Wetlands in River Valleys as an Effect of Fluvial Processes and Anthropopression - Wetlands and Water Framework Directive: Protection, Management and Climate Change - page 66

5.1 Introduction

Fluvial processes are responsible for developing the actual morphological type of
the river channels. Also wetlands found in the terraces are strictly dependent on the
river

flow regime. The water table connecting main channel and other branches or
tributaries varies with the change of the water level. Dependably on the channel
incision, land use or other factors, rivers can supply water or drain the terrace.
Additionally during

fl

cation of different kinds of erosion or suf-
fosion can appear so the river tends to create new channels or oxbow lakes. Aerial
photographs or old maps often reveal the richness of the old channel system. A
wide range of morphological structures in rivers and valleys is related to the
hydrological and morphological parameters, the most important being: water

fl floods the intensi

ow
and transported load alimentary, longitudinal slope, bed roughness and bed sta-
bility. Wetland ecosystems are part of quality elements for the classi

fl

cation of
ecological status within the Water Frame Directive (WFD). While used to be
localized in riparian zones, wetlands re fl ect the good hydromorphological charac-

teristics of water bodies.
Going further, wetlands indicate the close to nature land use as inscribed in the
advancement of the local community. From the end of the Second World War up to
the early 90s, the Polish government did not pay particular attention to the issue of
nature conservation, focusing on the intensi cation of industrial development or

agricultural production instead. The WFD gives a new perspective for the devel-
opment of local societies. The aim of the article is to stress the consequences of
changed intensity of

fluvial processes in rivers, their valleys and to analyse possi-
bilities of wetland restoration within the guidelines of WFD but also under current
land development. Even if the river training is done in these rivers, natural hy-
dromorphological processes have to be taken into consideration during the decision
making. While river ecosystems are strictly depended on the evaluation of these
processes, arti

fl

cial transformation of rivers and their valleys is often reckless.
Technical river training and

flood defence structures lead to narrowing of the river
migration zone and disturb the hydraulic balance in the river channels. Serious
problems grow during the intensi

fl

cation of the spatial development and many

con floodplain capacity and human business appear. For this reason,

even while needed, the restoration of wetlands in the river valleys is often relin-
quished. Reintroduction of wetlands in transformed river valleys would be con-
nected to the change of human activities so the renaturization costs may often be
unacceptable for the localities or connected to the elongated period of land-use
transformation.

fl icts between fl