gradients. The near-surface systems may also be
the general trends in the regional aquifer. This
confined spatially by permafrost, with little or no
may happen where the active layer or annual
connection to a subpermafrost aquifer. Water lev-
depth of thaw is shallow (less than 1.0 m). The
els, flow rates and flow directions in such a
subpermafrost aquifer can also be locally con-
perched aquifer may vary seasonally and diur-
fined or isolated by areas of materials that are
nally in ways that are significantly different from
permanently frozen into the underlying bedrock.
Figure 3. Aerial photograph of the discontinuous permafrost region generally north of the Chena River. Photo
taken 20 May 1993.
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