Catchments are systems that often consist of an organized architecture of typical patterns of topography, soils, vegetation and flow networks. These patterns are largely the geomorphic, and biologic response to temporally and spatially variable environmental conditions or human interference. This organization of catchment components controls the storage and release of water and nutrients. Consequently, understanding catchment organization is critical for:

- Creating catchment models that balance necessary complexity with possible simplicity,
- Understanding the degree of similarity between catchments, with the prospect of developing hydrological theories that are transferable in space and/or time,
- Increasing our understanding of catchment processes and behavior across various spatial and temporal scales, and
- Predicting the future evolution of catchment properties and hydrologic response in a non-stationary environment.

In this session we bring together catchment hydrologists and stream-/ecohydrologists who study these topics at different scales. We present experimental and modeling studies that analyze the role of catchment storage, catchment mixing and hyporheic exchange fluxes and determine how they control hydrologic and hydrochemical catchment response in time and space.

Solicited Speakers: Federica Remondi, ETH Zürich
Gonzalo Miguez-Macho, Universidade de Santiago de Compostela, Spain