DURESS has a nested design that reflects the natural nested structure of river catchments, from small sub catchments to whole basins. In all, data are available from over 500 sites covering nearly 4000 km2 of the Welsh uplands. 19 data sets of biological and associated environmental data are available as a unique resource of spatially extensive and long term data.  At several sites there have been catchment-scale experiments, and further interventions are planned during the project.

The design also encompasses temporal scales from minutes (e.g. stream temperature recordings at Llyn Brianne) to decades (e.g. the development of fish populations in the Wye catchment).