APES- Global Water Resources and Use
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Created by:
xamazingnessx on April 28, 2009
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28 terms
Terms | Definitions |
|---|---|
 How much of earths surface is covered in water? | over 70%` |
| Freshwater is contained in these places (most to least): | glacier and ice-caps, groundwater, lakes, soil moisture, atmospheric moisture, rivers, and streams |
| What are some of waters unique properties? | 1) Strong hydrogen bonds hold water molecules together 2) temp. of water changes slowly due to high specific heat capacity 3) water has a high boiling point 4) alot of energy is needed to evaporate water 5) water dissolves many compounds 5) water filters out UV radiation 6) water adheres to many solid surfaces 7) water expands when it freezes |
| Characteristics of countries with high per capita water availability | high precip, small pop. Iceland, Norway |
| Characteristics of countries with low per capita water availability | low precip. high pop Egypt Israel |
| watershed | drainage basin from which water drains |
| groundwater | Precipitation that infiltrates the ground and becomes trapped in cracks and pores of the soil and rock |
| water table | point where zone of aeration meets zone of saturationthe top of the water that accumulates on top of the bedrock |
| aquifers | geologic formation that contains water in quantities sufficient enough to support a well or springPorous layers of sand and rock through which groundwater flows |
| unsaturated zone | directly below surface, contains some water...air can also fill voids between cracks |
| zone of saturation | subsurface completey saturated with water |
| "perched" water | water accumulatig over an area of low permeabilitylike clau |
| Why are temp. differences more drastic in the N hemisphere than in the S. hemisphere? | land warms and cools more rapidly than water |
| where has the greatest amounto focean warming occured? | surface layers |
| Agriculture (water use) | the single largest user of water in the world. Most of that water is used for irrigating crops. |
| Irrigation | the process of transporting water from one area to another for the purpose of growing crops. |
| Flood irrigation | involves the flooding of a crop area located on generally flat land. This gravity flow method of water is relatively easy to implement, especially if the natural flooding of river plains is utilized, and therefore is cost-effective. However, much of the water used in flood irrigation is lost, either by evaporation or by percolation into soil adjacent to the intended area of irrigation. Because farmland must be flat for flood irrigation to be used, flood irrigation is only practical in certain areas (e.g. river flood plains and bottomlands). In addition, because land is completely flooded, salts from the irrigation water can buildup in the soil, eventually rendering it infertile. |
| Furrow irrigation | involves gravity flow of water on relatively flat land. However, in this form of irrigation, the water flow is confined to furrows or ditches between rows of crops. This allows better control of the water and, therefore, less water is needed and less is wasted. Because water can be delivered to the furrows from pipes, the land does not need to be completely flat. However, furrow irrigation involves higher operating costs than flood irrigation due to the increased labor and equipment required. It, too, involves large evaporative loss. |
| Drip irrigation | involves delivering small amounts of water directly to individual plants. Water is released through perforated tubing mounted above or below ground near the roots of individual plants. This method was originally developed in Israel for use in arid regions having limited water available for irrigation. It is highly efficient, with little waste of water. Some disadvantages of drip irrigation are the high costs of installation and maintenance of the system. Therefore, it is only practical for use on high-value cash crops. |
| Center-pivot sprinkler systems | deliver water to crops from sprinklers mounted on a long boom, which rotates about a center pivot. Water is pumped to the pivot from a nearby irrigation well. This system has the advantage that it is very mobile and can be moved from one field to another as needed. It can also be used on uneven cropland, as the moving boom can follow the contours of the land. Center-pivot systems are widely used in the western plains and southwest regions of the United States. With proper management, properly designed systems can be almost as efficient as drip irrigation systems. Center-pivot systems have high initial costs and require a nearby irrigation well capable of providing a sufficiently high flow. Constant irrigation with well water can also lead to salinization of the soil. |
| What are some domestic uses of water biggest to smallest | flushing toilet, bathing, laudry and dishes, drinking and cooking, brishing teeth etc. |
| where do artesian wells occur? | where water breaks through to the surface from aquifers |
| the rate of water consumption is growing hwo many times as fast as population? | 2 |
| why is water a limiting factor? | it limits the amt of food that can be grown |
| what are the primary reasons for rising sea level? | thermal expansion of water, melting of ice caps and glaciers |
| which areas are the most impacted by rising sea levels? | wetlands |
| Conservation of water | -changes in personal habits-construct dams and reservoirs-desalinate water-drip irrigation - education - recycled products that take less water to produce - engineer systems to collect more runoff - levy taxes or user fees - line irrigation channels and cover canals - meter all water used - plant crops that do not reuirea s much water - rebates for low water using products - reduce govt subsidies on water- reprocess water - seed clouds - tiered price scale - use of icebergs - use more groundwater |
| gCASE STUDIES ON WATER | P 65 |
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