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Unformatted text preview: nt drops. To maintain sustainability, the demand must decrease at the same rate as
supply. During droughts communities usually accomplish this through water conservation efforts or by
temporarily drawing on nonrenewable supplies such as deep groundwater. This example also illustrates that we
can temporarily use a renewable resource such as lake water faster than it is replenished. When we do, the lake
water level drops. If we continue to withdraw water faster than it is replenished, the lake will eventually dry up.
Food serves as another example. We can estimate the maximum number of people that can be fed in a
specific community, given the limitations of fertile land area, annual precipitation, etc.. Yet what if a drought
or flood wipes out half the crop? To increase resilience, the community could limit population to half the
maximum number that they could feed in a good year. In good years the community could store the surplus
food to use in lean years. When the community has the maximum number of people that can be fed in a good
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- Fall '14