In addition, the effluent caused sediment instability with erosion of the
streambed in
the upper reaches and deposition in the lower reaches. As a result of these
discharges, large areas of bottomland and swamp forests were destroyed in
three
stream systems on the SRS (Sharitz, etl a., 1974). These losses include 90
ha of
the delta of Fourmile Branch (Jensen, eta/., 1984), a stream impacted by
C-Reactor
(Figure 1).
Since this effluent persisted almost continually from 1955 to 1985, the normal
seed
bank and sprouting ability of the original forest was eliminated. Therefore,
secondary succession, observed as a consequence of other disturbances such
as
blowdown of clearcutting, was not possible.
Figure 1. Location of the Savannah River Site and the thermally impacted
area of
the Fourmile Branch delta.


Natural recovery of the vegetation in the delta of Fourmile Branch began
in 1985
when the reactor was shut down. Recovery of the vegetation is being documented
through the use of permanent plots. The vast majority of woody stems belong
to
early successional species with few individuals of later successional species
present.


107


I'


I