Geography Reference
In-Depth Information
Conclusions
Floodplain lakes have been studied by ecologists because of their effect on
river habitats, conditions and evolution. However, their essential element is
the structure and functioning of this part of the fluvial hydrosystem. The
morphology of a former channel is a key parameter that affects the frequency
of the connection, evolution and specific composition of a floodplain lake.
The relationship between the hydrologic connection and processes in a
floodplain lake are not linear, but the hydrologic connection model and the
changing morphology of a floodplain lake create a different framework of
discharge. Our work shows that the water and sedimentary fluxes are the
dominant elements that assure the proper functioning of these lakes. If these
fluxes are minimised or cut off from a system, the system changes its
behaviour and morphological style (reducing the number of channels), and
the natural evolution stops.
The processes of sedimentation and erosion affect the evolution of these
lakes. These processes are activated during floods and respond to the intensity
and frequency of the perturbations. The dynamics of floodplain lakes are
directly linked to the dynamics of the fluvial system. The principal hydrologic
factors are controlled by anthropic pressure.
The upstream/downstream connections were studied from an ecological
perspective in terms of the hydrologic changes, such as the effect of a dam on
water level fluctuations. Sedimentary connections are generally studied in the
field of geomorphology. The presence of a dynamic floodplain lake system is
the sign of a healthy fluvial system. Floodplain lakes are not only places for
the diversification of a river corridor but are also an important demonstration
of fluvial dynamics.
Floodplain lakes affect both the diversity of the former channels and their
importance in flood restoration. The maintenance of fluvial dynamics can be
stopped by levees and by the constructions of dams. These factors have
affected the incision of channels and decreased the frequency of the connec-
tions to the floodplain. The restoration and postrestoration management of
floodplain lake sedimentation is a major factor in the proper functioning of a
fluvial system.
Based on our study, we conclude that the effects of anthropic influences
are still present in the study area. We need to understand the historical and
actual anthropic pressures and evaluate the consequences of major human
activities. The models of fluvial management are the same even though the
local conditions are different. It is difficult to respond to the different expec-
tations of society, but the possibility of restoring the dynamics of the fluvial
system should be considered the ideal goal in order to preserve the morpho-
logical and ecological values of the system.
(continued)
