Operational Plan for the Restoration of Diadromous Fishes to the ...

location that would prevent fish from ascending to East Branch Lake from the Seboeis
Stream, or alternatively, closing the outlet to the Nollesemic drainage with a dike.
5.2
Wangan and Sanborn Brooks
Fish movement access to the Sanborn Brook watershed from Wangan Brook does
not currently exist due to the low divide separating the beaver flowage in the Wangan
Brook watershed from ephemeral stream channels that are tributaries to Sanborn Brook.
Although these channels are not connected to the beaver flowage, they begin to
form just a few hundred feet away from the flowage just beyond a low-relief divide. The
close proximity of this divide to the beaver dam in low-gradient topography means that
the integrity of this barrier may be potentially subject to any changing physical condition
of the beaver dam. The condition, size and volume of beaver flowages can be very
ephemeral. Likewise, the evulsive nature of the Wangan Brook channel where it passes
near the beaver dam means that the channel may migrate either away from, or toward the
beaver flowage over time. Under a scenario where the dam was re-built by beaver, a
higher flowage level may be restored that is nearer in elevation to that of the divide.
There is evidence that at high flow an existing side channel of Wangan Brook could
theoretically fill a restored beaver flowage to the point where the existing low-profile
divide might be breached. Any northern pike inhabiting the beaver flowage could, under
those very specific set of hydraulic conditions (that may persist only briefly) escape to the
Sanborn drainage. The probability of this occurring appears extremely low, however it
may be advisable to periodically re-inspect this site to confirm that the status of the
beaver flowage relative to Wangan Brook and the divide has not changed.
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