Elements of the Water Budget

1. Elements of the Water Budget P All the PRECIPITATION that falls in one month

2. Elements of the Water Budget P All the PRECIPITATION that falls in one month EP Potential Evapotranspiration The ENERGY available to evaporate water

3. Elements of the Water Budget P All the PRECIPITATION that falls in one month EP The ENERGY available to evaporate water P- EP If P-EP > 0, then.... If P-EP < 0, then.... There’s energy that can still evaporate more water There’s water left over When water is left over after evaporation, it can do either of 2 things..... Left over energy can “look” for more water.....(where?) Soak into the ground (“infiltrate”) “Run off” in streams In the soil! (called “Storage”)

4. Elements of the Water Budget St D P All the PRECIPITATION that falls in one month EP The ENERGY available to evaporate water P- EP If P-EP > 0, then.... If P-EP < 0, then.... There’s energy that can still evaporate more water There’s water left over When water is left over after evaporation, it can do either of 2 things..... Left over energy can “look” for more water.....(where?) Soak into the ground (“infiltrate”) “Run off” in streams In the soil! (called “Storage”) St Water stored in the Soil (soil moisture) When DSt is (+)... St < maximum, and P>EP When DSt is (-)... St >0 and P<EP called “Recharge” called “Usage”

5. Elements of the Water Budget St D P All the PRECIPITATION that falls in one month EP The ENERGY available to evaporate water P- EP If P-EP > 0, then.... If P-EP < 0, then.... There’s energy that can still evaporate more water There’s water left over When water is left over after evaporation, it can do either of 2 things..... Left over energy can “look” for more water.....(where?) Soak into the ground (“infiltrate”) “Run off” in streams In the soil! (called “Storage”) St Water stored in the Soil (soil moisture) When DSt is (+)... St < maximum, and P>EP When DSt is (-)... St >0 and P<EP called “Recharge” called “Usage” EA Actual amount of water evaporated. EA = EP when P+ St => EP EA > EP when NEVER! EA < EP when P + St < EP

6. Elements of the Water Budget St D P All the PRECIPITATION that falls in one month EP The ENERGY available to evaporate water P- EP If P-EP > 0, then.... If P-EP < 0, then.... There’s energy that can still evaporate more water There’s water left over When water is left over after evaporation, it can do either of 2 things..... Left over energy can “look” for more water.....(where?) Soak into the ground (“infiltrate”) “Run off” in streams In the soil! (called “Storage”) St Water stored in the Soil (soil moisture) When DSt is (+)... St < maximum, and P>EP When DSt is (-)... St >0 and P<EP called “Recharge” called “Usage” EA NEVER! Actual amount of water evaporated. EA = EP when P+ St => EP EA > EP when EA < EP when P + St < EP When there’s more water than energy at the end of the month, we say we have a SURPLUS When there’s energy that never finds water, we say we have a .... DEFICIT S D

7. Elements of the Water Budget St D P All the PRECIPITATION that falls in one month EP The ENERGY available to evaporate water P- EP If P-EP > 0, then.... If P-EP < 0, then.... There’s water left over There’s energy that can still evaporate more water When water is left over after evaporation, it can do either of 2 things..... Left over energy can “look” for more water.....(where?) Soak into the ground (“infiltrate”) “Run off” in streams In the soil! (called “Storage”) St Water stored in the Soil (soil moisture) When DSt is (+)... St < maximum, and P>EP When DSt is (-)... St >0 and P<EP called “Recharge” called “Usage” EA Actual amount of water evaporated. EA = EP when P+ St => EP EA > EP when NEVER! EA < EP when P + St < EP When there’s more water than energy at the end of the month, we say we have a SURPLUS When there’s energy that never finds water, we say we have a .... DEFICIT S D

8. Infiltration rate Infiltration rate Permeability Slope Porosity Infiltration rate Soil Storage Saturation INFILTRATION Infiltration refers to water soaking into the ground: Infiltration rate

9. RUNOFF Runoff refers to the water that is not evaporated, and that does not soak into the ground. It is the water we find in streams. Runoff occurs during seasons of high and relatively low In areas where there is a lot of runoff during one part of the year..... and dry and warm during another part of the year..... can be built to store (or reserve) the runoff for an “un-rainy day” EP P Rainy season, when there’s extra water When there’s plenty of energy but not enough water to “satisfy” the energy... RESERVOIRS

10. EVAPOTRANSPIRATION runoff Evaporation Evaporation infiltration infiltration runoff infiltration The Water (Hydrologic) Cycle -all the ways that water vapor enters the air Condensation Animal Respiration Transpiration