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SECTION MENU
- Site Description |
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Climate must
be considered in designing any geologic
repository.
Water is the primary means by which
the waste could be broken down into
radioactive particles and then transported
into the accessible environment.
Yucca Mountain is located adjacent
to one of the driest deserts in North
America. Thus, the dry climate limits
the amount of moisture available
to enter the repository.
Over time, however, climates can
change significantly. So we need
to understand not just the current
climate, but also future climates.
By studying the current and past
climates of the area, scientists
can project the likely future climates
of Yucca Mountain.
Yucca Mountain’s modern climate
is dry. The extremely hot summers
and the temperate winters produce
an average annual temperature of
about 63º F (17º C). The
mountain receives about 7.5 inches
of combined rain and snow per year,
more than 95% of which either runs
off, evaporates, and is taken up
by plants. Thus, there is little
water that infiltrates the surface
into the underlying rock.
Based on analogues and numerous
local studies, scientists have learned
that Yucca Mountain’s climate
has been notably cooler and wetter
during different climatic periods.
Thousands of years ago, some low-lying
basins in the area (such as Death
Valley) contained lakes; wetlands
were common on valley floors; and
more vegetation grew on the mountains
of the region.
With their understanding of the
past and current climates, scientists
have projected three likely climates
for Yucca Mountain during the 10,000-year
regulatory period. The expected climate
conditions are modern  (present
day), monsoon ,
and glacial-transition .
The present-day climate conditions
are expected to prevail for about
the next 400 to 600 years. Then,
monsoon climate conditions (i.e.,
with wetter summers than the modern)
are expected to prevail for the following
900 to 1,400 years. Glacial-transition
climate conditions, with cooler air
temperatures and higher annual precipitation
than the modern period, are expected
to begin in about 2,000 years and
continue through the rest of the
10,000-year period. During this glacial-transition
period, the average annual precipitation
is expected to be about 12.5 inches
per year.
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