River restoration can enhance river dynamics, environmental
heterogeneity and biodiversity, but the underlying processes governing
the dynamic changes need to be understood to ensure that restoration
projects meet their goals, and adverse effects are prevented. In
particular, we need to comprehend how hydromorphological variability
quantitatively relates to ecosystem functioning and services,
biodiversity as well as ground-and surface water quality in restored
river corridors. This involves (i) physical processes and structural
properties, determining erosion and sedimentation, as well as solute and
heat transport behavior in surface water and within the subsurface; (ii)
biogeochemical processes and characteristics, including the turnover of
nutrients and natural water constituents; and (iii) ecological processes
and indicators related to biodiversity and ecological functioning. All
these aspects are interlinked, requiring an interdisciplinary
investigation approach. Here, we present an overview of the recently
completed RECORD (REstored CORridor Dynamics) project in which we
combined physical, chemical, and biological observations with modeling
at a restored river corridor of the perialpine Thur River in
Switzerland. Our results show that river restoration, beyond inducing
morphologic changes that reshape the river bed and banks, triggered
complex spatial patterns of bank infiltration, and affected habitat
type, biotic communities and biogeochemical processes. We adopted an
interdisciplinary approach of monitoring the continuing changes due to
restoration measures to address the following questions: How stable is
the morphological variability established by restoration? Does
morphological variability guarantee an improvement in biodiversity? How
does morphological variability affect biogeochemical transformations in
the river corridor? What are some potential adverse effects of river
restoration? How is river restoration influenced by catchment-scale
hydraulics
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and which feedbacks exist on the large scale? Beyond summarizing the
major results of individual studies within the project, we show that
these overarching questions could only be addressed in an
interdisciplinary framework.