Geography 2050

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  • Topic: Water, Hydrology, Irrigation
  • Pages : 3 (695 words )
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  • Published : May 5, 2013
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CH 9 WATER RESOURCES

The Colorado river basin
oDroughts
oToo many people
oToo much agriculture
oPlanning still “supply” focused. Not accounting for depleting resource THE HYDROLIGIC CYCLE-- Water never stops going
Surface water
Precipitation reaching the earths surface follows two basic pathways oFlows overhead
oSoaks into the soil
Along the way interpection occurs when precipitation hits plants or other ground cover oDrains across plant leaves and down the stems to the ground=stem flow oFalls directly to the ground=through-fall

Water soaks into the ground through infiltration- penetration of the soil surface •It travels further into soil or rock through the downward movement of percolation

SOIL WATER BUDGET CONCEPT
An effective way to assess water resources for any area of earths surface oMeasure supply input and demand output –can examine any time frame(minutes to years)---think of this as a money budget •The soil water balance def.

oPRECIP Precipitation—
Our moisture supply
Measured with rain gauge
oACTET actual evapotranspiration
Evaporation—movement of water molecules from a wet surface into the air •Transpiration—cooling mechanism in plants (sweating for plants—cools them off) •Evapotranspiration-evaporation combined with transpiration—refers to the actual expenditure of water from land and plants oPOTET potential evapotranspiration

The amount of water that would evaporate and transpire under optimum moisture conditions •When there isn’t optimum moisture, the amount of POTET demand that went unmet is the shortage, or deficit (DEFIC) •When we subtract the deficit from the POTET, we get the actual ( ) •Determining POTET

oExact measurement difficult
Evaporation pan (just like the bowl example)
Lysimeter—takes subsection of soil—looks at top to bottom, layer by layer--can measure how much water is moving through the region oDEFIT- deficit
Receive water through...
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