What do we aim?
To analyse the spatial propagation of geomorphic and ecological impacts associated to gravel mining and their temporal persistence associated to floods.
Two fundamental research questions arise:
RQ1. What is the relaxation time associated to gravel mining? (see the conceptual model in Figure 1).
RQ2. What are the key controlling variables for physically and ecologically-based predictors?
Figure 1. Hypothetical trajectory of ecological status* following gravel mining (modified from the original idea form Petts and Gurnell 2005 -Geomorphology 71, 27-47- about fluvial metamorphosis after dam closure). Note that the ecological status reaches a new regime state (#2) after gravel mining (i.e. transient state) and after overcoming a series of physical state conditions during the relaxation time. These conditions will be dictated by morphosedimentary dynamics attributed to natural flood events. This conceptual diagram may be propagated upstream and downstream from the impacted reach. *Note ecological status is a broad term here. The term will be described properly after analysing what are the conditions that describe the ecological status in the Upper Cinca.
Knowledge of the interactions between physical and ecological processes in fluvial systems is fundamental to support restoration programs in modified catchments (a requirement of the EU Water Framework Directive); and to provide the scientific basis for management tools that are needed to help prediction of, and planning management responses to, long term hydrological alterations associated with global change.
MorphSed will analyse the morphosedimentary dynamics of a representative human-stressed fluvial system (suffering major local alterations due to gravel mining), their drivers and their impacts on the river’s ecological integrity. Physical (i.e. geomorphic) and ecological processes and their spatio-temporal dynamics will be compared to those in an unaltered system. The multi-event dataset obtained will enable the first links to be established between physical and ecological processes at scales integrated from the micro-habitat to the reach scale. These links will be a key goal for progress towards the system-scale understanding of the interactions between river disturbance and ecological responses, and provide the basis for an integrated methodology that can be used to aid prediction, management and restoration of human stressed fluvial systems.
Figure 2. Panoramic view of the Upper River Cinca just upstream the confluence of the River Ara.
Objectives and project conceptual framework
MorphSed will be developed in the active gravel-bedded Upper River Cinca (Ebro Basin, South Central Pyrenees) and implemented through the execution of four work phases: (PHI) project planning and training, (PHII) data acquisition, (PHIII) data analysis, interpretation and diffusion of results, and (PHIV) experimental validation. A total of six interrelated objectives will link the substantive steps in the execution of the project: (O1) monitoring contemporary fluvial geomorphic dynamics, (O2) sampling associated ecological diversity, (O3) identifying key physical drivers of habitat integrity, (O4) model evaluation, (O5) developing an integrated methodology for ecological diversity evaluation, and finally, an experimental objective (O6) validation of the integrated methodology through controlled experimental perturbations. Application of state-of-the-art approaches will allow MorphSed to create an unrivalled high-quality dataset on physical and ecological processes, dynamics and their links. This data set will be analysed to address key questions related to river integrity (and hence to increase scientific knowledge) as well as to develop integrated approaches, guidelines and recommendations that will aid sustainable catchment management. Specifically, the work will be valuable to river managers for preliminary assessing and sound supervising of mining activities, developing restoration programs in highly impacted areas and predicting the location-specific impact of global change. The work will also result in methodological advances (related to the use of geospatial survey technology) that will have wide relevance in the fields of fluvial hydrology and freshwater ecology worldwide.
Figure 3.The conceptual framework of MorphSed representing project phases, objectives, interrelations, study sites and monitoring sections, deliverables and the diffusion of results.