With the economic and social development, climate change and human activities have a profound impact on the natural water cycle. Amongst these changes, land use associated to development of peri-urban areas is one of the most important to be taken into account. These areas experience increase of impervious areas, straightening of natural water courses, runoff concentration into pipes but also sometimes, desertion of farming lands that turn into fallow lands and finally into sporadic deciduous forests. A higher proportion of built infrastructures has a significant impact on hydrologic and ecosystems functions and often result in excess runoff, lower groundwater recharge and non-point source pollution, thus increasing the vulnerability of these areas to floods, droughts and water quality problems. In Europe, in order to fulfil the requirements of the Water Framework directive, stakeholders are required to monitor and anticipate the impact or urbanization and planning on the hydrological cycles.
More generally, the driving force and social water cycle of "abstract – transport – consume - discharge" continue to increase watershed water circulation.
The basic theory of the dualistic water cycle "nature – artificial" and the related new ideas in modelling approaches, theoretical evolution, scientific regulation and control are becoming important research topics in modern hydrological sciences. Given the landscape heterogeneity and the complexity of these areas, the development of modelling tools able to tackle the problems of simulation of water and pollutant fluxes in these areas is not straightforward, neither the availability of the measurements allowing to evaluate the relevance of the proposed tools.

The aim of this session is to gather researchers of different disciplines working on these complex catchments in order to exchange on what could be achieved to answer the above questions by associating several communities.

Contributions dealing with the following topics are welcome:
• Pilot studies on the hydrological cycle within mixed natural and artificial catchments
• New developments in measurement techniques to understand and quantify the impacts of human activities on the hydrological cycle
• Studies aiming at determining the main processes to be taken into account in these mixed catchments
• Development of new models taking explicitly into account the mixed nature of natural/artificial catchments and/or the “abstract – transport – consume - discharge” cycle
• Quantification and modelling of water quantity and water quality changes in agriculture, industry, and domestic water consumption
• Impact of future climate change to the mixed natural and artificialized catchments
• Exploration of mechanism and driving forces of social-economic water demand and usage
• Basic theory, technology, and practice in water demand management