Abstract:
Modifications observed on the hydraulic regime of river systems caused by engineering works
led to growing awareness of the impacts caused by these engineering constructions. The need to harmonize
and integrate both the hydraulic and the ecological/environmental components has been growing, namely in
Portugal. This paper presents the work of a multidisciplinary team that carried out, from 1998 to 2003, an
evaluation of the ecological impacts of realignment and construction works implemented at the lower part of
Mondego river, in central Portugal, in the 80’s. The hydraulic and hydrologic alterations in Mondego river,
caused by regularization works, have been analyzed and quantified. The main conclusions of the study are that
the changes in the Mondego river geometry induced more homogeneous physical and hydraulic conditions and
reduced life diversity. However, the construction of a set of transversal groynes, and discontinuities of the bottom
elevation, had an opposite effect. Similar conclusions are reported in the literature.
