Liz et.al-
        Down here at Jamestown we are up against the same problem of maintaining a
large (80'x120') open area excavation. We have the mixed blessing of a tent
over the area we are currently excavating. If flat plastic blows around,
you can imagine what a 30'x70' tent does when the wind picks up. under the
tent, postholes, feature sections, and the ground surface all become
hardened from lack of water. As long as the tent doesn't get flooded often,
cracking is not a problem. In the other areas not covered by the tent,
features are preserved only with a lot of work. The sectioned postholes
that remain of an earthfast structure are lined with plastic and back
filled only to be re-excavated on a semi regular basis for show and tell as
well as photo sessions. The entire excavated area is covered with a woven
plastic filter cloth and nailed into the ground along the perimeter of the
site with gutter spikes at 6' intervals and then sandbagged. This filter
cloth allows enough water to pass through to keep the soil hydration at a
natural level but prevents erosional the  episodes I'm sure you are very
familiar with. Even after a winters worth of exposure to rain, wind, and
snow we can pull the filter cloth and the site will look surprisingly good,
and with a little troweling be photo ready.
I hope this helps,
     -Eric Deetz
      Jamestown Rediscovery
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Eric Deetz
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