(1) The drainage water mass from the dam was shown to
influence the physico-chemical characteristics of the river
such as the depth and bottom composition, and the enrichment
status of the river habitat.
(2) High flood-induced discharge rates can erode the small
particles from the bottom layer and replace the sediment
surface with coarse sands. This results in decreased organic
matter content of the surface sediment and deterioration of
the aquatic plant beds.
(3) In this study, two dominant plant species of H. verticillata
and P. malaianus were found. The succession potentials of
these two dominant species were found to be different. After
biomass deterioration, the recovery of H. verticillata required
more time than P. malaianus. In areas with water depth > ca.
0.6 m and water velocity > ca. 0.5 m/s, in particular,
H. verticillata community took ca. 1 year to recover. Some
areas, thus, became dominated by P. malaianus. The community
of H. verticillata seemed to prefer lower water velocities
(