a meandering stream velocity is lowest (High Potential Energy) along the inner banks because it is there that water encounters the most friction, and therefore the flow is reduced. Along a straight channel segment, water moves the fastest in mid-channel, near the surface. But as water moves around a bend, the zone of high velocity (High Kinetic Energy) swings to the outside of the channel. As water rushes past the outer part of the bend, sediment is continuously eroded from the riverbank and is swept downstream. With the slower flow concentrated around the inner side of each bend, coarse sediment accumulates. Thus, a meandering pattern is created along the course of the river, with shallow water and on the inside bends and steep banks on the outside.Since the material lining the banks does not remain uniform the entire length of a river system, another landform -- an oxbow lake -- can develop. If river water runs into resistant sediments, the movement of the meander can slow downstream. As other meanders continue to migrate through softer sediments upstream, they eventually intersect the slower-moving meander and cut off the channel between the two, forming an independent loop that will become a lake.Use the reading about lateral erosion to answer the following questions about lateral (side to side) stream erosion. As water moves around a bend, the zone of high velocity swings to the outside of the channel. So the point at which the greatest erosion is occurring is at point C and the point that has the least amount of erosion, and the greatest deposition, is point B. According to the picture, label whether the water will be moving fast and eroding the channel, or moving slower and depositing sediments. A moving slower and depositing sediment B moving fast and eroding the channel C moving fast and eroding the channel D moving slower and depositing sediment GroundwaterGroundwater is extremely important to our way of life. Most drinking water supplies and often irrigation water for agricultural needs are drawn from underground sources. More than 90 percent of the liquid fresh water available on or near the earth's surface is groundwater. Hot groundwater can also be a source of energy. Groundwater is derived from rain and melting snow that percolate downward from the surface; it collects in the open pore spaces between soil particles or in cracks and fissures in bedrock. The process of percolation is called infiltration.The percentage of a rock or sedimentary deposit that consists of voids and open space is its porosity—the greater its porosity, the greater its ability to hold water. Sediments are usually more porous than rocks.The ease with which fluid is transmitted through a rock's pore space is called permeability. Although a rock may be very porous, it is not necessarily very permeable. Permeability is a measure of how interconnected the individual pore spaces are in a rock or sediment. The rock and soil in which all the open spaces are filled with water is called the saturated (or saturation) zone. As the top of the saturated zone rises toward the surface, it reaches a level of equilibrium with the overlying unsaturated zone.The unsaturated zone (or zone of aeration) is the rock and sediment in which pore spaces contain mostly air and some water and therefore are not saturated. The unsaturated zone typically starts at the surface and extends downward to the saturated zone. The contact between the saturated and unsaturated zones is called the water table.Aquifers are porous, permeable, saturated formations of rock or soil that transmit groundwater easily. The best aquifers are coarse-grained sediments such as sand and gravel. Impermeable formations such as shale, clay, or unfractured igneous rocks that retard water flow are called aquitards.Wells are drilled into the water table to tap aquifers for domestic, industrial, and agricultural use. The level of the water table fluctuates with changing climatic conditions. During a dry period, the water table drops to a deeper level because water has drained out of the saturated zone into the rivers. During wet periods the water table rises because of the additional water percolating down from the surface into the zone of saturation.The water table tends to be closer to the surface in valleys than on hillsides. Recharge occurs in those areas where new water is added to the saturated zone and replenishes water that has been lost. Porosity Rock and sediment where the empty space between particles contains little water and mostly air; also called the unsaturated zone. Zone of Aeration Area where saturated and unsaturated zones meet. Saturated Zone Area underground where the empty space of rock and sediment is filled with water. Porosity property of rock or soil that describes how easily water can move through a rock or soil’s pore spaces. Aquifer Saturated rock or soil through which groundwater easily flows. Permeability The percentage of empty space in rocks or between soil particles. Use the paragraph below to fill in the blanksOceansThe Earth is called the “blue planet” because about 71% of it is covered with water, and about 97% of all the water on Earth resides in the oceans. Although all the oceans are connected, we generally classify 4 major oceans on Earth. Refer to the map at the right. The water in the oceans may look quit still on a map, but the water in the ocean is actually moving. This movement of ocean water around the continents is called a current. A current is like a vast river within the ocean, flowing from one place to another. Currents are responsible for the movement of the water found in the Earth’s oceansWhy do currents move?Currents move mainly because of differences in density. When water is warmer it rises, and cooler water sinks. The second thing that affects ocean water density is salinity, or the amount of salt in the water. Saltier water is heavier, and will sink, whereas fresher water is lighter and will move on top of the saltier water. There are two kinds of ocean currents, deep currents and surface currents. Surface currents move more quickly because they are driven by wind. If Earth had no landmasses, the global ocean would have simple belts of easterly and westerly surface currents. But the continents deflect ocean currents to the north and the south so that closed circular currents systems, gyres, develop. There are five major gyres: North Pacific, North Atlantic, South Pacific, South Atlantic, and Indian Ocean.Ocean currents affect climate. Warm ocean water coming from the equator moves along the east coast of North America in what is called the Gulf Stream. This warm ocean water warms the air on this side of North America. That warm air travels across the Atlantic ocean and brings unusually warm weather to parts of Northern Europe. This is why England gets less snow than Boston, even though it is located further north. Currents move because of two factors. The density of the water, and the salinity of the water. Density is the amount of substance in a given amount of space. Salinity is the amount of salts in the water.The ocean currents can affect climate. The warm ocean water from the equator moves along the east coast of North America and warms the air on this side of the North America. That warm air then travels across the Atlantic ocean and brings warm weather to parts of Northern Europe.