Geography 2050
CH 9 WATER RESOURCES
• The Colorado river basin o Droughts o Too many people o Too much agriculture o Planning 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 o Flows overhead o Soaks into the soil
• Along the way interpection occurs when precipitation hits plants or other ground cover o Drains across plant leaves and down the stems to the ground=stem flow o Falls 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 o Measure 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. o PRECIP Precipitation—
• Our moisture supply
• Measured with rain gauge o ACTET 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 o POTET 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 o Exact 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 o DEFIT- deficit
• Receive water
• The Colorado river basin o Droughts o Too many people o Too much agriculture o Planning 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 o Flows overhead o Soaks into the soil
• Along the way interpection occurs when precipitation hits plants or other ground cover o Drains across plant leaves and down the stems to the ground=stem flow o Falls 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 o Measure 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. o PRECIP Precipitation—
• Our moisture supply
• Measured with rain gauge o ACTET 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 o POTET 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 o Exact 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 o DEFIT- deficit
• Receive water