The TIMOTHY research is proposed by an interdisciplinary network composed of microbiologists, biogeochemists, bioengineers, hydro-geologists, physical and ecological modelers and environmental economists focusing activity on the modification of aquatic system functions in response to anthropogenic pressures and climate changes.
The general objective is to develop, validate and apply tools to describe and evaluate the past (1970 for quantitative data, back to several centuries ago for an overall view of the landscape construction), current and future (up to 2050) changes in quality of surface, ground and marine waters and to relate them to changing human activities on the watershed. The research methodology will involve and combine collection of historical and new field data, process-level studies, new experimental and numerical development and will be organised around the following specific objectives :

1. Implementation and validation of a suite of coupled physical-biogeochemical models that describe the current sources and the fate (transfer, transformation, retention) of key nutrients (nitrogen, phosphorus, silicon) and pollutants [metals (cadmium, copper), xenobiotics (PAHs, PCBs, dioxins), pathogens (faecal bacteria)] along the land-ocean aquatic continuum in response to anthropogenic and natural changes;
2. Development of new biogeochemical proxies (e.g. new isotopic tracers such as Si-Mg isotopes) to trace the impact of human activity along the land-ocean continuum;
3. Use of existing and newly-developed biological and geochemical indicators to characterize the modelled quality status of groundwater, and surface and marine waters;
4. Building of scenarios with varying realistic mitigating measures under contrasted environmental conditions (e.g. dry vs wet years), including those scheduled by the member-state implementation plan of the EU water framework Directive for 2015, the Millennium Ecosystem Assessment 4 scenarios (http://www.maweb.org/en/index.aspx) for 2030 and 2050 as well as anticipated local effects of climate changes.
5. Identification and valuation of the socio-economic impact of present-day water pollution and estimation of the costs for reaching quality objectives.

As a first step, the Scheldt watershed and the adjacent eastern Channel and Southern Bight of the North Sea is chosen as a case study and geographical domain and the chosen time scale will cover almost one century, from 30 years ago to the next 50 years. This choice is motivated by the well-known post-world war development of industrial, agricultural and domestic activities and its negative impact on surface water and groundwater pollution as well as on the eutrophication and contamination of the receiving coastal waters, and the expected improvement of water quality due to the ongoing implementation of the EU water framework directive (2000/60/CE). Choosing the Scheldt-coastal sea area for a first test study is also justified by the availability of large amounts of data, the state of the art models and a large expertise since the 1970’s. Once validated on the Scheldt basin, the methodology can be transferred to other river-coastal sea hydrosystems.