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Lesson 2

LA Climate, Water, and Your Watershed

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We also talked about how this equation can change depending on if you live in an urban environment versus a more natural environment.

If there is an increase in impervious surfaces (Ask what are examples of impervious surfaces: more concrete, streets, buildings), what happens to our ____ [runoff increases, while infiltration and ET decreases]

What is the tradeoff between having more urban areas vs. natural areas? Can you think of some benefits of each? [help students along as they call out answers]

Natural (and by natural, we mean undeveloped)

More wildlife, less pollution, value of “nature”--scenery, recreational opportunities, could be a sustainable resource.

Urban

Modern life and technology, thriving human population, increased communication, able to produce common goods for people to survive, convenience
what distinguishes an urban environment from a natural one? - Make list of differences

Pervious vs impervious
Lots vs little vegetation
Natural vs directed drainage
Infiltration vs runoff
Natural vs concrete streams

How does this increase or decrease different parts of the equation? Why?

Impervious surfaces increase runoff and decreases groundwater supply
Little vegetation increases runoff and decreases evapotranspiration
Directed drainage increases runoff and decreases groundwater

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Water Balance Equation

Precipitation

=

Evapotranspiration

+

Runoff

+

Infiltration

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Impaired Waterways in California

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